Photograph of 3 billion year old bacteria

Department of Zoology - Exchanges, Retirements - Dr. Timothy G. Marples, Dr. Peter Janssens, Mr. Ralph Ogden, Ms. Jenny Grigg, Mr. Tony Argyle, Warwick Smith, Tim Greville, Dr. Michael Howell, Kristin Ardlie, Dr. Bill Cowden, Dr. Peter Hunt, Dr. Ian Clark, Brad Imhaff, David Happold & other

In-situ analysis of solid bitumen in coal: examples from the Bowen Basin and the Illinois Basin

Solid bitumen and associated vitrinite from selected coals from the Bowen Basin and the Illinois Basin were studied using electron microprobe and micro-FTIR techniques. The coal studied covers a range of vitrinite reflectance from 0.59% to 1.33%. Carbon content in the bitumen is generally lower than in vitrinite in coals with vitrinite reflectance below 0.67%. In coals with reflectance above 0.67%, carbon content of bitumen is higher than in vitrinite, reflecting higher aromaticity due to hydrocarbon generation, Sulfur and iron content are comparable between vitrinite and bitumen. Functional group distribution suggests the presence of two types of bitumen in the Illinois Basin coals. The more aliphatic variety occurring in veins and cleats is interpreted as pre-gas generation bitumen, and the more aromatic variety filling cells and voids in inertinite as post-gas generation bitumen. (C) 2000 Elsevier Science B.V. All rights reserved

Earliest life on earth

This volume integrates the latest findings on earliest life forms, identified and characterized in some of the oldest rocks on Earth. It places emphasis on the integration of analytical methods with observational techniques and experimental simulations

Earliest life on earth: Habitats, environments and methods of detection

This volume integrates the latest findings on earliest life forms, identified and characterised in some of the oldest rocks on Earth. New material from prominent researchers in the field is presented and evaluated in the context of previous work. Emphasis is placed on the integration of analytical methods with observational techniques and experimental simulations. The opening section focuses on submarine hot springs that the majority of researchers postulates served as the cradle of life on Earth. In subsequent sections, evidence for life in strongly metamorphosed rocks such as those in Greenland is evaluated and early ecosystems identified in the well preserved Barberton and Pilbara successions in Southern Africa and Western Australia. The final section includes a number of contributions from authors with alternate perspectives on the evidence and record of early life on Earth

Lower palaeozoic and precambrian petroleum source rocks and the coalification path of alginite

Organic-rich samples derived from a Middle Cambrian Formation in the Georgina Basin, and from the Middle Proterozoic of the McArthur Basin in northern and central Australia, yielded alginite ranging from immature oil shale material to overmature residue. A maturation scale has been developed based on the thermal evolution of alginite as determined from reflectance and fluorescence. The coalification path of alginite is marked by jumps in contrast to the linear path of wood-derived vitrinite. Six zones have been recognised, ranging from undermature (zone I), through the mature (zones II/III), followed by a stable stage of no change (zone IV) to the overmature (zones V and VI). The onset of oil generation in alginite as evident from the present study is at 0.3% R and is expressed in a change of fluorescence from yellow to brown, and a coalification jump from 0.3 to 0.6% R of Alg. In many boreholes zone III can be distinguished between 0.6 and 0.8% R of Alg. where subsequent oil generation occurs. Zones II and III represent the oil window. A zone of little or no change designated zone IV, at 0.9 1.0% R of alginite follows zones II/III. A marked coalification jump characterises zone V, where a pronounced change in reflectance occurs to >1.0% R, signifying peak gas generation. The border of oil preservation lies at the transition of zone V and VI, at 1.6% R In zone VI gas generation only occurs. Comparison of reflectance results with experimental and geochemical pyrolysis data supports high activation energies for hydrocarbon generation from alginite, and therefore a later onset of oil generation than other liptinite macerals (i.e. cutinite, exinite, resinite) as well as a narrow oil window. Transmission electron microscopy (TEM) confirms that alginite does not go through a distinct intermediate stage but that the percentage of unreacted organic matter decreases as maturation proceeds. A clear distinction can be made in TEM between immature alginite, alginite after oil generation, and alginite residue following gas generation. Alginite beyond 1.6% R acquires very high densities and the appearance of inertinite in TEM. Bitumens/pyrobitumens make a pronounced contribution to the organic matter throughout the basins and have been shown to effect pyrolysis results by suppressing T. The bitumens/pyrobitumens have been divided into four groups, based on their reflectance and morphology, which in turn appears to be an expression of their genetic history. Their significance is in aiding the understanding of the basins' thermal history, and the timing of oil and gas generation

K-Ar evidence from illitic clays of a Late Devonian age for the 120 km diameter Woodleigh impact structure, Southern Carnarvon Basin, Western Australia

Woodleigh is a recently discovered impact structure with a diameter of 120 km, and thereby represents the third largest proven Phanerozoic impact structure known after Morocweng and Chicxulub. K-Ar isotopic studies of fine-grained authigenic illitic clay minerals (< 2 μm), considered to be impact-induced hydrothermal alteration products, indicate a Late Devonian (359 ± 4 Ma) age for the impact. Other evidence reported for Late Devonian extraterrestrial impacts include the strong iridium anomaly in the Canning Basin, Western Australia, and microtektites and elemental anomalies (including iridium) in South China. Given the large diameter of the Woodleigh impact structure and its relative proximity to iridium anomalies also of Late Devonian age in eastern Gondwana basins, environmental effects of the Woodleigh impact event are a likely contributor to a biotic crisis in the Late Devonian