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In this paper, a previously undescribed rock art style consisting of large human figures and animals with stroke-line infill is introduced. These depictions have been named Maliwawa Figures. They are primarily found in northwest Arnhem Land and to date have been recorded at 87 sites from Awunbarna (Mount Borradaile area) to the Namunidjbuk clan state of the Wellington Range. There are solitary figures and others arranged in compositions or scenes. We describe the features of this style, its distribution, subject matter and probable age. The results of a detailed analysis of all sites are discussed and a new, refined Arnhem Land rock art chronology is presented. It is concluded that Maliwawa Figures are most likely to date between 6,000 to 9,400 years of age and to be contemporaneous with Northern Running Figures and Yam Figures found at sites to the south. [ABSTRACT FROM AUTHOR]

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Swamps in the seasonal tropics have good potential for the reconstruction of late Quaternary monsoonal dynamics. Their successful use, however, has often been compromised by chronological limitations introduced by a variety of depositional and post-depositional processes actively modifying the swamp deposits. We here present and discuss the results of a multiple dating approach at Table Top Swamp (TTS) in northern Australia (the ‘Top End’). Single-grain luminescence dating of quartz was successfully used to provide chronology in the lowermost core where insufficient organic material prevents the application of radiocarbon dating. In the uppermost, fine-grained and peaty section of the core, two different organic fractions (pollen concentrate and humins) were dated with AMS radiocarbon yielding significantly different chronologies. While this could point to the incorporation of younger pollen into the profile along seasonal dry cracks, older humins may also move up in the profile due to vertical mixing. Additional, spatially highly resolved measurements of the bulk OSL signal (Ln and Ln/Tn) combined with data on down-core variation in K, Th, and U concentration, grain size and moisture content were used to (i) guide the development of an age-depth relationship (i.e. age model) for the entire core based on three different data input scenarios, and (ii) test the applicability of novel luminescence screening techniques in seasonal swamp settings. Results suggest only minor differences among the applied models and scenarios, providing an overall reliable representation of the depositional history in the swamp. Even though all resulting age-depth models have relatively large uncertainties in the lower part of the core, there are significant changes in sedimentation rate over time, providing a chronological basis for a more detailed palaeoenvironmental analysis at TTS. The approach used may also be useful in developing age models in other complex environments, and has shown the importance of understanding carbon pathways as well as controls on luminescence signals when developing age models. [ABSTRACT FROM AUTHOR]

Understanding discontinuities in the Australian archaeological record currently represents a major challenge for researchers especially where different interpretive frameworks are used to explain the same phenomena. The widespread Last Glacial Maximum (LGM) absence of dated archaeological evidence in desert lowlands is often interpreted as a lack of human occupation. While this scenario may be true in many cases, we believe this inference requires critical re-appraisal. Using case studies from the coastal Carnarvon bioregion, located in a maritime desert of NW Australia, we argue that discontinuities and occupational lacunae may be the result of a variety of different geomorphic and human behavioural processes where the absence of people may be only part of the equation. We argue that, by reconceptualising discontinuities with an explicit multi-scalar focus on depositional regimes and landscape patterns, richer explanations about human occupational patterning at both the local and regional levels can be generated. [ABSTRACT FROM AUTHOR]

Quaternary and late Neogene volcanism is widespread in northeastern Australia, producing at least 397 eruptions covering more than 20,000 km 2 , including at least 20 flows over 50 km long. Despite this abundance of young volcanism, before this study numerous eruptions had tentative ages or were undated, and the area requires a comprehensive evaluation of eruption patterns through time. To help address these issues we applied multi-collector ARGUS-V 40 Ar/ 39 Ar geochronology to determine the age of four of the younger extensive flows: Undara (160 km long, 189 ± 4/4 ka; 2σ, with full analytical/external uncertainties), Murronga (40 km long, 153 ± 5/5 ka), Toomba (120 km long, 21 ± 3/3 ka), and Kinrara (55 km long, 7 ± 2/2 ka). Verbal traditions of the Gugu Badhun Aboriginal people contain features that may potentially describe the eruption of Kinrara. If the traditions do record this eruption, they would have been passed down for 230 ± 70 generations – a period of time exceeding the earliest written historical records. To further examine north Queensland volcanism through time we compiled a database of 337 ages, including 179 previously unpublished K-Ar and radiocarbon results. The compiled ages demonstrate that volcanic activity has occurred without major time breaks since at least 9 Ma. The greatest frequency of eruptions occurred in the last 2 Ma, with an average recurrence interval of <10–22 ka between eruptions. Activity was at times likely more frequent than these calculations indicate, as the geochronologic dataset is incomplete, with undated eruptions, and intraplate volcanism is often episodic. The duration, frequency, and youthfulness of activity indicate that north Queensland volcanism should be considered as potentially still active, and there are now two confirmed areas of Holocene volcanism in eastern Australia – one at each end of the continent. More broadly, our data provides another example of 40 Ar/ 39 Ar geochronology applied to Holocene and latest Pleistocene mafic eruptions, further demonstrating that this method has the ability to examine eruptions and hazards at the youngest volcanoes on Earth. [ABSTRACT FROM AUTHOR]

Acacia dealbata Link, a leguminous tree native of Australia, has become a major problem due to its invasiveness throughout the world. However, little is known about its impact over time. In this study, we have explored the impact of A. dealbata on soil nutrients and on soil microbial community function and structure in 4 mixed invaded forest sites in NW Spain, in a chronosequence of invasion: (1) a minimum of 25 years; (2) an average of 15 years; (3) an average of 7 years and (4) less than 3 years. pH significantly diminished over time as organic matter increased. Soil nutrients were progressively altered under A. dealbata; total C, N and P invariably increased as different periods of invasion time also increased, whilst Ca2+, K+ and Mg2+ contents showed irregular trends during the different periods of invasion. In addition, soil enzymatic activities of acid phosphatase, β-glucosidase, urease and N-acetyl glucosaminidase increased significantly, and soil basal respiration enhanced over the sequence of the invasion. DGGE analyses suggested variations in the structure of microbial and fungal communities over the whole assessed period due to A. dealbata presence. This is the first time that chronological sequences have been included to investigate the impact of A. dealbata invasion. Our results show that the initial dominance of A. dealbata and its negative impact on soil and microbial parameters cannot be recovered even long periods after the invasion. [ABSTRACT FROM AUTHOR]

Abstract: The New England Orogen in eastern Australia developed as a subduction-related orogen in the Late Devonian to Carboniferous, and was modified in the Permian by deformation, magmatism and oroclinal bending. The geodynamics associated with the development of the New England oroclines and the exact timing of major tectonic events is still enigmatic. Here we present new 40Ar/39Ar results from metasedimentary and volcanic rocks from the southern New England Orogen. Eight grains from four metasedimentary samples (Texas beds) that originated in the Late Devonian to Carboniferous accretionary wedge yielded reproducible plateau ages of ~293, ~280, ~270 and ~260Ma. These results suggest a complex thermal history associated with multiple thermal events, possibly due to the proximity to Permian intrusions. Two samples from mafic volcanic rocks in the southernmost New England Orogen (Alum Mountain Volcanics and Werrie Basalt) yielded eruption ages of 271.8±1.8and 266.4±3.0Ma. The origin of these rocks was previously attributed to slab breakoff, following a period of widespread extension in the early Permian. We suggest that this phase of volcanism marked the transition from backarc extension assisted by trench retreat to overriding-plate contraction. The main phase of oroclinal bending has likely occurred during backarc extension in the early Permian, and terminated at 271–266Ma with the processes of slab segmentation and breakoff. [Copyright &y& Elsevier]

Mangrove trees tend to be larger and mangrove communities more diverse in tropical latitudes, particularly where there is high rainfall. Variation in the structure, growth and productivity of mangrove forests over climatic gradients suggests they are sensitive to variations in climate, but evidence of changes in the structure and growth of mangrove trees in response to climatic variation is scarce. Bomb-pulse radiocarbon dating provides accurate dates of recent wood formation and tree age of tropical and subtropical tree species. Here, we used radiocarbon techniques combined with X-ray densitometry to develop a wood density chronology for the mangrove Avicennia marina in the Exmouth Gulf, Western Australia (WA). We tested whether wood density chronologies of A. marina were sensitive to variation in the Pacific Decadal Oscillation Index, which reflects temperature fluctuations in the Pacific Ocean and is linked to the instrumental rainfall record in north WA. We also determined growth rates in mangrove trees from the Exmouth Gulf, WA. We found that seaward fringing A. marina trees (∼10 cm diameter) were 48±1 to 89±23 years old (mean ± 1σ) and that their growth rates ranged from 4.08±2.36 to 5.30±3.33 mm/yr (mean ±1σ). The wood density of our studied mangrove trees decreased with increases in the Pacific Decadal Oscillation Index. Future predicted drying of the region will likely lead to further reductions in wood density and their associated growth rates in mangrove forests in the region. [ABSTRACT FROM AUTHOR]

Abstract: By the time Europeans arrived on Australian shores several hundred years ago, the lifestyle of Aboriginal populations across the continent varied from region to region: they spoke many different languages, their social organization differed from one region to another, they partook of varied cultural practices, and they produced material culture which took diverse forms in different places. Taking rock art as an example of this diversity, this paper will describe the chronology and form of late-Holocene rock art from five major painted art provinces and discuss the arguments researchers have proposed for the relatively recent emergence of new regional art styles. Implicated are demographic change, environmental change including rising sea levels, increased social complexity, the introduction of a totemic belief system, territorial change, or the migration of people from outside Australia. Two detailed rock art studies, one from northwest Queensland and one from central Australia will be presented to provide insight into why new art styles were produced. Explanations for the emergence of new distinct rock art styles that differed from previous assemblages within these areas are predicated on an understanding of stylistic behaviour and the circumstances under which groups are likely to feel the need to differentiate themselves from their neighbours. Findings indicate that, rather than a single cause, multiple factors are likely to have played a role in the emergence of new regionally distinct rock art styles. [Copyright &y& Elsevier]

Abstract: Cave deposits of infill sediments and associated vertebrate fossils provide a valuable source of information on terrestrial palaeoenvironments, climatic conditions and palaeocommunities. In the deposits of the Naracoorte Caves World Heritage Area, such records span the last 500 ka and are renowned for their rich, diverse vertebrate assemblages. Previous research into the Grant Hall deposit of Victoria Fossil Cave suggested that it may preserve the only peak last interglacial (ca. 125 ka) faunal community within the World Heritage Area. The current work tested this existing model for the age of faunal remains from Grant Hall using multiple techniques. Physical and geochemical properties of the visually homogeneous sediments were analysed at regular intervals through the sequence to establish meaningful stratigraphic divisions and sediment provenance. Optically stimulated luminescence dating of individual quartz grains indicates that sediments accumulated in Grant Hall from 93 ± 8 to 70 ± 5 ka. Minimum ages provided by U/Th dating of fossil teeth (72.3 ± 2.2 to 38.2 ± 0.8 ka) are consistent with the luminescence chronology, and show that the deposit represents a more recent faunal accumulation than previously modelled for the site. U/Th ages on calcite straws within the deposit are significantly older than the sediments and fossil teeth (>500 to 186.4 ± 1 ka). As such they provide no further constraint on the chronology of the deposit but do indicate that speleothem deposition was active over much of the Middle Pleistocene. Sedimentary analyses resulted in the identification of five depositional units, contrasting with previous divisions which were based only on visual observation of the sedimentary sequence. Sediments within each unit are broadly classified as sandy silts with soil structures and may be indirectly derived from the lunettes of nearby Bool Lagoon, although their ultimate provenance is unknown. As a result of this work, palaeoenvironmental reconstruction based on fossil remains in the deposit may be more accurately related to prevailing climatic and environmental conditions at the time of accumulation. It also contributes to an understanding of the temporal occurrence of regional vertebrate faunas through the Late Pleistocene, reinforcing the value of developing stratigraphically constrained chronologies for cave deposits based on multiple techniques. [Copyright &y& Elsevier]

Abstract: We present a detailed description of the geological setting of the burial site of the WLH 50 human remains along with attempts to constrain the age of this important human fossil. Freshwater shells collected at the surface of Unit 3, which is most closely associated with the human remains, and a carbonate sample that encrusted the human bone were analysed. Gamma spectrometry was carried out on the WLH 50 calvaria and TIMS U-series analysis on a small post-cranial bone fragment. OSL dating was applied to a sample from Unit 3 at a level from which the WLH 50 remains may have eroded, as well as from the underlying sediments. Considering the geochemistry of the samples analysed, as well as the possibility of reworking or burial from younger layers, the age of the WLH 50 remains lies between 12.2 ± 1.8 and 32.8 ± 4.6 ka (2-σ errors). [Copyright &y& Elsevier]

Abstract: Lynch''s Crater on the Atherton Tablelands in NE-Australia formed about 230,000 years ago during an explosive eruption, creating a maar more than 80m deep. Since the eruption, the maar has been filled with lake sediments that are topped by peat material. A 64m long core was recovered and an OSL dating project was undertaken to extend the chronology beyond 16m depth, which according to 14C age control represents ∼60ka. The predominantly organic lake sediments contained abundant fine quartz of aeolian origin, and the Single Aliquot Regenerative Method (SAR) provided satisfactory equivalent dose (DE) estimates. However, the determination of the dose rate proved both critical and difficult. Extremely low radionuclide contents led to cosmic radiation being the dominant dose rate contribution for most samples. The OSL chronology presented in this paper thus relies on modelling the changing cover by sediments and lake water over the burial time. [Copyright &y& Elsevier]

Terrace remnants on Widden Brook, southeastern Australia, were examined and correlated longitudinally to establish their evolutionary history. Three discontinuous terrace sequences, the Baramul, Widden and Kewarra, were identified in a 26 km reach using sedimentology, topography and chronology. Each terrace sequence occurred within a geomorphically distinct valley setting: an upstream constriction, a valley expansion and a highly constricted downstream section. Radiocarbon and optically stimulated luminescence ages indicated that each terrace sequence was formed during the Late Pleistocene and Holocene (16.7-0.5 ka cal BP). However, their sedimentology and topography were shown to differ significantly. We present evidence that both climate and the exceedance of intrinsic geomorphic thresholds were major contributing factors responsible for the formation of these terrace sequences. [ABSTRACT FROM AUTHOR]

Abstract: This paper explores the palaeoclimatic significance of a fossil plant and insect record from Yarra Creek, on King Island, between Tasmania and the Australian mainland. The record dates, based upon a thermoluminescence chronology and other evidence, to Marine Isotope Stage 5 (MIS 5); the exact timing is impossible to ascertain given the resolution of the thermoluminescence results and the presence of an unconformity in the dated section. The presence of a cool-temperate rainforest flora, outside its modern range, and other independent evidence, suggest the sequence may represent the last interglacial (MIS 5e) rather than a later MIS 5 substage. Using coexistence methods that compare modern climatic ranges of the taxa in the assemblage we reconstruct independent beetle and plant based annual and seasonal temperate and precipitation parameters. The results imply the assemblage was deposited under a wetter summer climate and suggest conditions of enhanced temperature seasonality. It is probable that enhanced temperature seasonality is a methodological artefact reflecting the rarity of extremely equable climates (like King Island) in modern climate space. This would indicate a limitation of most methods of palaeoclimatic reconstruction that rely on modern datasets – it is only possible to reconstruct past climates as being within the range of values in that currently exist in modern climate space. [Copyright &y& Elsevier]

Abstract: Raman spectroscopy and FT-IR imaging analyses of cave wall pigment samples from north Queensland (Australia) indicate that some hand stencils were undertaken during a dry environmental phase indicating late Holocene age. Other, earlier painting episodes also took place during dry environmental periods of the terminal Pleistocene and/or early Holocene. These results represent a rare opportunity to attain chronological information for rock art in conditions where insufficient carbon is present for radiocarbon dating. [Copyright &y& Elsevier]

Data collected from the Hamersley Plateau over the last four decades are examined for patterns in the archaeological record. Data relating to the timing of the archaeological appearance of backed artefacts, seed-grinding technology and rock art are currently too few to indicate major cultural changes with certainty. Increases in numbers of radiocarbon dates from archaeological sites on the Hamersley Plateau are evident in the late Holocene. This can be interpreted as a pattern of cultural change or natural decay in datable material. 1 conclude that taphonomic bias is the most important variable in the distribution of the radiocarbon date sample from the Hamersley Plateau. That said, further accumulation of dales and data may show archaeological changes in the Hamersley Plateau that represent local expressions of broader trends in the Australian semi-arid and arid zones. [ABSTRACT FROM AUTHOR]

This paper is an update of Abbott, I (2002) Origin and spread of the cat, Felis catus, on mainland Australia, with a discussion of the magnitude of its early impact on native fauna. Wildlife Research 29, 51--74. An additional 33 journals of expeditions of exploration or excursions beyond settled areas before 1895 were located, and as expected from the current conceptual model, none of these recorded cats. These accounts of travel through country as yet unsettled or sparsely settled by Europeans necessitate only one small modification (relating to north-east Queensland) to the conceptual model presented previously. In addition, nearly 150 new records of cats were located in other parts of Australia, and all are consistent with the chronology of spread hypothesized in the previous paper. For Tasmania, following their introduction in 1804, cats were first recorded there as feral in the 1840s. Incidental records were found indicating that in parts of Australia the spread of the cat was assisted by their release in regions experiencing their first outbreaks of rabbits, by flood-linked irruptions of the long-haired rat (Rattus villosissimus), and by their release to control rodents destroying sugar cane plantations in northern Queensland. Feral cats of large size were first detected in various regions of Australia some 10--30 years after local settlement. [ABSTRACT FROM AUTHOR]

Abstract: Foliation Intersection/Inflection Axes within porphyroblasts (FIAs) allow the chronological and kinematic linking of deformation episodes with associated metamorphism. Measurement of FIAs in the Mesoproterozoic Eastern Fold Belt (EFB) of the Mount Isa Inlier, NE Australia, has revealed phases of deformation and metamorphism that could not previously be distinguished from one another. Both the ‘asymmetry switch’ and ‘FitPitch’ FIA measurement techniques have been applied to key localities of polymetamorphosed and multiply deformed EFB, and they yielded the same result. These independent techniques have revealed (1) E–W trending structures that formed during N–S bulk shortening (D1) and associated metamorphism (M1) formed during a period of orogenesis (O1) and N–S oriented structures that formed during E–W bulk shortening (D2) and associated metamorphism (M2) during a period of orogenesis (O2), and (2) the crustal scale tectonic processes associated with polymetamorphism. Middle to upper amphibolite facies metamorphic conditions occurred during O1 with crustal thickening followed by near-isothermal decompression leading to low-pressure/high-temperature (LP/HT) conditions with the emplacement of Williams and Naraku Batholiths around 1550 Ma. This was followed by a second period of middle-to upper-amphibolite facies metamorphism, O2. This history not only correlates better across the EFB, but also with the tectono-metamorphic model recently proposed for the Mesoproterozoic Georgetown Inlier of the north Australian Craton. [Copyright &y& Elsevier]

Presents events related to feminism from 1973 to 1979 including the National "Women's Liberation and Theory" Conference, Children's Craft Day at Women's Liberation House, and the Spring Festival of Women's Creativity.

Presents a chronology of events which led to the development of women's liberation in Australia. In the earlier part of 1970, Women's Liberation has issued postcards to be signed and sent to the federal government on issues related to tax deductions for childcare and the removal of 27 1/2% luxury sales tax on contraceptive pill, among others. On January 14, 1970, the Sydney Women's Liberation held its inaugural public meeting. Moreover, during that year, several women's groups held various public meetings.

Abstract: The presence of xenon isotopes from in-situ spontaneous fission of short-lived 244Pu has been confirmed in a suite of 16 Hadean detrital zircons from Western Australia. In order to investigate the effects of xenon loss on estimates of the inferred Pu/U ratio we have irradiated the zircons with thermal neutrons to generate Xe from 235U neutron fission. 131Xe/134Xe and 132Xe/134Xe ratios have been used to calculate the relative contributions from spontaneous fission of 244Pu and 238U and neutron fission of 235U and hence compare nominal Pu/U ratios and xenon retention ages. U–Xe ages are typically lower than the Pb–Pb ages, indicating that xenon loss is common. We show how the ternary mixing diagram can be used to place constraints on the timing and extent of this loss and to generate a corresponding Pu–U–Xe isochron. Although the zircons investigated in this study were extracted from the same metasedimentary unit, the timing of xenon loss is variable. This suggests that the loss may be the result of variable degrees of metamictization from grain to grain. Inferred (Pu/U)o ratios show a general decrease with the discordancy between Pb–Pb and U–Xe ages. For the least discordant samples we infer (Pu/U)o ∼0.008 which is close to the widely adopted chondritic value. While we cannot completely exclude the effects of Pu/U fractionation in magmatic and other processes between formation of the Earth and crystallisation of the zircons we conclude that they have been relatively small (

This paper reports new dates for mid to late Holocene occupation of the lower Adelaide River in northern Australia. Earth mounds located on the margins of the floodplains provide a series of radiocarbon determinations that suggest continuous settlement from at least 4000 years BP until recently. During that time the floodplains have undergone a dramatic environmental evolution from extensive mangrove swamps in the mid Holocene, through a variable mosaic of estuarine and freshwater conditions c.3000 years ago, to the freshwater floodplains extant since 2000 BP. These results have implications for the chronology of earth mounds elsewhere in northern Australia. [ABSTRACT FROM AUTHOR]

The International Union of Geological Sciences has approved a new addition to the geologic time scale: the Ediacaran Period. The Ediacaran is the first Proterozoic period to be recognized on the basis of chronostratigraphic criteria and the first internationally ratified, chronostratigraphically defined period of any age to be introduced in more than a century. In accordance with procedures established by the International Commission on Stratigraphy, the base of the Ediacaran Period is defined by a Global Stratotype Section and Point (GSSP) placed at the base of the Nuccaleena Formation cap carbonate directly above glacial diamictites and associated facies at Enorama Creek in the Flinders Ranges of South Australia. Its top is defined by the initial GSSP of the Cambrian Period. The new Ediacaran Period encompasses a distinctive interval of Earth history that is bounded both above and below by equally distinctive intervals. Both chemostratigraphic and biostratigraphic data indicate that the subdivision of the period into two or more series is feasible, and this should be a primary objective of continuing work by the Ediacaran Subcommission of the ICS. [ABSTRACT FROM AUTHOR]

Recent aerial photographs prove that stone structures in Lake Richmond, near Perth Western Australia, are modern structures and are not tidal weirs of Aboriginal origin. This evidence is contrary to the views expressed in a recent assessment of the chronology and development of Aboriginal fishing in south-western Australia. [ABSTRACT FROM AUTHOR]

Little Llangothlin Lagoon on the New England Tablelands of northeast New South Wales possesses the most detailed and best verified 210Pb chronology yet available in Australia. Recent criticisms of the length of the record are shown to be based on a faulty understanding of the principles of 210Pb dating. Attempts to revise the chronology of the lower part of the dated sequence by several decades must be rejected given that (a) fundamentally dissimilar chronological models yield ages that are statistically indistinguishable and (b) the most extreme manipulation of the modelling data fails to alter the basal dates in the profile by more than three years. The most telling criticism of the revisionist view, however, comes from the exact concordance between the dates from the basal part of the sequence, the historical date of official European contact and the massive changes in palynology, geochemistry and soil erosion resulting from that contact. The thesis that environmental disturbance immediately prior to the time of official European contact in Australia was the result of human activity is supported by a wealth of documentary evidence revealing the illegal or unsanctioned presence of Europeans throughout much of southern and eastern Australia years before official records began. Likewise, it is clear that many elements of the pre-contact Australian environment, including certain of its soils, were fragile and susceptible to rapid and dramatic disturbance under the impact of European land use. Finally, there is convincing evidence of stable chemical and mineralogical conditions in several southeast Australian lakes throughout the last millennium or more, conditions that were altered catastrophically with the arrival of the first Europeans and their stock. [ABSTRACT FROM AUTHOR]

Gale and Haworth (2002) suggest that European-induced soil erosion increases occurred before official settlement near Guyra on the New England Tableland (NSW). Their analysis assumes that the derived 210Pb chronology from Little Llangothlin Lagoon is precisely accurate and that the lake geochemistry record exhibits marked changes below sediment levels purported to date to 1837. A parsimonious interpretation of presented historical and pollen data indicates that substantial changes in the vegetation, argued to occur before official occupation, are merely the environmental imprint of the first (official) European settlers. In this context, the use of the pollen record to validate the 210Pb chronology and the lower part of the chronology itself is misleading. Gale and Haworth's (2002) interpretation of the geochemical record, though not as reliant on accurate dating, is nevertheless unsatisfactory since alterations identified as substantial are, variously, a continuation of long term trends, only minor in nature or within long-term... [ABSTRACT FROM AUTHOR]

Cook (2019) reviewed the timing and impact of European settlement in Australia, focusing on erosion and catchment soil loss. Cook (2019) argued that it is still reasonable to conclude that European settlers caused major environmental impacts outside the limits imposed on the colony before 1840 CE. Evidence for early, major impact by European settlers came from the first 210Pb dated sediment cores from Little Llangothlin Lagoon in eastern Australia (Gale et al., 1995, Gale and Haworth, 2002, 2005). An early (ca. 1810 CE) age was derived from these records based on assumptions regarding the 210Pb age model. The 210Pb age model was validated with a pollen record and a European impact "eroded soil" horizon. Since the work by Gale et al. (1995) and Gale and Haworth (2002, 2005), there have been five studies that show the pollen record and "eroded soil" horizon cannot be used as validation for the 210Pb record. The pollen record included a major misidentification and the "eroded soil" is actually ca. 9000 year old peat. Cook (2019) focused on only one of the five studies; a study that used a core away from the Gale et al. (1995) master core site. However, all of the other studies include cores that are effectively replicates of the original Gale et al. (1995) cores. Collectively the evidence shows that the early impact theory is no longer tenable and cannot be reasonably defended. • Cook (2019) reviewed the timing and impact of European settlement in Australia. • He argued that there is evidence for early impacts by illegal European settlers. • Little Llangothlin Lagoon was the only well dated record of early European impacts. • I identify major flaws in the interpretation of the Little Llangothlin Lagoon record. • The early impact theory is no longer tenable and cannot be reasonably defended. [ABSTRACT FROM AUTHOR]

Ever since parthenium weed (Parthenium hysterophorus L.) first left its native range more than two centuries ago, this noxious herb has now invaded 46 countries and territories. The weed has expanded its range from a couple of islands in 18th Century through 11 minor and eight major introductions around the world. Segmented regression analyses confirmed introductions and revealed that the weed has spread fastest in developing countries, especially after the 1950s in Asia and Africa. A review of historical records, research papers and reports suggests that while border traffic (36%) and unchecked imports (seeds 16%, other commodities 17%) have resulted in the majority of international introductions, local spread has been achieved through multiple pathways, including roads and vehicles, by water and wind, through contaminated seed feed lots and floral bouquets. The high proportion of adjacent counties (51%) and oversea islands (5%) over the unknown origins (32%) or directly from the native range (12%) reveal a steady and predictable international spread pattern. Prevention of spread by management was first practised in Australia, then followed by other five countries. Containment barriers were set up, legislation on biosecurity imposed, and management plans based on early detection and eradication were executed; and these measures have been effective. Awareness within international research groups is raising, however, insufficient coordination between invaded countries has occurred to date, with policies yet to be formalised and executed to prevent the spread and impact of this weed., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The article focuses on the study conducted by C. S. M. Turney and colleagues on the chronologies of megafaunal extinction and human arrival in Tasmania, Australia. It states that the authors reevaluated museum specimens of fossils from four formerly reported sites, and from an excavated at Mount Cripps in the northwest of the island, where three specimens of the giant kangaroo "Protemnodon anak" was discovered. It discusses that this discovery supports two conclusions. First is that megafauna survived later in Tasmania than on the Australian mainland. The second conclusion proposes that in Tasmania, the megafauna overlapped in time with humans as shown by undated human cultural artifacts lying below the level of the carbon-14-dated human horizon.

Published ages of >50 ka for occupation at Madjedbebe (Malakunanja II) in Australia's north have kept the site prominent in discussions about the colonisation of Sahul. The site also contains one of the largest stone artefact assemblages in Sahul for this early period. However, the stone artefacts and other important archaeological components of the site have never been described in detail, leading to persistent doubts about its stratigraphic integrity. We report on our analysis of the stone artefacts and faunal and other materials recovered during the 1989 excavations, as well as the stratigraphy and depositional history recorded by the original excavators. We demonstrate that the technology and raw materials of the early assemblage are distinctive from those in the overlying layers. Silcrete and quartzite artefacts are common in the early assemblage, which also includes edge-ground axe fragments and ground haematite. The lower flaked stone assemblage is distinctive, comprising a mix of long convergent flakes, some radial flakes with faceted platforms, and many small thin silcrete flakes that we interpret as thinning flakes. Residue and use-wear analysis indicate occasional grinding of haematite and woodworking, as well as frequent abrading of platform edges on thinning flakes. We conclude that previous claims of extensive displacement of artefacts and post-depositional disturbance may have been overstated. The stone artefacts and stratigraphic details support previous claims for human occupation 50-60 ka and show that human occupation during this time differed from later periods. We discuss the implications of these new data for understanding the first human colonisation of Sahul., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

In-situ electron-microprobe dating of monazite holds the promise of being an effective technique for obtaining chronologic data. Our research focuses on I- and S-type granitoids of the Lachlan Fold Belt, Australia, whose petrology and zircon chronology have been thoroughly characterized. This study documents the textural relationships, morphology, zoning, and ages of monazite in these granitoid rocks. The I-type granitoids that lack monazite usually contain other mineral phases enriched in rare earth elements, such as allanite, titanite, and bastnasite. Only silica-rich, highly evolved I-type granitoids contain monazite. This preference in I-type rocks for phases other than monazite to host the REE and Th limit the applicability of monazite dating for this group of igneous rocks. On the other hand, monazite is ubiquitous in S-type rocks, both as interstitial and included grains. High-resolution X-ray maps of individual monazites reveal complex patterns of chemical zoning. Weighted averages of multiple analyses for individual chemical domains show small but systematic differences in age. These weighted averages of the chemical domains are considered the best estimate of the age of the monazite. Monazites from 8 different S-type samples range in age from 405 to 759 Ma, with the majority being 490 Ma and older. These are premagmatic ages for these granitoids, which have crystallization ages of 400 to 430 Ma. These premagmatic ages are similar to Cambro-Ordovician ages obtained from inherited zircon cores in the same granitoids, indicating that monazite can survive anatexis in peraluminous rocks. Thus, monazite dating in peraluminous rocks may illuminate characteristics (composition and age) of source rocks and anatectic processes. [ABSTRACT FROM AUTHOR]