THE ROLE OF THE PRE-RIFT STRUCTURE IN THE ARCHITECTURE OF THE DAMPIER BASIN AREA, NORTH WEST SHELF, AUSTRALIA

1994 ◽  
Vol 34 (1) ◽  
pp. 602 ◽  
Author(s):  
Geoff Hill
Keyword(s):  
East Africa ◽  
Sedimentary Cover ◽  
Mobile Belt ◽  
Rift System ◽  
North West ◽  
Margin Setting ◽  
Crustal Block ◽  
Alternate Model ◽  
Extension Direction ◽  
Area North

The Dampier Sub-basin shows many faults oblique to the basin axis. Previous explanations for this range from syn-rift transfer systems through to deep seated wrenching.Multiple rift episodes, with differing stress directions, occur in the area's history, each utilising the pre-existing fault patterns. As basement is difficult to interpret beneath thick sedimentary cover, the initial architecture is interpreted from the tectonic setting.The sub-basin lies adjacent to the Archean Pilbara Craton, a stable crustal block surrounded by ancient mobile belts. The East Africa rift system has also formed in a Craton margin setting. In East Africa earthquake data and detailed seismic interpretation show the rift utilises faults within the mobile belt systems.In the Dampier area, the three different extension vectors combined with the pre-rift fabric and the East Africa analogue, are used to build an alternate model for the basin genesis. Permo-Carboniferous extension sets up a rift system partitioned by the Precambrian fabric. Jurassic extension reactivates these faults but with oblique slip and dip slip movement caused by the new extension direction. This oblique slip causes complex branching arrays of new faults within the cover section. A third extension vector in the Cretaceous subsequently modifies the fabric. The Dampier Sub-basin is seen as a complex failed rift utilising a Precambrian tectonic fabric. The structural inheritance of the pre-rift fabric by each rift episode has affected the geometry of hydrocarbon-bearing structures of the sub-basin.

scholarly journals Structure and evolution of Belomorian-Severodvinsk shear zone in the Late Proterozoic and Phanerozoic, East-European Platform

2019 ◽  
pp. 62-86
Author(s):  
S. Yu. Kolodyazhny ◽  
A. S. Baluev ◽  
D. S. Zykov
Keyword(s):  
Shear Zone ◽  
East European Platform ◽  
Sedimentary Cover ◽  
Deformation Mode ◽  
Mobile Belt ◽  
Rift System ◽  
Zone Length ◽  
East European ◽  
Tension And Compression ◽  
The Baltic

Tectonics, morphological features and development stages of Belomorian-Severodvinsk shear zone (north-western part) found in the East European platform are considered. We traced the shear zone (length ≈1000 km) from NW to SE from the Baltic shield to the Russian plate sedimentary cover. It inherited Paleoproterozoic structures of Belomorian-Lapland mobile belt and Riphean grabens of the White Sea rift system. Belomorian-Severodvinsk zone was represented in the modern structure by a system of neotectonic grabens limited by normal and normal–strike sleep faults and segmented by the transform fault zones. We came to conclusion that the shear zone experienced multiple repeated activation in different dynamic conditions in the Riphean–Phanerozoic. Cyclic alternation of riftogenic trans-tension and compression or transpression conditions in the sequence stages of its development was noted. We defined three cycles of transtensive-transpressive transformations of Belomorian-Severodvinsk shear zone in the Riphean and the Early Vendian. At least four times shear zone suffered changes of deformation mode and directions of shear displacement in the Phanerozoic. The postglacial neotectonic deformations in the Belomorian-Severodvinsk shear zone revealed under the Kola block horizontal movement to the S–E and subsequent counterclockwise rotation.

Stratigraphy, structure and geochemistry of Archaean supracrustal rocks from Oqaatsut and Naajaat Qaqqaat, north-east Disko Bugt, West Greenland

1999 ◽  
pp. 65-78
Author(s):  
Henrik Rasmussen ◽  
Lars Frimodt Pedersen
Keyword(s):  
Tectonic Setting ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
West Greenland ◽  
North West ◽  
North East ◽  
Metavolcanic Rocks ◽  
Arc Setting ◽  
Area North ◽  
Back Arc

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Rasmussen, H., & Frimodt Pedersen, L. (1999). Stratigraphy, structure and geochemistry of Archaean supracrustal rocks from Oqaatsut and Naajaat Qaqqaat, north-east Disko Bugt, West Greenland. Geology of Greenland Survey Bulletin, 181, 65-78. https://doi.org/10.34194/ggub.v181.5114 _______________ Two Archaean supracrustal sequences in the area north-east of Disko Bugt, c. 1950 and c. 800 m in thickness, are dominated by pelitic and semipelitic mica schists, interlayered with basic metavolcanic rocks. A polymict conglomerate occurs locally at the base of one of the sequences. One of the supracrustal sequences has undergone four phases of deformation; the other three phases. In both sequences an early phase, now represented by isoclinal folds, was followed by north-west-directed thrusting. A penetrative deformation represented by upright to steeply inclined folds is only recognised in one of the sequences. Steep, brittle N–S and NW–SE striking faults transect all rock units including late stage dolerites and lamprophyres. Investigation of major- and trace-element geochemistry based on discrimination diagrams for tectonic setting suggests that both metasediments and metavolcanic rocks were deposited in an environment similar to a modern back-arc setting.

Contribution of the different planktonic microbial assemblages to ETS activity in the Ligurian frontal area: north-west Mediterranean Sea

1992 ◽  
Vol 14 (6) ◽  
pp. 835-850 ◽  
Author(s):  
Claude Savenkoff ◽  
Nadja Lins da Silva ◽  
Dominique Lefèvre ◽  
Michel Denis ◽  
Fereidoun Rassoulzadegan
Keyword(s):  
Mediterranean Sea ◽  
Frontal Area ◽  
Ets Activity ◽  
North West ◽  
Area North

Distribution of crustal extension and regional basin architecture of the Albertine rift system, East Africa

2000 ◽  
Vol 17 (10) ◽  
pp. 1131-1150 ◽  
Author(s):  
G.D. Karner ◽  
B.R. Byamungu ◽  
C.J. Ebinger ◽  
A.B. Kampunzu ◽  
R.K. Mukasa ◽  
...  
Keyword(s):  
East Africa ◽  
Rift System ◽  
Crustal Extension ◽  
Albertine Rift

scholarly journals Deep structure of the Anapa flexural-rupture zone, Western Caucasus

2019 ◽  
pp. 3-11
Author(s):  
E. A. Rogozhin ◽  
A. V. Gorbatikov ◽  
Yu. V. Kharazova ◽  
M. Yu. Stepanova ◽  
J. Chen ◽  
...  
Keyword(s):  
Deep Structure ◽  
Sedimentary Cover ◽  
Western Caucasus ◽  
Tectonic Structures ◽  
Deep Roots ◽  
Near Surface ◽  
North West ◽  
The North ◽  
Deep Faults ◽  
Tectonic Zones

In the period from 2007 to 2017 complex geological and geophysical studies were carried out in the three largest flexural-rupture fault zones in the North-West Caucasus (Anapa, Akhtyrka and Moldavan). The micro-seismic sounding (MSM) was used as the main geophysical method. Studies with the help of MSM allowed us to identify the features of the deep structure of the earth’s crust in the study area and to associate them with specific tectonic structures on the surface.The binding was carried out by harmonizing the results of the MSM and the parameters of the section of the sedimentary cover and crustal boundaries according to the drilling data and the work previously performed by the reflected wave method (MOVZ). It was found that the Anapa flexure and longitudinal tectonic zones have clear deep roots, and also separate the pericline of the North-Western Caucasus from the Taman Peninsula and from the lowered blocks of the Northern slope of the folded system.Faults in the study area are divided into: (1) deep faults of the Caucasian stretch, penetrating into the lower crust and even to the upper mantle, and (2) near-surface faults, do not extend to the depths beyond the thickness of the sedimentary cover. The seismogenic role of these tectonic disturbances in the studied seismically active region has been determined.

A Discussion on natural strain and geological structure - Archaean deformation patterns in southern Africa

1976 ◽  
Vol 283 (1312) ◽  
pp. 313-331 ◽  
Keyword(s):  
Shear Zones ◽  
Geological Structure ◽  
Mobile Belt ◽  
Deformation Pattern ◽  
Strain Measurements ◽  
Regional Deformation ◽  
Greenstone Belts ◽  
Extension Direction ◽  
Orogenic Belts ◽  
Limpopo Belt

Strain measurements have been made to help quantify the intensity of deformation and amount of displacement across Archaean greenstone belts in Rhodesia and Botswana and across the gneisses of the Limpopo mobile belt. The area has been divided into three domains based on the orientation of the finite strain fabric and the orientation of the maximum extension direction in associated shear zones. The domains are considered to have different movement patterns and to be similar to small orogenic belts. Early deformation within the greenstone belts accompanied the intrusion of the diaipric granites, but there was also bulk translation and rotation of greenstone belt and gneiss leading to imbrication of the stratigraphic pile and the formation of large nappes of overturned rock. This was followed by regional phases of deformation which affected all the greenstone belts and the gneisses of the Limpopo belt. Detailed strain measurements show a variation in amount of shortening during this phase, from under 30 % across the Shabani-Bellingwe belt in central Rhodesia, to over 60 % across the Tati and Matsitama belts in northern Botswana. Many local variations in intensity of deformation occur within large ductile shear zones and deviations from plane strain may be partly due to such rotational deformation. The regional deformation pattern suggests that there was movement of the Rhodesian craton approximately 200 km to the southwest relative to the gneisses of the Limpopo belt, producing a dominantly flattening deformation in the southwest of Rhodesia, but dominantly simple shear with a nearly horizontal sinistral movement, in the southeast.

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