Geochemistry of ferromanganese micronodules recovered from sediment-core in the western Nigeria continental margin, Eastern Equatorial Atlantic: Implications on the genesis and depositional history.

2021 ◽  
Vol 184 ◽  
pp. 104369
Author(s):  
Samuel Olatunde Popoola ◽  
Adesina Thompson Adegbie ◽  
Edward Akintoye Akinnigbagbe ◽  
John Paul Unyimadu
Keyword(s):  
Sediment Core ◽  
Continental Margin ◽  
Equatorial Atlantic ◽  
Depositional History

New conodont records of the Los Sombreros Formation (Cambrian–Ordovician) from the Western Precordillera, Argentina: biostratigraphic and palaeoenvironmental implications

2019 ◽  
Vol 157 (4) ◽  
pp. 539-550
Author(s):  
Gabriela Torre ◽  
Guillermo L. Albanesi
Keyword(s):  
Continental Margin ◽  
Carbonate Platform ◽  
South American ◽  
The South ◽  
Depositional History ◽  
The Matrix ◽  
Minimum Age ◽  
History Of ◽  
Lower Palaeozoic ◽  
Early Palaeozoic

AbstractThe presence of a carbonate platform that interfingers towards the west with slope facies allows for the identification of an ancient lower Palaeozoic continental margin in the Western Precordillera of Argentina. The Los Sombreros Formation is essential for the interpretation of the continental slope of the Precordillera, which accreted to Gondwana as part of the Cuyania Terrane in the early Palaeozoic. The age of these slope deposits is controversial; therefore, a precise biostratigraphic scheme is critical to reveal the evolution of the South American continental margin of Gondwana. The study of lithic deposits of two sections of the Los Sombreros Formation, the El Salto and Los Túneles sections, provides important information for further understanding the depositional history of the slope. At El Salto section, the conodonts recovered from an allochthonous block refer to the Cordylodus proavus Zone (upper Furongian). The conodonts recovered from the matrix of a calclithite bed of the Los Sombreros Formation in the Los Túneles section are assigned to the Lenodus variabilis Zone (early Darriwilian), providing a minimum age for this stratigraphic unit. In addition, clasts from this sample yielded conodonts from the Paltodus deltifer − Macerodus dianae zones (upper Tremadocian). The contrasting conodont colour alterations and preservation states from the elements of two latter records, coming from the same sample, argue the reworked clasts originated in the carbonate platform and later transported to the slope during the accretion process of the Precordilleran Terrane to the South American Gondwanan margin during the Middle–Late Ordovician.

The crustal structure across the transform continental margin off Ghana, eastern equatorial Atlantic

1997 ◽  
Vol 102 (B1) ◽  
pp. 747-772 ◽  
Author(s):  
Rosemary A. Edwards ◽  
Robert B. Whitmarsh ◽  
Roger A. Scrutton
Keyword(s):  
Continental Margin ◽  
Crustal Structure ◽  
Equatorial Atlantic

Seismostratigraphy and Neogene-Recent depositional history of the south central continental margin of Cyprus

1993 ◽  
Vol 10 (5) ◽  
pp. 426-438 ◽  
Author(s):  
Jean E. McCallum ◽  
Roger A. Scrutton ◽  
Alastair H.F. Robertson ◽  
William Ferrari
Keyword(s):  
Continental Margin ◽  
The South ◽  
Depositional History ◽  
South Central ◽  
History Of ◽  
History Of The South

Tectonics and Depositional History of the Continental Margin Off Vancouver Island, British Columbia

1972 ◽  
Vol 9 (3) ◽  
pp. 280-296 ◽  
Author(s):  
D. L. Tiffin ◽  
B. E. B. Cameron ◽  
J. W. Murray
Keyword(s):  
Continental Margin ◽  
Deep Water ◽  
Depositional Environment ◽  
Marked Change ◽  
Vancouver Island ◽  
Late Eocene ◽  
Transform Faults ◽  
Depositional History ◽  
Seismic Profiling ◽  
History Of

Sampling and seismic profiling in the Tofino Basin west of Vancouver Island show there is a thick sequence of Tertiary rocks ranging in age from late Eocene to Pliocene. The rocks are mainly mudstones containing abundant foraminifera indicating a bathyal depositional environment throughout most of the Tertiary. Subsequent uplift has exposed the deep water sediments on the shelf over much of the area. Eocene-Oligocene sediments occur in a belt along the inner shelf, while Miocene and Pliocene rocks lie seaward of this. Pliocene rocks form a regressive sequence overlapping the older Tertiary, with the greatest thickness in the south.At least two major periods of deformation resulted in faulting, folding, and diapirism on the continental shelf. Deformational patterns show a marked change from north to south. North of Brooks Peninsula sediments are undeformed by folding but are truncated by faulting along the steep continental slope. The Kyuquot Uplift south of Brooks Peninsula exposes Eocene-Oligocene sediments across the shelf. Farther south Mio-Pliocene sediments unconformably overlie the uplift. Folding increases southward culminating in an area of diapirism off Nootka Sound. Elongate diapirs trend parallel or subparallel to the coastline.Tectonic features on the shelf and slope appear to be related to present and earlier configurations of nearby offshore spreading centers, plates, and transform faults. Crustal plate movements may have been responsible for the observed shelf and slope deformations.

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