A NORTH WEST SHELF TRIASSIC REEF PLAY: RESULTS FROM ODP LEG 122

1989 ◽  
Vol 29 (1) ◽  
pp. 328 ◽  
Author(s):  
P.E. Williamson ◽  
N.F. Exon ◽  
B. ul Haq ◽  
U. von Rad
Keyword(s):  
Seismic Reflection ◽  
Upper Triassic ◽  
Seismic Facies ◽  
Late Triassic ◽  
Seismic Reflection Data ◽  
Reef Complex ◽  
North West ◽  
Exmouth Plateau ◽  
The North ◽  
Reflection Data

Site 764 of the Ocean Drilling Program (ODP), drilled during Leg 122 in the Exmouth Plateau region, cored 200 m of Upper Triassic (Rhaetian) reef complex. This site, on the northern Wombat Plateau (northernmost Exmouth Plateau) represents the first discovery of Triassic reefal material near the Australian North West Shelf. Seismic reflection data through Site 764 show that the reef itself corresponds predominantly to a seismically poorly reflective zone. A number of regional unconformities appear to correspond, however, to traceable seismic horizons which pass with reduced amplitude through the reef, indicating stages of reef growth separated by erosion or non- deposition. Seismic facies around the edges of the reef are consistent with the deposition of wedges of prograding reef- derived detritus.Application of the seismic criteria for reef recognition established at ODP Site 764, to other seismic reflection data on the Wombat Plateau, demonstrates that a major Upper Triassic reef complex fringes the margins of the Wombat Plateau. The Wombat Plateau lies at the western end of the North West Shelf, which was part of the southern margin of a warm Tethys Ocean in the Late Triassic, at a palaeolatitude of 25- 30°S. Upper Triassic reefs are known from southeast Indonesia and Papua New Guinea, and now the Wombat Plateau, and may be common elsewhere along the outer margin of the North West Shelf. Upper Triassic reef complexes, with their associated reservoir, source and seal facies, could represent an exciting new petroleum exploration play for the entire North West Shelf. Facies analysis suggests that they are likely only on the outer shelf and slope. Shallow Triassic reef complexes are clearly identifiable using high resolution seismic reflection data. Seismic reflection data of lower resolution may well reveal the associated detrital carbonate wedges, which are more laterally extensive than the reefal core, deeper in the section.

Rift processes in the Westralian Superbasin, North West Shelf, Australia: insights from 2D deep reflection seismic interpretation and potential fields modelling

2015 ◽  
Vol 55 (2) ◽  
pp. 400 ◽  
Author(s):  
Catherine Belgarde ◽  
Gianreto Manatschal ◽  
Nick Kusznir ◽  
Sonia Scarselli ◽  
Michal Ruder
Keyword(s):  
Seismic Reflection ◽  
Potential Fields ◽  
Moho Depth ◽  
Late Permian ◽  
Forward Modelling ◽  
Seismic Reflection Data ◽  
North West ◽  
Reflection Seismic ◽  
The North ◽  
Reflection Data

Acquisition of long-offset (8–10 km), long-record length (12–18 sec), 2D reflection seismic and ship-borne potential fields data (WestraliaSpan by Ion/GXT and New Dawn by PGS) on the North West Shelf of Australia provide the opportunity to study rift processes in the context of modern models for rifted margins (Manatschal, 2004). Basement and Moho surfaces were interpreted on seismic reflection data. Refraction models from Geoscience Australia constrain Moho depth and initial densities for gravity modelling through standard velocity-density transformation. 2D joint inversion of seismic reflection and gravity data for Moho depth and basement density constrain depth to basement on seismic. 2D gravity and magnetic intensity forward modelling of key seismic lines constrain basement thickness, type and density. Late Permian and Jurassic-Early Cretaceous rift zones were mapped on seismic reflection data and constrained further by inversion and forward modelling of potential fields data. The Westralian Superbasin formed as a marginal basin in Eastern Gondwana during the Late Permian rifting of the Sibumasu terrane. Crustal necking was localised along mechanically-weak Proterozoic suture belts or Early Paleozoic sedimentary basins (such as Paterson and Canning). Mechanically-strong cratons (such as Pilbara and Kimberley) remained intact, resulting in necking and hyper-extension at their edges. Late Permian hyper-extended areas (such as Exmouth Plateau) behaved as mechanically-strong blocks during the Jurassic to Early Cretaceous continental break-up. Late Permian necking zones were reactivated as failed-rift basins and localised the deposition of the Jurassic oil-prone source rocks that have generated much of the oil discovered on the North West Shelf.

Three-dimensional geometry and growth of a basement-involved fault network developed during multiphase extension, Enderby Terrace, North West Shelf of Australia

2021 ◽  
Author(s):  
Hongdan Deng ◽  
Ken McClay
Keyword(s):  
Three Dimensional ◽  
Sedimentary Basins ◽  
Fault Reactivation ◽  
Late Triassic ◽  
Seismic Reflection Data ◽  
North West ◽  
Reflection Data ◽  
Data Volume ◽  
Vertical Linkages ◽  
Fault Network

<div>Basement fault reactivation, and the growth, interaction, and linkage with new fault segments are fundamentally three-dimensional and critical for understanding the evolution of fault network development in sedimentary basins. This paper analyses the evolution of a complex, basement-involved extensional fault network on the Enderby Terrace on the eastern margin of the Dampier sub-basin, NW Shelf of Australia. A high-resolution, depth-converted, 3D seismic reflection data volume is used to show that multiphase, oblique extensional reactivation of basement-involved faults controlled the development of the fault network in the overlying strata. Oblique reactivation of the pre-existing faults initially led to the formation of overlying, en échelon Late Triassic – Middle Jurassic fault segments that, as WNW–directed rifting progressed on the margin, linked by breaching of relay ramp to form two intersecting fault systems (F1 and F2-F4). Further reactivation in the Latest Jurassic – Early Cretaceous (NNW–SSE extension) produced an additional set of en échelon fault arrays in the cover strata. The final fault network consists of main or principal faults and subordinate or splay faults, together with branch lines that link the various components. Our study shows that breaching of relay ramps and/or vertical linkages produces vertical and horizontal branch lines giving complex final fault geometries. We find that repeated activity of the basement-involved faults tends to form continuous and planar fault architectures that favor displacement transfer between the main constituent segments along strike and with depth.</div>

Three-dimensional geometry and growth of a basement-involved fault network developed during multiphase extension, Enderby Terrace, North West Shelf of Australia

2021 ◽  
Author(s):  
Hongdan Deng ◽  
Ken McClay
Keyword(s):  
Three Dimensional ◽  
Sedimentary Basins ◽  
Fault Reactivation ◽  
Late Triassic ◽  
Seismic Reflection Data ◽  
North West ◽  
Reflection Data ◽  
Data Volume ◽  
Vertical Linkages ◽  
Fault Network

Basement fault reactivation, and the growth, interaction, and linkage with new fault segments are fundamentally three-dimensional and critical for understanding the evolution of fault network development in sedimentary basins. This paper analyzes the evolution of a complex, basement-involved extensional fault network on the Enderby Terrace on the eastern margin of the Dampier sub-basin, North West Shelf of Australia. A high-resolution, depth-converted, 3-D seismic reflection data volume is used to show that multiphase, oblique extensional reactivation of basement-involved faults controlled the development of the fault network in the overlying strata. Reactivation of the pre-existing faults initially led to the formation of overlying, en échelon Late Triassic−Middle Jurassic fault segments that, as WNW-directed rifting progressed on the margin, linked by breaching of relay zones to form two intersecting fault systems (F1 and F2−F4). Further reactivation in the latest Jurassic−Early Cretaceous (NNW-SSE extension) produced an additional set of en échelon fault arrays in the cover strata. The final fault network consists of main or principal faults and subordinate or splay faults, together with branch lines that link the various components. Our study shows that breaching of relay ramps and/or vertical linkages produces vertical and horizontal branch lines giving complex final fault geometries. We find that repeated activity of the basement-involved faults tends to form continuous and planar fault architectures that favor displacement transfer between the main constituent segments along strike and with depth.

Reprocessing of deep seismic reflection data from the North German Basin with the Common Reflection Surface stack

2009 ◽  
Vol 472 (1-4) ◽  
pp. 273-283 ◽  
Author(s):  
Mi-Kyung Yoon ◽  
Mikhail Baykulov ◽  
Stefan Dümmong ◽  
Heinz-Jürgen Brink ◽  
Dirk Gajewski
Keyword(s):  
Seismic Reflection ◽  
North German Basin ◽  
Seismic Reflection Data ◽  
Deep Seismic Reflection ◽  
The North ◽  
Reflection Data ◽  
Common Reflection Surface ◽  
The Common ◽  
German Basin

scholarly journals Pre-Zechstein structures around the MONA LISA deep seismic lines in the southern Horn Graben area

1999 ◽  
Vol 45 ◽  
pp. 99-116 ◽  
Author(s):  
T. Abramovitz ◽  
H. Thybo
Keyword(s):  
North Sea ◽  
Seismic Reflection ◽  
Normal Incidence ◽  
Lower Permian ◽  
Southeastern Part ◽  
Seismic Reflection Data ◽  
The North ◽  
Reflection Data ◽  
Mona Lisa ◽  
Seismic Lines

Seismic reflection data from the Horn Graben area in the southeastern part of the North Sea, off-shore Denmark, have been interpreted to illustrate the upper crustal structures around the MONA LISA deep seismic lines. The study area comprises the southern Horn Graben area and the eastern part of East North Sea High, where the Caledonian collision suture between Baltica and Eastern Avalonia bends such that the strike direction changes from ESE in the south to NNW in the north. Integrated interpretation of normal-incidence reflection data and wide-angle refraction data reveals substantial occurrences of lower and upper Palaeozoic strata in the area, thickest below the Horn Graben. This may indicate that Horn Graben developed as a graben structure during late Palaeozoic in the former Caledonian foredeep. On the northern and eastern parts of the MONA LISA deep seismic reflection lines 1 and 3, the main E- dipping boundary fault of the southern Horn Graben segment appears to be listric at depth with a sub-horizon-tal detachment at the top of the reflective lower crust. We have mapped the lateral extent of the lower Permian, volcanic Rotliegend reflector in the study area on the basis of seismic lines from the RTD-81 survey. Dipping reflections observed in the sedimentary strata below the Rotliegend reflector are interpreted as Cal-edonian structures generated by folding and deformation in Lower Palaeozoic Baltica shelf sediments in the Caledonian foreland basin. A sequence of S- and W-dipping reflections above 4 s twt are interpreted as preserved Caledonian thrusts in the upper crustal frontal part of the SW-dipping Caledonian Deformation Front.

Revisiting the deep structure of the Northern Carnarvon Basin: insights from new seismic reflection data

2015 ◽  
Vol 55 (2) ◽  
pp. 421
Author(s):  
Paul Bellingham ◽  
Leanne Cowie ◽  
Rod Graham ◽  
Brian Horn ◽  
Kenneth McDermott ◽  
...  
Keyword(s):  
Continental Crust ◽  
Oceanic Crust ◽  
Seismic Reflection ◽  
Deep Structure ◽  
Hydrocarbon Exploration ◽  
Seismic Reflection Data ◽  
Exmouth Plateau ◽  
Reflection Data ◽  
Delta System ◽  
Carnarvon Basin

The Carnarvon Basin has long been a focus for hydrocarbon exploration and development. Many models have been proposed for the basin’s lithospheric structure, although the great thickness of the Mungaroo delta system has hampered the clear imaging of the underlying rift and break-up structure. New deep, long offset seismic reflection data acquired across the basin as a part of ION’s Westralia SPAN survey provide unique imaging of the deep basement structures and the complete overlying sedimentary section. The survey crossed the offshore terrains, from weakly stretched continental crust to oceanic crust. The margin has developed during two major events; one of Permo-Carboniferous age, prior to the Mungaroo delta system, and one of Middle to Upper Jurassic age. There is a possibility that the basement terrain under parts of the Exmouth Plateau is actually Permo-Carboniferous oceanic crust, rather than hyper-extended continental crust or exhumed continental lithospheric mantle. Deformation during the second major event in the Jurassic was focussed in the Barrow-Dampier Sub-basin and at the present day ocean-continent transition with little deformation across the Exmouth Plateau in-between. The only basement involved extension appears to be in the Barrow-Dampier system and appears to be non-volcanic. The outer margin along the northwest edge of the Exmouth Plateau includes significant volcanic input, likely underplating and emplacement of seaward-dipping reflectors.

The prospectivity of the Late Triassic intervals in the outboard Exmouth Plateau, Western Australia

2020 ◽  
Vol 60 (2) ◽  
pp. 742
Author(s):  
Tom Paten
Keyword(s):  
Seismic Survey ◽  
Quality Data ◽  
Late Triassic ◽  
High Quality ◽  
Exploration Process ◽  
North West ◽  
Exmouth Plateau ◽  
The North ◽  
Amplitude Versus Offset ◽  
Northern Carnarvon Basin

The Exmouth Plateau is a deep-water plateau on the Australian continental margin underlain by 10–15 km of flat-lying, tilted and block-faulted Paleozoic–Mesozoic sedimentary rocks, which were deposited predominantly during periods of extension before continental break-up commenced in the middle Jurassic. The recent acquisition of the Mawson MC3D broadband seismic survey provides a modern, high-quality dataset located ~230 km to the north-west of Dampier, in the outboard Exmouth Plateau, in a relatively under-explored portion of the Northern Carnarvon Basin. The Late Triassic Mungaroo Formation is the primary reservoir target for the majority of the exploration in the Exmouth Plateau to date. A detailed investigation into the reservoir potential and prospectivity of the Mungaroo Formation is possible by utilising this modern dataset. The high-quality data presents a high-resolution view of the Rhaetian carbonate reef platforms and pinnacle reef complexes that are present within the Mawson survey footprint, revealing an under-explored play type within the region. The development of a detailed stratigraphic framework through the Late Triassic–Jurassic, combined with the use of attribute analyses and amplitude versus offset products can help de-risk identified prospects and highlight further prospectivity during the exploration process.

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