PETROLEUM OCCURRENCE IN THE GIPPSLAND BASIN AND ITS RELATIONSHIP TO RANK AND ORGANIC MATTER TYPE

1984 ◽  
Vol 24 (1) ◽  
pp. 196 ◽  
Author(s):  
G. C. S Smith ◽  
A. C. Cook
Keyword(s):  
Organic Matter ◽  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Late Eocene ◽  
Generative Capacity ◽  
Near Surface ◽  
Metamorphic History ◽  
Downhole Temperature ◽  
Gippsland Basin ◽  
Sediment Age

Coal rank, sediment age and downhole temperature data indicate that the rates of burial and palaeothermal gradients in the Gippsland Basin have varied both areally and with time over the Late Cretaceous to Recent period. The generation and occurrence of petroleum are controlled mainly by the burial metamorphic history. The inshore areas are gas prone because the Late Cainozoic burial meta-morphism is moderate and overprints an earlier phase of substantial burial metamorphism in the Late Cretaceous-Early Tertiary. The areas offshore in the Central Deep are oil prone because the earlier burial metamorphism was minor and the burial metamorphism during the last 20 Ma has been rapid and substantial.Vitrinite reflectance values (R̅vmax) vary from about 0.2 per cent at near-surface depths to over 1.2 per cent in the Upper Cretaceous sediments at depths of about 4 km and more. Exinite reflectance values (R̅emax) are about 0.05 per cent at near-surface depths increasing gradually to only 0.15 per cent at 3 km. Significant exinite metamorphism is evident at depths between 3 and 4 km, with major exinite metamorphism at 4-5 km and more at the base of the Upper Cretaceous sequence.The proportion of organic matter and its specific generative capacity increases up through the Latrobe Group. The Late Cretaceous to Early Eocene organic matter consists of orthohydrous vitrinite and diverse inertinite and is distinct from the Middle to Late Eocene coaly matter which consists of perhydrous vitrinite and minor amounts of inertinite. The Oligocene to Miocene organic matter is dominated by perhydrous vitrinites and is inertinite-poor. The overall proportion of exinite is roughly constant up through the Upper Cretaceous to Miocene terrestrial sequences although some forms of alginite are more common in the Eocene to Miocene sediments. Petrographic and geologic evidence suggests that much of the petroleum probably is generated from vitrinite in addition to exinite at low coal ranks (R̅vmax 0.4-0.8 per cent) and low burial depths (2-4 km).

GEOLOGIC EVOLUTION AND HYDROCARBON HABITAT GIPPSLAND BASIN

1972 ◽  
Vol 12 (1) ◽  
pp. 132 ◽  
Author(s):  
J. Barry Hocking
Keyword(s):  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Meteoric Water ◽  
Oil And Gas ◽  
Basin Evolution ◽  
Fold Belt ◽  
Apparent Lack ◽  
Northern Flank ◽  
Southeastern Australia ◽  
Gippsland Basin

The Gippsland Basin of southeastern Australia is a post-orogenic, continental margin type of basin of Upper Cretaceous-Cainozoic age.Gippsland Basin evolution can be traced back to the establishment of the Strzelecki Basin, or ancestral Gippsland Basin, during the Jurassic. Gippsland Basin sedimentation commenced in the middle to late Cretaceous and is represented as a gross transgressive-regressive cycle consisting of the continental Latrobe Valley Group (Upper Cretaceous to Eocene or Miocene), the marine Seaspray Group (Oligocene to Pliocene or Recent), and finally the continental Sale Group (Pliocene to Recent).The hydrocarbons of the Gippsland Shelf petroleum province were generated within the Latrobe Valley Group and are trapped in porous fluvio-deltaic sandstones of the Latrobe. At Lakes Entrance, however, oil and gas are present in a marginal sandy facies of the Lakes Entrance Formation (Seaspray Group).The buried Strzelecki Basin has played a fundamental role in the development and distribution of the Cainozoic fold belt in the northern Gippsland Basin. The Gippsland Shelf hydrocarbon accumulations fall within this belt and are primarily structural traps. The apparent lack of structural accumulations onshore in Gippsland is largely due to a Plio-Pleistocene episode of cratonic uplift that was accompanied by basinward tilting of structures and meteoric water influx.The non-commercial Lakes Entrance field, located on the stable northern flank of the basin, is a stratigraphic trap and may serve as a guide for future exploration.

scholarly journals Protolith age of the Altar and Carnero complexes and latest Cretaceous–Miocene deformation in the Caborca–Altar region of northwestern Sonora, Mexico

2019 ◽  
Vol 36 (1) ◽  
pp. 95-109 ◽  
Author(s):  
Carl E. Jacobson ◽  
César Jacques-Ayala ◽  
Andrew P. Barth ◽  
Juan Carlos García y Barragán ◽  
Jane N. Pedrick ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Detrital Zircon ◽  
Middle Jurassic ◽  
Upper Cretaceous ◽  
Age Distribution ◽  
Upper Jurassic ◽  
Late Eocene ◽  
Detrital Zircons ◽  
Normal Faults ◽  
Second Phase

In the Caborca–Altar area of northwest Sonora, variably deformed and metamorphosed sedimentary and volcanic rocks crop out in a northwest-southeast–trending belt (El Batamote belt) at least 70 km long. We obtained detrital zircon U-Pb ages from two distinctive components of the belt near Altar, here termed the Altar complex and Carnero complex. Zircon ages for metasandstone and metaconglomerate matrix from the Altar complex indicate a Late Cretaceous maximum age of sedimentation, with at least part of the complex no older than 77.5 ± 2.5 (2σ). Pre-Cretaceous detrital zircons in the complex were derived largely from local sources, including Proterozoic basement, the Neoproterozoic–Cambrian miogeocline and the Jurassic arc. The detrital zircon ages and lithologic character of the Altar complex suggest correlation with the Escalante Formation, the uppermost unit of the Upper Cretaceous El Chanate Group. In contrast, one sample from the Carnero complex yielded a Middle Jurassic maximum depositional age and a detrital zircon age distribution like that of the Jurassic eolianites of the North American Cordillera. The Carnero complex may correlate with the Middle Jurassic Rancho San Martín Formation but could also be a metamorphosed equivalent of the Upper Jurassic Cucurpe Formation, Upper Jurassic to Lower Cretaceous Bisbee Group, or El Chanate Group derived by recycling of Jurassic erg sandstones. The Late Cretaceous age for the Altar complex protolith contradicts models that relate deposition of the entire El Batamote protolith to a basin formed by oblique slip along the Late Jurassic Mojave-Sonora megashear. Instead, the belt is best explained as an assemblage of Middle Jurassic to Upper Cretaceous formations deformed and locally metamorphosed beneath a northeast-directed Laramide thrust complex. Potassium-argon and 40Ar/39Ar ages confirm previous inferences that deformation of El Batamote belt occurred between the Late Cretaceous and late Eocene. A second phase of deformation, involving low-angle normal faults, occurred during and/or after intrusion of the ~22-21 Ma Rancho Herradura granodiorite.

The crucial boundaries in the development of the late cretaceous biota of plankton foraminifers in the southern part of the Indian ocean

2019 ◽  
Vol 59 (6) ◽  
pp. 1074-1085
Author(s):  
E. A. Sokolova
Keyword(s):  
Indian Ocean ◽  
Species Composition ◽  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Planktonic Foraminifera ◽  
The Indian Ocean ◽  
Systematic Composition ◽  
Climatic Series

The article analyzes own data on the species composition of shells of planktonic foraminifera from the Upper Cretaceous sediments of the Indian Oceans, as well as from the sections of the offshore seas of Australia. The species of planktonic foraminifera are grouped and arranged in a climatic series. An analysis of the change in the systematic composition of foraminifers made it possible to distinguish periods of extreme and intermediate climatic states in the Late Cretaceous.

What happened to the organic matter from the Upper Cretaceous succession in Guatemala, Central America?

2021 ◽  
pp. 105246
Author(s):  
Wiesława Radmacher ◽  
Osmín J. Vásquez ◽  
Mario Tzalam ◽  
Mireya Jolomná ◽  
Anny Molineros ◽  
...  
Keyword(s):  
Organic Matter ◽  
Central America ◽  
Upper Cretaceous

scholarly journals The Role of Organic Matter on Uranium Precipitation in Zoovch Ovoo, Mongolia

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 310 ◽  
Author(s):  
Dimitrios Rallakis ◽  
Raymond Michels ◽  
Marc Brouand ◽  
Olivier Parize ◽  
Michel Cathelineau
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Late Cretaceous ◽  
Uranium Deposit ◽  
Vitrinite Reflectance ◽  
Driven Systems ◽  
Sem Observation ◽  
Organic Matter Type ◽  
Clay Layers

The Zoovch Ovoo uranium deposit is located in East Gobi Basin in Mongolia. It is hosted in the Sainshand Formation, a Late Cretaceous siliciclastic reservoir, in the lower part of the post-rift infilling of the Mesozoic East Gobi Basin. The Sainshand Formation corresponds to poorly consolidated medium-grained sandy intervals and clay layers deposited in fluvial-lacustrine settings. The uranium deposit is confined within a 60- to 80-m-thick siliciclastic reservoir inside aquifer driven systems, assimilated to roll-fronts. As assessed by vitrinite reflectance (%Rr < 0.4) and molecular geochemistry, the formation has never experienced significant thermal maturation. Detrital organic matter (type III and IV kerogens) is abundant in the Zoovch Ovoo depocenter. In this framework, uranium occurs as: (i) U-rich macerals without any distinguishable U-phase under SEM observation, containing up to 40 wt % U; (ii) U expressed as UO2 at the rims of large (several millimeters) macerals and (iii) U oxides partially to entirely replacing macerals, while preserving the inherited plant texture. Thus, uranium is accumulated gradually in the macerals through an organic carbon–uranium epigenization process, in respect to the maceral’s chemistry and permeability. Most macerals are rich in S and, to a lesser extent, in Fe. Frequently, Fe and S contents do not fit the stoichiometry of pyrite, although pyrite also occurs as small inclusions within the macerals. The organic matter appears thus as a major redox trap for uranium in this kind of geological setting.

The stability of the stratospheric ozone layer during the end-Permian eruption of the Siberian Traps

2007 ◽  
Vol 365 (1856) ◽  
pp. 1843-1866 ◽  
Author(s):  
David J Beerling ◽  
Michael Harfoot ◽  
Barry Lomax ◽  
John A Pyle
Keyword(s):  
Organic Matter ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Ultraviolet B ◽  
Large Reservoir ◽  
Near Surface ◽  
Siberian Traps ◽  
Northern Latitudes ◽  
The Stability ◽  
Mutagenic Effects

The discovery of mutated palynomorphs in end-Permian rocks led to the hypothesis that the eruption of the Siberian Traps through older organic-rich sediments synthesized and released massive quantities of organohalogens, which caused widespread O 3 depletion and allowed increased terrestrial incidence of harmful ultraviolet-B radiation (UV-B, 280–315 nm; Visscher et al . 2004 Proc. Natl Acad. Sci. USA 101 , 12 952–12 956). Here, we use an extended version of the Cambridge two-dimensional chemistry–transport model to evaluate quantitatively this possibility along with two other potential causes of O 3 loss at this time: (i) direct effects of HCl release by the Siberian Traps and (ii) the indirect release of organohalogens from dispersed organic matter. According to our simulations, CH 3 Cl released from the heating of coals alone caused comparatively minor O 3 depletion (5–20% maximum) because this mechanism fails to deliver sufficiently large amounts of Cl into the stratosphere. The unusual explosive nature of the Siberian Traps, combined with the direct release of large quantities of HCl, depleted the model O 3 layer in the high northern latitudes by 33–55%, given a main eruptive phase of less than or equal to 200 kyr. Nevertheless, O 3 depletion was most extensive when HCl release from the Siberian Traps was combined with massive CH 3 Cl release synthesized from a large reservoir of dispersed organic matter in Siberian rocks. This suite of model experiments produced column O 3 depletion of 70–85% and 55–80% in the high northern and southern latitudes, respectively, given eruption durations of 100–200 kyr. On longer eruption time scales of 400–600 kyr, corresponding O 3 depletion was 30–40% and 20–30%, respectively. Calculated year-round increases in total near-surface biologically effective (BE) UV-B radiation following these reductions in O 3 layer range from 30–60 (kJ m −2  d −1 ) BE up to 50–100 (kJ m −2  d −1 ) BE . These ranges of daily UV-B doses appear sufficient to exert mutagenic effects on plants, especially if sustained over tens of thousands of years, unlike either rising temperatures or SO 2 concentrations.

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