Pre-salt evolution of the South Atlantic conjugate margins

Author(s): Unternehr, Patrick
Author Affiliation(s): Primary:
TOTAL, Paris, France
Volume Title: 34th international geological congress; abstracts
Source: International Geological Congress [International Geological Congress, Abstracts = Congrès Géologique International, Résumés, Vol.34, p.261; 34th international geological congress, Brisbane, Queensl., Australia, Aug. 5-10, 2012. Publisher:], [location varies], International CODEN: IGABBY
Note: In English
Summary: Research into the formation of deep passive continental margins is incontestably undergoing a paradigm shift. For the last 15 years, Petroleum Exploration has been developed largely on Deep Offshore areas mainly on turbiditic plays related to post rift deposits and major oil fields have been discovered in several basins. Now, the main evolution for the Industry is to explore further (in bathymetry) and deeper (in burial) looking for new plays as "presalt synrift" in Ultra Deep Offshore. The large industrial seismic effort really improved the knowledge of these margins and allowed much unexpected observations relating to synrift models. Some of these observations are the discovery of hyper extended crust (and exhumed continental mantle?) devoid of significant normal faulting directly overlain by shallow marine or continental sediments (sag). Analogs from ancient hyper extended margins exposed in the Alps help to identify lithologies and structures similar to those drilled by the DSDP program along the Iberia-Newfoundland margins orthose supposedly comprising the pre-salt sag basins of the South Atlantic. In this presentation we show a few examples on South Atlantic margins which address some key problems: How to make a sag basin? What is the mechanism which thins the lithosphere? What is the meaning of the "Break up unconformity"? The understanding of the mechanisms which explain these observations is a key to making the best predictions in the deep distal parts of these prolific petroleum margins.
Year of Publication: 2012
Research Program: DSDP Deep Sea Drilling Project
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; 29 Economic Geology, Energy Sources; Africa; Angola; Atlantic Ocean; Brazil; Central Africa; Chemically precipitated rocks; Continental margin; Deep Sea Drilling Project; Evaporites; Lithostratigraphy; Mesozoic; Mineral deposits, genesis; Offshore; Passive margins; Petroleum; Petroleum exploration; Plate tectonics; Pre-salt layer; Sedimentary rocks; South America; South Atlantic; Stratigraphic traps; Traps; Triassic
Record ID: 2015032883
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by International Geological Congress Organizational Committee

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