TY - JOUR
T1 - Episodic burial and exhumation in NE Brazil after opening of the South Atlantic
AU - Japsen, Peter
AU - Bonow, Johan M.
AU - Green, Paul F.
AU - Cobbold, Peter R.
AU - Chiossi, Dario
AU - Lilletveit, Ragnhild
AU - Magnavita, Luciano P.
AU - Pedreira, Augusto
PY - 2012/5
Y1 - 2012/5
N2 - 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 finally 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 identified aspects of this interpretation, but we have defined 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 profiles 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.
AB - 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 finally 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 identified aspects of this interpretation, but we have defined 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 profiles 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.
UR - http://www.scopus.com/inward/record.url?scp=84863522519&partnerID=8YFLogxK
U2 - 10.1130/B30515.1
DO - 10.1130/B30515.1
M3 - Article
VL - 124
SP - 800
EP - 816
JO - Bulletin of the Geological Society of America
JF - Bulletin of the Geological Society of America
SN - 0016-7606
IS - 5-6
ER -