scholarly journals Tectonic evolution of the Pacific margin of Antarctica 2. Structure of Late Cretaceous-early Tertiary plate boundaries in the Bellingshausen Sea from seismic reflection and gravity data

2002 ◽  
Vol 107 (B12) ◽  
pp. EPM 6-1-EPM 6-20 ◽  
Author(s):  
Alex P. Cunningham ◽  
Robert D. Larter ◽  
Peter F. Barker ◽  
Karsten Gohl ◽  
Frank O. Nitsche
2002 ◽  
Vol 107 (B12) ◽  
pp. EPM 5-1-EPM 5-19 ◽  
Author(s):  
Robert D. Larter ◽  
Alex P. Cunningham ◽  
Peter F. Barker ◽  
Karsten Gohl ◽  
Frank O. Nitsche

1986 ◽  
Vol 11 ◽  
pp. 1-46
Author(s):  
Ole Valdemar Vejbæk

The Lower Cretaceous sequence of the Danish Central Trough has been studied by the use of seismic stratigraphic analysis. The sequence has been subdivided into 6 seismic stratigraphic units named LCA, LCB, LCC, LCD, LCE and LCF. The studied area includes the Feda Graben, the Gertrud Graben (new name), the Tail End Graben, the Arne-Elin Graben (new name) and the Salt Dome Province, whereas the Grensen Nose and the Outer Rough Basin are not included. These basins are separated by the Inge High, the Mads High, the Gert Ridge (new name), the Manda! High, the Heno Plateau (new name) and the Pollerne Ridge (new name). The fault controlled subsidence of the Lower Cretaceous basins is claimed to have been governed by left lateral transtensional wrenching. This wrenching gradually ceased and gave way to regional subsidence with intermittent events of inversion resulting from right lateral transpressive wrenching in the Late Cretaceous and Early Tertiary. The first weak inversion is shown to have occurred in the Late Hauterivian. Sedimentation was influenced by a general gradual relative rise in sea-level starting with a low in the Volgian - Early Ryazanian times coeval with the deposition of the Farsund Formation and culminating in the Late Cretaceous. At the beginning of the Early Cretaceous gravity flow became an important depositional mechanism and resulted in preferred deposition in topographical lows, which were generated by simple tensional block-faulting or by wrench-induced, rapid local subsidence. As tectonic activity decreased and the elastic source areas became more remote and worn down, depocentres became less pronounced, especially with the last unit of the Lower Cretaceous.


2020 ◽  
Vol 8 (2) ◽  
pp. SH1-SH17 ◽  
Author(s):  
J. Kim Welford ◽  
Deric Cameron ◽  
Erin Gillis ◽  
Victoria Mitchell ◽  
Richard Wright

A regional long-offset 2D seismic reflection program undertaken along the Labrador margin of the Labrador Sea, Canada, and complemented by the acquisition of coincident gravity data, has provided an extensive data set with which to image and model the sparsely investigated outer shelf, slope, and deepwater regions. Previous interpretation of the seismic data revealed the extent of Mesozoic and Cenozoic basins and resulted in the remapping of the basin configuration for the entire margin. To map the synrift package and improve understanding of the geometry and extent of these basins, we have undertaken joint seismic interpretation and gravity forward modeling to reduce uncertainty in the identification of the prerift basement, which varies between Paleozoic shelfal deposits and Precambrian crystalline rocks, with similar density characteristics. With this iterative approach, we have obtained new depth to basement constraints and have deduced further constraints on crustal thickness variations along the Labrador margin. At the crustal scale, extreme localized crustal thinning has been revealed along the southern and central portions of the Labrador margin, whereas a broad, margin-parallel zone of thicker crust has been detected outboard of the continental shelf along the northern Labrador margin. Our final gravity models suggest that Late Cretaceous rift packages from further south extend along the entire Labrador margin and open the possibility of a Late Cretaceous source rock fairway extending into the Labrador basins.


1972 ◽  
Vol 12 (2) ◽  
pp. 46
Author(s):  
John L. Elliott

The Gippsland, Bass and Otway Basins in southeastern Australia are filled with sediments ranging in age from earliest Cretaceous to Recent. These basins were formed from the processes and forces which fragmented the Pacific margin of Gondwanaland. Their sedimentary histories and tectonic styles locate and date the movement of those continental masses now detached.An Early Cretaceous rift valley extended from the Otway Basin through the Gippsland Basin and on to Lord Howe Rise, (a part of eastern Australia at that time). A transform fault separated Tasmania and Antarctica resulting in the continuing detachment of Antarctica.During the Late Cretaceous, Australia drifted from Antarctica sufficiently to allow the Southern Indian Ocean to invade the Otway Basin and the build-out of river deltas. The Otway continental crust was further stretched, resulting in normal faulting and block rotation. Crustal tension continued in the Gippsland Basin and opened the Bass Basin. Fluvial sediments were deposited in both basins. The Tasman Basin was opened.During the Early Tertiary, crustal tension continued to shape the Bass and Gippsland Basins, where thick, fluvial sediments were deposited. The first marine indicators in Gippsland are Paleocene in age and, during the Eocene, two large submarine valleys were cut and filled and a regional unconformity was developed. Early Tertiary marine elastics prograded into the Southern Indian Ocean.Mid-Tertiary marine shales, marls and limestones formed the continental margin of the Otway Basin and gently filled the Bass Basin. In the Gippsland Basin the same -aged sediments unconformably truncated and sealed Early Tertiary sandstones and contructed the continental slope into the Tasman Sea, while a right lateral shear formed the producing structures.


1995 ◽  
Vol 69 (4) ◽  
pp. 692-702 ◽  
Author(s):  
William J. Zinsmeister ◽  
Miguel Griffin

The new subfamily Struthiopterinae is proposed for the aporrhaid gastropods occurring in the Late Cretaceous-early Tertiary Weddellian Province along the southern margin of the Pacific. The following genera are placed within the Struthiopterinae: Struthioptera Finlay and Marwick, 1937; Austroaporrhais n. gen.; and Struthiochenopus n. gen. The temporal and biogeographic distribution of members of Struthiopterinae show a similar pattern to other Southern Hemisphere groups of Late Cretaceous and early Cenozoic molluscs with initial disappearance from the western Australasia of the Weddellian Province by the Paleocene while surviving in Antarctica until the late Eocene and eventually disappearing in southern South America during the early Miocene.Also included in this paper is a reappraisal of the species assignable to these genera from Late Cretaceous and early Tertiary of New Zealand, Antarctica, and southern South America together with the description of five new species. The following new species of the Struthiopterinae are described: Austroaporrhais larseni n. sp., A. stilwelli n. sp., A. dorotensis n. sp., Struthiochenopus antarcticus n. sp., and S. philippii n. sp.


1990 ◽  
Vol 64 (3) ◽  
pp. 373-376 ◽  
Author(s):  
William. J. Zinsmeister ◽  
Jeffrey D. Stilwell

A new species of the late Mesozoic–Cenozoic family Ringiculidae (Ringicula (Ringicula) cockburnensis n. sp.) is described from basal glauconitic beds of late Eocene age of Cockburn Island, Antarctica, and is the first reported occurrence of the family Ringiculidae from the continent of Antarctica. Ringicula (R.) cockburnensis n. sp. most closely resembles R. castigata from the middle Oligocene Duntroonian Stage of New Zealand and provides further support for the strong provinciality (Weddellian Province) that existed along the southern margin of the Pacific during the Late Cretaceous and early Tertiary.


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