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Fruit flies (Tephritidae: Dacini) are a frugivorous insect group that exhibit high endemic diversity in the rainforests of Australia and the western Pacific. In this region, biogeography has been influenced by tectonic plate movements and cycles of isolation and re‐connection of landmasses and rainforest habitats during glacial periods. However, how such factors have influenced the speciation and historical dispersal of the regional Dacini is largely unknown. To address this, we use a dated phylogeny to reconstruct the biogeographical history of the tribe. We found the Dacini radiated eastward into the Pacific islands largely from sources in New Guinea. We also found evidence for historical dispersal from both Australia and New Guinea into New Caledonia, a pathway unique to this island compared with neighbouring islands. There was also evidence for multiple, bidirectional dispersal events between Papua New Guinea and Australia, likely facilitated by the cyclically exposed Torres Strait land bridge. Cape York in far northern Australia was likely the only entry point for species dispersing into Australia; there was no evidence for entry of flies into Australia directly from West Papua or Wallacea. Several lineages radiated after entering Australia, such as members of the Bactrocera dorsalis species group. Within Australia, speciation was not associated with the biogeographic barriers known to have impacted other rainforest fauna in eastern Australia. Overall, we demonstrate that isolation between islands and large landmasses is important in the evolution of the Australo‐Pacific Dacini, but the reason for their extensive radiation within Australia and Papua New Guinea remains unclear. [ABSTRACT FROM AUTHOR]

Major aridification events in Australia during the Pliocene may have had significant impact on the distribution and structure of widespread species. To explore the potential impact of Pliocene and Pleistocene climate oscillations, we estimated the timing of population fragmentation and past connectivity of the currently isolated but morphologically similar subspecies of the widespread brushtail possum (Trichosurus vulpecula). We use ecological niche modeling (ENM) with the current fragmented distribution of brushtail possums to estimate the environmental envelope of this marsupial. We projected the ENM on models of past climatic conditions in Australia to infer the potential distribution of brushtail possums over 6 million years. D‐loop haplotypes were used to describe population structure. From shotgun sequencing, we assembled whole mitochondrial DNA genomes and estimated the timing of intraspecific divergence. Our projections of ENMs suggest current possum populations were unlikely to have been in contact during the Pleistocene. Although lowered sea level during glacial periods enabled connection with habitat in Tasmania, climate fluctuation during this time would not have facilitated gene flow over much of Australia. The most recent common ancestor of sampled intraspecific diversity dates to the early Pliocene when continental aridification caused significant changes to Australian ecology and Trichosurus vulpecula distribution was likely fragmented. Phylogenetic analysis revealed that the subspecies T. v. hypoleucus (koomal; southwest), T. v. arnhemensis (langkurr; north), and T. v. vulpecula (bilda; southeast) correspond to distinct mitochondrial lineages. Despite little phenotypic differentiation, Trichosurus vulpecula populations probably experienced little gene flow with one another since the Pliocene, supporting the recognition of several subspecies and explaining their adaptations to the regional plant assemblages on which they feed. [ABSTRACT FROM AUTHOR]

The continental shelf of Northwest Australia hosts an extensive tropical carbonate ramp that forms an important template for the interpretation of similar systems in the sedimentary record. Yet, little is known about its development from the middle to late Quaternary, a period of high frequency glacioeustatic changes in sea‐level and climate. This research describes core and seismic‐reflection data from a mid‐ramp to outer ramp transect at the Northwest Shelf. Core material includes the upper 70 m of International Ocean Discovery Program Site U1461 (Expedition 356), which covers the last 500 kyr. During arid glacials, sedimentation is characterized by inorganically precipitated carbonates, including aragonite‐needle mud and ooids. Ooids developed under shallow marine conditions on small‐scale flat‐topped platforms. Seismic and sedimentological evidence indicates that these platforms developed locally on top of the present‐day mid‐ramp and were typically only active during a single glacial period. Aragonite‐needle mud precipitated (inorganically) in shallow‐water areas. Much of these fine sediments were subsequently exported into deeper water where they mixed with pelagic carbonates. Humid interglacials are generally characterized by reduced sedimentation across the Northwest Shelf of Australia, resulting in the amalgamation of glacial lowstand deposits. Yet, substantial amounts of skeletal carbonates were deposited at the studied location during the Holocene and Marine Isotope Stage 11. These sediment accumulations are interpreted as a local feature caused by a decline in current energy. The study presented highlights a ramp system where climate is as important as sea‐level in controlling carbonate deposition. [ABSTRACT FROM AUTHOR]

The published latest Palaeocene to Early–Middle Eocene age limits of the Sabrina microfloras, offshore Aurora Subglacial Basin, East Antarctica, largely depend on 1970s age-range data for fossil pollen and spore species in the continental margin basins of southern Australia. This paper uses updated biostratigraphical data from southern Australia, including the basins closest to the Aurora Basin throughout the Late Cretaceous and Paleogene, to propose that the age of the terrestrial component of the Sabrina microfloras is Campanian to Maastrichtian, not Paleogene. However, the revised age limits do not preclude these microfloras being redeposited more or less intact during the development and expansion of ice-sheets on East Antarctica, i.e. most probably during the late Paleogene based on other evidence from East Antarctica. [ABSTRACT FROM AUTHOR]

Aim: The Last Glacial Maximum (LGM) remains an enigmatic period in southeast Australia due to the limited spatial and temporal resolution of its palaeoclimatic records. A major feature of the LGM landscape was the existence of the Bassian Land Bridge, joining Tasmania with the mainland of Australia during periods of low sea level, and potentially facilitating increased biotic movement between these regions. To better understand biogeographical changes on the land bridge and in southeast Australia generally during the LGM, we present a 35 ka‐year palaeoecological record from one of the larger islands of Bass Strait. Location: Bass Strait, southeast Australia. Taxon: Eucalyptus, Poaceae, Monotoca, Myriophyllum, Zygnemataceae, Botryococcus, Pediastrum. Methods: Pollen, charcoal, and non‐pollen palynomorphs were analysed in a 1.75‐m sediment core from truwana/Cape Barren Island, Bass Strait, to reconstruct changes in vegetation, fire regimes and lake levels on the Bassian Land Bridge. Results were then compared to existing palaeoenvironmental studies in the region to develop a broader context of the prevailing land bridge environment and the potential influence on biotic dispersals in Australia during the last glacial period. Results: Results suggest a major vegetation shift on the Bassian Land Bridge in response to the establishment of the LGM climate, with grassland expansion at the expense of woodland from ~29–11 ka. Floristic richness, biomass burned and lake levels also markedly decreased through this period, with the driest interval being ~25–18 ka. Dryland herbaceous taxa dispersed between the mainland and Tasmania when the landbridge was fully exposed. Main conclusions: In agreement with previous studies, our results show that the dry grassland that dominated southeast Australia (and Southern Hemisphere mid‐latitude areas) during the LGM also extended across the Bassian Land Bridge. The prevailing environment on the land bridge is likely to have exerted a selective influence on biotic dispersals in Australia during glacial periods. [ABSTRACT FROM AUTHOR]

Understanding the key dynamical and microphysical mechanisms driving precipitation in the Snowy Mountains region of southeast Australia, including the role of orography, can help improve precipitation forecasts, which is of great value for efficient water management. An intensive observation campaign was carried out during the 2018 austral winter, providing a comprehensive range of ground-based observations across the Snowy Mountains. We used data from three vertically pointing rain radars, cloud radar, a PARSIVEL disdrometer, and a network of 76 pluviometers. The observations reveal that all of the precipitation events were associated with cold front passages. About half accumulated during the frontal passage associated with deep, fully glaciated cloud tops, while the rest occurred in the postfrontal environment and were associated with clouds with supercooled liquid water (SLW) tops. About three-quarters of the accumulated precipitation was observed under blocked conditions, likely associated with blocked stratiform orographic enhancement. Specifically, more than a third of the precipitation resulted from moist cloudless air being lifted over stagnant air, upwind from the barrier, creating SLW-top clouds. These SLW clouds then produced stratiform precipitation mostly over the upwind slopes and mountain tops, with hydrometeors reaching the mountain tops mostly as rimed snow. Two precipitation events were studied in detail, which showed that during unblocked conditions, orographic convection invigoration and unblocked stratiform enhancement were the two main mechanisms driving the precipitation, with the latter being more prevalent after the frontal passage. During these events, ice particle growth was likely dominated by vapor deposition and aggregation during the frontal periods, while riming dominated during the postfrontal periods. [ABSTRACT FROM AUTHOR]

The timing and duration of the coldest period in the last glacial stage, often referred to as the last glacial maximum (LGM), has been observed to vary spatially and temporally. In Australia, this period is characterised by colder, and in some places more arid, climates than today. We applied Monte-Carlo change point analysis to all available continuous proxy records covering this period, primarily pollen records, from across Australia (n = 37) to assess this change. We find a significant change point occurred (within uncertainty) at 28.6 ± 2.8 ka in 25 records. We interpret this change as a shift to cooler climates, associated with a widespread decline in biological productivity. An additional change point occurred at 17.7 ± 2.2 ka in 24 records. We interpret this change as a shift towards warmer climates, associated with increased biological productivity. We broadly characterise the period between 28.6 (± 2.8) – 17.7 (± 2.2) ka as an extended period of maximum cooling, with low productivity vegetation that may have occurred as a combined response to reduced temperatures, lower moisture availability and atmospheric CO2. These results have implications for how the spatial and temporal coherence of climate change, in this case during the LGM, can be best interrogated and interpreted. [ABSTRACT FROM AUTHOR]

Debate about the nature of climate and the magnitude of ecological change across Australia during the last glacial maximum (LGM; 26.5–19 ka) persists despite considerable research into the late Pleistocene. This is partly due to a lack of detailed paleoenvironmental records and reliable chronological frameworks. Geochemical and geochronological analyses of a 60 ka sedimentary record from Brown Lake, subtropical Queensland, are presented and considered in the context of climate-controlled environmental change. Optically stimulated luminescence dating of dune crests adjacent to prominent wetlands across North Stradbroke Island (Minjerribah) returned a mean age of 119.9 ± 10.6 ka; indicating relative dune stability soon after formation in Marine Isotope Stage 5. Synthesis of wetland sediment geochemistry across the island was used to identify dust accumulation and applied as an aridification proxy over the last glacial-interglacial cycle. A positive trend of dust deposition from ca. 50 ka was found with highest influx occurring leading into the LGM. Complexities of comparing sedimentary records and the need for robust age models are highlighted with local variation influencing the accumulation of exogenic material. An inter-site comparison suggests enhanced moisture stress regionally during the last glaciation and throughout the LGM, returning to a more positive moisture balance ca. 8 ka. [ABSTRACT FROM AUTHOR]

Stratigraphic investigations, supported by palynological dating, detrital zircon and monazite dating, and quartz grain micromorphology were undertaken of the Early Cretaceous strata around the southern margin of the Eromanga Basin where they onlap older rocks of the northern Flinders Ranges. The presence of a tillite within the Early Cretaceous Cadna-owie Formation and another in the Trinity Well Sandstone are evidence of two significant glaciations: the oldest, the Livingston Tillite Member, is from the middle Valanginian; the younger, the Sheehan Tillite Member, is from the early Aptian. A significant hiatus encompassing the Barremian interrupts the succession. Extensive dropstones, minor diamictite lenses and beds and a bed containing glendonite crystals, together indicate that cold (limited glacial and/or seasonal freezing) conditions persisted through the Hauterivian and the Aptian, with cold conditions peaking in the late Aptian. [ABSTRACT FROM AUTHOR]

Abstract—The analysis of paleomagnetic data from Late Neoproterozoic complexes of Siberia and Australia is carried out. We show that the existing paleomagnetic datasets are in a disagreement with the concept of the axial-dipole configuration of the Late Neoproterozoic geomagnetic field: proposed non-actualistic models of the field do not reasonably explain the distribution of the paleomagnetic poles. We carried out analysis of paleomagnetic and virtual geomagnetic poles distribution based on simple geometric calculations. The analysis suggests that the configuration of the Late Neoproterozoic geomagnetic field was determined by the coexistence of a weak, long-lived source that was stably fixed in space, with a main dipole source that experienced sporadic multidirectional jumps within a certain preferred region of the Earth. Predominantly equatorial orientation of the main dipole source is substantiated by paleoclimate proxies. We propose a descriptive non-actualistic model of the Late Neoproterozoic geomagnetic field—the Devious Equatorial Dipole hypothesis, which brings paleomagnetic and paleoclimate data into accordance. [ABSTRACT FROM AUTHOR]

The evolution of the paleoclimate and the duration of the two glacial periods during the Cryogenian in the Yangtze Block are of great geological significance for understanding "Snowball Earth." We studied the evolution of the paleoclimate during the Cryogenian, using chemical weathering, and determined the warming time of the interglacial paleoclimate, using zircon U-Pb dating in the Yangtze region. A new laser ablation ICP-MS zircon U-Pb age of 659.9 ± 3.2 Ma is reported from the middle Datangpo Formation. The chemical index of alteration (CIA) for the Cryogenian fine clastic rock samples from a drill core shows that the climate in the provenance area during the Gucheng and Nantuo glacial periods was dry and cold and that the chemical weathering was weak; the average CIA values were 63.3 and 64.2, respectively. In the early stage of the Datangpo period, the climate in the provenance area was still dry and cold, with a CIA average of 60.7, compatible with that in the two glacial periods; in the middle and late stages, the climate was warm and humid, chemical weathering was enhanced, and the average CIA rose to 77.4, compatible with the 76.9 of the Liantuo period before the Cryogenian. The evolution of other chemical weathering (paleoclimate) proxies, such as the chemical index of weathering, the plagioclase index of alteration, and Rb/Sr, is compatible with that of the CIA. The warming time of the interglacial paleoclimate during the Cryogenian in the Yangtze Block was ca. 660 Ma, roughly consistent with the ending time of the Sturtian in Australia and Mongolia, indicating that the lower part of the Datangpo Formation may still represent Sturtian glacial deposits, thus further suggesting the global consistency of the end of the Sturtian. [ABSTRACT FROM AUTHOR]

Depositional evidence for glaciation (dropstones, diamictites) is common in Neoproterozoic strata, and often debated, but erosional evidence (e.g., unconformities cut directly by ice) is rare. Only two such unconformities are known to have been well preserved globally from the Ediacaran Period (in western Australia and central China). This paper provides the first full description of a spectacular subglacial landscape carved beneath ice masses in the Shimengou area of central China, with classical subglacial bed forms including general faceted forms, müschelbruche, cavetto, spindle forms, and striations that testify to an abundance of meltwater during subglacial erosion. These features were produced during the southward, somewhat sinuous, flow of a temperate to polythermal ice mass. [ABSTRACT FROM AUTHOR]

Australia is a continent seemingly without a cryohistory. But take a closer look. Its cryohistory differs dramatically from that of the northern hemisphere-a contrast that long baffled Victorian geologists seeking evidence of glaciation in the Great South Land. Just as historians have sought to redress the image of a static Arctic through a new attention to its cryohistory, so too historians of Australia have sought to recover a continent that is anything but a "timeless land." Its long geological history-its cryohistory-framed Aboriginal lifeways across the continent, which in turn, shaped colonial encounters in the aftermath of British invasion in 1788. Guiding this historical project have been the moral challenges of the settler nation's legacy of Indigenous dispossession and displacement, and the unfolding planetary crisis of the Anthropocene and its implications for critically understanding deep time. This article examines the colonial hydrology of water scarcity in the goldfields of arid Western Australia in the late nineteenth century. It shows how access to freshwater became a flashpoint for relations between Indigenous and non-Indigenous peoples on an extractive frontier. At the turn of the twentieth century, water was the means by which to improve health, hygiene and cleanliness, without which the privileges of white civilisation could not be afforded. Although such conditions also developed elsewhere in settler Australia, the limited water availability on the eastern goldfields made the circumstances that emerged there especially dire. Accordingly, the material conditions of the arid inland- the product of Australia's Pleistocene-came to bear on the nature of the encounters between Indigenous and non-Indigenous peoples from the mid-nineteenth century. The very absence of ice in Australia's cryohistory left its mark on the peoples of the eastern goldfields. [ABSTRACT FROM AUTHOR]

Ocean basins are the ultimate repositories of sediment. Their slow, continuous accumulation over geologic history provides valuable archives that document major climate events and transitions in Earth history. Mineral dust plumes borne by prevailing winds are dominant sources of terrigenous sedimentation off regions such as the Saharan, Arabian, Kalahari, Patagonian, and Australian deserts. Scientific ocean drilling off Africa and Arabia has recorded consistent glacial-stage increases in eolian dust fluxes throughout the Pliocene-Pleistocene, where elevated dust flux values during glacial periods and stadia have been interpreted as reflecting real hydroclimate progression toward greater glacial aridity. International Ocean Discovery Program Expeditions 356, 363, and 369 (conducted in 2015, 2016, and 2017, respectively) recovered extensive sedimentary climate archives off Australia. Ongoing analyses of these strata reveal a marine record of the onset of continental aridity as Australia migrated northward by 25° over the last 50 million years. These Southern Hemisphere oceanic records will continue to yield key information on global climate evolution, allowing us to understand how deserts and monsoonal systems have evolved through time. [ABSTRACT FROM AUTHOR]

Recently acquired seismic data in the eastern portion of the Amadeus Basin of central Australia have enabled disconformities at the base of both the Sturt and Elatina glaciogenic sequences within the Neoproterozoic succession to be mapped on a semi-regional scale. On a more detailed scale, along the shallowly shelving eastern flank of the basin, seismic data have revealed features that demarcate the transition from a grounded to floating, or possible absent, Sturt ice-sheet. Coincident with this transition is an extensive mound-like accumulation of glacial debris, some 10 to 15km wide, 300 m high and extending at least 150km subparallel to the northeast-southwest-oriented basin margin. This glacial debris entered the basin subglacially through meandering tunnel valleys, one of which can be mapped seismically. [ABSTRACT FROM AUTHOR]

Abstract Over the last four decades of palaeoclimate research, significant emphasis has been placed on the Last Glacial Maximum (LGM) spanning 26.5–19 thousand years ago (ka), a period that saw significant (∼125 m) sea-level reductions and major ice caps adorning large parts of the Northern Hemisphere. Here, we present evidence for another major glacial period spanning 71–59 ka (Marine Isotope Stage 4: MIS4) from a well-dated marine sequence offshore South Australia. The astronomically-tuned chronology of this deep-sea core is confirmed using single-grain optically stimulated luminescence dating (OSL), providing confidence in our high-resolution age model. Our approach to the study of our MD03-2607 core has been to employ many different proxies. These are: δ18O of both planktic and benthic foraminifera for stratigraphic purposes, faunal counts of planktonic foraminifera to reconstruct the position of oceanic fronts and currents, alkenone palaeothermometry, XRF core scanning to determine the presence of aeolian dust, and εNd isotope to identify fluvial discharge over the core site. We compare our new proxy findings with other archives for mainland Australia and Tasmania. Our multi-proxy palaeoclimate reconstructions are consistent with other marine, terrestrial and cryosphere archives across the Southern Hemisphere and suggest, for the first time, that MIS 4 was almost as dramatic as the LGM. During MIS4, global sea-level was reduced by ∼100 m, glaciers across Australasia were more significant compared to the LGM, and sea-surface temperatures were much reduced. These glacial conditions uniformly peaked around 65 ka. Global comparisons show major glacial conditions and vegetation shifts elsewhere during MIS4, but many are poorly dated. The significant environmental changes taking place during this glacial period were paralleled by waves of human dispersal across Eurasia and the earliest evidence of human occupation in northern Australia at 65 ka. Highlights • MIS4 was a major glacial period between 71 and 59 ka in the Southern Hemisphere. • Glacial conditions peaked at 65 ka, sea level dropped ∼100 m and SST dropped ∼5 °C. • Glaciers In New Zealand, Australia and Papua New Guinea were more pronounced at MIS4. • Multiproxy data confirm significant oceanic frontal changes offshore South Australia. • The deuterium excess change implies higher moisture reaching Antarctica during MIS4. [ABSTRACT FROM AUTHOR]

High-resolution clay mineral assemblages and siliciclastic grain-size records were collected from the International Ocean Discovery Program (IODP) high sedimentation Site U1483 off the Scott Plateau of the northwest Australian margin and studied to identify the clay mineral sources, transport processes, and ocean current behavior, as well as to evaluate the Australian summer monsoon over the last 410 kyr. Clay minerals are primarily composed of smectite (41–70%), followed by kaolinite (10–28%), illite (13.5–25%), and trace chlorite (3–14%). The provenance study revealed that the primary sources of clay minerals at Site U1483 are the Victoria and Ord rivers in northwest Australia. Smectite is mainly derived from the mafic volcanic and smectite-rich Bonaparte Gulf, whereas kaolinite and illite are primarily derived from felsic igneous and metamorphic rocks, respectively, found in the drainage areas of these rivers. Chlorite is primarily contributed by the Indonesian Throughflow (ITF), with a minor contribution from the northwest Australian rivers. Variations in the clay mineral assemblages and grain-size records indicate strong glacial–interglacial cyclicity, with small grain sizes, high smectite content, and low kaolinite and illite content during glacial periods. During interglacial periods, grain size, kaolinite, and illite percentages increase. Smectite is the dominant clay mineral during both the glacial and interglacial periods. (Kaolinite + illite + chlorite)/smectite and kaolinite/smectite ratios are adopted as proxies for the Leeuwin Current strength and the Australian summer monsoon, respectively. During glacial periods, low kaolinite/smectite and (kaolinite + illite + chlorite)/smectite ratios indicate a weak summer monsoon, resulting in low river discharge and a weak Leeuwin Current, which can transport small smectite-sized sediments to the core location. High kaolinite/smectite and (kaolinite + illite + chlorite)/smectite ratios during interglacial periods correspond to intense Australian monsoons and a strong ITF and Leeuwin Current, which contributed relatively more kaolinite and illite than during glacial periods. The proxy records' spectral analysis indicates a strong eccentricity period of 100-kyr, an obliquity period of 41-kyr, and a precession period of 23-kyr, implying that the clay mineral input along the northwest Australian margin is influenced by both high-latitude ice sheet forcing and low-latitude tropical processes. • Victoria and Ord Rivers have contributed clay minerals to the location of Site U1483 off northwest Australian margin. • The ITF, Leeuwin Current, and the Australian monsoon were weak during glacials while relatively strong during interglacials. • Terrigenous input has been controlled by ocean current strength, sea-level oscillation, and the Australian summer monsoon. [ABSTRACT FROM AUTHOR]

Change of global monsoon (GM) during the Last Glacial Maximum (LGM) is investigated using results from the multi-model ensemble of seven coupled climate models participated in the Coupled Model Intercomparison Project Phase 5. The GM changes during LGM are identified by comparison of the results from the pre-industrial control run and the LGM run. The results show (1) the annual mean GM precipitation and GM domain are reduced by about 10 and 5 %, respectively; (2) the monsoon intensity (demonstrated by the local summer-minus-winter precipitation) is also weakened over most monsoon regions except Australian monsoon; (3) the monsoon precipitation is reduced more during the local summer than winter; (4) distinct from all other regional monsoons, the Australian monsoon is strengthened and the monsoon area is enlarged. Four major factors contribute to these changes. The lower greenhouse gas concentration and the presence of the ice sheets decrease air temperature and water vapor content, resulting in a general weakening of the GM precipitation and reduction of GM domain. The reduced hemispheric difference in seasonal variation of insolation may contribute to the weakened GM intensity. The changed land-ocean configuration in the vicinity of the Maritime Continent, along with the presence of the ice sheets and lower greenhouse gas concentration, result in strengthened land-ocean and North-South hemispheric thermal contrasts, leading to the unique strengthened Australian monsoon. Although some of the results are consistent with the proxy data, uncertainties remain in different models. More comparison is needed between proxy data and model experiments to better understand the changes of the GM during the LGM. [ABSTRACT FROM AUTHOR]

It is widely recognised that arid Australia (including semi- and seasonally arid regions) supports an extremely diverse ant fauna. However, the truly remarkable extent of its diversity is not well appreciated, even among myrmecologists, and the reasons for such diversity are poorly understood. The vast majority of ant species in arid Australia are undescribed, and I argue that a recognition of the true diversity of the fauna would re-define the conventional understanding of global ant diversity patterns. For example, Monomorium Mayr and Tetramorium Mayr are formally recognised as widespread but essentially Afrotropical genera, whereas the large majority of species actually occur in arid Australia. The Australian fauna includes many genera each with >100 arid-adapted species, and several of these have >300 species. Melophorus Lubbock is likely to have well over 1000 species, making it one of the world's richest ant genera despite being endemic to Australia. I estimate that the total size of the ant fauna of arid Australia is as much as 7500 species, which would make it rival, if not surpass, that of the Amazon basin. I argue that the phenomenal ant diversity of arid Australia is a product of its unique history of aridity and associated patterns of speciation and extinction over the past few million years. I propose that the Pleistocene glaciations that caused waves of mass extinctions throughout the northern hemisphere actually promoted speciation in Australia. Australia remained relatively warm during glacial periods, but there was massive movement of sand during these times of peak aridity, with up to 85% of the continent covered by desert dunes. This would have resulted in a highly fragmented biota confined to a very large number of isolated refugia, providing the perfect storm for speciation. [ABSTRACT FROM AUTHOR]

Phylogeographic studies around the world have identified refugia where fauna were able to persist during unsuitable climatic periods, particularly during times of glaciation. In Australia the effects of Pleistocene climate oscillations on rainforest taxa have been well studied but less is known about the effects on mesic-habitat fauna, such as the eastern grey kangaroo (Macropus giganteus). The eastern grey kangaroo is a large mammal that is common and widespread throughout eastern Australia, preferring dry mesic habitat, rather than rainforest. As pollen evidence suggests that the central-eastern part of Australia (southeast Queensland and northern New South Wales) experienced cycles of expansion in mesic habitat with contraction in rainforests, and vice versa during glacial and interglacial periods, respectively, we hypothesise that the distribution of the eastern grey kangaroo was affected by these climate oscillations and may have contracted to mesic habitat refugia. From 375 mitochondrial DNA control region sequences from across the distribution of eastern grey kangaroos we obtained 108 unique haplotypes. Phylogenetic analysis identified two clades in Queensland, one of which is newly identified and restricted to a small coastal region in southern Queensland north of Brisbane, known as the Sunshine Coast. The relatively limited geographic range of this genetically isolated clade suggests the possibility of a mesic habitat refugium forming during rainforest expansion during wetter climate cycles. Other potential, although less likely, reasons for the genetic isolation of the highly distinct clade include geographic barriers, separate northward expansions, and strong local adaptation. [ABSTRACT FROM AUTHOR]

The angular unconformity at the base of the Grant Group forms a distinctive surface evident both at outcrop and in the subsurface on seismic and well logs. Detailed analysis of a 2D seismic dataset, integrated with available well data, suggests a complex suite of processes controlling the formation, deformation and resultant morphology of this surface. They can be subdivided into three categories depending on whether the mechanisms pre-dated, were coeval with, or post-dated deposition of the Grant Group. Pre-Grant faulting during the Devonian–Lower Carboniferous Pillara Extension resulted in development of significant paleotopography that influenced the morphology of the Base Grant Group unconformity. The pre-Grant interval contained thick salt, which was locally removed in the Silurian, with the development of isolated bodies of thickened Worral Formation. Later after deposition of the Grant group, the remainder of the Mallowa salt underwent dissolution/withdrawal, resulting in collapse of the flanks of earlier Worral pods of sediments, forming a ‘sombreros’ structure and folding the Base Grant Group unconformity. The main syn-Grant processes include regional glacial erosion, and extensive development of paleo-tunnel valleys that formed beneath and at the margin of the Permian–Carboniferous ice sheet as it advanced into the Fitzroy Trough. This created significant relief on the Base Grant Group unconformity, with tunnel valleys characterised by steep-sided, often U-shaped valleys up to 525 m deep and 12 km wide. Post Grant deposition, the unconformity surface was subsequently modified during the Triassic–Jurassic Fitzroy Movement, resulting in fault reactivation and development of a series ofen-echelonanticlines associated with a regional wrench system. [ABSTRACT FROM PUBLISHER]

Branched glycerol dialkyl glycerol tetraether (GDGT) distributions observed in a sediment core from Lake McKenzie were utilized to quantitatively reconstruct the pattern of mean annual air temperature (MAAT) from coastal subtropical eastern Australia between 37 and 18.3calkaBP and 14.0calkaBP to present. Both the reconstructed trend and amplitude of MAAT changes from the top of the sediment core were nearly identical to a local instrumental MAAT record from Fraser Island, providing confidence that in this sediment core branched GDGTs could be used to produce a quantitative record of past MAAT. The reconstructed trend of MAAT during 37 to 18.3calkaBP and timing of the Last Glacial Maximum (LGM) in the Lake McKenzie record were in agreement with previously published nearby marine climate records. The amplitude of lower-than-present MAAT during the LGM potentially provides information on the latitude of separation of the Tasman Front from the East Australian current in the subtropical western Pacific. The Lake McKenzie record shows an earlier onset of near modern day warm temperatures in the early Holocene compared to marine records and the presence of a warmer than present day period during the mid-Holocene. [ABSTRACT FROM AUTHOR]

Palaeoshorelines and associated palaeo-coastal features are studied to reconstruct past sea level, climate, and depositional environments. Their identification typically depends on direct field observations and is therefore challenging in the marine environment, where the interpretation mostly relies on sparse geophysical data. This review presents, based on 118 published case studies, a summary of morphological evidence that can be used to identify submerged relict coastal features worldwide, using only geophysical data. Four coastal feature categories that can be used as palaeoshoreline indicators were identified: (1) beach ridges of wind and wave origin; (2) shoreface strata; (3) marine terraces; and (4) coral-reef terraces. In light of this proposed classification, an area of ~200,000 km2 was investigated along the Rowley Shelf (North West Shelf, Australia), a carbonate-dominated platform, based on the integration of high-resolution bathymetry (i.e., seismic-derived bathymetry, satellite-derived bathymetry, multibeam echosounder bathymetry, spot depth soundings) and 2D reflection seismic lines. Relict features were discriminated from modern bedforms using five criteria: (1) stratigraphic position; (2) emersion features; (3) similarity with modern and published analogues; (4) integration of modern ocean conditions; and (5) evidence of early cementation. In total, over 500 submerged relict coastal features were identified, making this review the most comprehensive catalogue published to date. Relict features are concentrated over specific depths, referred to as modal sea-level depths (MSLDs), which correspond to depths where the relative sea level remained stable over long periods of time. Nine MSLDs are observed at 20, 35, 50, 60, 70, 80, 90, 105 and 125 m below sea level. Each MSLD is the result of the accumulation of coastal features through multiple glacial/ interglacial cycles. Most of the features may nevertheless be related to the last glacial sea-level fall and were likely formed between Marine Isotopes Stages (MIS) 5 and 2. The analysis of the submerged coastal features indicates that the overall shelf morphology is controlled by the distribution of these features, and that, while in a carbonate province, their formation is related to wind, tide, fluvial and wave processes. The higher concentration of relict fluvial-influenced features at shallower depths and of relict tide-influenced features at greater depths suggest that fluvial runoffs were limited during glacial periods. This, in turn, supports the hypothesis of a prevalent dry climate during glacial periods and in contrast, of a humid climate during interglacial periods. Finally, the study reveals that most modern coral reefs of the Rowley Shelf are growing on top of relict coastal features and that seabed ridges previously interpreted as drowned coral reefs are, in fact, likely to be relict coastal features formed through clastic processes. Results from this study will support the identification of submerged palaeoshorelines on continental shelves around the globe and highlight the influence of associated relict coastal features on shelf morphologies. Additionally, this study provides new insights on processes shaping carbonate provinces. [ABSTRACT FROM AUTHOR]

Abstract: The Australia/New Zealand region of the Southern Ocean is influenced by several of the major global water masses of the oceans and is the prime entry point for cold deep waters into the Pacific basin. During the last glacial there was increased sea-ice extent around Antarctica (as far north as 55°S), as well as increased iceberg presence inferred from ice-rafted debris. Evidence from microfossil assemblages suggests that sea surface temperatures (SST) were up to 7 °C cooler, consistent with recent estimates of cooling for New Zealand derived from glacier modelling and other terrestrial proxies. The Subtropical Front (STF), Subantarctic Front (SAF) and Polar Front (PF) had migrated north, except where the position of the fronts were controlled bathymetrically. Despite the potential for iron fertilisation by increased dust input into the ocean during the glacial, there is limited evidence for higher total biological productivity in the Pacific sector of the Southern Ocean. The altered oceanic circulation during the glacial also decreased nutrients in the surface waters and affected the outgassing of CO2. This contributed to an increased storage of CO2 in the deep waters and lowering of the carbonate lysocline. During the deglaciation, sea-ice retreat and SST increased rapidly at ∼18 ka, roughly synchronous with the reinvigoration of deep water circulation in the Southern Ocean and the release of CO2 stored in the deep waters. The gradient in carbon isotopes (δ13Cbenthic) between Antarctic Intermediate Water (AAIW) and lower Circumpolar Deep Water (LCDW) was greatest at the start of the deglaciation, suggesting that the AAIW ventilation preceded LCDW ventilation, or there was a significant change in air-sea fractionation of δ13C. There was a slight enrichment in δ18Oplanktic, decrease in SSTs and a reduction in intermediate and deep water circulation between ∼14 and 12.5 ka BP during the Antarctic Cold Reversal (ACR), coincident with glacier advances in the New Zealand Southern Alps and other terrestrial records of cooling. Following the ACR, there was a second, more minor, release of deep water CO2, most likely related to reinvigoration of North Atlantic Deep Water (NADW). From 10 ka onwards the modern intermediate and deep water circulation was established. Air temperatures and SSTs reached a maximum in the early Holocene, with the STF located at its most southerly position, and there was a widespread retreat of Antarctic ice sheets to their modern position. A decline to modern SST and air temperatures in the mid to late Holocene followed. While millennial cycles overprinted on the SST and δ18Oplanktic records, may be the result of subtle changes in the position and strength of the westerly winds during the Holocene. [Copyright &y& Elsevier]

Abstract: Recent studies of the Last Glacial period Indo-Australian summer monsoon (IASM) have revealed links to both northern and southern hemisphere high latitude climate as well as to regional ocean conditions. Particular interest has been paid to the monsoon response to Heinrich events, with variability explained by meridional shifts in positioning of the intertropical convergence zone (ITCZ), but this model has not been adequately tested. In addition, the shorter-lived Dansgaard/Oeschger (D/O) events have not been detected (beyond D/O-1, the Bølling/Allerød) in land-based records from the Indo-Pacific, despite their prominent expression in stalagmites from southern Asia, raising questions about the sensitivity of the IASM to these events. Here we present a Southern Hemisphere stalagmite oxygen isotopic time series from Ball Gown Cave (BGC), tropical northern Australia, located on the margins of the modern austral summer ITCZ, that spans 40–31 and 27–8 ka. Elevated IASM rainfall coincides with Heinrich stadials and the Younger Dryas, while decreased rainfall characterizes D/O interstadials, a response that is anti-phased with sites spanning the Indo-Pacific Warm Pool and with Chinese records of the East Asian summer monsoon. The BGC time series thus reveals a precipitation dipole consistent with a southward (northward) migration of the ITCZ during periods of high northern latitude cooling (warming) as the primary driver of millennial-scale IASM variability during the Last Glacial period. Our record indicates a strengthening of the IASM after the Younger Dryas period, likely as a result of rising sea level and sea surface temperatures, breaking the link with the high latitudes. [Copyright &y& Elsevier]

Abstract: A total of 20 morphological types of microbially induced sedimentary structures (MISS) are recognized from the late Neoproterozoic tillite-bearing successions of the Kimberley, northwestern Australia which include alpha-petees, triradiate cracks, multidirectional linear ridges, millimeter ripples, erosional remnants and pockets and so on. Of these, triradiate cracks, multidirectional linear ridges, and millimeter ripples are reported for the first time from the Neoproterozoic worldwide. Most Kimberley MISS are morphologically comparable with their ancient and present-day counterparts whose biogenicity have been well demonstrated. In the Kimberley, during the interglacial period MISS have colonization preference to relatively coarse sandy substrates (Ranford Formation) and their abundance decreased towards the younger strata (Throssell Shale). In contrast, MISS abundance increased from the older strata (Yurabi Formation) towards the younger strata (Flat Rock Formation) during the postglacial period. However, overall, both MISS abundance and bedding plane coverage percentage increased from the Marinoan-younger Marinoan/Gaskiers interglacial successions to younger Marinoan/Gaskiers postglacial successions, indicating a proliferation of microbial mats after the younger Marinoan/Gaskiers glaciation. The increase of microbial mats could have ameliorated marine biogeochemical conditions and ecosystems, and thus laid the foundation for the rise of Ediacaran biota in Australian basins. [Copyright &y& Elsevier]

Aim Climatic fluctuations during the Pleistocene have shaped the population structure of many extant taxa. However, few studies have examined widespread species inhabiting the Australian continent, where periods of increased aridity characterized the Pleistocene. Here we investigate the phylogeography and population history of a widespread and vagile southern Australian marsupial, the western grey kangaroo ( Macropus fuliginosus). Location Southern Australia. Methods We examined the variation of the mitochondrial DNA (mtDNA) control region from 511 individuals of M. fuliginosus sampled throughout their transcontinental distribution. Maximum likelihood and Bayesian analyses were used to investigate the phylogeography and coalescence analyses were then used to test hypothesized biogeographical scenarios. Results The combined results of the phylogeographical and coalescence analyses revealed a complex evolutionary history. Macropus fuliginosus originated in the south-west of the continent, with north-western and south-western populations subsequently diverging as a result of vicariance events during the mid-Pleistocene. Subsequent arid phases affected these populations differently. In the north-west, the expansion and contraction of the arid zone resulted in repeated vicariance events and multiple divergent north-western mtDNA subclades. In contrast, the south-western population was less impacted by climatic oscillations but gave rise to a major transcontinental eastward expansion. Main conclusions Macropus fuliginosus exhibits the genetic signature of divergence due to unidentified barriers in south-western Western Australia, while previously identified barriers across southern Australia appear to have had little impact despite evidence of a broad-scale range expansion prior to the Last Glacial Maximum (LGM). This pattern of localized expansion and contraction is comparable to unglaciated regions in both the Northern and Southern Hemispheres. Furthermore, this study indicates that despite the potential similarities between Northern Hemisphere glaciation and the activation of dune systems in the Australian arid zone, both of which rendered large areas inhospitable, the biotic responses and resultant phylogeographical signatures are dissimilar. Whereas a limited number of major geographically concordant refugia are observed in glaciated areas, the Southern Hemisphere arid zone appears to be associated with multiple species-specific idiosyncratic refugia. [ABSTRACT FROM AUTHOR]

Abstract: New geochemical data from two continental-scale soil surveys in Europe and Australia are compared. Internal project standards were exchanged to assess comparability of analytical results. The total concentration of 26 oxides/elements (Al2O3, As, Ba, CaO, Ce, Co, Cr, Fe2O3, Ga, K2O, MgO, MnO, Na2O, Nb, Ni, P2O5, Pb, Rb, SiO2, Sr, Th, TiO2, V, Y, Zn, and Zr), Loss On Ignition (LOI) and pH are demonstrated to be comparable. Additionally, directly comparable data for 14 elements in an aqua regia extraction (Ag, As, Bi, Cd, Ce, Co, Cs, Cu, Fe, La, Li, Mn, Mo, and Pb) are provided for both continents. Median soil compositions are close, though generally Australian soils are depleted in all elements with the exception of SiO2 and Zr. This is interpreted to reflect the generally longer and, in places, more intense weathering in Australia. Calculation of the Chemical Index of Alteration (CIA) gives a median value of 72% for Australia compared to 60% for Europe. Element concentrations vary over 3 (and up to 5) orders of magnitude. Several elements (total As and Ni; aqua regia As, Co, Bi, Li, Pb) have a lower element concentration by a factor of 2–3 in the soils of northern Europe compared to southern Europe. The break in concentration coincides with the maximum extent of the last glaciation. The younger soils of northern Europe are more similar to the Australian soils than the older soils from southern Europe. In Australia, the central region with especially high SiO2 concentrations is commonly depleted in many elements. The new data define the natural background variation for two continents on both hemispheres based on real data. Judging from the experience of these two continental surveys, it can be concluded that analytical quality is the key requirement for the success of global geochemical mapping. [Copyright &y& Elsevier]

Recent work on the Late Palaeozoic Ice Age in eastern Australia has shown the Joe Joe Group in the eastern Galilee Basin, Queensland, to be of critical importance as it is one of few records of Pennsylvanian glacial activity outside South America. This paper presents detailed sedimentological data, from which the Late Palaeozoic environment of the region is reconstructed and which, consequently, allows for robust comment on the broader Gondwanan glaciation. The Jericho Formation, in the lower Joe Joe Group, was deposited in an active extensional basin in lacustrine to fluvial environments, during the mid-Namurian to early Stephanian. The region experienced a cool climate during this time, and polythermal mountain or valley-type glaciers periodically advanced into the area from highlands to the north-east. The Jericho Formation preserves a suite of proglacial to terminal glacial facies that is characterized by massive and stratified diamictites deposited from debris flows, massive and horizontally laminated conglomerates and sandstones deposited from hyperconcentrated density flows, laminated siltstones with outsized clasts and interlaminated siltstone/conglomerate deposited through ice-rafting into lakes, and sedimentary dykes and breccias deposited through overpressurization of groundwater beneath permafrost. Non-glacial facies are dominated by fluvial sandstones and lacustrine/overbank siltstones. The glacigenic rocks of the Jericho Formation are confined to discrete packages, recording three separate glacial advances during the latest Namurian to late Westphalian. This arrangement is consistent with the temporal distribution of glacigenic rocks from around the remainder of Australia and Gondwana, which supports the theory that glacial deposits occurred in discrete intervals. The Joe Joe Group is a key succession in the world in this context as, at this time, eastern Australia provides the only unequivocal evidence of a Namurian/Westphalian glaciation outside South America. The continuous record of sedimentation through the Pennsylvanian and Early Permian is indicative of significant warming between glacial intervals, which is difficult to reconcile with the development of long-lived, cold-based ice sheets across the supercontinent. [ABSTRACT FROM AUTHOR]

The stratigraphy in Vines 1, a 2017.5 m-deep cored stratigraphic hole drilled by the Geological Survey of Western Australia in 2001 near the Western Australian - South Australian border, has been reinterpreted with implications for the Neoproterozoic to Cambrian geological history of the Officer Basin. A previous interpretation considered the intersected succession as a conformable stratigraphic package, the Vines Formation. An assemblage of palynomorphs, found throughout the hole and previously used to infer an age of no older than earliest Cambrian, is now thought to consist of contaminants. An older assemblage, which is considered to be reworked and inherited from underlying rocks, provides a new maximum age constraint of mid-Neoproterozoic. Based on sedimentological interpretations and comparisons with other drillholes in the western Officer Basin, and the succession in the eastern Officer Basin, the Vines 1 succession is reinterpreted as four discrete sedimentary packages, the Pirrilyungka (new name), Wahlgu, Lungkarta and Vines (redefined) Formations, in ascending order. The Pirrilyungka and Wahlgu Formations include glacigenic sediments and may correlate with similar glacial successions in Supersequences 2 and 3 (mid to late Cryogenian) of the Centralian Superbasin, and the Sturt Tillite and Elatina Formation and their equivalents in the Adelaide Rift Complex of South Australia, respectively. The eolian Lungkarta Formation and fluvial Vines Formation are considered, on regional evidence, to be most likely of Ediacaran to earliest Cambrian age. [ABSTRACT FROM AUTHOR]

Abstract: Facies, provenance and palaeocurrent analysis of the predominantly siliciclastic Neoproterozoic succession of the east Kimberley district of northwestern Australia indicates southwesterly-directed regional palaeoice-flow directions associated with continental glaciation. Facies relationships at three key study sites in the east Kimberley record glacial advance, retreat and marine transgression and the likely effects of ice dynamics on local basin depositional history. Ice-scour linked with provenance data indicate ice advance from the northeast. Additional ice-flow data from the west Kimberley and the Daly River area of Northern Territory are consistent and record a regional palaeoice-flow direction towards the southwest. Palaeocurrent data and facies relationships in the east Kimberley, however, suggest that sediment transport directions within the east Kimberley basin were influenced by a combination of ice-induced lithospheric flexure, pre-existing topography and modification of basin topography and sediment dispersal paths by ice-induced redistribution of debris. A basin evolution model incorporating these concepts within the framework of ice advance, retreat and marine inundation is proposed. Identification of regional ice-flow trends of this scale should ultimately prove a useful tool in testing possible palaeogeographic reconstructions of continent configurations in a post-Rodinian world. [Copyright &y& Elsevier]

Abstract: Up to the 1950s, the Precambrian was regarded as unrewardingly unfossiliferous, records of fossils being isolated, few in number and dubious. The change came with the discovery by Reg Sprigg of body fossils in latest Proterozoic sediments in South Australia. Although there had been descriptions of isolated fossils (now recognised as Ediacaran) from rocks of this age in the nineteenth century and at the start of the twentieth century, in Newfoundland and Namibia, respectively, the Ediacara finds stimulated researches and now, at the start of the twenty-first century, diversified fossil assemblages are known, all over the world, from the period 600–543 Ma, known formerly as the Vendian and now officially as the Ediacaran. In this account, a brief description of the history of these finds is given, followed by descriptions of the most important provinces [South Australia, Leicestershire, Namibia, Russia (Podolia, the White Sea Coast, Urals and Siberia), Newfoundland (Avalon Peninsula) and Northwest Canada]: then of 27 other known occurrences of this dominantly soft-bodied and perplexing fauna(?)–it seems certain that some, at least of the fossils, are animal fossils, although some, even the greater part, could be a unique form of life, not animals or plants (“Vendobionta”). These descriptions, derived in the course of a literature search lasting over a year, are followed by discussions of important special aspects: trace fossils; geochronology and correlation; geotectonics; glaciation (the “Snowball Earth” concept applied to the Varangian/Laplandian/Marinoan glaciation, which ushered in this last subdivision of the Proterozoic); the evidence for Ediacaran and other life forms existing in the Proterozoic prior to its last, Ediacaran, chronological subdivison; the Vendozoa concept. The last section consists of short summary of conclusions. This text essentially constitutes an objective record of what has been published to 2005 on the Ediacaran System. [Copyright &y& Elsevier]

Although Earth is widely believed to have undergone a series of extreme low-latitude snowball glaciations during the Neoproterozoic (ca. 1000-543 Ma), only one reliable pa- leomagnetic result, from Elatina, South Australia, places glacial rocks close to the equator. We report new paleomagnetic data from the Neoproterozoic Huqf Supergroup of Oman that pass fold and reversal tests and yield a paleopole at 52.3°S, 074.4°E (N = 25 sites; α95 = 7.3°). This paleopole places the Muscat region of Oman at a latitude of 13° in the late Neoproterozoic and provides the first direct evidence that both glacial and overlying cap carbonate units were deposited in the tropics. The presence of glacial-interglacial cyclicity within the Huqf Supergroup indicates that areas close to the equator may have been largely free of ice at the time of deposition, a result that is inconsistent with the classic snowball Earth model. Our result precludes the possibility that contrasting lithologies mark a phase of rapid plate motion and provides the first evidence for low-latitude glaciation in Arabia. A series of magnetic reversals in the Fiq tillite and the overlying Had ash dolomite, in northern and central Oman, correlates well with a similar sequence in the Mirbat Formation in southern Oman and indicates that recovery from glacial conditions took place over long time scales (possibly >105_106 yr). [ABSTRACT FROM AUTHOR]

The bathyal Ocean Drilling Program Site 765 at 5725 m water depth, offshore northwest Australia at 16°S is directly under the influence of the Australian monsoon during the Austral summer and is the recipient of continental dust during the Austral winter. It is downstream of the Indonesian Throughflow, which is a major arm of the global thermohaline circulation. As such it is ideally situated to record the climate and oceanic consequences of Quaternary climate variability. Despite being over 400 km from northwest Australia, palynomorphs (pollen and spores) are relatively common in this section, sourced via aeolian (during the dry winter) and benthic transportation processes and sediment plumes (during the summer monsoon). Detailed palynological analyses of this flora in the upper part of this core reveals intermittent snap shots of environmental and climate change over the last 300 kyrs. Interglacial stages are interpreted to be characterised by palynomorph-rich turbidite and calcareous ooze deposition whereas palynomorph-poor slowly accumulating siliceous oozes (deposited below the Calcium Carbonate Compensation Depth) are present during glacials. The dominance of Poaceae sourced from the Australian mainland in interglacial periods suggests that vegetation during these periods was similar to today. Interglacial palynofloral assemblages suggest a more intense wet season (Australian monsoon) with higher rainfall that allowed more active erosion and deposition onto the shelf. The presence of Indonesian sourced pollen and fern spore taxa, as well as warm water dinoflagellate species suggest enhanced Leeuwin Current and monsoonal intensity during interglacials times. The youngest part of the core is dominated by siliceous ooze, likely deposited during the Last Glacial Maximum and the early Holocene. The lack of calcareous ooze near the top of the core is likely caused by Holocene to Recent erosive processes or core disturbance. The presence of common charcoal in all samples over the last 300 kyrs shows that fire was a constant feature of the landscape in northwest Australia prior to human occupation of the region 65,000 years ago. • Palynomorphs in bathyal ODP Site 765 record 300kys of Quaternary climate variability. • Fossil palynomorphs are sourced via dry season aeolian or monsoonal sediment plumes. • Interglacials are turbidites/calcareous oozes whereas glacials are siliceous oozes. • Poaceae from Australia dominated interglacials due to an enhanced Australian Monsoon. • Common charcoal shows fire was a constant landscape feature prior to human occupation 65,000kyrs. [ABSTRACT FROM AUTHOR]

The Quaternary is well known for being a period of the geological record that saw significant and alternating climatic fluctuations. Here, we concentrate on the last 94 millennia that saw Australia and its surrounding seas undergo significant environmental changes. Importantly also it is during that this period of time includes the arrival and settlement of humans in Australia. Following on from Marine Isotopic Stage 4 (MIS4) that saw, over the period of 71-59 ka BP, a significant eustatic sea level drop (∼100 m), low sea-surface temperatures as well as glacial conditions on land, Australia experienced wet conditions again, but eventually progressively entered into a glacial phase. By then, humans had arrived on this large continent and later the megafauna progressively became extinct. This paper describes in detail the climate over this period, based principally on the high-resolution record of two marine sediment cores located offshore of the southern Australian margin, and that are then compared with known events on land as well as other deep-sea cores. Particular emphasis is placed on the period that spans the Last Glacial Maximum (LGM), the extent of which thus far had been poorly defined in the Australian region. Emphasis is placed on the period from 34 to 14 ka to demonstrate that (1) the LGM, defined here as the period 24 to 18 ka, was not always extremely dry and cold, and (2) that people were able to live in inland Australia as water existed in places, despite generally cold conditions. We also show using a series of ten maps - at 2 ka intervals over the 34-14 ka period - the waxing and waning of oceanic fronts such as the Subtropical and Subantarctic Fronts, link sea-surface temperatures (SST) with periods of glacial expansion in the Australian Alps and Tasmania, as well as the South Island of New Zealand, and the extent of the Leeuwin Current down to south of Australia. Aeolian dust was transported at sea over the main core site from ∼26 to 18 ka period, pointing to arid conditions in Australia, but this period was punctuated by two significant reductions in dust transport to both core sites, coinciding with a retreat of the Subantarctic Front away from the Australian southern coastline, and slight SST shifts for a few centuries at ∼24 and 22-21 ka BP. At the peak of the cold phase, from 23 to 18.4 ka, summer SST were of the order of 9 °C below that experienced during the middle of the Holocene at about 6 ka BP. A similar temperature drop was also experienced offshore the northwestern corner of Western Australia. Periglacial activity dates for the Australian mainland and Tasmania pool around ∼22 ka. On either side of the 24 ka event, the chain of lakes in the Willandra Lakes retained water and human activity was registered in the area. Elsewhere in Australia, water was present to sustain human populations during the cold and dry times. It is postulated here that northern Australia was at times quite wet, especially during MIS4. The cessation of the LGM is set on 18.4 ka from offshore southern Australia as confirmed for the deep-sea cores by several proxies, and more likely at 18 ka inland. Finally, we document that it took two millennia for "glacial" conditions to end in the Australian region as registered in our deep-sea core records, well after the lowest global sea level ∼20.6 and 20 ka, respectively, started to rise. There is also evidence of another very cold period determined on the Australian mainland, Tasmania and the South Island of New Zealand centred around 27 ka, after which time warmer conditions occurred before the start of the LGM. This is matched with our deep-sea records with very cold conditions and changes in oceanographic conditions. • 2 deep-sea cores provide information on the waxing and waning of oceanic fronts south of Australia. • The Last Glacial Maximum for the Australian region spans 24-18 ka. • 10 maps detail conditions in the Australian region spaning the period 34–14 ka. • Environmental conditions for MIS2 & MIS4 are compared in great detail in the cores. • Australia was arid and cold during the LGM but there was water to support human occupation. [ABSTRACT FROM AUTHOR]

International Ocean Discovery Program (IODP) Expedition 356 Site U1461 represents one of the few records from the North West Australian shelf that provides information about aridity fluctuations in Australia during the Quaternary. A combination of chronostratigraphic indicators revealed the (partial) preservation of two major glaciations (Marine Isotope Stage (MIS) 2 and MIS 12) in the sedimentary record. The faunal content (mainly benthic foraminifera, corals and bryozoans) was analyzed to estimate paleo-environments and paleo-depths in order to determine if these sediments have been remobilized by reworking processes. Despite the occurrence of a depositional hiatus (including MIS 5d to MIS 9-time interval), the excellent preservation of faunal content suggests that the preserved sediment is in situ. The geochemical composition of the sediments (Nd and major elements) indicates that during MIS 12 riverine input was likely reduced because of enhanced aridity, and the sediment provenance (mainly atmospheric dust) is likely in the central (Lake Eyre) or eastern (Murray Darling Basin) parts of the Australian continent. MIS 2 is confirmed to be one of the driest periods recorded in Australia but with mixed dust sources from the eastern and western parts of the continent. More humid conditions followed the glacial maximum, which might correspond to the peak of the Indian-Australian Summer Monsoon. [ABSTRACT FROM AUTHOR]

Multiple stable isotope investigations from upper Eocene to lower Oligocene deep-water marine sequences record the transition from global greenhouse to the icehouse conditions (Oi-1 glacial). While Southern Ocean high latitude deep sea records of this transition are well known, their shallow marine equivalents are rare and have the potential to record the eustatic and oceanic consequences of Paleogene glacial variability. The well-known high paleolatitude (~55°S) neritic carbonate sequence at Browns Creek and Castle Cove in the Otway Basin in southeast Australia spans the Eocene-Oligocene boundary. During this time the area lay on the northeastern margin of the Australo-Antarctic Gulf facing the evolving Southern Ocean. The importance of this record has been hampered by a lack of a consistent stratigraphy and contradictory microfossil interpretations. To reconcile these issues we combine new bio-, chemo- and lithostratigraphic analyses of the outcrops and a new core (Colac-2) with pre-existing data to revise the stratigraphy. This confirms the middle/upper Eocene boundary is near the base of the section. The overlying upper Eocene siliciclastic strata are truncated by an unconformity (of ~0.8 Ma in duration) and overlain by glauconitic sand (the Notrostrea greensand) deposited after ~35.9 Ma. Subsequently deepening to middle to outer neritic depths deposited cyclic carbonates. Shallowing after ~35 Ma deposited laterally variable calcareous siliciclastic facies. These strata were tilted and eroded prior to 34 Ma leading to shallow water facies that may have been subaerially exposed during uplift. Brachiopod strontium isotope dates and an 0.5‰ carbon isotope excursion above this unconformity suggests the top of the Browns Creek and the base of the Castle Cove section correlate to Eocene-Oligocene transition (EOT-1) at ~34 Ma. The subsequent persistence of positive C/O isotope values above this level records the transition to the Oi-1 glaciation at ~33.7 Ma. Strong cyclicity in the inner shelf Castle Cove limestone is interpreted to record the commencement of obliquity dominated glacio-eustacy during the Oi-1 glacial phase. The shallowing from outer to inner shelf palaeodepths from the late Eocene to the early Oligocene is likely related to the onset of cryosphere expansion, however, palaeodepth estimates are complicated by the onset of regional compressional tectonism at the Eocene/Oligocene boundary that caused localized tilting and an unconformity with possible antisiphoning effects in this near-field site. • High paleolatitude records of Oi-1are rare and usually identified in deep sea sediments. • We describe a shelfal record of the Eocene-Oligocene Transition in south Australia. • The sequence records strong evidence for 41kyr obliquity during the Oi-1 glaciation. • A 41kyr obliquity driver for Oi-1 has previous been demonstrated only in isotope data. [ABSTRACT FROM AUTHOR]

A new fossil paracypridine ostracod, Tasmanocypris lochardi sp.nov. is described from late Miocene shallow marine strata of southeastern Australia. It has morphological features similar to a number of modern southern Australian and southwest African Tasmanocypris species, here termed the dartnalli -group. This species group was likely present in early Cenozoic temperate, shallow seas around Antarctica. The first appearance of Tasmanocypris lochardi in late Miocene marine strata of the Bass Strait hinterland of SE Australia, equates to a late Miocene (9–7 Ma) intensification and northward latitudinal shift of the Antarctic Circumpolar Current (ACC). Late Miocene occurrences of Tasmanocypris lochardi in southeast Australia were likely associated with temperate eastward flows of the ACC north of the Subantarctic Front. During the early Pliocene, the warm Zeehan Current (aka Leeuwin Current) replaced the ACC as the dominant easterly flowing current across Bass Strait, and this 4.4 Ma palaeoceanographical event correlates with the temporary, but widespread disappearance of T. lochardi from southeast Australian marine waters. However, the presence of refugia populations of T. lochardi along the east Australian continental shelf between 4.4 and 3.4 Ma, likely enabled the brief re-establishment of T. lochardi in the east of Bass Strait during the late Pliocene (3.2–3.0 Ma). Tasmanocypris lochardi became permanently extinct in this region during the latest Pliocene to early Pleistocene (< 2.6 Ma), broadly correlating with the onset of the global Quaternary glaciation, and inception of the cold Bass Cascade winter current within Bass Strait. • Miocene influence of Antarctic Circumpolar Current in Bass Strait, SE Australia. • Taxonomic clarification of the ostracod genus Tasmanocypris. • Rafting of shallow marine ostracods via the Antarctic Circumpolar Current. • Ostracods as proxies for mapping changes in surface ocean currents through time. [ABSTRACT FROM AUTHOR]

• Upper Paleozoic glacial conglomerates in the Lhasa Terrane contain tonalitic clasts. • Isotopic and geochemical data indicate an Australian provenance for these clasts. • The Lhasa Terrane was close to Australia during the Paleozoic. Paleogeographic reconstructions of the Lhasa Terrane of the southern Tibetan Plateau are uncertain in Paleozoic, and investigating the paleogeographic location of the terrane via the current geographical configuration is difficult. However, gravels contained within glacial sediments offer an opportunity to solve this problem. The Lagar Formation in the central Lhasa sub–Terrane contains glacial–marine deposits that incorporate gravel clasts composed of granitoids, sandstone, quartzite, limestone, and rhyolite. These diamictites were derived from continental glaciation and were deposited mainly near a grounding line or ice front in littoral–neritic to neritic environments. We present new zircon U–Pb isotopic and whole-rock geochemical data for the tonalitic conglomerates of the Lagar Formation. The results indicate that the tonalites crystallized during the Paleoproterozoic (~1.76 Ga) and show a geochemical affinity with I-type granite. The tonalites typically have negative Eu anomalies (δEu = 0.31–0.37), high concentrations of rare-earth elements, depletion in high-field-strength elements, enrichment in Th, marked positive zircon ε Hf (t) values (6.46–14.68), ε Nd (t) values of −1.24 to +1.76, and T DM 2 ages of 2.37–2.13 Ga. All of these data indicate that the tonalites were produced by the partial melting of modified mafic crust or underplate in a subduction-related environment. On the basis of a comprehensive analysis of all 1.8–1.7 Ga magmatism in east Gondwana, we propose that the most likely provenance of the tonalitic conglomerates is southern Arunta and Mt. Isa in northern Australia. Therefore, the central Lhasa sub–Terrane may have been located near Australia during the Paleozoic. [ABSTRACT FROM AUTHOR]

Marine Isotope Stage 2 (MIS 2) is the latest glacial period and includes the Last Glacial Maximum, which is known as the period when global ice volume reached its maximum and global temperature lower than today. An advantage of MIS 2 is the availability of radiocarbon dating to make it possible to compare sea-level data with other paleoclimatic proxies. However, the number and accuracy of sea-level records during MIS 2 is currently lacking. Here we present the history of MIS 2 sea-level and ice-sheet change as recorded in the Bonaparte Gulf, northwestern Australia, by reconstructing relative sea level and then modeling glacial isostatic adjustment. The isostatically-corrected global sea-level history indicates that sea-level plateaued around 23 cal kyr BP prior reaching its minimum (~19 cal kyr BP). These large changes in ice volume over such a short time indicates that the continental ice sheets never reached their isostatic equilibrium during the Last Glacial Maximum. [ABSTRACT FROM AUTHOR]