Lithospheric Strength and Rift Migration Controls on Synrift Stratigraphy and Breakup Unconformities at Rifted Margins: Examples From Numerical Models, the Atlantic and South China Sea Margins

Pérez-Gussinyé，M.1; Andrés-Martínez，M.1; Araújo，M.1,2; Xin，Y.1,3; Armitage，J.4; Morgan，J. P.5

2020-12-01

10.1029/2020TC006255

TECTONICS   影响因子和分区

0278-7407

1944-9194

Synrift stratigraphy and the distribution of breakup-related erosional unconformities vary vastly between passive margins and cannot be explained by classical rifting models. Here we use numerical modeling to predict their spatiotemporal distribution. We show that synrift stratigraphy mimics rift architecture, which is controlled by lithospheric strength. Basinward rift migration during extension produces (1) oceanward younging, syntectonic and posttectonic sequences, (2) rift migration unconformities, RMUs, predating breakup, and (3) a breakup unconformity, BU, that only extends over the outermost margins, since breakup is not linked with a sudden stress drop. With small synrift sedimentation, the RMUs and BU laterally merge to form a margin-wide unconformity. In symmetric, wide conjugate margins, which arise for weak lithospheres such as the South China Sea, a long phase of distributed deformation with little subsidence results in early synrift sediment over most of the margins. RMUs merge into a single event that marks the subsequent focusing of deformation into a narrow breakup area, which experiences short-lived intense thinning and subsidence. In asymmetric conjugate margins, lateral rift migration transports shallowly deposited, early synrift sediments from the narrow to the wide, hyperextended margin, leading to a condensed syntectonic sequence and a single BU in the narrow margin and a series of RMUs in the wide one. For very weak lower crusts, lateral rift migration generates large synrift sag basins in the wide margin, as in Angola and Congo margins. Our models resemble the observed margins tectonic diversity and may be used as templates for interpreting their distal, unexplored areas.

breakup rifting stratigraphy synrift architecture tectonic architecture unconformity

SCI ; EI

英语

其他

WOS:000603666700017

20205209694563

Architecture ; Deformation ; Subsidence ; Tectonics ; Numerical models

Buildings and Towers:402 ; Geology:481.1 ; Soils and Soil Mechanics:483.1 ; Mathematics:921

GEOSCIENCES

2-s2.0-85098119886

Scopus

1.MARUM—Center for Marine Environmental Sciences,University of Bremen,Bremen,Germany
2.CENPES Research Center,Petrobras,Rio de Janeiro,Brazil
3.Key Laboratory of Ocean and Marginal Sea Geology,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou,China
4.IFP Energies Nouvelles,Rueil-Malmaison,France
5.Department of Ocean Science and Engineering,SUSTech,Shenzhen,China

Pérez-Gussinyé，M.,Andrés-Martínez，M.,Araújo，M.,et al. Lithospheric Strength and Rift Migration Controls on Synrift Stratigraphy and Breakup Unconformities at Rifted Margins: Examples From Numerical Models, the Atlantic and South China Sea Margins[J]. TECTONICS,2020,39(12).

Pérez-Gussinyé，M.,Andrés-Martínez，M.,Araújo，M.,Xin，Y.,Armitage，J.,&Morgan，J. P..(2020).Lithospheric Strength and Rift Migration Controls on Synrift Stratigraphy and Breakup Unconformities at Rifted Margins: Examples From Numerical Models, the Atlantic and South China Sea Margins.TECTONICS,39(12).

Pérez-Gussinyé，M.,et al."Lithospheric Strength and Rift Migration Controls on Synrift Stratigraphy and Breakup Unconformities at Rifted Margins: Examples From Numerical Models, the Atlantic and South China Sea Margins".TECTONICS 39.12(2020).