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We further support the development of adaptation pathways for the future directions for water management in light of expected climate changes (Finlayson I et al i ., [9]; Gell I et al i ., [17]), being aware that the Australasian chapter in the recent report by the Intergovernmental Panel on Climate Change (Lawrence I et al i ., [32]) has drawn attention to the difficulties that may arise with water sharing in the basin. ([4]) advocate with confidence that Lake Alexandrina must be kept fresh (as defined by Lester I et al., i [33], presumably) for the foreseeable future, as it was ever thus. ([4]) paper, as it was in similar advocacy papers and reports emerging from South Australia (Fluin I et al i ., [12]; Sim & Muller, [38]; Tibby I et al i ., [42]; and even Chiew I et al i ., [5]; who despite noting the records of the "mid-basin cores [are] indicative of intermediate salinity" [[5], p. 24], conclude that the lake was "largely fresh"). Maybe too, the father of Australian coastal geomorphology, Prof. Eric Bird, was misguided when he wrote in 1962 'After winter rains, and particularly after flooding in the Murray valley, the lakes became I almost fresh i , but in drought periods the reduction in freshwater inflow led to invasion of the lakes by sea water, and I high levels of salinity i were attained' (Bird, [3], p. 204). [Extracted from the article]

Brocx and Semeniuk's (2019) paper is discussed, particularly in relation to the concept of geodiversity and their proposed sequence of '8Gs'. Their ideas on these topics are at odds with the majority of published papers and Internet sources on geodiversity. We argue that geodiversity as a concept has real value and that (a) the planet's geodiversity occurs at all scales from global downwards, (b) it deserves an absolutely central place in any sequence of 'Gs' since it is the backbone of international and national geoheritage and geoconservation strategies, and the basis for geoheritage assessments, and (c) that as well as underpinning biodiversity, geodiversity is the source of many other geosystem services, including geotourism. Finally, a revised proposal for the relationship between geology, geodiversity, geoheritage, geoconservation and other 'Gs' is presented. [ABSTRACT FROM AUTHOR]

The Musgrave Province of central Australia was the focus of long-lived mantle upwelling that produced large volumes of magnesian basaltic to tholeiitic magma and their felsic derivatives. The Musgrave Province contains one of the greatest concentrations of mafic–ultramafic layered intrusions globally, grouped as the Giles intrusions. In the present paper, we study the magmatic ore potential of the Kalka, Gosse Pile and Ewarara layered intrusions located in South Australia. Ewarara and Gosse Pile appear to have relatively low potential for platnium-group element (PGE) reefs and magmatic Ni–Cu, based on lack of evident metal enrichment and the absence of a mafic–ultramafic transition zone that hosts most PGE reefs globally. However, mafic–ultramafic pipes within the intrusions that could have higher ore potential have not been studied by us. At Kalka, the mafic–ultramafic transition interval is exposed, rendering this intrusion potentially more prospective for PGE reefs. However, based on the available data, this zone appears to be barren. Instead, there are signs of PGE enrichment and metal ratio variation in the magnetite-bearing upper portion of the intrusion suggestive of undiscovered PGE reefs. This interpretation is consistent with subtle Cu–Pd enrichment of soils adjacent to the upper portion of the intrusion. First assessment of magmatic ore potential of Kalka, Ewarara and Gosse Pile layered intrusions in South Australia. Kalka shows signs of PGE enrichment in upper, magnetite-bearing portion of intrusion, suggesting enhanced potential for a PGE reef. Ewarara and Gosse Pile appear to be less prospective for PGE–Ni–Cu, but picrite pipes remain unstudied. [ABSTRACT FROM AUTHOR]

Late Mesozoic mafic dykes, which are widely developed in the North Qinling Orogenic Belt (NQOB), include abundant geodynamic information. This paper describes the mafic dykes that intrude the Late Jurassic granite in the Dayu and Kuyu areas, and reports important petrological constraints for the late Mesozoic tectonic transition from compression to extension in the NQOB. Three zircon U–Pb results show that the minimum ages of the mafic dykes are 139.8 ± 1.4 Ma, 137.4 ± 1.7 Ma and 133.4 ± 0.9 Ma, indicating that the emplacement age of the Dayu and Kuyu mafic dykes is 140–133 Ma. Petrogeochemical analyses suggest that the mafic dykes belong to the high-K calc-alkaline shoshonite series with low SiO2 (46.93–56.73 wt%), MgO (1.88–9.10 wt%) and TiO2 (1.17–1.82 wt%), and high Al2O3 (13.98–17.46 wt%), TFe2O3 (7.81–10.92 wt%) and K2O (1.28–4.78 wt%). The mafic dykes are enriched in large ion lithophile elements (e.g. Rb, Ba, K, La, Sr) and depleted in high-field-strength elements (e.g. Nb, Ta, Zr, Ti). These samples have the right-sloping chondrite-normalised rare earth element patterns, which suggest light rare earth element enrichment and heavy rare earth elements depletion with no obvious Eu anomalies (δEu = 0.94–1.11). The ISr, εNd(t), εHf (t) and TDM2(crust) values are 0.7056–0.7060, −10.60 to −5.98, −14.1 to −2.8, and 1382.4 ± 25.1 to 2081.9 ± 47.6 Ma, respectively. Both elemental and isotopic geochemistry show that the formation of Dayu and Kuyu mafic dykes is due to the partial decompression melting of previously enriched lithospheric mantle during a delamination process. The mafic dykes have undergone fractionation crystallisation of Mg–Fe phase minerals during magma ascent, accompanied by some crustal contamination. Combined with the regional tectonic setting, we suggested that the NQOB experienced intra-continental extension during the Early Cretaceous. Early Cretaceous (140–133 Ma) mafic dykes have been discovered in the middle part of the North Qinling Orogenic Belt. The remote effect of the Paleo-Pacific Plate subduction has reached the middle of the North Qinling Orogenic Belt. The North Qinling Orogenic Belt entered the extensional stage in the Early Cretaceous (140–133 Ma). [ABSTRACT FROM AUTHOR]

Folded reservoir rocks (Eumeralla Formation) within the Otway Basin are of significant exploration interest for their geothermal and tight gas reservoir potential. Brittle deformation within the Eumeralla Formation (ca 113–100 Ma), along the Otway coastline of Victoria, reflects a protracted history of extension, contraction, erosion and uplift, since Australian–Antarctic separation in the Early Cretaceous. This paper investigates the relative timing of heterogeneously distributed fracture populations within both folded and unfolded areas along the Otway coastline. Data collection occurred across two stratigraphic units spanning the Early Cretaceous (Eumeralla Formation) to the late Cenozoic (Demons Bluff Group), in order to measure fracture geometries and determine the relative timing of fracture formation. An unmanned aerial vehicle has been used to facilitate the systematic and inexpensive acquisition of high-resolution orthophotographs along coastal platforms, in order to complement traditional field mapping of fracture populations. A NE–SW-orientated fracture set is observed exclusively within the Eumeralla Formation (St George fold hinge), while a NW–SE-orientated fracture set pre-dates hinge-parallel fractures. Significant fracture formation has been linked to a period of mid-Cretaceous uplift within the eastern Otway Basin (ca 95 Ma). The Eumeralla Formation and Demons Bluff Group also host a NNW–SSE-orientated fracture set that is inferred to largely post-date mid-Cretaceous folding. Sinistral displacement of fold hinges within the Eumeralla Formation, combined with thrust faulting within Cenozoic sediments, is interpreted to have occurred during an episode of late Miocene to early Pliocene shortening. This paper provides new insights into the history of brittle deformation in the eastern Otway Basin. [ABSTRACT FROM AUTHOR]

Chemical weathering indices (CWIs) based on bulk chemical rock composition can potentially provide an objective tool for estimation of weathering intensity and classification of weathering products. However, despite their long history and the large number of indices that have now been developed, their applicability still has serious limitations. To overcome most of the limitations, this paper proposes a new weathering index based on the review of geochemical and mineral rock evolution during weathering and analysis of the existing CWIs. The new index, the alumina + ferric oxide to bases ratio (AFB), is expressed as AFB = AFBw/AFBp where AFB = (Al2O3+Fe2O3)/(K2O + Na2O + CaO + MgO); w, weathered rock and p, parent rock, with all elements in molecular proportions. The index provides a basis for comparison of weathering intensities between different lithologies by linking the chemical and mineral transformations that characterise the regolith profile. It is sensitive to all stages of weathering, including lateritisation by using the ratio of the stable (relatively immobile) to mobile metals expressed as oxides. An extensive, worldwide chemical database on 40 well-documented regolith profiles developed on felsic, mafic and ultramafic substrate was used for testing the proposed index and its comparison with the most common indices. The rocks were mostly weathered under tropical or subtropical conditions. The results confirmed consistent increase in the AFB value with intensifying weathering. The index is applicable to all silicate rock types including Al-poor ultramafic rocks. Use of parent rock normalisation allows a more accurate comparison of weathering intensities between different lithologies. At the expense of these benefits, the parent normalised index AFB requires data for the unweathered protolith that is commonly difficult to obtain. The index is also sensitive to inhomogeneity of the original rocks. The unreferenced to parent rock AFBu index has potentially broader applications including provenance and the weathering history of sediments, soil and engineering studies, although collection of more data is required for understanding the index constraints for various conditions and rock types. A new chemical weathering index, expressed as the alumina+ferric oxide to bases ratio normalised to parent rock provides reasonable results for all major types of silicate lithologies. The index is applicable for all types of weathering including the lateritic environment. On the downside, the index is sensitive to inhomogeneity of the original substrate and to later epigenetic modifications of the residual regolith. [ABSTRACT FROM AUTHOR]

This paper summarises an evaluation of the application of artificial intelligence to hyperspectral drill-core scans for more effective mineral exploration. The dataset used was based on publicly available core scans and related geochemical analysis from Australia. Prior to unification, a detailed quality assessment of the geochemical data was undertaken. Special focus was paid to gold, silver, copper, iron, uranium, nickel, lead, tin, antimony, arsenic and bismuth contents. The dataset was labelled with defined ore grades related to economic cutoff values. The impact on predictions of different setups is related to the amounts of data used for learning, data design and implementation of the geological domains. Based on 1-metre bins, the results from more than 700 km of drill cores were used and analysed with the potential for geological exploration in different scenarios discussed. The results indicate the enormous potential of the use of hyperspectral scans in combination with artificial intelligence for the development of exploration scenarios and to provide support for exploration geologists and target detection. The application of predictors on scanned drill cores from Australia also indicates mineralised zones that have not been analysed chemically for all metals above economic cutoffs. This result shows the enormous potential of the approach for strategic exploration but also mining operations. Prediction of geochemical concentrations for gold, copper and iron based on a neural network in drill cores is possible. Using mineral abundances from hyperspectral core scans as learning records, and existing elemental geochemical analyses as labels, the predictions are given with an accuracy of better than 80–90%. The trained artificial intelligence system has for the first time enabled direct estimation of metal grades from hyperspectral scans. It also shows potential for applications to analyse airborne hyperspectral data for direct mapping of metal grades. Finally, it may pave the way for better plant management by the usage of hyperspectral data for direct grade estimations in operational mining and ore sorting. [ABSTRACT FROM AUTHOR]

Geochemical data are frequently collected from mineral exploration drill-hole samples to more accurately define and characterise the geological units intersected by the drill hole. However, large multi-element data sets are slow and challenging to interpret without using some form of automated analysis, such as mathematical, statistical or machine learning techniques. Automated analysis techniques also have the advantage in that they are repeatable and can provide consistent results, even for very large data sets. In this paper, an automated litho-geochemical interpretation workflow is demonstrated, which includes data exploration and data preparation using appropriate compositional data-analysis techniques. Multiscale analysis using a modified wavelet tessellation has been applied to the data to provide coherent geological domains. Unsupervised machine learning (clustering) has been used to provide a first-pass classification. The results are compared with the detailed geologist's logs. The comparison shows how the integration of automated analysis of geochemical data can be used to enhance traditional geological logging and demonstrates the identification of new geological units from the automated litho-geochemical logging that were not apparent from visual logging but are geochemically distinct. [ABSTRACT FROM AUTHOR]

In this paper, we summarise advancements in top-of-hole sensing achieved within the Deep Exploration Technologies Cooperative Research Centre (DET CRC). It was demonstrated that the drill fines, which were previously discarded, show high potential to act as a representative sample media of the lithologies intersected by the drill hole and can be successfully used for analysis in real time. The Lab-at-RigVR (LARVR) system was developed for prospecting rigs (diamond drilling in the first instance and coil tube drilling in the future) and encompasses sample capture, sample preparation and presentation to sensors. In the initial setup of the LAR platform, there are two sensors, a portable X-ray fluorescence (pXRF) and a portable X-ray diffraction, capable of delivering chemical and mineralogical data in near real time. Laser-induced breakdown spectroscopy was also explored as a potential additional sensor for future versions of the LAR system, as it can yield information on elemental composition including essential light elements not currently measured by air-based pXRF detectors (e.g. Li, Na and Mg at low levels) or other elements problematic by pXRF (e.g. Au). The LAR system implements X-ray diffraction (XRD) analysis from which mineralogical data (mineral identification and most importantly mineral quantification) must be obtained in near real time. The existing challenge with XRD is that any data processing and especially data interpretation with available software packages requires some expertise in the field and background in crystallography and is time-consuming. Hence, SwiftMinVR, the world's first algorithm for automated processing of XRD data, was developed. It provides mineral identification and quantification and performs all calculations and processing independent from a user. SwiftMin returns a result in seconds and is able to batch process hundreds of XRD patterns in a matter of minutes. The above means, that SwiftMin is a technology that allows processing of large amount of XRD data quickly, saving time, costs and labour. The overall concept and vision developed within the DET CRC in top-of-hole sensing by coupling chemical and mineralogical analyses of drilling materials is to provide an end-to-end solution that supports rapid decision making by a geologist, at the time-scale of drilling the hole. [ABSTRACT FROM AUTHOR]

This paper proposes a mechanism called the mode-switching model that is presented as an alternative to the fault-valve model. This mechanism is relevant to open-flow, low-porosity, fluid-saturated systems deforming by pressure solution creep. As opposed to most constitutive models discussed in the geological literature, the yield envelope is capped at high normal stresses, as demonstrated by experimental studies. A low-permeability rock has relatively high pore fluid pressure for a given input fluid flux. This increases the dissolution rate for quartz that in turn leads to a higher-permeability rock, low fluid pressure for the same flux and decreased quartz solubility and deposition, returning to a low permeability. This cycle continues indefinitely so long as the rock mass is stressed, a fluid flux is applied, and pressure solution operates. The high fluid pressure drives the Mohr stress circle to the tensile end of the yield envelope resulting in crack-seal and extensional veins. The low fluid pressure drives the Mohr stress circle to the cap end of the yield envelope resulting in laminated veins in rocks undergoing mineral reactions with large net volume losses coupled with solute transfer. Failure at the cap end of the yield envelope results in displacement discontinuities inclined at high angles to σ1. Previously, these orientations have been taken to represent reactivated normal faults, an integral component of the fault-valve process. In the model presented, the yield surface prohibits the system ever reaching super-lithostatic pressures. The process of effective stress-driven switching between tensile and cap ends of the yield envelope arises from competition between dissolution and deposition, and is independent of any seismic events, fault reactivation or the episodic breaching of an impermeable seal. It provides a unifying, self-consistent concept for the interpretation of joints, faults and veins in hydrothermal systems. The open-ended Mohr–Coulomb yield surface is replaced by a capped yield surface, closed at high normal stresses. Failure can occur with decreased fluid pressures resulting in non-Andersonian orientations of failure discontinuities such as veins at high angles to σ1. Pressure solution in open-flow hydrothermal systems leads to alternations of failure modes at the tensile and cap ends of the yield surface with no need for a seal. Stress-driven oscillations in failure modes, resulting in episodic fluid flow and episodic formation of Andersonian and non-Andersonian failure modes, are an aseismic alternative to fault-valve behaviour. [ABSTRACT FROM AUTHOR]

Rock porosity is one of the most significant parameters in fluid-flow simulation in the context of carbonate reservoirs. The hydrocarbon industry uses porosity to assess the production potential of oil and gas in carbonate environments. Traditional methods to determine porosity are limited to discrete measurements and generally demand extra resources associated with careful analysis of logs, rock sampling and laboratory analysis. This paper investigates an alternative to estimate porosity in carbonate rocks using pointwise hyperspectral data and machine learning. The method is contiguous, does not require rock sampling and was validated in various rock plug samples collected from two distinct carbonate outcrops. The samples were analysed in the laboratory to determine ground-truth values for the effective porosity and reflectance in visible and infrared regions of the spectra. The supervised regression methods applied were able to estimate a robust relationship between the effective porosity of carbonate rocks and spectral behaviour in characteristic spectral features of carbonate, hydroxyl, molecular water and Fe/Mn. The results obtained here suggest the soundness of the indirect approach to estimate porosity with most of the models trained achieving a coefficient of determination above 0.8 and mean absolute deviation of less than 2%. Hyperspectral data can be used as proxy for porosity estimation in carbonate rocks. All the tested learners achieved R2 greater than 0.7. Regularised linear regression can be used to estimate porosity. Support vector regression estimation of porosity achieves a mean absolute error of 1.0249 in our dataset. [ABSTRACT FROM AUTHOR]

The provenance of the upper Cambrian to Upper Ordovician sedimentary rocks of Tasmania and Waratah Bay in southern Victoria provides information about the complex and dynamic tectonic environment present during their deposition. This paper uses U–Pb detrital zircon data to constrain stratigraphic comparisons and tectonic reconstructions of these rock sequences. Multivariate statistics are used to investigate the similarity between the U–Pb ages and quantify the disparity among different samples from various locations. In western and central Tasmania, the Tyennan region supplied most detrital zircons during the late Cambrian and Early Ordovician. The overlying Middle Ordovician Pioneer Sandstone records a switch in provenance with zircons derived from the Mount Read Volcanics (MRV) mixed with zircons similar to those from continental-derived Paleozoic sedimentary rocks deposited throughout east Gondwana. The Middle to Upper Ordovician Gordon Group in western and central Tasmania lacks detrital zircons younger than 1.2 Ga, which indicates a return to a local provenance from Precambrian rocks. In southern Tasmania, the switch to zircons derived from the MRV and east Gondwana-like sources occurred earlier within the Cambrian Deadmans Bay Formation, which is dominated by the east Gondwana Paleozoic zircon age signature. In the East Tasmania Terrane, Ordovician sedimentary rocks from Lefroy have detrital zircon populations dominated by Neoproterozoic and earliest Paleozoic sources similar to the Ordovician sedimentary rocks in the Lachlan Orogen. In southern Victoria, the Bear Gully Chert from Waratah Bay exhibit both Tyennan and distal Gondwana detrital sources. The switching of detrital zircon sources in the west Tasmanian sedimentary sequences implies the docking of Tasmania with mainland Australia during the Cambrian Tyennan Orogeny. The arrival of the distal zircons into these basins occurred at different times in the different areas, reflecting a complex local topography and paleogeography. Paleozoic sedimentary rocks in Tasmanian exhibit multisource detrital U–Pb age signatures that change over time, implying tectonic activity during their deposition. Paleozoic sedimentary rocks in northeastern Tasmania show Gondwana-wide detrital signatures similar to Lachlan Orogen. The Ordovician Bear Gully Chert at Waratah Bay in southern Victoria shows mixed Tasmanian and distal Gondwana detrital populations. The change in detrital zircon signature in western Tasmania suggests that VanDieland docked with the Australian continent during the Cambrian Tyennan Orogeny. [ABSTRACT FROM AUTHOR]

Recent claims based on hydrodynamic modelling within a sequence stratigraphical perspective of incised valley fill sedimentation have argued that the Lower River Murray and its terminal lakes Alexandrina and Albert represented a marine–estuarine lake system, with marine salinities for some 200 km upstream from the Murray Mouth. These claims have encouraged proposals for the removal of barrages near the Murray Mouth to restore the 'original natural condition' of the lakes. It has also been suggested that fine-grained terrestrial sediments were trapped in this mega-lake, necessitating a re-assessment of the Holocene climatic history of southeastern Australia determined from the study of continental slope cores. We show that throughout Holocene time (the past 11.7 ka), the Lower River Murray remained a freshwater-dominated system, based on a range of mutually complementary sedimentary evidence. Radiocarbon dating of Aboriginal middens adjacent to the river and lakes comprising freshwater mussels (dominantly Velesunio ambiguous), crayfish (Euastacus armatus), turtles (Emydura macquarii) and otoliths of freshwater fish species, such as Murray cod (Maccullochella peelii), confirm freshwater riverine and lacustrine conditions throughout the Holocene. Lake Alexandrina also contains endemic obligate freshwater fishes, including a genetically divergent and locally adapted lineage of southern pygmy perch (Nannorpeca australis), revealing an evolutionary history linked to freshwater habitat in the lakes since the late Pleistocene. Freshwater diatoms from fine-grained fluvial clay successions at Riverglen Marina, and diatoms and lacustrine sediments, including sapropels in the lower lakes and their former embayments of Cooke Plains and Waltowa Swamp, also chronicle a history of freshwater deposition. Lakeshore ridges of terrestrially derived quartz sand formed during elevated freshwater lake levels 8.0 ± 1.2 ka ago, while consolidated masses of the freshwater clam Corbicula australis, radiocarbon dated at 2650 ± 90 year BP, also attest to long-term freshwater conditions. An open Murray Mouth is prima facie evidence for sustained river discharge, and the mouth remained open throughout the Holocene based on geomorphological evidence. The barrages that were built to retain freshwater within the lower lakes, in response to upstream water abstractions, which had reduced river flows, provide the closest analogue of the 'original' conditions of this environment. With increased automation, nuanced barrage operation could even better simulate the original environment, whereas removing the barrages and building a weir at Wellington would destroy the character of this internationally significant Ramsar Wetland, with detrimental impacts farther upstream. Paleoclimatic, geomorphological and modelling reconstructions, together with sedimentary records based on freshwater diatoms, molluscs, fish, turtles and lacustrine systems and evidence of genetically divergent and locally adapted obligate freshwater fishes, demonstrate that predominantly freshwater conditions were present in the Lower River Murray and its terminal lakes throughout Holocene time (11.7 ka). The empirical observations presented in this paper reveal that a large marine-dominated mid-Holocene estuary was not present in the Lower River Murray, Australia. Proposals to remove the barrages near the Murray Mouth would destroy the long-term freshwater environment of this Internationally Significant Wetland Site with negative ecological impacts. [ABSTRACT FROM AUTHOR]

Gemmologists distinguish two rock types in the jade group: nephrite and jadeite jade (or jadeitite). Both are extremely tough monomineralic rocks. New Guinea is favourable for jade occurrence. Giant faults of the New Guinea Mobile Belt (NGMB) extend the 2200 km length of the island and are associated with extensive linear belts of tectonised and serpentinised ultramafic rocks and metabasites, blueschist rocks, intrusive masses of serpentinite containing tectonic inclusions, tremolitised rocks and talc. Geological conditions are favourable for serpentinite-related metasomatic and carbonate replacement nephrite deposits and serpentinite-related vein and pod jadeite jade deposits. Jade is found in eastern New Guinea in the Suckling–Dayman massif, where widespread nineteenth-century use of nephrite tools, including adze blades, axe blades and lime spatulas, occurred in surrounding coastal and inland villages in the Cloudy Bay, Collingwood Bay, Holincote Bay and Musa River region. Several quarries are located along the Mai'iu Fault. Nephrite is also recorded in the Kumusi River area, east of Kokoda. In the Central Fold Belt, jadeite jade, omphacitic pyroxene, rodingite veins and dykes and tremolitised metabasite occur in the headwaters of the April River, Salumei River, Karawari River and Korosameri River regions, and jadeite jade and locally abundant chloromelanite occur in the headwaters of the Leonard Schultze River in the eastern and western sections, respectively, of the April–Lagaip megashear. Numerous quarries are located in the Wario River area. At the Ya'li'me quarries in the Irian Jaya Ophiolite Belt, chloromelanite was quarried for stone-tool manufacture. Jade is also found in the Cyclops Mountains–Lake Sentani ultramafic belt where blocks of chloromelanite for tool manufacture were quarried in the upper Torare River area. This paper describes the history of discoveries, presents an overview of jade petrogenesis and describes the geological settings of NGMB jade occurrences. The geology of New Guinea is favourable for jade occurrence. Jade is found in extensive linear belts of tectonised and serpentinised ultramafic rocks and metabasites, blueschist rocks, intrusive masses of serpentinite, tremolitised rocks and talc. The use of jade was widespread in parts of eastern New Guinea in the nineteenth century. Nephrite tools (adze blades, axe blades and lime spatulas) were common in coastal and inland villages in an area including Cloudy Bay, Collingwood Bay, Holincote Bay and the Musa River. Jade is known from three localities in the Central Fold Belt of New Guinea. Jadeite jade, locally abundant chloromelanite and omphacitic pyroxene are found in the April–Lagaip megashear. Chloromelanite is found in the Ya'li'me quarries, located in the Irian Jaya Ophiolite Belt. Chloromelanite was quarried in the Cyclops Mountains–Lake Sentani region. Blocks used in the manufacture of adze blades and other implements were sourced from upper Torare River. Some tools were traded widely, including across the Bismarck Archipelago to Emirau Island. [ABSTRACT FROM AUTHOR]

While Australia has a long history in conservation, less well known are Australia's efforts to identify and conserve important sites of geoheritage significance. This paper provides a background to geoheritage and geoconservation in Australia and reviews the policies and legislation that underpin listing of sites of geoheritage significance in all Australian jurisdictions and shows that there are inconsistencies and inadequacies in the current set of processes to identify and protect such sites in Australia. The recent Australian Heritage Strategy provides an overarching framework by which Australia's heritage places can be better identified and managed to ensure their long-term protection and proposes new ways to support and fund heritage places. However, it is yet to be implemented, and this paper outlines the need for a systematic inventory-based system of identifying representative geoheritage. To achieve the objectives of the Australian Heritage Strategy, a renewed focus on geoheritage and geoconservation is required. Finally, this paper also includes a brief description of the emerging field of building stone heritage. [ABSTRACT FROM AUTHOR]

Paleocurrent reconstruction is an important aspect of basin research, playing a key role in the reconstruction of sediment development and understanding the evolution of sedimentary environments. The reconstruction of paleowind direction is an important part of the study of paleoatmospheric circulation, playing a vital role in revealing the characteristics and evolution of paleoclimate. Water flow and wind movement present similar interactions with ground objects and leave direction information. This paper summarises the current common reconstruction theories of paleocurrent and paleowind direction, analyses the advantages and disadvantages of the reconstruction theories, and analyses the characteristics of reconstruction results. Based on the technical structure of paleocurrent and paleowind direction reconstruction, the development of reconstruction theories, processes and results are highlighted. The analysis shows that paleocurrent and paleowind directions can be used for paleoatmospheric circulation research, resource exploration, paleogeographic environment reconstruction and planetary geological research. The current common theories of paleocurrent and paleowind direction reconstruction are outlined. The advantages, disadvantages and scope of application of the reconstruction theory are summarised. Applications and developments in the reconstruction of paleocurrent and paleowind directions are identified. [ABSTRACT FROM AUTHOR]

After the Elatina glaciation of Snowball Earth, at least four distinct glacial advances and sea-level retreats punctuated Ediacaran time: Gaskiers glaciation (580 Ma), Fauquier glaciation (571 Ma), Bou-Azzer glaciation (566 Ma) and Hankalchough glaciation (551 Ma). Tillites or diamictites are commonly controversial, but periglacial paleosols with distinctive physical structure and degree of chemical weathering offer supporting evidence of glaciation and sea-level change useful for stratigraphic correlation. This paper reviews glacial advances of the Ediacaran stratotype and other sequences, and also reveals the value of paleosols and chemical index of alteration to understand the upper Squantum and Brookline members of the Roxbury Conglomerate near Boston, Massachusetts. The Boston Bay ice wedges are periglacial paleosols, and evidence of maritime glacial climate like that of modern coastal Greenland and Arctic Canada. Simple discoidal vendobiont fossils (Aspidella terranovica) in the Dorchester Member of the Roxbury Conglomerate and in the Cambridge Argillite are in heterolithic shale–siltstone facies that are interpreted as intertidal to shallow marine environments. Local marine transgressions and other paleosols showing significant chemical weathering represent temperate interglacial paleoclimates. Short glacial advances affecting climate and sea-level enable subdivision of the Ediacaran Period. Four distinct glacial advances and sea-level retreats punctuated Ediacaran time: Gaskiers (580 Ma), Fauquier (571 Ma), Bou-Azzer (566 Ma), Hankalchough (551 Ma). Paleosols with distinctive structures such as ice wedges were periglacial. Squantum Member diamictites near Boston, Massachusetts are Gaskiers age. [ABSTRACT FROM AUTHOR]

Rare earth element and yttrium (REY) deposits are important strategic resources widely used in high-tech applications, such as solar cells and wind turbines. This paper summarises the temporal-spatial characteristics and genesis of REY deposits in China classified as alkaline carbonatite, ion-adsorption, placer, sedimentary metamorphism, marine sedimentary phosphorite and coal-hosted REY types. This study focuses on alkaline carbonatite and ion-adsorption deposits, because of their importance in terms of both exploitation and global reserves. The general characteristics, genesis, and enrichment of these REY deposit types are summarised, and eight districts have been identified as having prospectivity for REY, based on geological and geochemical data. An overview of these districts is presented, together with a detailed investigation of four important districts in terms of geological settings, mineralisation, regional deposit models and metallogenic prospect. REY deposits in China can be classified as alkaline carbonatite, ion-adsorption, placer, sedimentary metamorphism and marine sedimentary phosphorite and coal-hosted REY types. Ion-adsorption REY in the weathering profile of granitic rocks is strongly controlled by the resistance to weathering, climate, topography and layers of weathering crust. Carbonatite and alkaline rocks are major hosts for REYs and commonly have high concentrations of REY-bearing accessory minerals. Eight districts have been identified as having prospectivity for REY in China. [ABSTRACT FROM AUTHOR]

In this paper, we describe porosity variations in Miocene to Holocene carbonates off the west coast of Australia and assess their compaction trends. The porosity values were measured using discrete samples of Sites U1459–U1464 obtained by the International Ocean Discovery Program Expedition 356. The carbonate deposits have been influenced by a range of textures and diagenetic conditions throughout a nearly continuous sequence of geological ages from the Miocene to Holocene and at core depths from 0 to 1100 m below the seafloor. The collected samples were mostly grainstone, packstone, wackestone and mudstone textures. Dolostones and dolomitic carbonates were described at the Miocene intervals. Compaction trends were estimated exponentially and linearly based on cored sites, carbonate textures and dominant mineralogies (dolomite, calcite/aragonite). At all six sites, porosity distribution and reduction were generally depth-dependent. The porosity converged to about 30% between 750 and 1100 m, which suggests that the carbonates were close to the densest packing by mechanical compaction at a burial depth of ∼750 m. The porosity deviations are associated with textures and dominant mineralogies. Increasing mud content from grainstone to mudstone is a controlling factor for initial porosity and porosity reduction rate. Dolomitisation, dolomitic cementation, aragonite needle-rich mud and non-skeletal grains cause deviations from the depth-dependent compaction trends. Reflux-related cementation generally decreases porosity in Miocene dolomitic intervals. Higher porosity values of the Quaternary wackestone and mudstone at Site U1461 resulted from the presence of aragonite needle-rich mud hosting abundant micropores and from a high sedimentation rate. The occurrence of non-skeletal grains, such as ooids and peloids, as well as occasional meteoric exposure led to porosity inversion, occluding interparticle permeability and the creation of moldic pores. Porosity variations of Miocene–Holocene carbonates off the west Australian coast are primarily depth-dependent. Mechanical compaction affected porosity reduction down to a value of ∼30% at a burial depth of ∼750 m. Differences in texture-based compaction trends were affected by increasing mud content. Major porosity deviations are associated with dolomitisation, dolomitic cementation, aragonite needle-rich mud and non-skeletal grains. [ABSTRACT FROM AUTHOR]

Conglomerate reservoirs in alluvial fans commonly contain economic crude oil, but it is challenging to depict the distribution of conglomerate reservoirs or to summarise the sedimentary model in alluvial fans deposits owing to their complex lithofacies changes and variable hydrodynamic conditions. This paper focuses on the Poplar River alluvial fan in the northwest Junggar Basin, China, as a special case to analyse its sedimentary processes and to build a sedimentary model through detailed outcrop mapping and grainsize analysis. The Poplar River alluvial fan is a braided river-dominated fan with the characteristics of a large fan size (approximate 327.6 km2), gentle slope (∼<0.04–0.07°), coarse sediments (mainly cobbles or finer pebbles) and rare fine-mud sediments deposited from floods. In this alluvial fan, 15 lithofacies are identified that mainly formed in five hydrodynamic environments: (i) debris-flow deposits; (ii) high-flow traction current deposits; (iii) low-flow traction current deposits; (iv) still-water deposits; and (v) eolian deposits. Moreover, the sedimentary processes on the Poplar River alluvial fan can be divided into flood and interflood periods. During flood periods, sediment deposition plays a major role on the alluvial fan. From the proximal to distal parts, six lithofacies associations can be identified: feeder-channel and sheet-flow deposits in the proximal part, sheet flood and braided-stream deposits in the intermediate part, and channel deposits and wetland deposits in the distal fan areas. During the interflood periods, sediment reworking is the most important function, and three lithofacies associations are identified: main-channel deposits in the proximal fan, braided-trench deposits in the intermediate fan and wetland deposits in the distal area. The braided-stream deposits, braided-trench deposits and sheet-flood deposits have the best potential for high-quality aquifers or oil reservoirs based on their moderately well-sorted grains and high primary permeable intervals. Fifteen lithofacies and eight lithofacies associations are identified in the Poplar River braided river-dominated alluvial fan. The aggradation process of the studied alluvial fan can be divided into flood and interflood periods. The flood-period braided-fluvial deposits, interflood main-channel and braided-trench channel deposits are the facies with best reservoir potential. [ABSTRACT FROM AUTHOR]

Mesozoic and Cenozoic granites are widely distributed in the South Lhasa terrane of southern Tibet and record information about subduction of the Tethys oceanic plate and the India–Eurasia collision. This paper presents petrological, geochemical, zircon U–Pb and Hf isotopic characteristics of Cenozoic intrusive rocks in the Luocang area, South Lhasa terrane. Our data show these granites have ages of 54.4 ± 0.5 Ma and 47.2 ± 0.3 Ma (early Eocene), and are high-K, calc-alkaline, peraluminous, differentiated, I-type granites. The εHf(t) values of two samples are −9.59 to −4.15 and −7.85 to −5.36. These results suggest that the granites were derived from melting of the crust with no input of mantle source material. A review of data from Cenozoic granites of the South Lhasa terrane shows that they formed in a tectonic environment characterised by a gradual west-to-east transition to a post-collisional setting and are associated with breakoff of the Neo-Tethys oceanic plate. During the early Eocene continental collision, breakoff of the Neo-Tethys oceanic lithosphere caused the Indian plate to fold back resulting in a major asthenospheric disturbance. This was accompanied by an input of heat to the overlying continental crust, which caused melting of the mid to lower crust of the Lhasa terrane. The ascending magma underwent fractional crystallisation and was intruded to form the Eocene granites in the Luocang area. Two granitoids in the Luocang area of the South Lhasa terrane (southern Tibet) are high-K, calc-alkaline, peraluminous, differentiated, I-type granites and have negative εHf(t) values (−10 to −4). The U–Pb zircon ages of these two granitoids are 54.4 ± 0.5 Ma and 47.2 ± 0.3 Ma (early Eocene). The Luocang granites were formed by mantle heat input into the lower to middle crust of the Lhasa terrane; these crustal melts underwent fractional crystallisation during emplacement. [ABSTRACT FROM AUTHOR]

This paper presents the results of a small number of dates from sand samples collected at building sites in the eastern suburbs of Sydney. OSL ages of well-sorted, quartz sand ranges from 31 to 24 ka from within well-developed podzol soil profiles within a metre of the surface. The source of this sand appears to be from the east off the inner continental shelf during a period just prior to the maximum of the Last Glacial Maximum (LGM, Marine Isotope Stage 2) when sea-level was approximately 70-90 m below present level. During a later phase of the LGM, there is evidence from other coastal sites in central NSW and Gippsland, Victoria, that the dominant wind was from the west consistent with evidence from arid and semiarid Australia. Dune orientations in northern NSW into Queensland and other evidence at this time appear to reflect winds from the southeast quadrant. This study highlights the existence of a potential pivot area in dominant wind direction during the LGM between sustained westerly flow in southern area including Victoria and northeast Tasmania and southeast flow of northern NSW into Queensland. In central NSW, the circulation switched from easterly in Stage 2 to westerly as the glacial stage intensified in the LGM sometime after ca 25 ka. [ABSTRACT FROM AUTHOR]

This paper investigates the much-debated Jurassic/Cretaceous (J/K) boundary as well as the Early Cretaceous climate using palynomorphs of the Chichali Formation, Upper Indus Basin, North Pakistan. Based on the palynostratigraphy, two dinoflagellates and one spore/pollen assemblage are recorded, suggesting a Kimmeridgian to Valanginian age for the sediments of the Chichali Formation. The palynostratigraphic results further suggest that the Tithonian to Berriasian strata are truncated along the J/K boundary. The warm and humid conditions are supported by the consistent dominance of ferns corresponding to the Schizaeaceae and the intermittent appearance of herbs from Gleicheniaceae. Such climatic conditions are further supported by the consistent presence of evergreen trees with a broad leave of Cyatheaceae and Matoniaceae. The warm and humid conditions are also supported by conifers of the Araucariaceae in association with Cycadaceae. Such conditions during the Valanginian are further supported by the switch from the Bajocian–Oxfordian shallow carbonates of the Samana Suk Formation to the Kimmeridgian–Valanginain clastics of the Chichali Formation. Hence, the expansion of warm and humid tropical flora to the middle latitude (∼40°S) during the Valanginain hints strongly for global warming instead of previously suggested global cooling. Palynostratigraphic investigation shows Kimmeridgian to Valanginian age for the Chichali Formation, Upper Indus Basin, Pakistan. The J/K boundary is marked by an unconformity along which the Tithonian to Berriasian time record is missing. The reconstruction of paleovegatation indicates warm humid climate during the Valanginian instead of previously reported global cooling. [ABSTRACT FROM AUTHOR]

This paper is focused on the detailed lithostratigraphic facies characterisation of the paleo-environments of the uppermost Silurian through Lower Devonian Winduck Interval strata from the Bancannia South 1, Pondie Range 1 and Booligal Creek 1 and 2 wells, across the central Darling Basin of western New South Wales. Based on data from both wireline logs and drill cores and cuttings, an interpretation of paleo-environments and evolution of the depositional facies is presented. Our approach involves two key interpretations. The first outcome was the delineation of the Winduck Interval section (maximum observed thickness of approximately 1475 m) and formal subdivision into lower and upper Winduck Intervals, based on well data from the central Bancannia Trough, southern Pondie Range Sub-basin and northwestern flank of the Blantyre Sub-basin. The second outcome is based on the internal lithostratigraphy of the Winduck Interval represented by 11 sedimentary lithofacies organised into three lithofacies associations (LFAs). LFA-X1 is interpreted as distributary-channel sandstone complex deposits, LFA-X2 is interpreted as distributary mouth bar with small-scale braided delta plain complex deposits and LFA-X3 is interpreted as tidal channel sands with proximal delta front complex deposits. Subsurface lithostratigraphic facies analysis relationships and depositional environments of the Winduck Interval section have implications for evaluating the hydrocarbon potential and may assist future exploration efforts in the central Darling Basin, especially the Bancannia Trough and Pondie Range Sub-basin. A detailed lithostratigraphic facies characterisation of the paleo-environments of the uppermost Silurian–Lower Devonian Winduck Interval strata in the central Darling Basin is presented. Evaluation and interpretation of the Winduck Interval section in study area was subdivided into two informal stratigraphic units, a lower Winduck Interval and an upper Winduck Interval. Eleven distinct sedimentary lithofacies codes (LFs), which have been recognised in the internal lithostratigraphy of the Winduck Interval from the Bancannia South 1, Pondie Range 1 and Booligal Creek 1 and 2 wells, have been grouped into three lithofacies associations (LFAs). Lithostratigraphic facies analysis relationships and depositional environments of the Winduck Interval section has implications for evaluating the hydrocarbon potential and may assist future exploration in the Bancannia Trough and Pondie Range Sub-basin. [ABSTRACT FROM AUTHOR]

Hot dry rock (HDR) geothermal resources have great development potential and prospects, owing to their wide distribution and high thermal storage temperature. HDR resources are abundant in China, but their exploration and exploitation remain in the early stages. The Yishu fault zone in Shandong Province in eastern China is in a high-temperature geothermal zone of the Pacific Rim. Three craters and 15 hot springs are in this area, which possesses abundant geothermal resources and favourable conditions for the occurrence of HDR resources. Nevertheless, HDR resources in this area have not been studied in detail, and the index-evaluation system for HDR is still imperfect. In this paper, five index layers are selected, including: the gravity and magnetic fields, geothermal field, tectonic activity, reservoir and cover characteristics, and remotely sensed features. Thirteen index elements were also selected as evaluation factors. In combination, these index layers and index elements have established a favourable evaluation index system for HDR resources in this region, and the analytic hierarchy process has been used to determine the weight of each factor. Then, the GIS spatial analysis function is used to carry out spatial superposition analyses for each index element, and finally the distribution characteristics of HDR resources east of the Yishu fault zone were determined, with four favourable selection areas being delineated. The occurrence conditions of HDR resources are analysed in detail with evaluation indexes. It is believed that HDR resources are closely related to neotectonic movement, volcanism and rocks with high heat-generation rates. Searching for areas with geothermal anomalies is indispensable for the evaluation of HDR resources. This study provides a basis for the exploration and development of HDR resources in the region, and it can also provide a reference for similar work in other parts of the country. A set of evaluation indexes to determine favourable areas for HDR resources, including gravity, geothermal field, geological structure and crustal stability, heat storage and heat cover and features on remotely sensed images, is established. East of Yishu fault zone, there is a great potential of HDR resources, with an area of 19 399 km2 of favourable and more favourable areas, accounting for approximately 38.8% of the total area. HDR resources are likely closely associated with neotectonics, igneous activity, geothermal anomalies and rocks with a high heat-generation rate such as granites. [ABSTRACT FROM AUTHOR]

The Flinders Ranges in the north and Mount Lofty Ranges in the south form a continuous highland chain extending ∼1000 km in eastern South Australia. This region corresponds to outcropping rocks of the Neoproterozoic to Cambrian Adelaide Rift Complex. The semi-arid ranges of the north with their historic mining heritage and the agriculture and vineyards of the south are heavily promoted as iconic natural and cultural tourism attractions, increasingly combining with indigenous landscape stories. With the exception of Arkaroola and Kangaroo Island, these regions are linked by the 600 km Heysen Walking Trail and adjacent Mawson Cycle Trail. Research on the Ediacara fossil biota in the Flinders Ranges has raised public awareness of geological history and the early evolution of life on Earth and developed into a multi-site Flinders Ranges World Heritage Nomination project. This is supported by the South Australian Government as part of its Nature Tourism programme to provide opportunities for conservation, education, tourism initiatives and local employment, all of which are aspirations of the United Nations Educational Scientific and Cultural Organisation (UNESCO). South Australia has a World Heritage Fossil site at the Naracoorte Caves complex, which is a compact National Park with many staff and security for laboratories and underground fossil deposits. The multi-site World Heritage proposal for the semi-remote Flinders Ranges presents a very different approach for protection and public visitation. Following an emerging global trend for geotourism and developing geotrails, this paper proposes a 400-km loop geotrail across the region linking the nominated Flinders World Heritage elements with other 'Geological Monuments', listed State Heritage and historical sites. This strategy has the potential to involve wider community interest, engagement, support and involvement in its management. The concept would be a natural link to the Heysen and Mawson trails, both named after prominent South Australians with strong links to the Flinders Ranges landscape. It could be named the Ediacara Geotrail, Sprigg Geotrail or Arkaroo Geotrail after the indigenous dreamtime creator of the northeastern Flinders Ranges. [ABSTRACT FROM AUTHOR]

Quaternary alluvial and colluvial sediments infill major river valleys and form alluvial fans and colluvium-filled bedrock depressions on the range fronts and within the Mount Lofty Ranges of southern Australia. A complex association of alluvial successions occurs in the Sellicks Creek drainage basin, as revealed from lithostratigraphy, physical landscape setting and optically stimulated luminescence (OSL) ages. Correlation of OSL ages with the Marine Oxygen Isotope record reveals that the alluvial successions represent multiple episodes of alluvial sedimentation since the penultimate glaciation (Marine Isotope Stage 6; MIS 6). The successions include a penultimate glacial maximum alluvium (Taringa Formation; 160 ± 15 ka; MIS 6), an unnamed alluvial succession (42 ± 3.2 ka; MIS 3), a late last glacial colluvial succession within bedrock depressions (ca 15 ka; MIS 2) and a late last glacial alluvium (ca 15 ka; MIS 2) in the lowest, distal portion of Sellicks Creek. In addition, the Waldeila Formation, a Holocene alluvium (3.5 ± 0.3 ka; MIS 1), and sediments deposited during a phase of Post-European Settlement Aggradation (PESA) are also identified. The age and spatial distribution of the red/brown successions, mapped as the Upper Pleistocene Pooraka Formation, directly relate to different topographic and tectonic settings. Neotectonic uplift locally enhanced erosion and sedimentation, while differences in drainage basin sizes along the margin of the ranges have influenced the timing and delivery of sediment in downstream locations. Close to the Willunga Fault Scarp at Sellicks Creek, sediments resembling the Pooraka Formation have yielded a pooled mean OSL age of 83.9 ± 7 ka (MIS 5a) corroborating the previously identified extended time range for deposition of the formation. Elsewhere, within major river valleys, the Pooraka Formation was deposited during the last interglacial maximum (128–118 ka; MIS 5e). In general, alluviation occurred during interglacial and interstadial pluvial events, while erosion predominated during drier glacial episodes. In both cases, contemporaneous erosion and sedimentation continued to affect the landscape. For example, in the Sellicks Creek drainage basin, which lies across an actively uplifting fault zone, late glacial age sediments (MIS 2) occur within the ranges and near the distal margin of the alluvial fan complex. OSL dating of the alluvial successions reported in this paper highlights linkages between the terrestrial and marine environments in association with sea-level (base-level) and climatic perturbations. While the alluvial successions relate largely to climatically driven changes, especially in major river valleys, tectonics, eustasy, geomorphic setting and topography have influenced erosion and sedimentation, especially on steep-sloped alluvial fan environments. Luminescence dating of the Sellicks Creek alluvial fan complex reveals that sedimentation occurred predominantly during the later stages of glacial cycles accompanying lower sea-levels than present. Luminescence dating confirms that the stratigraphically lower portions of the Pooraka Formation are beyond the range of radiocarbon dating. Upper Pleistocene alluvial fan sedimentation at Sellicks Creek correlates with pluvial events in southeastern Australia. [ABSTRACT FROM AUTHOR]

Fluid flow characteristics of cleat systems in coalbed methane reservoirs are crucial in reservoir management and field development plans. This paper aims to evaluate the cleat system properties including cleat porosity, permeability, and aperture as well as the impact of permeability growth on production performance in the Bandanna Coal Formation of the Fairview Field, eastern Queensland. Owing to the presence of bad hole conditions and poor core recovery of the coal intervals, the petrophysical well logs and laboratory measurements cannot be used as a source of information for this purpose. Hence, a new approach is employed that utilises early water production data to measure water in place and absolute permeability of the coal. In addition, micro-computed tomography (CT) scan method is used to investigate the cleat system that is preserved in a core sample and results are compared with the ones obtained by analysis of production data. Cleat system evaluation by analysis of production data and micro-CT scan technique provides a comprehensive approach that brings confidence in measurements and helps to obtain cleat properties at the sufficient scale for reservoir engineering purposes. The necessary information including production data and core samples are collected from a dewatering well and the nearby observation well in the study area. Analysis of early water production data (single-phase flow) indicates that coal permeability is 189 mD and the average cleat porosity is approximately 5%. High cleat porosity describes the large volume of water produced over the life of the study well. The 3D model of thefossilisedcleat system constructed by the micro-CT scan method reveals that coal is well-cleated and cleat spacing and mean cleat aperture are 4 and 0.136 mm, respectively. The average cleat porosity that is measured by the micro-CT scan method is 5.7%, which is fairly close to the cleat porosity measured by analysis of production data. Production data analysis indicates that effective permeability to gas starts to grow at the midlife of the well and it strongly controls the shape of the production profile. The results of this study help in future field development and infill drilling programs in the Fairview Field and provide important insights into cleat system of Bandanna Coal Formation. [ABSTRACT FROM AUTHOR]

Over several decades, there has been considerable disagreement about heavy-metal contamination in mining communities as to whether the contamination arose from natural processes such as oxidation and weathering over millennia or from mining activities. More sophisticated geochemical methods and isotopic tracing especially for lead (Pb) may or may not provide definitive answers. We suggest that relatively simple approaches using the microscopic techniques of optical microscopy complemented by scanning electron microscopy and energy-dispersive analyses along with X-ray diffraction can provide definitive answers to the conundrum. Heavy liquid and –53 + 48 µm fractions of soil, pavement and gutter sweepings, dust depositional gauges, long-term dust accumulation, vacuum cleaner dust and ceiling dust were investigated using the above methods. The most common Pb-bearing particles consisted of Pb, Fe, Mn, Al, Si and O. The majority of grains were rounded with cavities and overgrowths, and showed evidence of transport and recrystallisation, probably deriving from post-mining activities and/or earlier geological processes. A small number of samples from ceiling dust, pavement sweepings, vacuum cleaner dust and long-term dust accumulation contained galena with a high degree of crystallinity suggesting a derivation from recent mining and ore concentration activities. High-precision Pb isotopic analyses showed that some samples with extensive oxidation and weathering had absorbed Pb from sources other than mine Pb, and these could be from gasoline, paint or weathering of the country rocks. [ABSTRACT FROM PUBLISHER]

Two north–south-trending belts of high-temperature–low-pressure (HTLP) sub-regional metamorphism have been identified in the New England Orogen of eastern Australia. Metamorphic complexes in the ∼1300 km long Early-Permian Inland belt have ages ca 300–290 Ma, and those of the ∼400 km long Mid-Permian Coastal belt ca 275–270 Ma. These periods correspond to the beginning and end of an extended (early–mid Permian) phase of subduction rollback and crustal thinning in eastern Australia. This paper describes and incorporates recent work on the Wongwibinda Metamorphic Complex in the southern New England Orogen as a basis for comparison with thirteen other HTLP sub-regional occurrences within the orogen. These are described in as much detail as is currently available. Some outcrops of HTLP rocks in difficult terrain have been subject to limited study and only conditional comparisons can be made. However, a significant number of characteristics shared between the complexes including: their location at the higher-temperature end of broad areas of very low-grade to greenschist facies metamorphic rocks, indicative of tilted crustal blocks; their association with major shear zones; the presence of migmatite at the high-temperature end of a steep metamorphic field gradient; the presence of two-mica granite formed by the melting of the local sedimentary pile; and temporal association with S-type granites; imply a common extension-related mechanism of formation for these HTLP belts. The connection with major faults and shear zones suggests the belts trace major crustal-scale extensional structures that migrated eastwards from ca 300 to 270 Ma. Two previously undocumented belts of HTLP subregional metamorphism are identified within the NEO. Available dating indicates that metamorphism occurred along the belts at the beginning and end of a major early–mid Permian extensional phase in eastern Gondwana/Australia. The characteristics of the HTLP complexes including their association with shear zones indicates they may delineate major loci of extension. [ABSTRACT FROM AUTHOR]

The Jurassic–Cretaceous Great Artesian Basin is the most extensive, and largest volume, sedimentary feature of continental Australia. The source of its mud-dominated Cretaceous infill is attributed largely to contemporary magmatism along the continental margin to the east, but the source of its Jurassic infill, dominated by quartz sandstone, remains unconstrained. This paper investigates the question of a Jurassic sediment source for the northern part of the basin. Jurassic uplift and exhumation of the continental margin crustal sector to the east provided the primary Jurassic sediment source. (U–Th)/He data are presented for zircon and apatite from Pennsylvanian to mid Permian granitoids of the Kennedy Igneous Association distributed within the northern Tasmanides between the Townsville and Cairns regions and for coeval granites of the Urannha batholith from the Mount Carlton district (N Bowen Basin), also within the northern Tasmanides. The data from zircon indicate widespread Jurassic exhumation of a crustal tract located to the east of the northern Great Artesian Basin and largely occupied by rocks of the Tasmanides. Detrital zircon age spectra for samples of the Jurassic Hutton and Blantyre sandstones from the northeastern margin of the Great Artesian Basin show their derivation to be largely from rocks of the northern Tasmanides. In combination, the detrital age spectra and (U–Th)/He data from zircon indicate exhumation owing to uplift generating appreciable physiographic relief along the north Queensland continental margin during the Jurassic, shedding sediment westward into the Great Artesian Basin during its early development. A portion of (U–Th)/He data for zircon are consistent with late Permian–mid Triassic exhumation within the Tasmanides, attributable to the influence of the Hunter--Bowen Orogeny. Evidence of Cretaceous and Paleocene exhumation episodes is also indicated for some samples, mainly by apatite (U–Th)/He analysis, consistent with data previously published from fission track studies. Overall, new data from the present study reveal that the exhumation related to Jurassic regional uplift and the subsequent erosional reworking of the northeast Australian continental margin is critical for the evolution and development of the northern side of the Great Artesian Basin in eastern Australia. Apart from this, another two previously suggested Permian–Triassic and Cretaceous exhumation and uplift episodes along the northeast Australian continental margin are also confirmed by the dataset of this study. U–Pb detrital zircon ages of sandstone samples from the northeastern Eromanga Basin reveal Paleozoic (480–280 Ma) and Proterozoic (1800–1400 Ma) age clusters. (U–Th)/He zircon and apatite dating results of granitoids samples from Cairns, Townsville and the Mount Carlton districts are dominated by Jurassic (198–164 Ma) and Permian–Triassic (272–238 Ma) age clusters. Combination of above two datasets proves the regional uplift-driving Jurassic exhumation episode in the northeast Australian continental is vital for the development of the northern Great Artesian Basin. [ABSTRACT FROM AUTHOR]

There is significant economic interest in the Murray Basin of southeastern Australia as it is proving to be a major heavy mineral sands (HMS) province that will be one of Australia's major source for production of rutile, zircon and ilmenite. The distribution and provenance of HMS resources in the Murray Basin is poorly understood because of its huge size, limited exploration and the complex depositional, structural and weathering mechanisms in their development. In this paper, we focus on the Copi North and Magic deposits some 130–180 km south of Broken Hill, NSW. The heavy mineral assemblages of the Copi North and Magic deposits are very similar, with the main economic minerals being ilmenite, leucoxene, pseudorutile, rutile and zircon. Intensive fracturing and brecciation are identified in many samples and are inferred to have been initially caused by multi-stage deformational processes associated with metamorphism and then further developed through alluvial and eolian transportation. Both deposits are classified as 'medium sands, symmetrical, mesokurtic and moderately well-sorted'. The majority of economic minerals are of low to medium sphericity and subrounded, along with abundant polished eolian quartz grains. The Copi North deposit has coarser and more poorly sorted sediments with higher HMS grades and magnetics content than the Magic deposit, reflecting a higher energy depositional environment. The main source for the HMS for the Copi North and Magic deposits is largely ascribed to the Broken Hill Block. Previous studies have shown that the Broken Hill orebody underwent substantial sub-aerial weathering over hundreds of millions of years. In addition, the complex metamorphic events experienced by the Broken Hill Block were capable of forming the broad series of minerals identified within the Copi North and Magic deposits. The HMS were believed to have been transported through paleovalleys near the Mulculca Fault in a southeast direction representing a feeder system into the NW Murray Basin. Both deposits feature a relatively linear geometry (roughly parallel to the strike of the paleoshoreline), with high HMS grades, modest tonnages, and coarser sediments when compared to WIM-style offshore deposits. Compared to other strandline HMS deposits of the Murray Basin, they are smaller in size although have similar high grades of 3.7–6.9% THM and similar proportions of the HMS assemblage of ilmenite, leucoxene, rutile and zircon. Deposits of similar size and grade are likely to occur throughout the northern part of the Murray Basin. Both the Copi North and Magic deposits contain similar mineral assemblages with the provenance of the heavy minerals ascribed to the Broken Hill Block. A relatively high energy inshore environment is inferred for the Copi North deposit while a lower energy environment associated with either a foreshore or backshore environment is inferred for the Magic deposit. Deposits of similar mineralogy, grades and size are likely to occur elsewhere throughout the northern Murray Basin. [ABSTRACT FROM AUTHOR]

This paper summarises current knowledge on metamorphism within the entire New England Orogen (NEO) of eastern Australia. Rocks recording metamorphic assemblages characteristic of each of the three metamorphic facies series (high, medium and low P/T) have been identified within the orogen. These include high P/T blueschists and eclogites, mid P/T orogenic metamorphism and low P/T contact aureoles and sub-regional high-temperature–low-pressure (HTLP) metamorphism (regional aureoles). Metamorphism is described as it relates to six tectonic phases of development of the NEO that together comprise two major cycles of compression–extension. Medium–high-grade contact metamorphism spans all six tectonic phases while low-grade burial and/or orogenic metamorphism has been identified for four of the six phases. In contrast, exposure of high P/T eclogites and blueschists, and generation of sub-regional low P/T metamorphism is restricted to extensional phases of the orogen. Hallmarks of the orogen are two newly identified zones of HTLP metamorphism, the older of which extends for almost the entire length of the orogen. The orogen is dominated by low-temperature rocks while high-temperature amphibolite to granulite facies rocks are restricted to small exposures in HTLP complexes and contact aureoles. Blueschist metamorphism falls into two categories; that associated with subduction during the Currabubula-Connors continental arc phase occurring at depths of ∼13–30 km; and the other of Cambrian–Ordovician age, exposed within a serpentinite melange and associated with blocks of eclogite. The eclogite, initially from depths of ∼75–90 km, appears to have been entrained in the deep crust for an extended period of geological time. A comprehensive review of contact metamorphism in the orogen is lacking and as studies on low-grade metamorphism are more extensive in the southern part of the orogen than the north, this highlights a second research gap. [ABSTRACT FROM AUTHOR]

Mineral matter in coals has been found to host valuable elements including germanium, lithium and rare-earth elements (REE), but such content of Australian coals remains under-explored. The aim of this paper is to provide a proof-of-concept study that determines elemental concentrations in the mineral matter of the high-ash, Fort Cooper Coal Measures (FCCM), Bowen Basin, Queensland. Coal in the FCCM has good coking properties but has not been extensively explored owing to its high ash content. This study performs a preliminary assessment of the elements from the coal portion that would typically become waste after washing or combustion. Given that the needs for industrial extraction methods will change over time, cataloguing and documenting the elemental composition of coal may assist future development of multiple products for the benefit of both the coal and mineral industries. This preliminary study has revealed similar elevations of REE and higher-than-average crustal concentrations of lithium, bismuth and scandium in some of the samples. Further analyses will be required on a larger dataset to better understand elemental associations and explore spatial patterns of elemental content that may indicate localised enrichments. Understanding the potential of valuable elements in the FCCM may stimulate interest in multiple-product-coal (or elemental-coal) mining in this under-exploited resource and further encourage the reduction of waste from other Australian coals at the wash-plant stage. [ABSTRACT FROM AUTHOR]

The sedimentary facies of the Huagang Formation, the major petroleum exploration horizon in the Xihu Depression in the East China Sea Basin, have not been well constrained, owing to limited drilling and core recovery. Interpretations are vague and vary from beach bar, braided river and braided-river delta front sediments. In this paper, the paleosedimentary environments of the Huagang Formation are discussed based on detailed organic and inorganic geochemical analysis and proxies used to interpret the sedimentary facies. Kerogen, dominated by sapropelinite, is mainly of Type I and Type II, and n-Paraffins are dominated by short-chain and medium-chain, with no obvious odd-over-even advantages. The distribution of isoprenoid alkanes and steroids indicates that the organic matter in mudstones is mainly of lacustrine and mixed origins. Elemental ratios of Th/U (4–6), V/Cr (1–4), Ni/Co (3–11) and V/(V + Ni) (0.5–0.75) indicate that in the area studied, the Huagang Formation was deposited under anoxic to reduced conditions with some oxygen-enriched horizons. Both inorganic and organic geochemical signatures show that the Huagang Formation was mainly deposited in an aquatic environment but with some minor periods of subaerial exposure. The sequence of the Huagang Formation is characterised by interbedded grey-white thick sandstones and grey-black thin mudstones. Normally graded cycles are widely developed, with rare mudstone in the upper part and scoured surfaces at the base. The cumulative grainsize distribution curve is mainly a two-stage type. The sedimentary facies indicative markers are dominated by braided-river channel deposits and combined with the paleosedimentary environments it is inferred that the sedimentary system in the study area was typical of a braided-river delta front. The cores available were intensively analysed using a hand-held X-ray fluorescence spectrometer to probe the variations in the paleoclimate and show that the braided-river channels were controlled by paleoclimate. During arid climatic settings, the sediments within individual channels were thin, and grainsizes varied significantly; at the base of each channel, basal conglomerates were common. In contrast, under humid climatic settings, thin multi-stage channels were superimposed, and the bottom often developed erosion surface. The paleosedimentary environments are discussed based on detailed organic and inorganic geochemical analysis. The Huagang Formation was deposited in a freshwater lacustrine basin under warm and humid climatic settings. The Huagang Formation is characterised by braided-river delta front facies. The development of braided-river channels was controlled by paleoclimate. [ABSTRACT FROM AUTHOR]

For the past 200 years, there have been numerous investigations and much speculation concerning the formation of the dramatic valleys of the Blue Mountains of NSW. In this paper, further evidence for the uplift and erosional history of the Blue Mountains is obtained from longitudinal river profiles, detailed mapping of the Rickabys Creek Gravel on the Lapstone Structural Complex and consideration of the topographical position of Miocene basalts. Knickpoints on the main rivers flowing east from the Great Dividing Range are identified and interpreted to be due to uplift events linked to the northward movement of the Australian continent over mantle inhomogeneities. At the Lapstone Structural Complex on the eastern range front, the occurrence of the Rickabys Creek Gravel and the nature of the over-steepened reaches on the rivers and streams crossing the Complex, suggest a more recent ongoing phase of uplift and antecedent river erosion. The Miocene basalts provide evidence of this landscape 20–15 Ma. Their locations with respect to the current rivers and ridges are interpreted to show additional evidence for recent uplift that has resulted in the formation of the Lapstone Structural Complex. It is suggested that this uplift commenced 10–5 Ma when the contemporary compressive stress field was established. Longitudinal profiles for major rivers in the Blue Mountains are consistent with a model of initial Cretaceous uplift followed by further Cenozoic uplift associated with dynamic topography. Mapping of Rickabys Creek Gravel within the Lapstone Structural Complex suggests the presence of antecedent rivers. Within the Lapstone Structural Complex, stream profiles, gravels and nearby outcrops of Miocene basalts are interpreted to indicate a third phase of uplift, possibly since 10 Ma. [ABSTRACT FROM AUTHOR]

Evidence for hydrothermal activity, such as siliceous rocks, iron dolomite layer deposits, and hydrothermal mineral combinations of ilmenite + pyrite + anhydrite, has been found in the high-quality source rocks from the Chang 7 layer in the Triassic Yanchang Formation from the southern margin of the Ordos Basin, China. In this paper, elemental geochemical analysis is carried out on a large number of samples collected from an outcrop geological section and drill core from the Chang 7 layer. We use elemental ratios to study the hydrothermal activity; the Al/(Al + Fe + Mn) ratio reflects the paleoproductivity, and the P/Al and P/Ti ratios and total S contents reflect the redox environment. The relationships between the hydrothermal activity and paleoproductivity, redox conditions and organic matter content are discussed. The correlation coefficients between the hydrothermal index Al/(Al + Fe + Mn) and the (Fe + Mn)/Ti ratio and total organic carbon are as high as –0.88 and 0.87, respectively, demonstrating a close relationship between hydrothermal activity and source-rock deposition. The correlation coefficients between the Al/(Al + Fe + Mn) ratio and the P/Al and P/Ti ratios, and total S contents are –0.81, –0.80, and –0.89, respectively, supporting this relationship. Hydrothermal activity can promote productivity at the lake surface and the development of a bottom-water anoxic environment. The paleoproductivity level of the Chang 7 sedimentary period is relatively high and represents an oxygen-poor anaerobic environment. The hydrothermal activity in the southern margin of the basin is strong, whereas the activity in the north is gradually weakened. Studies have shown that the hydrothermal activity at the bottom of the lake plays an important role in promoting the large-scale development of the Chang 7 high-quality source rocks. The organic matter abundance in samples with hydrothermal alteration are greater than in samples elsewhere. [ABSTRACT FROM AUTHOR]

During the past 50 years, many geological and ore-deposit investigations have led to the discovery of the Fe–P–(Ti)-oxide deposits associated with mafic–ultramafic–carbonatite complexes in the Kuluketage block, northeastern Tarim Craton. In this paper, we discuss the genetic and ore-forming ages, tectonic setting, and the genesis of these deposits (Kawuliuke, Qieganbulake and Duosike). LA-ICP-MS zircon U–Pb dating yielded a weighted mean 206Pb/238U ages of 811 ± 5 Ma, 811 ± 4 Ma, and 840 ± 5 Ma for Kawuliuke ore-bearing pyroxenite, Qieganbulake gabbro and Duosike ore-bearing pyroxenite, respectively. The CL images of the Kawuliuke apatite grains show core–rim structure, suggesting multi-phase crystallisation, whereas the apatite grains from Qieganbulake and Dusike deposits do not show any core–rim texture, suggesting a single-stage crystallisation. LA-ICP-MS apatite 207Pb-corrected U–Pb dating provided weighted mean 206Pb/238U ages of 814 ± 21 Ma and 771 ± 8 Ma for the Kawuliuke ores, and 810 ± 7 Ma and 841 ± 7 Ma for Qieganbulake and Duosike ores, respectively. The core–rim texture in apatite by CL imaging as well as two different ore-forming ages in the core and rim of the apatite indicate two metallogenic events for the Kawuliuke deposit. The first metallogenic period was magmatic in origin, and the second period was hydrothermal in origin. The initial ore-forming age of the Kawuliuke Fe–P–Ti mineralisation was ca 814 Ma and the second one was ca 771 Ma. On the other hand, the ore-forming ages of the Qieganbulake and Duosike deposits were ca 810 Ma and ca 841 Ma, respectively. Qieganbulake and Duosike deposits were of magmatic origin. Combined with previous geochronological data and the research on the tectonic background, we infer that the Kawuliuke, Qieganbulake and Duosike Fe–P–(Ti)-oxide deposits were formed in a subduction-related tectonic setting and were the product of subduction-related magmatism. [ABSTRACT FROM AUTHOR]

HyLogger profile scanning is commonly utilised for drill-core logging but the limited scanning area may not detect all important geological features. The study presented in this paper aims to develop a mineral mapping solution for this core-logging process by leveraging the colour image captured during the scanning process. A machine-learning-based computer vision program was developed by implementing a k-means clustering and a global colour profiling algorithm. A suite of drill-core images was used to validate the developed program. Results indicate that there is a direct correlation between the mineral assemblage of a rock type and its colour specifications. The identified mineral type and relative abundance were comparable with HyLogger scan results. [ABSTRACT FROM AUTHOR]

The Cliefden Caves area in central-western New South Wales includes the scientifically most important and irreplaceable examples of fossiliferous Ordovician rocks in the State. Exposures of the stratigraphically lower parts of the Cliefden Caves Limestone Subgroup on the aptly named Fossil Hill are world-famous among paleontologists and internationally significant for preserving the earliest in situ shell beds documented in the literature. They also contain some of the oldest known rugose corals, and an exceptional example of one of the oldest coralline biostromes, as well as many examples of invertebrate fossils and cyanobacterial mat structures that either are unique to this locality or were first described from here. Other stratigraphic levels throughout the total 363 m-thick Cliefden Caves Limestone Subgroup are similarly endowed with highly significant fossils, such as a globally unique in situ shell bank with rare examples of the trimerellide brachiopod Belubula spectacula, a wealth of shelly fossils and trilobites on Dunhill Bluff (adjacent to Fossil Hill to the east), and the appropriately named Trilobite Hill. Less well known to the general public, but of international importance to paleontologists, is the unique deep-water sponge fauna of the overlying Malongulli Formation that occurs at several levels in limestone lenses within this unit. Fossils from the Cliefden Caves Limestone Subgroup and the Malongulli Formation have been documented in more than 60 scientific papers and monographs since paleontological investigations into the site were first published in 1895. Despite concerted scientific endeavour in the region over the past 50 years, much more study needs to be done to fully document the paleontological riches of the Cliefden Caves area. These sites are interpreted as the remains of a tropical island, fringed by limestone and flanked by deep-water environments in which the Malongulli Formation was deposited. Preservation of such islands is exceptionally rare in the geological record. It is therefore vital for the area to remain accessible to scientific researchers to continue their studies. Flooding of the Belubula Valley by a proposed dam downstream from the Cliefden Caves area would hinder future research work on this unique geoheritage resource. Fortunately, a successful public campaign has led to listing of the site on the State Heritage Register that will provide essential protection of the caves from inundation while ensuring continued access to researchers. [ABSTRACT FROM AUTHOR]

In order of impact, the main anthropogenic threats to caves in eastern Australia are and have been for the European history of Australia: mining, inundation, vandalism, wear and tear, lampenflora, lint and dust, scientists and poorly informed decisions. Destruction of caves by natural processes is not a focus of this paper as it occurs over a geological time scale and there are few historical accounts of natural catastrophic cave failure. Saving and protecting caves are difficult due to the reliance and insistence on conservation by secrecy used by cavers and the organisations that represent them. Other issues that inhibit cave conservation are: limited public exposure, perceptions of land managers and farmers about caves, a shortage of research-based information on caves and difficulties with establishing the significance of a cave. Cave monitoring and the education of managers and cave guides are known to enhance the conservation of show caves. Actions that would help to save and conserve caves throughout Australia include: changes to planning legislation, establishment of a cave conservation organisation, introduction of specific cave protection legislation and the establishment of a Research Centre for Caves, Karst and Geoheritage. [ABSTRACT FROM AUTHOR]

The Woolshed Creek fossil site near the Royal Military College, Duntroon, Canberra, contains brachiopods Atrypa duntroonensis (early Homerian, early Silurian, ca 430.5 Ma) within a mudstone of the Canberra Formation. Their discovery in 1844 by the Reverend William B. Clarke ("the Father of Australian Geology"), and subsequent comparison with other fossil collections from around the world, contributed significantly to the nineteenth century debate about the oldest rocks in Australia. The fossil site is now on the ACT Government Heritage List and recent site improvements make it readily accessible via a pathway from the sports grounds of the Royal Military College. [ABSTRACT FROM AUTHOR]

The petroglyphs of the Murujuga (Burrup Peninsula and Dampier Archipelago) in Western Australia are of exceptional cultural value for the nation. It is Australia's largest and most significant collection of aboriginal rock art essentially as petroglyphs, with the number estimated at more than one million engravings. The Murujuga is a textbook example of ancient and modern times colliding as it also hosts potentially polluting, major industrial complexes such as iron ore and salt ports; liquefied natural gas, liquid ammonia and ammonium nitrate plants; railway lines, pipelines and rock quarries. The work presented in this paper is underpinned by an annual monitoring study of 10 selected sites including two control sites located on Dolphin and Gidley islands and eight test sites located closer to the industrial areas. The main rock types of the Murujuga, gabbro and granophyre, have been affected by weathering consisting of a cm-thick leached zone capped by a skin of orange and red iron and manganese oxides. The petroglyphs were engraved by removing the few top millimetres of the iron oxide-rich layer and the contrast with the paler leached zone clearly showing the carved motifs. Phosphorus is abnormally enriched in the leached zone and the surface coating, with manganese exclusively on the surface coating, demonstrating the impact of bird droppings and 'desert varnish' on the rocks. The colour difference and the hematite–goethite ratio, measured with a field portable reflectance spectrometer, between the background and engraving provides a tool to estimate the relative age of the petroglyphs and the selection of the backgrounds. As the fine-grained granophyres were preferentially chosen from the coarser-grained gabbros to host the petroglyphs, the goethitic (or yellower) backgrounds were prepared as canvas before being engraved. Many petroglyphs register the food items of the area, which changed as the last ice age ended and sea levels rose. We hypothesise that based on their locations and colour difference the constraint for the oldest age of the petroglyphs exceeds 17 000 years BP. [ABSTRACT FROM AUTHOR]

Late Holocene environmental changes were examined in Dee Why Lagoon, New South Wales, based on the sedimentological, geochemical and geochronological analysis of six cores collected from the fluvial delta and lagoon basin. The lagoon formed about 7300–7200 cal yr BP, following the post-glacial marine transgression and establishment of a sand barrier. Infilling of the lagoon occurred at a rate of 0.09–0.15 mm/yr until about 3300–3200 cal yr BP, when the barrier closed, resulting in mostly freshwater conditions, as evidenced by a change from pyrite-rich units to sediment containing little sulfur and a lack of foraminifera. Sedimentation rates increased to 0.23 then 0.43 mm/yr until about 100 years ago. Post-European land clearance led to an increase in sedimentation rates to 1.0–1.3 mm/yr on the fluvial delta, which are lower than those from other wave-dominated estuaries in New South Wales as well as those estimated by previous studies in Dee Why Lagoon. Our study shows that the fluvial delta started forming much earlier than originally thought, based on results of radiometric dating, and confirmed using sedimentological and geochemical data, as well as a critical examination of historic aerial photographs. Human impact has resulted in an increase in heavy metal (Cu, Pb, Zn) and metalloid (As) concentrations in the recent sediment, most likely attributed to stormwater discharge. Pb and As concentrations are above the ANZECC high sediment quality guideline values at the site closest to the stormwater outlet, with As-based pesticides one of the possible sources. Using the mean enrichment quotient, which is based on normalised Cu, Pb and Zn concentrations over their normalised background concentrations, we show that the surface sediments in Dee Why Lagoon are severely enriched, reflecting the recent anthropogenic impact that has also led to an increase in sedimentation rates. [ABSTRACT FROM AUTHOR]

In order to better predict the geometry and spatial distribution of reservoir facies and permeability barriers, it is critical to understand stratigraphic geometries and architecture at all scales within a basin. Stratigraphic forward modelling (SFM) allows geologists to forward project the deposition and evolution of sedimentary facies within a stratigraphic framework with given prior boundary conditions. The method can approximate depositional processes while taking into consideration a range of factors that affect basin evolution and sedimentation. This paper presents an overview of recent developments in stratigraphic forward models that are currently available and have been successfully employed in simulating stratigraphic development, including geometric models, diffusion models, Fuzzy Logic models and hydraulic models. In addition, the paper discusses SFM used in the simulation of the behaviour of natural sedimentary systems and verification of the potential for hydrocarbon entrapment and accumulation in a basin using an example from the Ordos Basin, western China. [ABSTRACT FROM AUTHOR]

The basal succession of the Condamine Valley, which overlays the boundary between the Surat and Clarence-Moreton basins (eastern Australia), contains a clay-rich horizon 'the Transition Zone' that marks a pronounced unconformity between the Jurassic Walloon Coal Measures and the Quaternary Condamine Alluvium. This paper provides insights into the tectonic and drainage evolution of the Condamine Valley through integrated analysis of U–Pb ages of detrital zircon from three samples (494 concordant analyses), stable oxygen isotope analysis on eight authigenic clay samples, X-ray fluorescence of primary and trace elements, and hyperspectral mineral analysis from two drill cores (Lone Pine 17 and Daandine 164). The Transition Zone is interpreted to consist of both weathered Jurassic sediments and Cenozoic clay deposits. Two sequential cycles of erosion, deposition and pedogenesis, related to geomorphological and climatic conditions are recognised. Distinctive oxygen isotope signatures of the two weathering fronts demonstrated an initial Early Cretaceous phase (δ18O = 11.9–15.7‰ VSMOW) associated with laterisation and possible uplift, followed by Paleogene (δ18O = 16.4–17.3‰ VSMOW) silcretisation of reworked Jurassic sediments. Detrital zircon geochronology yielded Jurassic maximum constraints for the age of deposition of three samples that are indistinguishable within error, the oldest of which (163 ± 8 Ma from the lateritic profile) corresponds to the age of the underlying Walloon Coal Measures. The two overlaying samples from a silcrete profile and granular alluvium yielded overlapping yet younger ages of 150 ± 6 Ma and 156 ± 9 Ma, respectively. Vitrinite reflectance used as a proxy for the thermal condition of the coal strata enabled an estimated 2–3 km of burial and subsequent (likely Early Cretaceous) uplift. Geochemical insights from the Condamine Valley correspond to broad-scale climatic and tectonic conditions, suggesting that 'transition zone equivalents' and corresponding groundwater dynamics may occur in similar sedimentary settings throughout eastern Australia. [ABSTRACT FROM AUTHOR]

Long, well-dated records of climate change in Australia are rare because most of the continent is prone to deflation and sediments are difficult to date beyond 40 ka. Deep-sea cores, containing terrigenous material, provide an ideal alternative to terrestrial records, because of continuous sedimentation and a robust chronology derived from oxygen isotopes. In this paper, the first of a series of two, we present pollen and spores data from core Fr1/94-GC3 from the East Tasman Plateau. This core is positioned at the southern extreme of the East Australia Current and simultaneously records changes in both oceanography and environments both offshore and in southeastern Australia. In an area of slow sedimentation, this core provides a continuous record of vegetation change in southeastern Australia and the southern Tasman Sea over approximately the last half a million years. Through time, glacial periods have progressively become warmer and shorter. Alpine plant taxa become more restricted with time and rainforest taxa expand to a far more restricted degree during the present interglacial period than the previous one, representing a fundamental shift in the vegetation of Tasmania. We apply transfer functions to reconstruct past rainfall and land temperatures based on the palynoflora that are then compared against the marine proxy record. [ABSTRACT FROM AUTHOR]