THE REGIONAL GEOLOGY OF THE EXMOUTH PLATEAU

1976 ◽  
Vol 16 (1) ◽  
pp. 1
Author(s):  
J.B. Willcox ◽  
N.F. Exon
Keyword(s):  
Source Rocks ◽  
Shallow Marine ◽  
Regional Geology ◽  
Northern Margin ◽  
Exmouth Plateau ◽  
Plateau Area ◽  
Adjacent Part ◽  
Terrestrial Sediments ◽  
Carbonate Sequence ◽  
Seismic Reflection Profiles

The Exmouth Plateau and adjacent continental slopes cover 300 000 km 2 beyond the Northwest Shelf, in water depths ranging from 800 to 5000 m. The regional geology has been interpreted from 18 000 km of seismic reflection profiles, and ties to exploration wells.The plateau is formed over a major arch and syncline. These structures parallel the Rankin Platform and lie 250 and 100 km respectively to the northwest of it. The dominant structural grain is northeasterly, but easterly and southeasterly cross-trends occur along the northern and southwestern margins respectively. Extensive normal faulting affects the pre-Cretaceous sequence.Basement is overlain by up to 10 000 m of Phanerozoic strata, about half of which probably comprises shallow marine and terrestrial sediments of Silurian to Permian age. As much as 4 000 m of Triassic shallow marine to fluvial sediments overlie the Palaeozoic. The Triassic surface is uneven, extensively block-faulted, and unconformably overlain by up to 2 000 m of Middle Jurassic to Neocomian deltaic sediments. An average of 200 m of mid-Cretaceous shallow marine clastic sediments overlies the Neocomian, and are in turn unconformably overlain by a carbonate sequence of Santonian to Recent age containing two major hiatuses and averaging 700 m thick.The period of block-faulting preceded formation of a northeasterly-trending spreading-centre in the Late Jurassic, which separated the area from the adjacent part of Gondwanaland to the west. An associated easterly-trending transcurrent fault probably formed the northern margin of the Exmouth Plateau. In the Late Cretaceous the area southwest of the plateau collapsed rapidly along a northwesterly-trending fault. Gradual subsidence of the plateau took place throughout the Cainozoic and, at the northern margin, collapse along old easterly trending fault-lines gave rise to grabens south of marginal sub-plateaux. Late Cainozoic warping formed the Exmouth Plateau Arch.Petroleum source rocks, especially Palaeozoic to Neocomian shales and siltstones, and reservoir rocks, especially Triassic and Neocomian sandstones, appear to exist in the Exmouth Plateau area. The depth of burial has probably been adequate to form hydrocarbons from pre-Cretaceous source rocks. Numerous fault traps in Triassic sediments, analogous to those of the Rankin Platform, appear to exist. Other likely petroleum targets are stratigraphic traps in the Jurassic—Neocomian deltaic sequence.

Occurrence and regional geological setting of Paleozoic rocks on the Grand Banks of Newfoundland

1986 ◽  
Vol 23 (4) ◽  
pp. 504-526 ◽  
Author(s):  
Lewis H. King ◽  
Gordon B. J. Fader ◽  
W. A. M. Jenkins ◽  
Edward L. King
Keyword(s):  
Oil And Gas ◽  
Black Shales ◽  
Source Rocks ◽  
Upper Ordovician ◽  
Acoustic Basement ◽  
Lower Paleozoic ◽  
Shallow Marine ◽  
Grand Banks ◽  
Younger Age ◽  
Seismic Reflection Profiles

Analyses of seismic reflection profiles supported by lithological and palynological studies of core samples from submarine outcrops indicate that the lower Paleozoic succession of the Avalon Terrane, southeast Newfoundland, is continuous offshore. The succession crops out over an area greater than 30 000 km2 and is approximately 8 km thick. The sequence is dominantly siltstone and is of Late Cambrian to ?Devonian or younger age. It is relatively unmetamorphosed, underlain by Hadrynian acoustic basement, and overlain along its eastern and southern margins by a Mesozoic–Cenozoic succession that is economically important from an oil and gas perspective.Lithofacies studies indicate that in Early Ordovician time restricted shallow-marine conditions probably prevailed over a vast area of the Avalon Terrane. Upper Ordovician and Silurian siltstones show evidence of deposition under more-dynamic and well-oxygenated conditions and probably represent a normal shallow-marine environment. Redbeds of possible Devonian or younger age are interpreted to be of continental origin. Black shales of Ordovician age are potential source rocks for the generation of hydrocarbons.

Sequence stratigraphy of source and reservoir rocks in the Upper Permian and Jurassic of Jameson Land, East Greenland

1998 ◽  
pp. 43-54 ◽  
Author(s):  
Lars Stemmerik ◽  
Gregers Dam ◽  
Nanna Noe-Nygaard ◽  
Stefan Piasecki ◽  
Finn Surlyk
Keyword(s):  
Sequence Stratigraphy ◽  
Middle Jurassic ◽  
Sedimentary Basins ◽  
Upper Jurassic ◽  
Oil Field ◽  
Source Rocks ◽  
Upper Permian ◽  
Shallow Marine ◽  
East Greenland ◽  
Reservoir Rocks

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Stemmerik, L., Dam, G., Noe-Nygaard, N., Piasecki, S., & Surlyk, F. (1998). Sequence stratigraphy of source and reservoir rocks in the Upper Permian and Jurassic of Jameson Land, East Greenland. Geology of Greenland Survey Bulletin, 180, 43-54. https://doi.org/10.34194/ggub.v180.5085 _______________ Approximately half of the hydrocarbons discovered in the North Atlantic petroleum provinces are found in sandstones of latest Triassic – Jurassic age with the Middle Jurassic Brent Group, and its correlatives, being the economically most important reservoir unit accounting for approximately 25% of the reserves. Hydrocarbons in these reservoirs are generated mainly from the Upper Jurassic Kimmeridge Clay and its correlatives with additional contributions from Middle Jurassic coal, Lower Jurassic marine shales and Devonian lacustrine shales. Equivalents to these deeply buried rocks crop out in the well-exposed sedimentary basins of East Greenland where more detailed studies are possible and these basins are frequently used for analogue studies (Fig. 1). Investigations in East Greenland have documented four major organic-rich shale units which are potential source rocks for hydrocarbons. They include marine shales of the Upper Permian Ravnefjeld Formation (Fig. 2), the Middle Jurassic Sortehat Formation and the Upper Jurassic Hareelv Formation (Fig. 4) and lacustrine shales of the uppermost Triassic – lowermost Jurassic Kap Stewart Group (Fig. 3; Surlyk et al. 1986b; Dam & Christiansen 1990; Christiansen et al. 1992, 1993; Dam et al. 1995; Krabbe 1996). Potential reservoir units include Upper Permian shallow marine platform and build-up carbonates of the Wegener Halvø Formation, lacustrine sandstones of the Rhaetian–Sinemurian Kap Stewart Group and marine sandstones of the Pliensbachian–Aalenian Neill Klinter Group, the Upper Bajocian – Callovian Pelion Formation and Upper Oxfordian – Kimmeridgian Hareelv Formation (Figs 2–4; Christiansen et al. 1992). The Jurassic sandstones of Jameson Land are well known as excellent analogues for hydrocarbon reservoirs in the northern North Sea and offshore mid-Norway. The best documented examples are the turbidite sands of the Hareelv Formation as an analogue for the Magnus oil field and the many Paleogene oil and gas fields, the shallow marine Pelion Formation as an analogue for the Brent Group in the Viking Graben and correlative Garn Group of the Norwegian Shelf, the Neill Klinter Group as an analogue for the Tilje, Ror, Ile and Not Formations and the Kap Stewart Group for the Åre Formation (Surlyk 1987, 1991; Dam & Surlyk 1995; Dam et al. 1995; Surlyk & Noe-Nygaard 1995; Engkilde & Surlyk in press). The presence of pre-Late Jurassic source rocks in Jameson Land suggests the presence of correlative source rocks offshore mid-Norway where the Upper Jurassic source rocks are not sufficiently deeply buried to generate hydrocarbons. The Upper Permian Ravnefjeld Formation in particular provides a useful source rock analogue both there and in more distant areas such as the Barents Sea. The present paper is a summary of a research project supported by the Danish Ministry of Environment and Energy (Piasecki et al. 1994). The aim of the project is to improve our understanding of the distribution of source and reservoir rocks by the application of sequence stratigraphy to the basin analysis. We have focused on the Upper Permian and uppermost Triassic– Jurassic successions where the presence of source and reservoir rocks are well documented from previous studies. Field work during the summer of 1993 included biostratigraphic, sedimentological and sequence stratigraphic studies of selected time slices and was supplemented by drilling of 11 shallow cores (Piasecki et al. 1994). The results so far arising from this work are collected in Piasecki et al. (1997), and the present summary highlights the petroleum-related implications.

scholarly journals A missing link in the peri-Gondwanan terrane collage: the Precambrian basement of the Moroccan Meseta and its lower Paleozoic cover

2018 ◽  
Vol 55 (1) ◽  
pp. 33-51 ◽  
Author(s):  
Dominik Letsch ◽  
Mohamed El Houicha ◽  
Albrecht von Quadt ◽  
Wilfried Winkler
Keyword(s):  
Carbonate Platform ◽  
Source Area ◽  
Source Rocks ◽  
Lower Paleozoic ◽  
Northern Margin ◽  
Precambrian Geology ◽  
The North ◽  
Late Cambrian ◽  
Paleozoic Rocks ◽  
Rifted Margin

This article provides stratigraphic and geochronological data from a central part of Gondwana’s northern margin — the Moroccan Meseta Domain. This region, located to the north of the Anti-Atlas area with extensive outcrops of Precambrian and lower Paleozoic rocks, has hitherto not received much attention with regard to its Precambrian geology. Detrital and volcanic zircon ages have been used to constrain sedimentary depositional ages and crustal affinities of sedimentary source rocks in stratigraphic key sections. Based on this, a four-step paleotectonic evolution of the Meseta Domain from the Ediacaran until the Early Ordovician is proposed. This evolution documents the transition from a terrestrial volcanic setting during the Ediacaran to a short-lived carbonate platform setting during the early Cambrian. The latter then evolved into a rifted margin with deposition of thick siliciclastic successions in graben structures during the middle to late Cambrian. The detritus in these basins was of local origin, and a contribution from a broader source area (encompassing parts of the West African Craton) can only be demonstrated for postrifting, i.e., laterally extensive sandstone bodies that seal the former graben. In a broader paleotectonic context, it is suggested that this Cambrian rifting is linked to the opening of the Rheic Ocean, and that several peri-Gondwanan terranes (Meguma and Cadomia–Iberia) may have been close to the Meseta Domain before drifting, albeit some of them seem to have been constituted by a distinctly different basement.

Petrography and geochemistry of the siliciclastic Araba Formation (Cambrian), east Sinai, Egypt: implications for provenance, tectonic setting and source weathering

2015 ◽  
Vol 154 (1) ◽  
pp. 1-23 ◽  
Author(s):  
HOSSAM A. TAWFIK ◽  
IBRAHIM M. GHANDOUR ◽  
WATARU MAEJIMA ◽  
JOHN S. ARMSTRONG-ALTRIN ◽  
ABDEL-MONEM T. ABDEL-HAMEED
Keyword(s):  
Tectonic Setting ◽  
Source Area ◽  
Xrd Analysis ◽  
Climatic Conditions ◽  
Source Rocks ◽  
Northern Margin ◽  
Rock Fragments ◽  
Geochemical Parameters ◽  
Clastic Sediments ◽  
Chemical Index

AbstractCombined petrographic and geochemical methods are utilized to investigate the provenance, tectonic setting, palaeo-weathering and climatic conditions of the Cambrian Araba clastic sediments of NE Egypt. The ~ 60 m thick Araba Formation consists predominantly of sandstone and mudstone interbedded with conglomerate. Petrographically the Araba sandstones are mostly sub-mature and classified as subarkoses with an average framework composition of Q80F14L6. The framework components are dominated by monocrystalline quartz with subordinate K-feldspar, together with volcanic and granitic rock fragments. XRD analysis demonstrated that clay minerals comprise mixed-layer illite/smectite (I/S), illite and smectite, with minor kaolinite. Diagenetic features of the sandstone include mechanical infiltration of clay, mechanical and chemical compaction, cementation, dissolution and replacement of feldspars by carbonate cements and clays. The modal composition and geochemical parameters (e.g. Cr/V, Y/Ni, Th/Co and Cr/Th ratios) of the sandstones and mudstones indicate that they were derived from felsic source rocks, probably from the crystalline basement of the northern fringe of the Arabian–Nubian Shield. The study reveals a collisional tectonic setting for the sediments of the Araba Formation. Palaeo-weathering indices such as the chemical index of alteration (CIA), chemical index of weathering (CIW) and plagioclase index of alteration (PIA) of the clastic sediments suggest that the source area was moderately chemically weathered. On the northern margin of Gondwana, early Palaeozoic weathering occurred under fluctuating climatic conditions.

THE GEOLOGY AND EVOLUTION OF THE SCOTT PLATEAU

1978 ◽  
Vol 18 (1) ◽  
pp. 34 ◽  
Author(s):  
H. M. J. Stagg
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Structural Evolution ◽  
Source Rocks ◽  
Petroleum Potential ◽  
Reservoir Rocks ◽  
Carbonate Sedimentation ◽  
Sea Bed ◽  
Adjacent Part ◽  
Water Depths

The Scott Plateau and the adjacent Rowley Terrace cover about 130,000 km2 beyond Australia's Northwest Shelf in water depths ranging from 300 m to 3000 m. The regional geology and structural evolution of the area have been interpreted from about 13,000 km of seismic reflection profiles.The Scott Plateau forms a subsided oceanward margin to the Browse Basin. For much of the period from the Carboniferous to the Middle Jurassic, preceding the breakup which formed this part of the continental margin, the Scott Plateau was probably above sea level shedding sediment into the developing Browse Basin. After breakup in the Bathonian to Callovian, the plateau subsided, until by the Late Cretaceous open marine conditions were prevalent over most of the area, with the probable exception of some structurally high areas which may have remained emergent until early in the Tertiary. Carbonate sedimentation commenced in the Santonian and has continued to the present, with major hiatuses in the Paleocene and Oligocene. Analysis of magnetic and seismic data indicates that, over much of the plateau, economic basement of possible Kimberley Block equivalents is probably no more than 3 to 4 km below sea bed. To the south of the Scott Plateau, the Rowley Terrace is underlain by a wedge of at least 6 km of Mesozoic and Tertiary sediments of the northeast- trending Rowley Sub - basin. The Rowley Sub -basin connects with the Beagle Sub-basin to the southwest and probably connects with the Browse Basin to the northeast. It has been largely unaffected by episodes of faulting, except in the southwest where faulting and folding are pronounced. The petroleum potential of the Scott Plateau is not rated highly. The potential hydrocarbon-bearing sediments here are probably no younger than Palaeozoic. These are quite likely to be only 2 to 4 km thick, and any hydrocarbons generated within them would probably have been lost during the protracted period of emergence and erosion that preceded breakup. The hydrocarbon potential appears to be greater in the Rowley Sub-basin, where Triassic to Cretaceous shale and siltstone source rocks, and Triassic to Lower Cretaceous sandstone reservoir rocks are expected to be present. However, the potential of these sequences is downgraded because hydrocarbon shows in exploration wells on the adjacent part of the Northwest Shelf have been only minor, and by the apparent scarcity of suitable traps. Exploitation of any hydrocarbons would be costly owing to the great water depths.

SOUTHERN GEORGINA BASIN: A NEW PERSPECTIVE

1990 ◽  
Vol 30 (1) ◽  
pp. 137 ◽  
Author(s):  
W.R. Lodwick ◽  
J.F. Lindsay
Keyword(s):  
Mirror Image ◽  
Source Rocks ◽  
Carbonate Production ◽  
Northern Margin ◽  
Middle Ordovician ◽  
Upper Proterozoic ◽  
Clastic Sediments ◽  
Early Palaeozoic ◽  
New Perspective ◽  
Reservoir Potential

The Georgina Basin formed as a shallow intracratonic depression on the Australian craton along with a number of other basins in the Proterozoic and early Palaeozoic, probably in response to the break up of the Proterozoic supercontinent. Since all of these basins evolved under similar tectonic and sea-level controls, the basins all have similar sediment successions and, it might thus be assumed, similar petroleum prospectivity. One basin, the Amadeus Basin, currently has petroleum production, suggesting a potential for exploration success in the other intracratonic basins.In the Amadeus Basin the main petroleum prospects lie within or adjacent to major sub-basins that formed along the Basin's northern margin. The Georgina Basin has sub-basins that formed along its southern margin, almost as a mirror image of the Amadeus Basin. The lower Palaeozoic section of the Toko Syncline in the southern Georgina Basin has hydrocarbon shows in Middle Cambrian to Middle Ordovician rocks. Source rocks appear to have developed within the transgressive systems tract and the condensed interval of the highstand systems tract, at times when the basin was starved for clastic sediments and carbonate production was restricted.Seismic data acquired in the 1988 survey are of a higher quality than that previously obtained in the area. Its interpretation portrays the westward thrusting French Fault at the eastern edge of the Toko Syncline with potential hangingwall and footwall traps. Cambro- Ordovician Georgina Basin sediments subcrop the overlying Eromanga Basin with angularity, providing potentially large stratigraphic traps. Fracturing of the Cambrian and Ordovician carbonates within fault zones, and solution porosity at the unconformity, would also enhance reservoir potential in the area. Perhaps most significantly, the new data also shows an earlier, apparently independent basin completely buried beneath the Georgina section. The concealed section may simply be a very thick, early Upper Proterozoic section, or perhaps an equivalent to, or a lateral extension of the McArthur Basin. Recent work in the McArthur Basin has shown considerable source potential in the McArthur and Roper Groups, which may support the possibility of an additional, as yet unrecognised, source beneath the Georgina Basin.

A REVIEW OF RECENT GEOLOGICAL WORK IN THE OFFICER BASIN, SOUTH AUSTRALIA

1980 ◽  
Vol 20 (1) ◽  
pp. 209 ◽  
Author(s):  
G.M. Pitt ◽  
M.C. Benbow ◽  
Bridget C. Youngs
Keyword(s):  
South Australia ◽  
Source Rocks ◽  
Organic Carbon Content ◽  
Petroleum Potential ◽  
Geological Surveys ◽  
Potential Source ◽  
Potential Reservoir ◽  
Carbonate Sequence ◽  
Geological Work ◽  
Australian Department

The Officer Basin of South and Western Australia, in its broadest definition, contains a sequence of Late Proterozoic to pre-Permian strata with an unknown number of stratigraphic breaks. Recent investigations by the South Australian Department of Mines and Energy (SADME), which included helicopter-based geological surveys and stratigraphic drilling, have upgraded the petroleum potential of the basin.SADME Byilkaoora-1, drilled in the northeastern Officer Basin in 1979, contained hydrocarbon shows in the form of oil exuding from partly sealed vugs and fractures in argillaceous carbonates. Equivalent carbonates were intersected in SADME Marla-1A and 1B. Previously, in 1976, SADME Murnaroo-1 encountered shales and carbonates with moderate organic carbon content overlying a thick potential reservoir sandstone, while SADME Wilkinson-1, drilled in 1978, contained a carbonate sequence with marginally mature to mature oil-prone source rocks. Acritarchs extracted from the last mentioned carbonates indicate an Early Cambrian age.All ?Cambrian carbonate sequences recognised to date in the Officer Basin of South Australia are correlated with the Observatory Hill Beds, which are now considered to be the major potential source of petroleum in the eastern Officer Basin.

The Late Cenozoic evolution of the Aksu basin (Isparta Angle; SW Turkey). New insights

2011 ◽  
Vol 182 (2) ◽  
pp. 133-148 ◽  
Author(s):  
André Poisson ◽  
Fabienne Orszag-Sperber ◽  
Erdal Kosun ◽  
Maria-Angella Bassetti ◽  
Carla Müller ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Normal Faults ◽  
The West ◽  
Shallow Marine ◽  
Northern Margin ◽  
Sea Level Fluctuations ◽  
Marine Deposits ◽  
The North ◽  
Sw Turkey ◽  
Isparta Angle

Abstract The Mio-Pliocene basins around the Antalya gulf in SW Turkey developed above the Tauric Mesozoic platforms on which the Antalya nappes had been thrusted (in Late Cretaceous-Paleocene times). The closure of the initial Isparta Angle during these events (E-W compression) initiated the N-S orientation of the main structural lines, which persisted later and explains the orientation of the Aksu basin in contrast with the E-W orientation of the eastern Neo-gene Mediterranean basins. The area, and all southwestern Turkey, became emergent at the end of the Oligocene and were the site of shallow-marine carbonate deposits in the Chattian-Aquitanian, giving way to the wide Lycian basin in Burdigalian-Langhian times. The progressive emplacement of the Lycian nappes from the north over this basin provoked first its subsidence and then its emersion when the nappes attained their final position over the Bey Daglari platform in Langhian times. Coinciding, or in response to the Lycian nappes emplacement, the Aksu basin was initiated as an elongated N-S graben which was filled by thick accumulations of terrestrial and marine deposits(including coral reefs), which derived from the erosion of the Lycian allochton and its basement (Langhian?, Serravallian and Tortonian times). The syn-sedimentary tectonics : reactivation of the normal faults along the west margin of the basin, the continuous uplift of the neighbouring continental areas (beginning of the Aksu thrust), governed the geometry of the basin. As a result and due to the uplift of its northern margin, the Aksu basin migrated towards the south and in Messinian times it was reduced to a narrow gulf along the eastern margin of which the Gebiz limestones were deposited as fringing coral reefs. The age of these limestones has been debated. Our new data allow us to attribute them to the Messinian. The drastic retreat of the sea at the end of this period, provoked the erosion of large parts of the Messinian deposits and the formation of deep canyons on land and under the sea down to the Antalya abyssal plain, in which evaporites were deposited. During the Zanclean transgression, the Eskiköy-Kargi canyon was filled by coarse clastics of a Gilbert delta derived from the northern continental area following a model well known elsewhere in the Mediterranean basins. Southward, shallow-marine sands and marls unconformably cover the remnants of the Messinian deposits and the emergent areas of the southern Antalya gulf. After Zanclean times (end of Pliocene?), the Aksu basin was deformed, due to the west-directed Aksu compressional event (end of the Aksu thrust). Quaternary terraces of the Aksu river at various altitudes, as well as the terraces of the Antalya tufa can be related to sea level fluctuations.

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