Department of State Development

• Volcano-sedimentary moraine in East Antarctica unveils the burial history of a late Mesoproterozoic subglacial basin. • Coupled detrital and authigenic geochronology bridges deep crustal and near-surface processes. • Rifting in the upper crust was coupled with mid-lower-crustal ductile flow, all linked to post-orogenic collapse. • Sensitive low-temperature chronometers show no evidence for Cambrian reworking by the Indo–Australo–Antarctic suture. Geochronological data from detrital zircon, two generations of titanite, and authigenic sericite in glacial erratics transported to the Bunger Hills provide new insights into a deep subglacial basin in East Antarctica. Basin formation occurred during the late Mesoproterozoic, with diagenesis coinciding with granulite facies metamorphism in the underlying basement rocks. In line with previous studies, we interpret this basin to have formed as a rift sequence, but we extend this model by proposing that rifting was directly associated with Mesoproterozoic orogenesis, and that upper crustal extension was coupled with mid–lower-crustal ductile flow. The basin detritus was primarily sourced from a felsic magmatic-rich carapace emplaced at ca. 1180–1160 Ma. The authigenic mineralogy of the erratics, supported by chlorite thermometry and authigenic titanite geochronology, suggests that within the ensuing ca. 50–70 million years, the detritus was buried deeply and subjected to low-grade metamorphism (∼300 °C). Sericite ages complement the zircon and titanite dataset and reveal that the basin was largely unaffected by Cambrian tectonism, meaning that it was situated in thermomechanically stable crust and geographically distant to the major Gondwanan Indo–Australo–Antarctic suture. This study demonstrates the utility of coupled authigenic and detrital mineral geochronology in constraining sedimentary basin formation ages, and linking deep-crustal and near-surface processes.

Geochemical data are frequently collected from mineral exploration drill-hole samples to more accurately define and characterise the geological units intersected by the drill hole. However, large multi-element data sets are slow and challenging to interpret without using some form of automated analysis, such as mathematical, statistical or machine learning techniques. Automated analysis techniques also have the advantage in that they are repeatable and can provide consistent results, even for very large data sets. In this paper, an automated litho-geochemical interpretation workflow is demonstrated, which includes data exploration and data preparation using appropriate compositional data-analysis techniques. Multiscale analysis using a modified wavelet tessellation has been applied to the data to provide coherent geological domains. Unsupervised machine learning (clustering) has been used to provide a first-pass classification. The results are compared with the detailed geologist’s logs. The comparison shows how the integration of automated analysis of geochemical data can be used to enhance traditional geological logging and demonstrates the identification of new geological units from the automated litho-geochemical logging that were not apparent from visual logging but are geochemically distinct. KEY POINTS To reduce computational complexity and facilitate interpretation, a subset of geochemical elements is selected, and then a centred log-ratio transform is applied. The wavelet tessellation method is used to domain the drill holes into rock units at a range of scales. Several clustering methods were tested to identify distinct rock units in the samples and multiscale domains for classification. Results are compared with geologist’s logs to assess how geochemical data analysis can inform and improve traditional geology logs.

We present results of 334 ultra-wide band MT stations across an area of 100 km × 100 km in the prospective eastern Gawler Craton. The survey area is situated ~100 km south of the supergiant Olympic...

Global temperatures are rising; extreme environmental heat can result in adverse health effects including heatstroke. Acute effects of heat are well recognised, but there is less understanding of potential long-term adverse outcomes. Our aim was to review recent medical literature for clinical cases of environmental heatstroke with a focus on neurological outcome. Structured search strategies were designed to retrieve publications of heatstroke case reports using Ovid Medline and Embase (2000-2016). One thousand and forty-nine abstracts were identified, and after application of exclusion criteria 71 articles deemed relevant. Ninety cases were identified from 71 articles. 100% presented with acute neurological symptoms; 87.8% presented with non-neurological symptoms. 44.4% patients recovered fully, 23.3% died, 23.3% suffered convalescent or long-term neurological sequelae, and in 8.9% no long-term follow up was available. 57.1% of the patients who died or had a neurological deficit had no documented co-morbidity. Patterns of neurological deficits included 66.7% patients with motor dysfunction, 9.5% cognitive impairment, 19% both motor and cognitive impairment and 4.7% other. In total 71.4% of the impaired patients had long-term cerebellar dysfunction. Adverse long-term neurological outcomes were common in surviving patients presenting with environmental heatstroke. Permanent neurological deficits were present in 34.4% of survivors where outcome was known; many were young, healthy individuals. Cerebellar injury was common suggesting cerebellar structures are vulnerable to heat. These findings highlight that people of all ages and pre-morbid states are at risk of severe heat-related illness. In the face of climate change, effective interventions for heat-related illness, including both treatment and prevention are necessary.

Global temperatures are rising; exposure to environmental extremes of heat can result in a range of adverse health effects including heat stroke. Acute adverse effects of heat are well recognised, however, there is less understanding of potential long-term adverse outcomes. To review recent medical literature for clinical cases of environmental heat stroke with a focus on acute, convalescent and long-term neurological outcome. Electronic searches of Ovid Medline and Embase (2000–2016); search strategies structured to retrieve publications on effect of heat stroke on the nervous system. 537 articles identified with search strategies containing subject headings and keywords: heat, heat stroke, neurology, neurological disorders. 493 articles excluded (116 duplicates, 166 non-environmental heat stroke, 161 not relevant, 38 published prior to 2000, 12 unable to obtain); leaving 44 articles. Data extracted included: demographics, acute and convalescent neurological and non-neurological symptoms, treatment and long-term neurological outcome. Clinical patterns of neurological sequelae were identified and described. 60 cases (39 females, 21 males) were identified from 44 articles. The mean age was 49, range 12–87 years. 21 cases were reported from Asia, 14 USA, 14 Europe, 8 Middle East and 3 from Australia. All cases presented with acute neurological symptoms, as defined by the search strategy, 78.3% also presented with acute non-neurological symptoms. 22 (37%) patients fully recovered, 13 (21.7%) died, 19 (31.7%) suffered convalescent or long-term neurological sequelae and 6 (10%) no long-term follow up available. 19 (59.4%) of the patients who died or had a neurological deficit had no documented co-morbidity. Follow up period was 1–18 months. Pattern of neurological deficits included 10 (52.6%) patients with motor dysfunction, 2 (10.5%) cognitive impairment, 6 (31.6%) both motor and cognitive impairment and 1 (5.3%) other. In total, 12 (63.2%) patients had long-term cerebellar dysfunction. Treatment varied and predominantly involved external cooling. Adverse long-term neurological outcomes are common in patients presenting with environmental heat stroke that is complicated by acute neurological impairment. Permanent neurological deficits were present in 40% of survivors. Many of these were young, otherwise healthy individuals. Cerebellar injury was common suggesting cerebellar structures are more vulnerable to the effects of heat.

A geoprocessing methodology has been developed to capture potential field anomalies from residual gravity and reduced to pole total magnetic intensity (RTP TMI) datasets. Anomalies captured using this process are converted to GIS polygons and attributed with descriptive statistics of the underlying grids. The polygons are subsequently included as criteria in a GIS analysis to target IOCG-style deposits beneath extensive cover in the Eastern Gawler Craton. The application of gravity anomaly polygons within this study was as potential trap sites, based on the assumption that a localised increase in density manifested as an anomalous gravity response may be associated with mineral accumulation. The characterisation of residual potential field anomalies for use in prospectivity modelling has resulted in the accurate identification of existing deposits of IOCG-style mineralisation and has suggested additional targets warranting further investigation.

The Cooper Basin is a late Carboniferous-Middle Triassic intracratonic sag basin in northeastern South Australia and southwestern Queensland. The basin is one of Australia’s premier onshore hydrocarbon producing provinces and, by providing domestic gas for the East Coast Gas Market, is nationally significant. This study reviews the distribution, quality and maturity of source rocks across the Cooper Basin and forms part of Geoscience Australia’s source rock program. All publicly-available total organic carbon (TOC) content and Rock-Eval pyrolysis data for the Cooper Basin were compiled into a single database, quality checked and compiled by well and formation to highlight the multiple viable source rock units throughout the Permian. The Toolachee and Patchawarra formations represent the principal source rocks in the basin. These comprise coals and carbonaceous shales deposited in fluvial deltaic and peat swamp environments and show good to very good oil and gas source potential. Additional source intervals include the gas prone lacustrine Roseneath and Murteree shales, as well as coals and carbonaceous shales of the Daralingie and Epsilon formations. Permian source rock distribution was investigated using lithofacies mapping combined with geochemistry data. Lithofacies maps published for South Australia were integrated with electrofacies data from Queensland to produce new, internally consistent, net source thickness maps for key intervals, including coals and carbonaceous shales of the Toolachee and Patchawarra formations, and the Roseneath and Murteree shales. Pyrolysis data that indicate the presence of an in-situ source rock with remaining hydrocarbon generation potential (i.e. TOC > 2% and S1+S2 > 3 mg hydrocarbons/g rock) were mapped by formation, demonstrating the broad extent of Permian source rocks across the basin. Toolachee and Patchawarra source rocks are present in most major depocentres, including the Windorah Trough and Ullenbury Depression in the northern part of the basin, where maximum coal thicknesses still reach more than 10 m. Source rocks within the Roseneath and Murteree shale are generally restricted to the southern Cooper Basin.

We present 1D anisotropic inversion of magnetotelluric (MT) data as a new and innovative tool for mapping structural permeability in sedimentary basins. Using 1D inversions of a 171 site, broadband MT data set from the Koroit region, Victoria, Australia, we have delineated an electrically anisotropic layer at approximately 2.5 to 3.5 km depth. The anisotropy strike is consistent between stations at approximately 160°. The depth of anisotropy corresponds to the top of the Early Cretaceous Crayfish Group, and the anisotropy factor increases from west to east. We interpret the north-northwest oriented anisotropy as being fluid-filled fractures resulting in enhanced electrical and hydraulic conductivity. This interpretation is consistent with both data from well formation tests and structure and stress field information from the surrounding region.