Abstract: Tectonic-Stratigraphic Evolution of Offshore Potiguar Basin, Brazil

Living benthic foraminifera (>63 µm) were studied to characterize the continental slope of the Potiguar Basin (SW Atlantic). Foraminifers from the surface (0–2 cm), subsurface (2–5 cm), and integrated (0–5 cm) sediment layers were analyzed to verify their contribution to environmental characterization. It was also estimated if and which changes occur when the subsurface is added. Sampling stations were distributed in five transects in four isobaths (150, 400, 1000, and 2000 m). Sediment samples were fixed with 4% buffered formaldehyde and stained with Bengal rose. Were recorded 396 species in the surface layer, 228 in the subsurface, and 449 in integrating both layers. This study did not include tubular agglutinated species. The assemblages from 150 m isobath indicated the upper slope, from 400 m indicated the middle slope and the ones from the 2000 m indicated the lower slope. The surface layer’s assemblage at 1000 m isobath was more similar to the middle slope; in contrast, its subsurface layer´s assemblage had more similarity with the lower slope. Rarefaction curves, Permanova, and NMDS routines indicated a high resemblance between surface and integrated layers. Therefore, the first two centimeters were sufficient to characterize this region based on living benthic foraminifera.

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HIGH-RESOLUTION SEQUENCE STRATIGRAPHY APPLIED FOR THE IMPROVEMENT OF HYDROCARBON PRODUCTION AND RESERVES: A CASE STUDY IN CRETACEOUS FLUVIAL DEPOSITS OF THE POTIGUAR BASIN, NORTHEAST BRAZIL

Marine and Petroleum Geology ◽

10.1016/j.marpetgeo.2021.105124 ◽

2021 ◽

pp. 105124

Author(s):

A.H. Melo ◽

A.J.C. Magalhães ◽

M.C. Menegazzo ◽

D.C.F. Galvão ◽

C.P. Florencio ◽

...

Keyword(s):

High Resolution ◽

Sequence Stratigraphy ◽

Northeast Brazil ◽

Hydrocarbon Production ◽

Fluvial Deposits ◽

Potiguar Basin ◽

High Resolution Sequence Stratigraphy

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Stratigraphic revision and reconstruction of the deep-sea fan of the Voirons Flysch (Voirons Nappe, Chablais Prealps)

Swiss Journal of Geosciences ◽

10.1186/s00015-020-00383-1 ◽

2021 ◽

Vol 114 (1) ◽

Author(s):

Jérémy Ragusa ◽

Lina Maria Ospina-Ostios ◽

Pascal Kindler ◽

Mario Sartori

Keyword(s):

Deep Sea ◽

Distal Part ◽

Accretionary Prism ◽

Proximal Part ◽

Late Eocene ◽

Lithostratigraphic Units ◽

Stratigraphic Record ◽

Sea Fan ◽

Stratigraphic Evolution ◽

Depositional Setting

AbstractThe Voirons Flysch (Caron in Eclogae Geologicae Helvetiae 69:297–308, 1976), is a flysch sequence aggregated into the sedimentary accretionary prism of the Chablais and Swiss Prealps. Its palaeogeographic location is still debated (South Piemont or Valais realm). We herein present a stratigraphic revision of the westernmost unit of the former Gurnigel Nappe sensu Caron (Eclogae Geologicae Helvetiae 69:297–308, 1976): the Voirons Flysch. This flysch is subdivided into three lithostratigraphic units at the formation level (the Voirons Sandstone, the Vouan Conglomerate, the Boëge Marl), with an additional unit (Bruant Sandstone) of uncertain attribution, ranging from the early Eocene to probably the late Eocene. We further propose a new model of the depositional setting of the deep-sea of the Voirons Flysch based on palaeocurrent directions, the overall geometry and sedimentary features. This model depicts an eastward deflected deep-sea fan. The stratigraphic record of the proximal part of this fan is fairly complete in the Voirons area, whereas its most distal part is only represented by one small exposure of thinly bedded sandstones in the Fenalet quarry. The stratigraphic evolution of the Voirons Flysch shows two major disruptions of the detrital sedimentation at the transition between Voirons Sandstone—Vouan Conglomerate and Vouan Conglomerate—Boëge Marl. The cause of these disturbances has to be constrained in the framework of the palaeogeographic location of the Voirons Flysch.

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