CONTINENTAL SHELF BASINS ON THE WEST TASMANIA MARGIN

1992 ◽  
Vol 32 (1) ◽  
pp. 231 ◽  
Author(s):  
A.M.G. Moore ◽  
J.B. Willcox ◽  
N.F. Exon ◽  
G.W. O'Brien
Keyword(s):  
Continental Shelf ◽  
Continental Slope ◽  
Late Cretaceous ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Strike Slip ◽  
Source Rocks ◽  
Fault System ◽  
The West ◽  
Shallow Marine

The continental margin of western Tasmania is underlain by the southern Otway Basin and the Sorell Basin. The latter lies mainly under the continental slope, but it includes four sub-basins (the King Island, Sandy Cape, Strahan and Port Davey sub-basins) underlying the continental shelf. In general, these depocentres are interpreted to have formed at the 'relieving bends' of a major left-lateral strike-slip fault system, associated with 'southern margin' extension and breakup (seafloor spreading). The sedimentary fill could have commenced in the Jurassic; however, the southernmost sub-basins (Strahan and Port Davey) may be Late Cretaceous and Paleocene, respectively.Maximum sediment thickness is about 4300 m in the southern Otway Basin, 3600 m in the King Island Sub-basin, 5100 m in the Sandy Cape Basin, 6500 m in the Strahan Sub-basin, and 3000 m in the Port Davey Sub-basin. Megasequences in the shelf basins are similar to those in the Otway Basin, and are generally separated by unconformities. There are Lower Cretaceous non-marine conglomerates, sandstones and mudstones, which probably include the undated red beds recovered in two wells, and Upper Cretaceous shallow marine to non-marine conglomerates, sandstones and mudstones. The Cainozoic sequence often commences with a basal conglomerate, and includes Paleocene to Lower Eocene shallow marine sandstones, mudstones and marl, Eocene shallow marine limestones, marls and sandstones, and Oligocene and younger shallow marine marls and limestones.The presence of active source rocks has been demonstrated by the occurrence of free oil near TD in the Cape Sorell-1 well (Strahan Sub-basin), and thermogenic gas from surficial sediments recovered from the upper continental slope and the Sandy Cape Sub-basin. Geohistory maturation modelling of wells and source rock 'kitchens' has shown that the best locations for liquid hydrocarbon entrapment in the southern Otway Basin are in structural positions marginward of the Prawn-1 well location. In such positions, basal Lower Cretaceous source rocks could charge overlying Pretty Hill Sandstone reservoirs. In the King Island Sub-Basin, the sediments encountered by the Clam-1 well are thermally immature, though hydrocarbons generated from within mature Lower Cretaceous rocks in adjacent depocentres could charge traps, providing that suitable migration pathways are present. Whilst no wells have been drilled in the Sandy Cape Sub-basin, basal Cretaceous potential source rocks are considered to have entered the oil window in the early Late Cretaceous, and are now capable of generating gas/condensate. Upper Cretaceous rocks appear to have entered the oil window in the Paleocene. In the Strahan Sub-Basin, mature Cretaceous sediments in the depocentres are available to traps, though considerable migration distances would be required.It is concluded that the west Tasmania margin, which has five strike-slip related depocentres and the potential to have generated and entrapped hydrocarbons, is worthy of further consideration by the exploration industry. The more prospective areas are the southern Otway Basin, and the Sandy Cape and Strahan sub-basins of the Sorell Basin.

Walker Creek fault zone, central Rocky Mountains, British Columbia-southern continuation of the Northern Rocky Mountain Trench fault zone

2000 ◽  
Vol 37 (9) ◽  
pp. 1259-1273 ◽  
Author(s):  
M E McMechan
Keyword(s):  
Fault Zone ◽  
Late Cretaceous ◽  
Lateral Displacement ◽  
Shear Bands ◽  
Rocky Mountain ◽  
Strike Slip ◽  
Fault System ◽  
Early Eocene ◽  
Fold And Thrust Belt ◽  
Slip Displacement

Walker Creek fault zone (WCFZ), well exposed in the western Rocky Mountains of central British Columbia near 54°, comprises a 2 km wide zone of variably deformed Neoproterozoic and Cambrian strata in fault-bounded slivers and lozenges. Extensional shear bands, subhorizontal extension lineations, slickensides, mesoscopic shear bands, and other minor structures developed within and immediately adjacent to the fault zone consistently indicate right-lateral displacement. Offset stratigraphic changes in correlative Neoproterozoic strata indicate at least 60 km of right-lateral displacement across the zone. WCFZ is the southern continuation of the Northern Rocky Mountain Trench (NRMT) fault zone. It shows a through going, moderate displacement, strike-slip fault system structurally links the NRMT and the north-central part of the Southern Rocky Mountain Trench. Strike-slip motion on the WCFZ occurred in the Late Cretaceous to Early Eocene at the same time as northeast-directed shortening in the fold-and-thrust belt. Thus, oblique convergence in the eastern part of the south-central Canadian Cordillera was apparently resolved into parallel northwest-striking zones of strike-slip and thrust faulting during the Late Cretaceous to Early Eocene. The change in the net Late Cretaceous to Early Eocene displacement direction for rocks in the Rocky Mountain trenches from north (56-54°N) to northeast (52-49°N) suggests that the disappearance of strike-slip displacement and increase in fold-and-thrust belt shortening in the eastern Cordillera between 56° and 49°N is largely the result of a north-south change in relative plate motion or strain partitioning across the Cordillera, rather than the southward transformation of right-lateral strike-slip displacement on the Tintina - NRMT fault system into compressional deformation.

Structure Evolution of Qinjiatun-Qindong Fault System in Lishu Subbasin

2013 ◽  
Vol 734-737 ◽  
pp. 170-177
Author(s):  
Shao Dong Qu ◽  
Chi Yang Liu ◽  
Li Jun Song ◽  
Hui Deng ◽  
Long Zhang ◽  
...  
Keyword(s):  
Fault Zone ◽  
Structure Analysis ◽  
Late Cretaceous ◽  
Seismic Data ◽  
Three Dimensional ◽  
Strike Slip ◽  
Fault System ◽  
Structure Evolution ◽  
Active Stage ◽  
Regional Stress

Three-dimensional(3-D) seismic data and structure analysis of the Lishu subasin in Songliao basin indicates that Qinjiatun fault zone is composed of two faults: East-Qin and West-Qin fault. This fault system initially formed at Huoshiling stage, peaked at Shahezi stage and faded dramatically from Yingcheng stage. The Qinjiatun fault was important in controlling strata thickness and distribution of the Huoshiling formation. Qindong fault, a typical strike-slip fault, developed relatively later, cutting the Qinjiatun fault, The major active stage was in Denglouku-Quantou stage, and weakened in the end of late Cretaceous. Qinjiatun fault zone was reversed at Denglouku stage when the regional stress went compressive, generating a structure nose that was potentially beneficial for hydrocarbon to accumulate. The strike-slip Qindong fault became active relatively later, cutting through the previous strata and proving pathways for both accumulation and effusion of hydrocarbon.

The effects of strike-slip motion along the Cobequid - Chedabucto - southwest Grand Banks fault system on the Cretaceous-Tertiary evolution of Atlantic Canada

2004 ◽  
Vol 41 (7) ◽  
pp. 799-808 ◽  
Author(s):  
Georgia Pe-Piper ◽  
David J.W Piper
Keyword(s):  
Late Cretaceous ◽  
Fracture Zone ◽  
Large Scale ◽  
Strike Slip ◽  
Fault System ◽  
Grand Banks ◽  
Tectonic Model ◽  
Geological Features ◽  
Cretaceous Volcanism ◽  
Slip Motion

The Newfoundland Fracture Zone, the southwest Grand Banks transform, and the Cobequid–Chedabucto fault zone form a linked strike-slip fault system from the Atlantic Ocean to southeastern Canada. This paper suggests that several large-scale geological features in southeastern Canada are the result of a small amount of strike-slip motion on the system during the mid Cretaceous and Oligocene. Regional extension features developed in the releasing bend in the Laurentian sub-basin during the mid Cretaceous, but the same area experienced Oligocene compression. This tectonic model accounts for the distribution of mid-Cretaceous volcanism, fault-bounded basins, and regional unconformities, as well as mid to late Cretaceous subsidence of the Scotian basin and Oligocene uplift of the eastern Scotian Shelf.

Late Cretaceous – Tertiary sediments offshore central West Greenland: lithostratigraphy, sedimentary evolution, and petroleum potential

1985 ◽  
Vol 22 (7) ◽  
pp. 1001-1019 ◽  
Author(s):  
Flemming Rolle
Keyword(s):  
Upper Cretaceous ◽  
Source Rocks ◽  
Petroleum Potential ◽  
Shallow Marine ◽  
West Greenland ◽  
Reservoir Rocks ◽  
Sedimentary Sequences ◽  
Sedimentary Evolution ◽  
Petroleum Generation ◽  
Exploratory Wells

Five dry exploratory wells were drilled through Upper Cretaceous and Tertiary sediments on the West Greenland shelf in 1976 and 1977. Two of these entered Precambrian basement, two bottomed in Paleocene or Upper Cretaceous basalt, and one in Campanian mudstone. On the basis of samples and logs supplied to the Geological Survey of Greenland the sedimentary sequence has been divided into seven new formations: the Campanian Narssarmiut Formation, consisting of coarse basement wash and black mudstone; the Campanian to Eocene Ikermiut Formation, consisting of marine organic-rich mudstone; the Upper Paleocene to Eocene Hellefisk Formation, comprising shallow-marine to paralic sandstone and mudstone; the Eocene Nukik Formation, consisting of turbiditic sandstone and mudstone; the Eocene to Oligocene Kangâmiut Formation of shelf to shallow-marine clean and argillaceous sandstone; the Oligocene to Neogene Manîtsoq Formation, consisting of coarse paralic to fan delta sandstone; and the Neogene Ataneq Formation, consisting of protected shallow-marine mudstone.The sedimentary evolution of the area fits well with earlier proposed models for the tectonic evolution of the Baffin Bay–Labrador Sea region.Potential petroleum source rocks are present in the Upper Cretaceous to Paleocene mudstone, and, even though they are largely immature in the drilled sections, they are expected to have entered the petroleum generation zone in the deeper parts of the basin. Their potential is mainly for gas, but some oil potential is also present. No reservoir rocks were encountered in the deeper parts of the sedimentary sequences, and the porous sandstones that occur higher in the sequence lack seals.

scholarly journals Spatial evolution of Zagros collision zone in Kurdistan, NW Iran: constraints on Arabia–Eurasia oblique convergence

Solid Earth ◽  
2016 ◽  
Vol 7 (2) ◽  
pp. 659-672 ◽  
Author(s):  
Shahriar Sadeghi ◽  
Ali Yassaghi
Keyword(s):  
Late Cretaceous ◽  
Strike Slip ◽  
Suture Zone ◽  
Fault System ◽  
Spatial Evolution ◽  
Nw Iran ◽  
Collision Zone ◽  
Deformation Partitioning ◽  
Oblique Convergence ◽  
External Part

Abstract. Stratigraphy, detailed structural mapping and a crustal-scale cross section across the NW Zagros collision zone provide constraints on the spatial evolution of oblique convergence of the Arabian and Eurasian plates since the Late Cretaceous. The Zagros collision zone in NW Iran consists of the internal Sanandaj–Sirjan, Gaveh Rud and Ophiolite zones and the external Bisotoun, Radiolarite and High Zagros zones. The Main Zagros Thrust is the major structure of the Zagros suture zone. Two stages of oblique deformation are recognized in the external part of the NW Zagros in Iran. In the early stage, coexisting dextral strike-slip and reverse dominated domains in the Radiolarite zone developed in response to deformation partitioning due to oblique convergence. Dextral-reverse faults in the Bisotoun zone are also compatible with oblique convergence. In the late stage, deformation partitioning occurred during southeastward propagation of the Zagros orogeny towards its foreland resulting in synchronous development of orogen-parallel strike-slip and thrust faults. It is proposed that the first stage was related to Late Cretaceous oblique obduction, while the second stage resulted from Cenozoic collision. The Cenozoic orogen-parallel strike-slip component of Zagros oblique convergence is not confined to the Zagros suture zone (Main Recent Fault) but also occurred in the external part (Marekhil–Ravansar fault system). Thus, it is proposed that oblique convergence of Arabian and Eurasian plates in Zagros collision zone initiated with oblique obduction in the Late Cretaceous followed by oblique collision in the late Tertiary, consistent with global plate reconstructions.

scholarly journals The Jurassic–Cretaceous lithostratigraphy of Kilen, Kronprins Christian Land, eastern North Greenland

2018 ◽  
Vol 66 ◽  
pp. 61-112 ◽  
Author(s):  
Jussi Hovikoski ◽  
Gunver K. Pedersen ◽  
Peter Alsen ◽  
Kristian Svennevig ◽  
Henrik Nøhr Hansen ◽  
...  
Keyword(s):  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Field Work ◽  
Shallow Marine ◽  
Fine Grained ◽  
North Greenland ◽  
Sandy Mudstone ◽  
Cretaceous Sediment

Kilen, Kronprins Christian Land, contains the thickest and stratigraphically most complete Jurassic and Cretaceous sediment succession in North Greenland. This study revises and formalises the lithostratigraphic framework of these deposits. The work is based on recent extensive stratigraphic field work supplemented by photogeological mapping and biostratigraphic studies, and builds on the earlier stratigraphic work conducted mainly in the 1980s and 1990s. According to the new stratigraphic scheme, the more than 500 m thick Jurassic succession is divided into four formations. The poorly dated Gletscherport Formation comprises lagoonal heterolithic sandstones. The Mågensfjeld and Birkelund Fjeld Formations consist of shallow marine fine-grained sandstones of Bajocian–Bathonian and Kimmeridgian age, respectively. The Kuglelejet Formation comprises mainly shallow marine sandy mudstone and sandstone of Volgian age and includes the mudstone-dominated Splitbæk Member. The Lower Cretaceous interval is estimated to be more than 1500 m thick and is divided into three formations. The Dromledome Formation comprises deep shelf to offshore transition, black mudstones of late Ryazanian to Hauterivian age. It is erosively overlain by unfossiliferous, fluvial and estuarine sandstones of the Lichenryg Formation. The overlying, late Aptian to middle Cenomanian Galadriel Fjeld Formation comprises six members, of which the Tågekyst and Kangoq Ryg Members occur in the Gåseslette area, whereas the Pil, Valmue, Stenbræk and Hondal Members occur in the Kilen Fjelde area. The Galadriel Fjeld Formation is characterised by interbedded mudstones and sandstones from offshore–shoreface environments. The 650 m thick Upper Cretaceous succession is assigned to the Sølverbæk Formation, which is undivided in the Gåseslette area and divided into the Skalbæk and Scaphitesnæse Members in the Kilen Fjelde area. The Sølverbæk Formation is dominated by marine mudstones and sandstonemudstone heteroliths of late Cenomanian to Santonian age. The new lithostratigraphic framework and significant biostratigraphic advances allow a closer correlation of the Mesozoic units between North Greenland and other Arctic basins.

scholarly journals Last Cretaceous Geology of Taranaki Basin, New Zealand

2021 ◽  
Author(s):  
◽  
Glenn Paul Thrasher
Keyword(s):  
New Zealand ◽  
Late Cretaceous ◽  
Coastal Plain ◽  
New Caledonia ◽  
Strike Slip ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Petroleum Reservoir ◽  
The North ◽  
Potential Source Rock

<p>Taranaki Basin is a large sedimentary basin located along the western side of New Zealand, which contains all of this countries present petroleum production. The basin first formed as the late-Cretaceous Taranaki Rift, and the first widespread sediments are syn-rift deposits associated with this continental rifting. The Taranaki Rift was an obliquely extensional zone which transferred the movement associated with the opening of the New Caledonia Basin southward to the synchronous Tasman Sea oceanic spreading. Along the rift a series of small, en-echelon basins opened, controlled by high-angle normal and strike-slip faults. These small basins presently underlie the much larger Taranaki Basin. Since the initial rift phase, Taranaki Basin has undergone a complex Cenozoic history of subsidence, compression, additional rifting, and minor strike-slip faulting, all usually involving reactivation of the late-Cretaceous rift-controlling faults. One of the late-Cretaceous rift basins is the Pakawau Basin. Rocks deposited in this basin outcrop in Northwest Nelson as the Pakawau Group. Data from the outcrop and from wells drilled in the basin allow the Pakawau Group to be divided into two formations, the Rakopi Formation and the North Cape Formation, each with recognizable members. The Rakopi Formation (new name) is a sequence of terrestrial strata deposited by fans and meandering streams in an enclosed basin. The North Cape Formation is a transgressive sequence of marine, paralic and coastal-plain strata deposited in response to regional flooding of the rift. The coal-measure strata of the Rakopi Formation are organic rich, and are potential petroleum source rocks where buried deeply enough. In contrast, the marine portions of the North Cape Formation contain almost no organic matter and cannot be considered a potential source rock. Sandy facies within both formations have petroleum reservoir potential. The Rakopi and North Cape formations can be correlated with strata intersected by petroleum exploration wells throughout Taranaki Basin, and all syn-rift sediments can be assigned to them. The Taranaki Rift was initiated about 80 Ma, as recorded by the oldest sediments in the Rakopi Formation. The transgression recorded in the North Cape Formation propagated southwards from about 72 to 70 Ma, and the Taranaki Rift remained a large marine embayment until the end of the Cretaceous about 66.5 Ma. Shortly thereafter, a Paleocene regression caused the southern portions of Taranaki Basin to revert to terrestrial (Kapuni Group) sedimentation. The two distinct late Cretaceous sedimentary sequences of the Rakopi and North Cape formations can be identified on seismic reflection data, and the basal trangressive surface that separates them has been mapped throughout the basin. This horizon essentially marks the end of sedimentation in confined, terrestrial subbasins, and the beginning of Taranaki Basin as a single, continental-margin-related basin. Isopach maps show the Rakopi Formation to be up to 3000m thick and confined to fault- controlled basins. The North Cape Formation is up to 1500m thick and was deposited in a large north-south embayment, open to the New Caledonia basin to the northwest. This embayment was predominantly a shallow-marine feature, with shoreline and lower coastal plain facies deposited around its perimeter</p>

scholarly journals Project Westmar, A shallow marine geophysical survey on the West Greenland continental shelf

1979 ◽  
Vol 87 ◽  
pp. 1-29
Author(s):  
C.P Brett ◽  
E.F.K Zarudzki
Keyword(s):  
Continental Shelf ◽  
Geophysical Survey ◽  
The West ◽  
Shallow Marine ◽  
Western Margin ◽  
Sea Floor ◽  
West Greenland ◽  
Maximum Water ◽  
Shelf Margin ◽  
Morphological Relationship

An extensive shallow geophysical survey has been carried out on the West Greenland continental shelf between 64° and 69°30'N. Preliminary interpretation of the data reveals that between 64° and 67°30'N at least, the entire shelf was glaciated to its western margin during the Pleistocene, the glaciation processes leaving a variable (< 20-200 m thick) cover on the Tertiary sedimentary wedge underlying the shelf. A morphological relationship exists between the degree of sea floor roughness and the types of glaciation forms. The distribution and contacts of the three main shallow bedrock units in the area (Precambrian gneisses, Lower Tertiary volcanics and Tertiary sediments) are delineated. Widespread prograding is observed in sediments along the shelf margin. Extensive iceberg scouring of the sea floor is observed north of 67°30'N reaching a maximum water depth of 340 m.

Sign in / Sign up

Export Citation Format

Share Document