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Episodic burial and exhumation in NE Brazil after opening of the South Atlantic

Abstract : It is a common assumption that elevated passive continental margins have remained high since rifting and breakup. Here, we show that the Atlantic margin of NE Brazil has under gone a more complex history. Our synthesis of geological data, landscape analysis, and paleothermal and paleoburial data reveals a four-stage history: (1) After Early Cretaceous breakup, the margin under went burial beneath a thick sedimentary cover; (2) uplift episodes in the Campanian and Eocene led to almost complete removal of these deposits; (3) the resulting large-scale, low-relief erosion surface (peneplain) was deeply weathered and fi nally reburied at the Oligocene-Miocene transition; and (4) Miocene uplift and erosion produced a new, lowerlevel peneplain by incision of the uplifted and re-exposed Paleogene peneplain. Previous studies have identifi ed aspects of this interpretation, but we have defi ned the absolute timing and magnitude of discrete events of burial and exhumation that followed Early Cretaceous rifting and Eocene-Oligocene peneplanation. We suggest that a late sedimentary cover protected Paleogene weathering profi les until the present day. The uplift phases in Brazil are synchronous with uplift phases in Africa and the Andes. The Andean phases coincided with rapid convergence on the western margin of South America, and the Campanian uplift coincided with a decline in spreading rate at the Mid-Atlantic Ridge. Consequently, we suggest that both vertical movements and lateral changes in the motion of the plates have a common cause, which is lateral resistance to plate motion.
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https://hal-insu.archives-ouvertes.fr/insu-00705178
Contributor : Isabelle Dubigeon <>
Submitted on : Thursday, June 7, 2012 - 9:30:04 AM
Last modification on : Friday, April 5, 2019 - 8:17:30 PM

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Peter Japsen, Johan-M. Bonow, Paul-F. Green, Peter R. Cobbold, Dario Chiossi, et al.. Episodic burial and exhumation in NE Brazil after opening of the South Atlantic. Geological Society of America Bulletin, Geological Society of America, 2012, 124 (5-6), pp.800-816. ⟨10.1130/B30515.1⟩. ⟨insu-00705178⟩

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