ORCID Profile
0000-0002-0611-2703
Current Organisations
Hospital Ruber Internacional
,
University of New South Wales
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Geochemistry | Isotope Geochemistry | Geology | Inorganic Geochemistry | Petroleum and Coal Geology | Palaeontology (incl. Palynology) | Ore Deposit Petrology | Organic Chemical Synthesis | Earth Sciences Not Elsewhere Classified | Manufacturing Engineering not elsewhere classified | Igneous and Metamorphic Petrology | Instruments And Techniques | Geochronology | Organic Geochemistry | Geodynamics | Inorganic Geochemistry Not Elsewhere Classified | Other Physical Sciences | Environmental Monitoring | Stratigraphy (incl. Biostratigraphy and Sequence Stratigraphy) | Geology not elsewhere classified | Tectonics
Expanding Knowledge in the Earth Sciences | Mineral Exploration not elsewhere classified | Cultural Understanding not elsewhere classified | Information Services not elsewhere classified | Earth sciences | Atmospheric composition | Environmentally Sustainable Mineral Resource Activities not elsewhere classified | Oil and Gas Exploration | Expanding Knowledge in the Environmental Sciences | Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Biological Sciences | Ceramics |
Publisher: Informa UK Limited
Date: 17-11-2014
Publisher: GeoScienceWorld
Date: 02-2010
DOI: 10.1130/L80.1
Publisher: Informa UK Limited
Date: 07-2012
Publisher: Springer Science and Business Media LLC
Date: 02-2008
DOI: 10.1038/NGEO116
Publisher: Elsevier BV
Date: 08-2006
Publisher: Wiley
Date: 10-2003
Publisher: Elsevier BV
Date: 10-2009
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 09-2015
Publisher: Elsevier BV
Date: 07-2011
Publisher: Springer Science and Business Media LLC
Date: 31-08-2016
DOI: 10.1038/NATURE19355
Abstract: Biological activity is a major factor in Earth's chemical cycles, including facilitating CO
Publisher: International Union of Crystallography (IUCr)
Date: 05-07-2018
DOI: 10.1107/S1600576718007343
Abstract: Crystallography has a long history of providing knowledge and methods for applications in other disciplines. The identification of minerals using X-ray diffraction is one of the most important contributions of crystallography to earth sciences. However, when the crystal itself has been dissolved, replaced or deeply modified during the geological history of the rocks, diffraction information is not available. Instead, the morphology of the crystal cast provides the only crystallographic information on the original mineral phase and the environment of crystal growth. This article reports an investigation of crystal pseudomorphs and crystal casts found in a carbonate-chert facies from the 3.48 Ga-old Dresser Formation (Pilbara Craton, Australia), considered to host some of the oldest remnants of life. A combination of X-ray microtomography, energy-dispersive X-ray spectroscopy and crystallographic methods has been used to reveal the original phases of these Archean pseudomorphs. It is found with a high degree of confidence that the original crystals forming in Archean times were hollow aragonite, the high-temperature polymorphs of calcium carbonate, rather than other possible alternatives such as gypsum (CaSO 4 ·2H 2 0) and nahcolite (NaHCO 3 ). The methodology used is described in detail.
Publisher: Elsevier BV
Date: 09-2016
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 07-2015
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 04-2020
Publisher: Elsevier BV
Date: 11-2019
Publisher: Elsevier
Date: 2019
Publisher: Elsevier BV
Date: 11-1993
Publisher: Elsevier BV
Date: 02-2020
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 02-2010
Publisher: Informa UK Limited
Date: 07-2010
Publisher: Elsevier BV
Date: 08-2008
Publisher: Schweizerbart
Date: 23-07-2008
Publisher: Elsevier
Date: 2007
Publisher: Geological Society of America
Date: 22-10-2014
DOI: 10.1130/B31025.1
Publisher: Elsevier BV
Date: 03-1998
Publisher: American Journal of Science (AJS)
Date: 12-2010
DOI: 10.2475/10.2010.01
Publisher: Informa UK Limited
Date: 08-2006
Publisher: Springer Science and Business Media LLC
Date: 09-05-2017
DOI: 10.1038/NCOMMS15263
Abstract: The ca. 3.48 Ga Dresser Formation, Pilbara Craton, Western Australia, is well known for hosting some of Earth’s earliest convincing evidence of life (stromatolites, fractionated sulfur/carbon isotopes, microfossils) within a dynamic, low-eruptive volcanic caldera affected by voluminous hydrothermal fluid circulation. However, missing from the caldera model were surface manifestations of the volcanic-hydrothermal system (hot springs, geysers) and their unequivocal link with life. Here we present new discoveries of hot spring deposits including geyserite, sinter terracettes and mineralized remnants of hot spring pools/vents, all of which preserve a suite of microbial biosignatures indicative of the earliest life on land. These include stromatolites, newly observed microbial palisade fabric and gas bubbles preserved in inferred mineralized, exopolymeric substance. These findings extend the known geological record of inhabited terrestrial hot springs on Earth by ∼3 billion years and offer an analogue in the search for potential fossil life in ancient Martian hot springs.
Publisher: Wiley
Date: 09-08-2018
DOI: 10.1111/GBI.12304
Abstract: Eighteen microfossil morphotypes from two distinct facies of black chert from a deep-water setting of the c. 2.4 Ga Turee Creek Group, Western Australia, are reported here. A primarily in situ, deep-water benthic community preserved in nodular black chert occurs as a tangled network of a variety of long filamentous microfossils, unicells of one size distribution and fine filamentous rosettes, together with relatively large spherical aggregates of cells interpreted as in-fallen, likely planktonic, forms. Bedded black cherts, in contrast, preserve microfossils primarily within, but also between, rounded clasts of organic material that are coated by thin, convoluted carbonaceous films interpreted as preserved extracellular polymeric substance (EPS). Microfossils preserved within the clasts include a wide range of unicells, both much smaller and larger than those in the nodular black chert, along with relatively short, often degraded filaments, four types of star-shaped rosettes and umbrella-like rosettes. Large, complexly branching filamentous microfossils are found between the clasts. The grainstone clasts in the bedded black chert are interpreted as transported from shallower water, and the contained microfossils thus likely represent a phototrophic community. Combined, the two black chert facies provide a snapshot of a microbial ecosystem spanning shallow to deeper-water environments, and an insight into the ersity of life present during the rise in atmospheric oxygen. The preserved microfossils include two new, distinct morphologies previously unknown from the geological record, as well as a number of microfossils from the bedded black chert that are morphologically similar to-but 400-500 Ma older than-type specimens from the c. 1.88 Ga Gunflint Iron Formation. Thus, the Turee Creek Group microfossil assemblage creates a substantial reference point in the sparse fossil record of the earliest Paleoproterozoic and demonstrates that microbial life ersified quite rapidly after the end of the Archean.
Publisher: Informa UK Limited
Date: 06-2005
Publisher: Elsevier BV
Date: 04-2002
Publisher: Canadian Science Publishing
Date: 07-1993
DOI: 10.1139/E93-127
Abstract: The Early Proterozoic Torngat Orogen resulted from the oblique collision of the Archean Nain and southeastern Rae provinces and evolved in four stages: (0) deposition of platformal supracrustal assemblages followed by subduction-related arc magmatism in the margin of the Rae Province (I) crustal thickening and nappe tectonics (II) sinistral transpression and formation of the Abloviak shear zone (III) uplift on steeply dipping, east-verging mylonites along the eastern orogenic front.U–Pb geochronology on zircon and monazite from major rock units and syntectonic intrusions indicates that arc magmatism at ca. 1880 Ma was followed by 40 Ma. of deformation and high-grade metamorphism from ca. 1860 to 1820. Subsequent uplift and final cooling occurred ca. 1795 – 1770 Ma. Several ages of mineral growth that correspond to distinct structural and metamorphic events have been recognized: (1) 1858 – 1853 Ma zircon and monazite dates are interpreted as the minimum age of stage I and peak metamorphic conditions (2) 1844 Ma zircons from anatectic granitoids in the Tasiuyak gneiss complex (TGC), syntectonic with stage II deformation, are interpreted to date the formation of the Abloviak shear zone (3) 1837 Ma magmatic zircons from an intrusive granite vein deformed along the western contact of the TGC represent a discrete intrusive event (4) 1825 – 1822 Ma metamorphic overgrowths and newly grown zircons in granitic veins from the western portion of the orogen (Lac Lomier complex) represent a period of renewed transpressional deformation (5) 1806 Ma magmatic zircons from a post-stage II granite emplaced along the eastern edge of the Abloviak shear zone defines the transition between stage II and stage III events (6) 1794 – 1773 Ma zircons from leucogranites and pegmatites that are associated with uplift of the orogen (stage III). 1780 – 1740 Ma dates for monazite and a 40 Ar/ 39 Ar hornblende age correspond to the latest stages of uplift and cooling of the orogen.
Publisher: Springer Science and Business Media LLC
Date: 21-02-2010
DOI: 10.1038/NGEO772
Publisher: Wiley
Date: 26-04-2020
DOI: 10.1111/GBI.12395
Publisher: Elsevier
Date: 2007
Publisher: Springer Science and Business Media LLC
Date: 08-10-2018
Publisher: Geological Society of America
Date: 29-04-2013
DOI: 10.1130/G34243.1
Publisher: Wiley
Date: 20-07-2015
DOI: 10.1111/GBI.12150
Abstract: The 3.4-Ga Strelley Pool Formation (SPF) at the informally named 'Waterfall Locality' in the Goldsworthy greenstone belt of the Pilbara Craton, Western Australia, provides deeper insights into ancient, shallow subaqueous to possibly subaerial ecosystems. Outcrops at this locality contain a thin (<3 m) unit of carbonaceous and non-carbonaceous cherts and silicified sandstones that were deposited in a shallow-water coastal environment, with hydrothermal activities, consistent with the previous studies. Carbonaceous, sulfide-rich massive black cherts with coniform structures up to 3 cm high are characterized by erse rare earth elements (REE) signatures including enrichment of light [light rare earth elements (LREE)] or middle rare earth elements and by enrichment of heavy metals represented by Zn. The massive black cherts were likely deposited by mixing of hydrothermal and non-hydrothermal fluids. Coniform structures in the cherts are characterized by diffuse laminae composed of sulfide particles, suggesting that unlike stromatolites, they were formed dominantly through physico-chemical processes related to hydrothermal activity. The cherts yield microfossils identical to previously described carbonaceous films, small and large spheres, and lenticular microfossils. In addition, new morphological types such as clusters composed of large carbonaceous spheroids (20-40 μm across each) with fluffy or foam-like envelope are identified. Finely laminated carbonaceous cherts are devoid of heavy metals and characterized by the enrichment of LREE. This chert locally contains conical to domal structures characterized by truncation of laminae and trapping of detrital grains and is interpreted as siliceous stromatolite formed by very early or contemporaneous silicification of biomats with the contribution of silica-rich hydrothermal fluids. Biological affinities of described microfossils and microbes constructing siliceous stromatolites are under investigation. However, this study emphasizes how erse the microbial community in Paleoarchean coastal hydrothermal environment was. We propose the ersity is at least partially due to the availability of various energy sources in this depositional environment including reducing chemicals and sunlight.
Publisher: Wiley
Date: 02-05-2020
DOI: 10.1111/GBI.12392
Abstract: The shallow marine and subaerial sedimentary and hydrothermal rocks of the ~3.48 billion‐year‐old Dresser Formation are host to some of Earth's oldest stromatolites and microbial remains. This study reports on texturally distinctive, spherulitic barite micro‐mineralization that occur in association with primary, autochthonous organic matter within exceptionally preserved, strongly sulfidized stromatolite s les obtained from drill cores. Spherulitic barite micro‐mineralization within the sulfidized stromatolites generally forms submicron‐scale aggregates that show gradations from hollow to densely crystallized, irregular to partially radiating crystalline interiors. Several barite micro‐spherulites show thin outer shells. Within stromatolites, barite micro‐spherulites are intimately associated with petrographically earliest dolomite and nano‐porous pyrite enriched in organic matter, the latter of which is a possible biosignature assemblage that hosts microbial remains. Barite spherulites are also observed within layered barite in proximity to stromatolite layers, where they are overgrown by compositionally distinct (Sr‐rich), coarsely crystalline barite that may have been sourced from hydrothermal veins at depth. Micro‐spherulitic barite, such as reported here, is not known from hydrothermal systems that exceed the upper temperature limit for life. Rather, barite with near‐identical morphology and micro‐texture is known from zones of high bio‐productivity under low‐temperature conditions in the modern oceans, where microbial activity and/or organic matter of degrading biomass controls the formation of spherulitic aggregates. Hence, the presence of micro‐spherulitic barite in the organic matter‐bearing Dresser Formation sulfidized stromatolites lend further support for a biogenic origin of these unusual, exceptionally well‐preserved, and very ancient microbialites.
Publisher: Frontiers Media SA
Date: 11-09-2018
Publisher: Elsevier BV
Date: 2015
Publisher: Mary Ann Liebert Inc
Date: 11-2010
Abstract: Morphologically erse structures that may constitute organic microfossils are reported from three remote and widely separated localities assigned to the ca. 3400 Ma Strelley Pool Formation in the Pilbara Craton, Western Australia. These localities include the Panorama, Warralong, and Goldsworthy greenstone belts. From the Panorama greenstone belt, large (> 40 μm) lenticular to spindle-like structures, spheroidal structures, and mat-forming thread-like structures are found. Similar assemblages of carbonaceous structures have been identified from the Warralong and Goldsworthy greenstone belts, though these assemblages lack the thread-like structures but contain film-like structures. All structures are syngenetic with their host sedimentary black chert, which is associated with stromatolites and evaporites. The host chert is considered to have been deposited in a shallow water environment. Rigorous assessment of biogenicity (considering composition, size range, abundance, taphonomic features, and spatial distributions) suggests that cluster-forming small ( 15 μm) spheroids and simple film-like structures is less certain. Although further investigations are required to confirm the biogenicity of carbonaceous structures from the Strelley Pool Formation, this study presents evidence for the existence of morphologically complex and large microfossils at 3400 Ma in the Pilbara Craton, which can be correlated to the contemporaneous, possible microfossils reported from South Africa. Although there is still much to be learned, they should provide us with new insights into the early evolution of life and shallow water ecosystems.
Publisher: Elsevier BV
Date: 09-2016
Publisher: Elsevier BV
Date: 09-2015
Publisher: Elsevier BV
Date: 05-2013
Publisher: Springer Berlin Heidelberg
Date: 03-12-2010
Publisher: Wiley
Date: 03-2019
DOI: 10.1111/MAPS.13242
Publisher: Springer Science and Business Media LLC
Date: 27-03-2015
DOI: 10.1007/S00248-015-0598-3
Abstract: Modern microbial mats from Shark Bay present some structural similarities with ancient stromatolites thus, the functionality of microbial communities and processes of diagenetic preservation of modern mats may provide an insight into ancient microbial assemblages and preservation. In this study, the vertical distribution of microbial communities was investigated in a well-laminated smooth mat from Shark Bay. Biolipid and compound-specific isotopic analyses were performed to investigate the distribution of microbial communities in four distinct layers of the mat. Biomarkers indicative of cyanobacteria were more abundant in the uppermost oxic layer. Diatom markers (e.g. C25 HBI alkene, C20:4ω6 and C20:5ω3 polar lipid fatty acids (PLFAs)) were also detected in high abundance in the uppermost layer, but also in the deepest layer under conditions of permanent darkness and anoxia, where they probably used NO3 (-) for respiration. CycC19:0, an abundant PLFA of purple sulfur bacteria (PSB), was detected in all layers and presented the most (13)C-depleted values of all PLFAs, consistent with photoautotrophic PSB. Sulfur-bound aliphatic and aromatic biomarkers were detected in all layers, highlighting the occurrence of early sulfurisation which may be an important mechanism in the sedimentary preservation of functional biolipids in living and, thus, also ancient mats.
Publisher: Public Library of Science (PLoS)
Date: 25-01-2016
Publisher: Mary Ann Liebert Inc
Date: 04-2020
Publisher: Elsevier BV
Date: 2007
Publisher: Frontiers Media SA
Date: 24-02-2022
DOI: 10.3389/FNEUR.2022.827571
Abstract: Post-traumatic epilepsy (PTE) is a devastating neurological outcome of traumatic brain injury (TBI), which may negatively impact the quality of life of patients with TBI, and may impose a huge socioeconomic burden. This burden may be due to long-term functional outcomes associated with PTE, particularly cognitive dysfunction. To date, the relationship between TBI and PTE remains unclear, with little known about how the effect of their link on cognitive function as well. Thus, this systematic review aimed at elucidating the relationship between PTE and cognitive impairment in adults after TBI based on available clinical studies, in hopes to aid in the development of therapeutic strategies for PTE. A systematic literature search was performed using 6 databases MEDLINE, Embase, CINAHL, Psych INFO, Web of Science, and Cochrane to retrieve relevant clinical studies investigating the link between PTE and cognition in the context of TBI. The Newcastle-Ottawa Scale (NOS) was used to assess the methodological quality of relevant studies. A total of six eligible studies were included for critical appraisal in this review after performing the inclusion and exclusion criteria, which involved 1,100 in iduals, from 1996 to 2021. The selected studies were derived from the civilian and military population, with a follow-up period that ranged from 6 months to 35 years. The average quality of the involved studies was moderate (6.6, SD = 1.89). Five out of six studies found poorer cognitive performance in people with PTE, compared with those without PTE. Although the association between PTE and cognitive impairment was insignificant after controlling for specific covariates, there was a statistical trend toward significance. This systematic review suggests that there may be a possible link between PTE and cognitive decline in TBI patients, with the latter being reported to occur up to 35 years post injury. Variations in s le sizes, follow-up periods, and neuropsychological assessment tools may be the limitations affecting the interpretation and significance of this relationship. Therefore, future studies with standard cognitive assessment tools may be warranted to solidify the link between TBI-PTE-cognitive dysfunction, prior to the development of therapeutic strategies. Systematic Review Registration: www.crd.york.ac.uk rospero/display_record.php?ID=CRD42020221702 , prospero identifier: CRD42020221702.
Publisher: Geological Society of London
Date: 13-11-2014
DOI: 10.1144/SP389.13
Publisher: American Geophysical Union (AGU)
Date: 27-01-2004
DOI: 10.1029/2002TC001452
Publisher: Geological Society of London
Date: 03-09-2015
DOI: 10.1144/SP389.12
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 02-2013
Publisher: Wiley
Date: 03-1999
Publisher: MDPI AG
Date: 16-12-2021
DOI: 10.3390/LIFE11121413
Abstract: Metal ions strongly affect the self-assembly and stability of membranes composed of prebiotically relevant hiphiles (proto hiphiles). Therefore, evaluating the behavior of such hiphiles in the presence of ions is a crucial step towards assessing their potential as model protocell compartments. We have recently reported vesicle formation by N-acyl amino acids (NAAs), an interesting class of proto hiphiles containing an amino acid linked to a fatty acid via an amide linkage. Herein, we explore the effect of ions on the self-assembly and stability of model N-oleoyl glycine (NOG)-based membranes. Microscopic analysis showed that the blended membranes of NOG and Glycerol 1-monooleate (GMO) were more stable than pure NOG vesicles, both in the presence of monovalent and alent cations, with the overall vesicle stability being 100-fold higher in the presence of a monovalent cation. Furthermore, both pure NOG and NOG + GMO mixed systems were able to self-assemble into vesicles in natural water s les containing multiple ions that were collected from active hot spring sites. Our study reveals that several aspects of the metal ion stability of NAA-based membranes are comparable to those of fatty acid-based systems, while also confirming the robustness of compositionally heterogeneous membranes towards high metal ion concentrations. Pertinently, the vesicle formation by NAA-based systems in terrestrial hot spring s les indicates the conduciveness of these low ionic strength freshwater systems for facilitating prebiotic membrane-assembly processes. This further highlights their potential to serve as a plausible niche for the emergence of cellular life on the early Earth.
Publisher: Geological Society of America
Date: 2014
Publisher: Springer Science and Business Media LLC
Date: 08-06-2018
DOI: 10.1038/S41467-018-04621-X
Abstract: The Great Oxidation Event (GOE) has been defined as the time interval when sufficient atmospheric oxygen accumulated to prevent the generation and preservation of mass-independent fractionation of sulphur isotopes (MIF-S) in sedimentary rocks. Existing correlations suggest that the GOE was rapid and globally synchronous. Here we apply sulphur isotope analysis of diagenetic sulphides combined with U-Pb and Re-Os geochronology to document the sulphur cycle evolution in Western Australia spanning the GOE. Our data indicate that, from ~2.45 Gyr to beyond 2.31 Gyr, MIF-S was preserved in sulphides punctuated by several episodes of MIF-S disappearance. These results establish the MIF-S record as asynchronous between South Africa, North America and Australia, argue for regional-scale modulation of MIF-S memory effects due to oxidative weathering after the onset of the GOE, and suggest that the current paradigm of placing the GOE at 2.33–2.32 Ga based on the last occurrence of MIF-S in South Africa should be re-evaluated.
Publisher: Springer Science and Business Media LLC
Date: 03-2002
DOI: 10.1038/416076A
Publisher: Elsevier BV
Date: 04-2016
Publisher: American Association for the Advancement of Science (AAAS)
Date: 14-09-2007
Abstract: Microscopic sulfides with low 34 S/ 32 S ratios in marine sulfate deposits from the 3490-million-yearold Dresser Formation, Australia, have been interpreted as evidence for the presence of early sulfate-reducing organisms on Earth. We show that these microscopic sulfides have a mass-independently fractionated sulfur isotopic anomaly (Δ 33 S) that differs from that of their host sulfate (barite). These microscopic sulfides could not have been produced by sulfate-reducing microbes, nor by abiologic processes that involve reduction of sulfate. Instead, we interpret the combined negative δ 34 S and positive Δ 33 S signature of these microscopic sulfides as evidence for the early existence of organisms that disproportionate elemental sulfur.
Publisher: Geological Society of London
Date: 1996
Publisher: Elsevier BV
Date: 10-2005
Publisher: Geological Society of London
Date: 1996
Publisher: Elsevier BV
Date: 06-2007
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier BV
Date: 10-2011
Publisher: Elsevier BV
Date: 07-2013
Publisher: Informa UK Limited
Date: 20-03-2015
Publisher: Wiley
Date: 02-2007
Publisher: Portland Press Ltd.
Date: 12-2018
DOI: 10.1042/BIO04006018
Abstract: There are many different scientific aspects involved in the challenge of understanding the origin of life (OoL). These include organic geochemistry – how to make RNA and DNA molecules from the simple organic building blocks delivered from space in the form of amino acids and some other compounds. Other aspects involve the study of inorganic geochemistry – how elements are made available to promote organic molecule complexification, under what conditions will lipid membranes form and how to bring together the different components that make a functioning cell.
Publisher: Wiley
Date: 29-02-2016
DOI: 10.1111/GBI.12175
Abstract: This study describes a previously undocumented dolomitic stromatolite-thrombolite reef complex deposited within the upper part (Kazput Formation) of the c. 2.4-2.3 Ga Turee Creek Group, Western Australia, across the rise of atmospheric oxygen. Confused by some as representing a faulted slice of the younger c. 1.8 Ga Duck Creek Dolomite, this study describes the setting and lithostratigraphy of the 350-m-thick complex and shows how it differs from its near neighbour. The Kazput reef complex is preserved along 15 km of continuous exposure on the east limb of a faulted, north-west-plunging syncline and consists of 5 recognisable facies associations (A-E), which form two part regressions and one transgression. The oldest facies association (A) is characterised by thinly bedded dololutite-dolarenite, with local domical stromatolites. Association B consists of interbedded columnar and stratiform stromatolites deposited under relatively shallow-water conditions. Association C comprises tightly packed columnar and club-shaped stromatolites deposited under continuously deepening conditions. Clotted (thrombolite-like) microbialite, in units up to 40 m thick, dominates Association D, whereas Association E contains bedded dololutite and dolarenite, and some thinly bedded ironstone, shale and black chert units. Carbon and oxygen isotope stratigraphy reveals a narrow range in both δ(13) Ccarb values, from -0.22 to 0.97‰ (VPDB: average = 0.68‰), and δ(18) O values, from -14.8 to -10.3‰ (VPDB), within the range of elevated fluid temperatures, likely reflecting some isotopic exchange. The Kazput Formation stromatolite-thrombolite reef complex contains features of younger Paleoproterozoic carbonate reefs, yet is 300-500 Ma older than previously described Proterozoic ex les worldwide. Significantly, the microbial fabrics are clearly distinct from Archean stromatolitic marine carbonate reefs by way of containing the first appearance of clotted microbialite and large columnar stromatolites with complex branching arrangements. Such structures denote a more complex morphological expression of growth than previously recorded in the geological record and may link to the rise of atmospheric oxygen.
Publisher: Proceedings of the National Academy of Sciences
Date: 20-04-2015
Publisher: Elsevier
Date: 2007
Publisher: Springer Science and Business Media LLC
Date: 07-12-2016
DOI: 10.1038/SREP38503
Abstract: Hf isotope ratios measured in igneous zircon are controlled by magmatic source, which may be linked to tectonic setting. Over the 200–500 Myr periodicity of the supercontinent cycle - the principal geological phenomenon controlling prevailing global tectonic style - juvenile Hf signals, i.e. most radiogenic, are typically measured in zircon from granites formed in arc settings (crustal growth), and evolved zircon Hf signals in granites formed in continent-collision settings (crustal reworking). Interrogations of Hf datasets for excursions related to Earth events commonly use the median value, however this may be equivocal due to magma mixing. The most juvenile part of the Hf signal is less influenced by crustal in-mixing, and arguably a more sensitive archive of Earth’s geodynamic state. We analyze the global Hf dataset for this juvenile signal, statistically correlating supercontinent amalgamation intervals with evolved Hf episodes, and breakup leading to re-assembly with juvenile Hf episodes. The juvenile Hf signal is more sensitive to Pangaea and Rodinia assembly, its litude increasing with successive cycles to a maximum with Gondwana assembly which may reflect enhanced subduction-erosion. We demonstrate that the juvenile Hf signal carries important information on prevailing global magmatic style, and thus tectonic processes.
Publisher: Elsevier BV
Date: 2001
Publisher: Elsevier BV
Date: 07-2020
Publisher: Elsevier BV
Date: 2019
Publisher: Elsevier BV
Date: 09-1998
Publisher: American Association for the Advancement of Science (AAAS)
Date: 07-03-2008
Abstract: Our knowledge of the sulfur cycle on early Earth is still in its infancy. Nevertheless, there exist enough geochemical constraints from the rock record to show that the theoretical mixing models proposed by Bao et al . are highly unlikely to account for the range of δ 34 S and Δ 33 S values recorded for the microscopic sulfides at the North Pole.
Publisher: Oxford University Press (OUP)
Date: 2016
Publisher: Canadian Science Publishing
Date: 12-1997
DOI: 10.1139/E17-126
Abstract: Large variations in metamorphic grade over short distances, disparate orientations and erse kinematics of contemporaneous structures, and a previously unexplained, 90° counterclockwise bend in the orogenic boundary of the hibolite- to granulite-facies northern segment of the Paleoproterozoic Torngat Orogen are shown to be the result of multiple tectonic events acting upon an orogenic boundary perturbation. The perturbation was initiated when a promontory on the Nain Province margin, composed of a 1910–1885 Ma continental magmatic arc (Burwell domain), indented the Rae Province hinterland during the onset of collisional orogeny at ca. 1870 Ma (D n+1 ). Sinistral transpression at ca. 1845–1822 Ma (D n+2 ) caused formation of the orogen-parallel Abloviak shear zone and oblique burial of the Nain Province margin beneath a tilted section of the hot, buoyant magmatic arc. Reactivation of the orogen at ca. 1798–1770 Ma (D n+3 ) involved crustal-scale flexural slip folding of the perturbation and simultaneous exhumation of the Burwell domain and the previously buried Nain crust across the Komaktorvik shear zone, which represents a sheared, tightened fold train localized along the western limit of thinned Nain crust affected by preorogenic rifting, but which does not represent a fundamental plate boundary. The along-strike heterogeneities in the Torngat Orogen document the influence of geometrical and competency heterogeneities in the colliding margins on subsequent deformation and the fact that heterogeneities in the deep crust persist through high-grade metamorphism.
Publisher: Wiley
Date: 05-05-2016
DOI: 10.1111/GBI.12184
Abstract: Hyperspectral imaging (400-2496 nm) was used to quantitatively map surface textures and compositional variations in stromatolites to determine whether complexity of textures could be used as evidence to support biogenicity in the absence of preserved biomarkers. Four s les of 2.72-2.4 Ga stromatolites from a variety of settings, encompassing marine and lacustrine environments, were selected for hyperspectral imaging. Images of the sawn surfaces of s les were processed to identify reflectance and mineral absorption features and quantify their intensity (as an index of mineral abundance) using automated feature extraction. Amounts of ferrous iron were quantified using a ratio of reflectance at 1650 and 1299 nm. Visible near infrared imagery (400-970 nm) did not reveal additional textural patterns to those obtained from visual inspection. Shortwave infrared imagery (1000-2496 nm), however, revealed complex laminar and convoluted patterns, including a distinctive texture of sharp peaks and broad, low troughs in one s le, similar to living tufted microbial mats. Spectral analysis revealed another s le to be composed of dolomite. Two other s les were dominated by calcite or chlorite ± illite. Large variations in amounts of ferrous iron were found, but ferric iron was exclusively located in the oxidation crust. Hyperspectral imaging revealed large differences between parts of a s le of biogenic and non-biogenic origin. The former was characterized by calcite with varying amounts of ferrous iron, distributed in lenticular, convoluted patterns the latter by Mg-Fe chlorite with large amounts of aluminium silicate, distributed as fine laminar layers. All minerals identified by hyperspectral imaging were confirmed by thin section petrography and XRD analyses. Spatial statistics generated from quantitative minerals maps showed different patterns between these different parts of the s le. Thus, hyperspectral imaging was shown to be a powerful tool for detecting structures in stromatolites that could be used, together with other lines of evidence, to support biogenicity.
Publisher: Elsevier BV
Date: 09-2014
Publisher: Society of Economic Geologists
Date: 07-2002
Publisher: Elsevier BV
Date: 11-2013
Publisher: Elsevier BV
Date: 03-2015
Publisher: Springer Science and Business Media LLC
Date: 11-03-2020
Publisher: American Geophysical Union (AGU)
Date: 08-1996
DOI: 10.1029/95TC03771
Publisher: Geological Society of America
Date: 2008
Publisher: Geological Society of America
Date: 2007
DOI: 10.1130/G23534A.1
Publisher: Elsevier BV
Date: 07-2014
Publisher: Cold Spring Harbor Laboratory
Date: 11-11-2022
DOI: 10.1101/2022.11.10.22282171
Abstract: Approximately 69 million people worldwide are annually affected by traumatic brain injury (TBI). In Malaysia, the traumatic injury was the leading cause of hospital admission and death, accounting for one in three emergency visits. Among the most recognised complication of TBI is post-traumatic epilepsy (PTE), which is an essential contributor to morbidity and mortality. However, there is a lack of local epidemiological data on PTE in Malaysia. This study aims to describe the incidence and predictors of PTE among TBI patients admitted to a tertiary healthcare centre in Kuala Lumpur, Malaysia. We hypothesised that increases in age, race, and severity of brain injury are among the main potential predictors of PTE. It will also provide evidence that patients with epilepsy following TBI are associated with significant impairment in cognitive performance than TBI patients without epilepsy. An analysis of a two years retrospective cohort will be employed, of which adults with a history of admission for TBI in 2019 and 2020 will be contacted, and the development of epilepsy will be ascertained using a validated tool and confirmed by our neurologists during visits. The patients will then be grouped into two, with PTE and without PTE, and assessed their cognitive performance by clinical psychologists. Given that the management of TBI and PTE patients involves a multidisciplinary team, the findings might be significant to many healthcare providers in determining policy and strategise a better treatment.
Publisher: Elsevier BV
Date: 06-2018
Publisher: Elsevier BV
Date: 10-2007
Publisher: Frontiers Media SA
Date: 06-10-2022
DOI: 10.3389/FPHAR.2022.991244
Abstract: Epilepsy represents a challenge in the management of patients with brain tumors. Epileptic seizures are one of the most frequent comorbidities in neuro-oncology and may be the debut symptom of a brain tumor or a complication during its evolution. Epileptogenic mechanisms of brain tumors are not yet fully elucidated, although new factors related to the underlying pathophysiological process with possible treatment implications have been described. In recent years, the development of new anti-seizure medications (ASM), with better pharmacokinetic profiles and fewer side effects, has become a paradigm shift in many clinical scenarios in neuro-oncology, being able, for instance, to adapt epilepsy treatment to specific features of each patient. This is crucial in several situations, such as patients with cognitive sychiatric comorbidity, pregnancy, or advanced age, among others. In this narrative review, we provide a rationale for decision-making in ASM choice for neuro-oncologic patients, highlighting the strengths and weaknesses of each drug. In addition, according to current literature evidence, we try to answer some of the most frequent questions that arise in daily clinical practice in patients with epilepsy related to brain tumors, such as, which patients are the best candidates for ASM and when to start it, what is the best treatment option for each patient, and what are the major pitfalls to be aware of during follow-up.
Publisher: Wiley
Date: 03-2019
DOI: 10.1111/MAPS.13232
Publisher: Society of Economic Geologists
Date: 07-2002
Publisher: Elsevier
Date: 2019
Publisher: Elsevier BV
Date: 03-2005
Publisher: Geological Society of London
Date: 08-2004
Publisher: Elsevier BV
Date: 06-2004
Publisher: Elsevier BV
Date: 09-2019
Publisher: Proceedings of the National Academy of Sciences
Date: 02-02-2015
Abstract: An ancient deep-sea mud-inhabiting 1,800-million-year-old sulfur-cycling microbial community from Western Australia is essentially identical both to a fossil community 500 million years older and to modern microbial biotas discovered off the coast of South America in 2007. The fossils are interpreted to document the impact of the mid-Precambrian increase of atmospheric oxygen, a world-changing event that altered the history of life. Although the apparent 2-billion-year-long stasis of such sulfur-cycling ecosystems is consistent with the null hypothesis required of Darwinian evolution—if there is no change in the physical-biological environment of a well-adapted ecosystem, its biotic components should similarly remain unchanged—additional evidence will be needed to establish this aspect of evolutionary theory.
Publisher: Springer Science and Business Media LLC
Date: 16-08-2017
DOI: 10.1038/NCOMMS16149
Abstract: Nature Communications 8: Article number: 15263 (2017) Published: 9 May 2017 Updated: 16 August 2017. The original manuscript presented evidence that the deposits studied were fluvial rather than marine to support the conclusion that evidence of life on land had been discovered in the 3.4 Ga Dresser Formation, Pilbara Craton, Australia.
Publisher: Elsevier BV
Date: 05-2007
Publisher: Elsevier BV
Date: 06-2004
Publisher: Springer Science and Business Media LLC
Date: 19-04-2018
Publisher: Society of Exploration Geophysicists
Date: 09-05-2022
Abstract: In recent years, there has been a rapid development of the computer-aided interpretation of seismic data to reduce the otherwise intensive manual labor. A variety of seed detection algorithms for horizon and fault identification are integrated into popular seismic software packages. Recently, there has been an increasing focus on using neural networks for fully automatic fault detection without manually seeding each fault. These networks are usually trained with synthetic fault data sets. These data sets can be used across multiple seismic data sets however, they are not as accurate as real seismic data, particularly in structurally complex regions associated with several generations of faults. The approach taken here is to combine the accuracy of manual fault identification in certain parts of the data set with a convolutional neural network that can then sweep through the entire data set to identify faults. We have implemented our method using 3D seismic data acquired from the Arabian Basin in Saudi Arabia covering an area of 1051 km 2 . The network is trained, validated, and tested with s les that included a seismic cube and fault images that are labeled manually corresponding to the seismic cube. The model successfully identifies faults with an accuracy of 96% and an error rate of 0.12 on the training data set. To achieve a robust model, we further enhance the prediction results using postprocessing by linking discontinued segments of the same fault line, thus reducing the number of detected faults. The postprocessing improves the prediction results from the test data set by 77.5%. In addition, we introduce an efficient framework to correlate the predictions and the ground truth by measuring their average distance value. Furthermore, tests using this approach also have been conducted on the F3 Netherlands survey with complex fault geometries and find promising results. As a result, fault detection and diagnosis are achieved efficiently with structures similar to the trained data set.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 22-07-2011
Abstract: Analysis of diamonds from the subcontinental mantle reveals that plate tectonics started 3 billion years ago.
Publisher: Elsevier BV
Date: 03-2017
Publisher: Elsevier BV
Date: 10-2016
Publisher: Public Library of Science (PLoS)
Date: 27-04-2009
Publisher: Elsevier BV
Date: 02-2006
Publisher: Elsevier
Date: 2019
Publisher: Springer Science and Business Media LLC
Date: 23-07-2018
Publisher: Elsevier
Date: 2007
Publisher: Copernicus GmbH
Date: 15-03-2018
Abstract: Abstract. Archaean hydrothermal chert veins commonly contain abundant organic carbon of uncertain origin (abiotic vs. biotic). In this study, we analysed kerogen contained in a hydrothermal chert vein from the ca. 3.5 Ga Dresser Formation (Pilbara Craton, Western Australia). Catalytic hydropyrolysis (HyPy) of this kerogen yielded n-alkanes up to n-C22, with a sharp decrease in abundance beyond n-C18. This distribution (≤ n-C18) is very similar to that observed in HyPy products of recent bacterial biomass, which was used as reference material, whereas it differs markedly from the unimodal distribution of abiotic compounds experimentally formed via Fischer–Tropsch-type synthesis. We therefore propose that the organic matter in the Archaean chert veins has a primarily microbial origin. The microbially derived organic matter accumulated in anoxic aquatic (surface and/or subsurface) environments and was then assimilated, redistributed and sequestered by the hydrothermal fluids (“hydrothermal pump hypothesis”).
Publisher: Elsevier BV
Date: 08-2006
Publisher: Geological Society of America
Date: 25-09-2019
DOI: 10.1130/G46365.1
Abstract: Stromatolites of the ∼3.5 billion-year-old Dresser Formation (Pilbara Craton, Western Australia) are considered to be some of Earth’s earliest convincing evidence of life. However, uniquely biogenic interpretations based on surface outcrops are precluded by weathering, which has altered primary mineralogy and inhibited the preservation of microbial remains. Here, we report on exceptionally preserved, strongly sulfidized stromatolites obtained by diamond drilling from below the weathering profile. These stromatolites lie within undeformed hydrothermal-sedimentary strata and show textural features that are indicative of biogenic origins, including upward-broadening and/or upward-branching digitate forms, wavy to wrinkly laminae, and finely laminated columns that show a thickening of laminae over flexure crests. High-resolution textural, mineralogical, and chemical analysis reveals that the stromatolites are dominated by petrographically earliest, nano-porous pyrite that contains thermally mature, N-bearing organic matter (OM). This nano-porous pyrite is consistent with a formation via sulfidization of an originally OM-dominated matrix. Evidence for its relationship with microbial communities are entombed OM strands and filaments, whose microtexture and chemistry are consistent with an origin as mineralized biofilm remains, and carbon isotope data of extracted OM (δ13COM = −29.6‰ ± 0.3‰ VPDB [Vienna Peedee belemnite]), which lie within the range of biological matter. Collectively, our findings provide exceptional evidence for the biogenicity of some of Earth’s oldest stromatolites through preservation of OM, including microbial remains, by sulfidization.
Publisher: Elsevier BV
Date: 11-2003
Publisher: Mary Ann Liebert Inc
Date: 12-2019
Abstract: Boron is associated with several Archean stromatolite deposits, including the tourmaline-rich Barberton stromatolites in South Africa and tourmaline-bearing pyritic laminae associated with stromatolites of the 3.48 Ga Dresser Formation in the Pilbara Craton, Australia. Boron is also a critical element in prebiotic organic chemistry, including in the formation of ribose, a crucial component in RNA. As geological evidence and advances in prebiotic chemistry are now suggesting that hot spring activity may be associated with the origins of life, an understanding of boron and its mobility and isotopic fractionation in geothermal settings may provide important insights into the setting for the origin of life. Here, we report on the boron isotopic compositions and elemental concentrations in a range of fluid, sediment, and mineral s les from the active, boron-rich Puga geothermal system in the Himalayas, India. This includes one of the lowest boron isotope values ever recorded in modern settings: diatom-rich sediments (δ
Publisher: Mary Ann Liebert Inc
Date: 04-2020
Publisher: Elsevier BV
Date: 03-2020
Publisher: Elsevier BV
Date: 10-2007
Publisher: Elsevier BV
Date: 11-2019
Publisher: GeoScienceWorld
Date: 04-2014
DOI: 10.1130/L356.1
Publisher: Elsevier BV
Date: 04-2005
Publisher: Elsevier BV
Date: 10-11-2008
Publisher: Elsevier BV
Date: 15-05-2009
Publisher: Elsevier
Date: 2007
Publisher: Elsevier BV
Date: 04-2009
Publisher: GeoScienceWorld
Date: 02-2014
DOI: 10.1130/L296.1
Publisher: Canadian Science Publishing
Date: 03-1991
DOI: 10.1139/E91-038
Abstract: Thin (tens of metres wide by tens of kilometres long) sheets of metagabbroic anorthosite are a common and intriguing feature of the Central Gneiss Belt (CGB), southwestern Grenville Province. Their origin, however, as either tectonic remnants of originally much larger parent masses or as moderately strained magmatic sheets is controversial because regional high strain has largely obliterated original contact relationships and modified primary textures. The origin of three sheets of metagabbroic anorthosite within the Fishog subdomain of the CGB is examined. Field relationships and geochemical analyses indicate that the sheets are composed of two distinct subunits (A = anorthositic, with An 57–63 B = dioritic, with An 41–47 ) that may be genetically related but have been contaminated by a significant crustal component during intrusion. Grenvillian deformation was accommodated by the sheets through early ductile flow and subsequent brittle rupturing during folding that was accompanied by the intrusion of pegmatite veins. Field observations and the results of Robin's method of strain analysis applied to representative s les of the least strained of these sheets, the Head River unit (HRU), show that internal strain was low. Preserved contact relationships of gabbroic anorthosite magma into dioritic country rocks and of granitic sheets into the HRU can be used to infer that ductile thrusting was not an important mechanism in the formation of the sheets' narrow geometry but that it simply modified the shape of magmatic sheets. A magmatic sheet hypothesis is proposed for the origin of meta-anorthositic sheets and associated rocks of the Fishog subdomain and may serve as a viable model for the precursors to some of the more highly strained sheets of meta-anorthositic gneiss found throughout the CGB.
Publisher: Elsevier
Date: 2012
Start Date: 2018
End Date: 2021
Funder: Marsden Fund
View Funded ActivityStart Date: 2018
End Date: 2021
Funder: Australian Research Council
View Funded ActivityStart Date: 04-2018
End Date: 07-2023
Amount: $591,274.00
Funder: Australian Research Council
View Funded ActivityStart Date: 12-2020
End Date: 12-2024
Amount: $390,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 03-2016
End Date: 06-2019
Amount: $648,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 04-2017
End Date: 12-2021
Amount: $270,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 07-2006
End Date: 06-2007
Amount: $133,670.00
Funder: Australian Research Council
View Funded ActivityStart Date: 03-2018
End Date: 09-2019
Amount: $297,463.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2011
End Date: 12-2018
Amount: $12,400,000.00
Funder: Australian Research Council
View Funded Activity