THE SOUTH AUSTRALIAN CONTINENTAL SHELF AS A HABITAT FOR PETROLEUM

1964 ◽  
Vol 4 (1) ◽  
pp. 53
Author(s):  
Reg. C. Sprigg
Keyword(s):  
Continental Shelf ◽  
Lower Cretaceous ◽  
Structural Break ◽  
Continental Drift ◽  
South Australia ◽  
The South ◽  
The North ◽  
Preferred Habitat ◽  
Murray River ◽  
Petroleum Generation

The Continental Shelf off South Australia is predicted to be a preferred habitat of petroleum. Non-metamorphosed sediments which are known or presumed to extend onto this shelf include Permian, Cretaceous and Cainozoic sediments. A single presumed Permian trough lying seaward of, and sub-parallel to, the Coorong is interpreted (aeromagnetic data) to extend to possibly 4,000 feet. As part of the Permian fossil valley system of central-eastern South Australia is is predicted to be filled by shales and sands with limited marine facies, and by glacigene sediments. The north-south orientation of the trough would require a landmass to the south from which the Permian glaciers originated. Some form of continental drift may be required to satisfy this requirement.An east-west graben or geosyncline (Gambier-Otway Basin) choked with Cretaceous mudstones and sub-greywackes projects across the shelf in the extreme south-east. Landward dips at depth extending well out beneath the shelf, may suggest a southerly boundary to the basin consistent with a pre-existing landmass in this direction.Extensive erosion at the close of Lower Cretaceous times accords with major geological change at least in more southerly shelf areas. Marine sedimentary onlap and overlap become conspicuous elements, and the accumulation of oceanward thickening sedimentary deposits is more in keeping with outbuilding terrace development. A major structural break accordingly is indicated at the end of the Lower Cretaceous, at which time development of the modern continental shelf began.The Murray River had its principal outlets in the extreme south-east zone during mid-Cretaceous to early Tertiary times, but shifted to its present position during late Cainozoic at which time its sediments were swept across the developing shelf south of Kangaroo Island. Thick sedimentary developments in each of these areas provide promising environment for petroleum generation. These are areas of extensive coastal bitumen activity.Principal petroleum prospects are to be expected within the Middle Cretaceous to Tertiary developments, but older Cretaceous and Permian deposits are potentially prospective.

Dispersion of long-nosed fur seals (Arctocephalus forsteri) determined by tagging

2019 ◽  
Vol 67 (3) ◽  
pp. 173
Author(s):  
Peter D. Shaughnessy ◽  
Simon D. Goldsworthy
Keyword(s):  
Satellite Telemetry ◽  
South Australia ◽  
North Coast ◽  
The South ◽  
The West ◽  
Subtropical Front ◽  
The North ◽  
Fur Seals

Long-nosed fur seals (Arctocephalus forsteri) were tagged as pups in colonies on Kangaroo Island, South Australia in eight consecutive pupping seasons from 1988–89 to 1995–96. Thirty-nine tagged animals were sighted on the southern Australian coast, being 0.89% of those tagged. They were aged from 9 months to 14 years 6 months, with half in their second and third years. Most records (88%) were of animals that moved eastwards. The most distant records were from Sydney in the east (1700 km), south of Tasmania in the south (1240 km) and Head of Bight in the west (700 km). One animal was seen twice, both times on the north coast of Kangaroo Island, once underwater and two years later ashore. Satellite telemetry studies of juvenile A. forsteri from Kangaroo Island showed that they typically forage in pelagic waters ~1000 km further south in association with the subtropical front. The study reported here shows that some animals tagged as pups disperse widely as juveniles around the southern Australian coast. The possibility of genetic interchange between breeding colonies is suggested by sightings of three tagged females aged 4 years and older at non-natal colonies.

scholarly journals Organic matter identification in source and reservoir carbonate in the Lower Cretaceous Mauddud Formation in Kuwait

GeoArabia ◽  
2005 ◽  
Vol 10 (4) ◽  
pp. 17-34
Author(s):  
Fowzia H. Abdullah ◽  
Bernard Carpentier ◽  
Isabelle Kowalewski ◽  
Frans van Buchem ◽  
Alain-Yves Huc
Keyword(s):  
Gas Chromatography ◽  
Organic Matter ◽  
Source Rock ◽  
Lower Cretaceous ◽  
Carbonate Rocks ◽  
Total Organic Matter ◽  
The South ◽  
Core Samples ◽  
The North ◽  
Kerogen Type

ABSTRACT The purpose of this study is to identify the source rock, reservoirs and nonproductive zones in the Lower Cretaceous Mauddud Formation in Kuwait, using geochemical methods. This formation is one of the major Cretaceous oil reservoirs. It is composed mainly of calcarenitic limestone interbedded with marl and glauconitic sands. Its thickness ranges from almost zero in the south to about 100 m (328 ft) in the north. A total of 99 core samples were collected from six oil fields in Kuwait: Raudhatain, Sabiriyah and Bahra in the north, and from the Burgan, Ahmadi and Magwa in the south. Well logs from these fields (gamma ray GR, sonic, resistivity, density) were correlated and used in the study. The core samples were screened for the amount and nature of the organic matter by Rock-Eval 6 pyrolysis (RE6) using reservoir mode. A set of samples was selected to study the properties of the organic matter including the soluble and insoluble organic parts. The geochemical characterisation was performed using different methods. After organic solvent extraction of rock samples, the solvent soluble organic matter or bitumen was characterised in terms of saturates, aromatics and heavy compounds (resins and asphaltenes). Then the hydrocarbon distribution of saturates was studied using gas chromatography (GC/FID) and gas chromatography-mass spectrometry (GC/MS) for tentative oil-source rock correlation. After mineral matrix destruction of previously extracted rocks, insoluble organic matter or kerogen was analysed for its elemental composition to identify kerogen type. The geology and the analytical results show similarities between the wells in the southern fields and the wells in the northern fields. Average Total Organic Matter (TOC) in the carbonate facies is 2.5 wt.% and the highest values (8.0 wt.%) are in the northern fields. The clastic intervals in the northern fields show higher total organic matter (1.3 wt.%) relative to the southern fields (0.6 wt.%). The total Production Index is higher in the carbonate (0.6) than the clastic section (0.3). This reflects the amount of extractable hydrocarbons, which are usually associated with the carbonate section in this formation, representing its reservoir section. Although the carbonate rocks are dominated by richer total organic matter, there are some intervals, with low total organic matter values (0.07 wt.%), representing its poor reservoir sections. The kerogen type varies between type II-III and III in the shales with a slightly better quality in the carbonate section. It is immature in almost all the studied fields. The composition of the rock extract has no relation with the rock type. Some sandstone show similar extract composition to the carbonate rocks in the reservoir intervals. The extracts from these intervals show different genetic nature than those in the shales. The maturity level in the reservoir extract is much higher than in the shale intervals. Thus, the oil accumulated in the reservoir might be largely related to migrated oil from a more mature source rock deposited in a clearly different environment than the associated shaly intervals. The best candidates being a more deeply buried Early Cretaceous Sulaiy Formation and Upper Jurassic Najmah Formation.

scholarly journals A Cretaceous dinoflagellate cyst zonation for NE Greenland

2019 ◽  
Vol 157 (10) ◽  
pp. 1658-1692 ◽  
Author(s):  
H. Nøhr-Hansen ◽  
S. Piasecki ◽  
P. Alsen
Keyword(s):  
North Sea ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Barents Sea ◽  
The South ◽  
Norwegian Sea ◽  
Dinoflagellate Cyst ◽  
The North ◽  
Northern North Sea ◽  
First Time

AbstractA palynostratigraphic zonation is for the first time established for the entire Cretaceous succession in NE Greenland from Traill Ø in the south to Store Koldewey in the north (72–76.5° N). The zonation is based on samples from three cores and more than 100 outcrop sections. The zonation is calibrated to an updated ammonite zonation from the area and to palynozonations from the northern North Sea, Norwegian Sea and Barents Sea areas. The palynozonation is primarily based on dinoflagellate cyst and accessory pollen. The Cretaceous succession is divided into 15 palynozones: seven Lower Cretaceous zones and eight Upper Cretaceous zones. The two lowermost zones are new. The following five (Lower Cretaceous) zones have already been described. Two of the Upper Cretaceous zones are new. The zones have been subdivided into 20 subzones, 11 of which have been described previously and one of which has been revised/redefined. Nine subzones (Upper Cretaceous) are new. More than 100 stratigraphical events representing more than 70 stratigraphic levels have been recognized and presented in an event-stratigraphic scheme.

OIL AND GAS PROSPECTS OF THE GELTWOOD BEACH ANTICLINE, MILLICENT, SOUTH AUSTRALIA

1963 ◽  
Vol 3 (1) ◽  
pp. 69
Author(s):  
R. C. SPRIGG ◽  
J. B. WOOLLEY
Keyword(s):  
Continental Shelf ◽  
Oil And Gas ◽  
South Australia ◽  
Surface Expression ◽  
North West ◽  
The North ◽  
Published Evidence ◽  
Industrial Town ◽  
Half Graben ◽  
Oil Seepage

The Geltwood Beach (buried) anticline is located near the ocean coast in south-east South Australia, directly west of the agricultural and industrial town of Millicent. The structure is developed in Mesozoic to Tertiary sediments forming the inner part of the continental sedimentary terrace which in this situation coincides also with the Nelson "half-graben".The Geltwood Beach anticline is more than five miles long by two or more miles wide. It is part of a still larger regional development which pitches south-east into the deeper known portions of the Gambier-Otway Cretaceous to Tertiary Basin. There is no surface expression to the structure.Structural "closure" on the base of the Tertiary may not exceed 100 feet, but an extensive area of structural flattening along the crest of the anticline (defined by structural drilling and geophysical techniques) overlies a zone of extensive sedimentary wedge-out within the predicted and prospective cretaceous sediments in depth. The wedging is predicted to be in the nature of progressive overlap onto structural "nosing" or alternatively, buried-ridge development in presumed Otway Group sediments in depth.A thickness of 5,000 to 8,000 feet of unconsolidated Upper Cretaceous to Tertiary sediments, wedging to the north-west along the crest of the anticline in the deeper developments is expected to include the prospective Belfast Mudstone equivalents and related beds of the Port Campbell (Victoria) Association.The Geltwood Beach structure lies approximately half way between the Mt. Salt No. 1 and Beachport No. 1 wells. In the distance of 45 miles between the latter wells, the dominantly Cretaceous (post-Otway) sedimentary section wedges spectacularly from 7,000 feet (possibly considerably more) to no more than 100 feet. The available geophysical evidence suggests that most of this wedging occurs within the zone of the Geltwood Beach anticline. For this reason, the anticline is believed to be well located for the development of structural and stratigraphic traps in a marginal continental shelf environment of proven thick sedimentation.In the Mt. Salt No. 1 well, clays and shales encountered at at least five stratigraphic levels within the Lower Tertiary to Middle Cretaceous section provided adequate capping to underlying highly porous and permeable reservoir sands, the lowermost of which were brine-bearing.Geltwood Beach is a locale of preferred coastal bitumen stranding. The weight of published evidence now points to nearby submarine seepage within the reach of erosive storm waves: recorded earthquakes in this vicinity are known to have greatly affected the activity of these seepages.The conclusion is reached that the Geltwood Beach anticline is favourably situated up-dip on the inner continental shelf margin to accumulate hydrocarbons in potentially commercial quantities. The structure lies south of the Beachport-Kalangadoo "hinge-line" of the Nelson half-graben in a zone of submarine oil seepage. A proposed deep test well to be located near the culmination of shallower structure is expected to provide a satisfactory test in respect to both structural and (to a lesser extent) deeper stratigraphic entrapment of petroleum.

Trends in abundance of New Zealand fur seals, Arctocephalus forsteri, at the Neptune Islands, South Australia

2002 ◽  
Vol 29 (4) ◽  
pp. 363 ◽  
Author(s):  
P. D. Shaughnessy ◽  
A. McKeown
Keyword(s):  
New Zealand ◽  
South Australia ◽  
The South ◽  
The North ◽  
Fur Seals ◽  
Fur Seal ◽  
Seal Population ◽  
Island Group ◽  
Direct Counting ◽  
New Zealand Fur Seal

At the Neptune Islands in early February 2000 at the end of the 1999–2000 pupping season, the abundance of New Zealand fur seal pups was determined using a mark–recapture technique in large colonies and by direct counting in small ones. Pups (n = 2355) were marked by clipping hair on the head to reveal light-coloured underfur. At the North Neptune group, there were 4221 pups and at the South Neptune group 1767 pups, making a total of 5988 pups for the Neptune Island group as a whole. At the North Neptune Islands, pup numbers increased by 53% since February 1993, from 2756 to 4221. For the South Neptune group, pup numbers decreased by 6.7%, from 1893 to 1767. The decrease was spread over most colonies on the island. The large increase in pup numbers at the North Neptune group indicates that the population there is in the recolonisation phase of growth; at the South Neptune group, the fur seal population is likely to be in the maturity phase, with fluctuations in size expected in the future. The Neptune Island group supports the largest aggregation of pinnipeds in Australia.

Incidence on Polypogon monspeliensis of Clavibacter toxicus and Anguina sp., the organisms associated with 'flood plain staggers' in South Australia

1995 ◽  
Vol 35 (5) ◽  
pp. 567 ◽  
Author(s):  
T Bertozzi ◽  
AC McKay
Keyword(s):  
South Australia ◽  
Flood Plain ◽  
Survey Area ◽  
The South ◽  
Flood Plains ◽  
Murray River ◽  
Flood Prone Areas

During 1991-92, a survey was conducted in South Australia to determine the distribution of the nematode Anguina sp. and bacterium Clavibacter toxicus associated with 'flood plain staggers'. Polypogon monspeliensis (annual beardgrass) was examined at 265 sites in flood-prone areas in the South East. Seed-galls produced by Anguina sp. were observed at 96 sites, and at 78 of these, seed heads infected with C. toxicus were observed. Infected sites were observed throughout the survey area, with the greatest concentration between Naracoorte and Kingston. No infected Agrostis avenacea (annual blowngrass) was found in the South East or along the flood plains of the Murray River.

Introduction

1965 ◽  
Vol 258 (1088) ◽  
Keyword(s):  
Rock Magnetism ◽  
Continental Drift ◽  
Francis Bacon ◽  
The South ◽  
The North ◽  
The World ◽  
The Subject ◽  
Straits Of Magellan

When, about fifteen years ago, I along with many other new workers in the field of rock magnetism, started to read ourselves into the subject of continental drift, we found a complex, controversial and perplexing situation, with a very long history. In about 1620, Francis Bacon, in his search for regularities in nature, wrote: ‘...the very configuration of the world itself in its greater parts presents Conformable Instances which are not to be neglected. Take for example Africa and the region of Peru with the continent stretching to the Straits of Magellan, in each of which tracts there are similar isthmuses and similar promontories; which can hardly be by accident. Again, there is the Old and New W orld; both of which are broad and extended towards the north, narrow and pointed towards the south.’ Though Bacon thought the similarity of shape could not be by accident, he did not explicitly suggest that the two continents might have once been together. This hypothesis seems to have been first mentioned by von Humboldt about 1800: he also suggested a possible mechanism as to how the continents might have drifted apart:

scholarly journals A Model for the evolution of the Weald

2002 ◽  
Vol 49 ◽  
pp. 109-118
Author(s):  
David Lundbek Hansen ◽  
Søren Bom Nielsen ◽  
Derek J. Blundell
Keyword(s):  
Lower Cretaceous ◽  
Mechanical Model ◽  
Normal Faults ◽  
Crustal Extension ◽  
The South ◽  
Physical Explanation ◽  
Extensional Basin ◽  
The North ◽  
Sequence Of Events ◽  
Seismic Sections

The Weald Basin developed through the Jurassic–Lower Cretaceous as an extensional basin founded upon E–W trending low-angle faults that were probably Variscan thrusts, subsequently reactivated as normal faults. Later, the basin was inverted and uplifted into a broad dome, whilst the London Basin to the north, and the Hampshire–Dieppe Basin to the south, subsided as flanking basins during the late Palaeocene–Eocene. Seismic sections across the Weald indicate that inversion resulted from north-directed stress. A stratigraphic reconstruction based on a N–S profile across the Weald and flanking basins serves as a template for a forward, 2D thermo-mechanical model that simulates the evolution of the Weald Basin through crustal extension and its inversion, and subsidence of the flanking basins, through compression. The model provides a physical explanation for this sequence of events, requiring a region of crust of reduced strength relative to its flanks. This weak region is the location of crustal-scale Variscan thrusts that have been reactivated subsequently. The strong crust on the flanks is essential for the development of flanking basins during inversion and uplift of the Weald.

The Auk Field, Block 30/16, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 227-236 ◽  
Author(s):  
Nigel H. Trewin ◽  
Mark G. Bramwell
Keyword(s):  
North Sea ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
The South ◽  
Well Control ◽  
Western Margin ◽  
The North ◽  
Fault Block ◽  
Definition Of ◽  
Central North Sea

AbstractThe Auk field is located in Block 30/16 at the western margin of the Central Graben. Oil is contained in a combination stratigraphic and structural trap which is sealed by Cretaceous chalk and Tertiary claystones. An oil column of up to 400 ft is contained within Rotliegend sandstones, Zechstein dolomites, Lower Cretaceous breccia and Upper Cretaceous chalk. Production has taken place since 1975 with 80% coming from the Zechstein, in which the best reservoir lithology is a vuggy fractured dolomite where porosity is entirely secondary due to the dolomitization process and leaching of evaporites. Both Rotliegend dune slipface sandstones, and the Lower Cretaceous breccia comprising porous Zechstein clasts in a sandy matrix, also contribute to production. Poor seismic definition of the reservoir results in reliance on well control for detailed reservoir definition. The field has an estimated ultimate recovery of 93 MMBBL with 13 MMBBL remaining at the end of 1988.The Auk field is situated in Block 30/16 of the Central North Sea about 270 km ESE from Aberdeen in 240-270 ft of water (Fig. 1). The field covers an area of about 65 km2 and is a combination of tilted horst blocks and stratigraphic traps, located at the western margin of the South West Central Graben. The Auk horst is about 20 km long and 6-8 km wide, with a NNW-SSE trend. It is bounded on the west by a series of faults with throws of up to 1000 ft, and the eastern boundary fault has a throw of 5000 ft in the north reducing to zero in the south (Fig. 2). The horst is a westward tilted fault block in the north which grades into a faulted anticline in the south. The Auk accumulation is largely contained within Zechstein dolomites and is ultimately sealed by Cretaceous chalk which overlies the base Cretaceous erosion surface. An E-W cross-section of the field is illustrated by Fig. 3. Auk was the first of the alphabetical sequence of North Sea sea-bird names used for Shell/ Esso fields.

Chemical and biological observations on some volcanic lakes in the south-east of South Australia

1964 ◽  
Vol 15 (2) ◽  
pp. 123 ◽  
Author(s):  
IAE Bayly ◽  
WD Williams
Keyword(s):  
Ionic Composition ◽  
South Australia ◽  
Biological Data ◽  
Chemical Data ◽  
The South ◽  
North West ◽  
The North ◽  
Volcanic Lakes

Chemical and biological data are given relating to the four lakes near Mount Gambier, South Australia, and to Lake Leake about 32 km to the north-west. The chemical data reveal that despite some similarities there are clear differences in ionic composition between the lakes. These differences are explained as being due to the differing importance of terrestrial and atmospheric ion supply. The biological data are discussed principally from a distributional viewpoint.

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