FN Archimer Export Format
PT J
TI Seismic structure of the northwestern margin of the South China Sea: implication for asymmetric continental extension
BT 
AF Huang, Haibo
   Qiu, Xuelin
   Pichot, Thibaud
   Klingelhoefer, Frauke
   Zhao, Minghui
   Wang, Ping
   Hao, Tianyao
AS 1:1;2:1;3:2;4:3;5:1;6:1;7:4;
FF 1:;2:;3:;4:PDG-REM-GM-LAD;5:;6:;7:;
C1 Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
   Beicip-Franlab, 232 avenue Napoléon Bonaparte Rueil-Malmaison, Paris 92500, France
   Department of Marine Geosciences, IFREMER, Brest 29280, France
   Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
C2 CHINESE ACAD SCI, CHINA
   BEICIP-FRANLAB, FRANCE
   IFREMER, FRANCE
   CHINESE ACAD SCI, CHINA
SI BREST
SE PDG-REM-GM-LAD
IN WOS Ifremer UPR
   copubli-france
   copubli-int-hors-europe
   copubli-sud
IF 2.574
TC 25
UR https://archimer.ifremer.fr/doc/00500/61189/64720.pdf
   https://archimer.ifremer.fr/doc/00500/61189/64721.pdf
LA English
DT Article
DE ;Seismic tomography;Continental tectonics: extensional;Crustal structure;Rheology: crust and lithosphere
AB Evolution of the continental margins of the South China Sea (SCS) is one of the open questions when discussing continental breakup and seafloor spreading. We processed data from a wide-angle seismic profile (OBS2011–1), which passes through the northwestern margin of the SCS, and performed travel time modeling to obtain the seismic velocity structures. The modeling results show a stepwise variation of the crustal thicknesses from continental margin to oceanic basin. Stretching factor of the upper crust is nearly double the estimate of the lower crust along the Zhongsha Trough. The lower crust shows asymmetrical upwelling towards the trough center, accompanied by ∼0.3 km/s of the velocity increase due to magmatic addition. The upper and lower crusts have almost the same stretching factor beneath continental blocks, indicating a uniform extension. Crustal structures of the conjugate margins of the Southwest Sub-basin show similar velocity range and different thickness distribution, supporting the common origin and asymmetric extension of these two margins. The Ocean-Continent Transition zones (OCT) are much wider in the southern part (∼50 km) than the northern part (∼25 km) crossing the margins. We propose a tectonic model for the asymmetry of both the conjugate margins and the OCTs, favoring the highly stretched upper crust and accompanied by rising of the ductile middle-lower crust controlled by major low-angle faults. The rigid blocks may also act as a kind of hindrance for further evolution of the failed rifts and affect the shape of the OCT. 
PY 2019
PD AUG
SO Geophysical Journal International
SN 0956-540X
PU Oxford University Press (OUP)
VL 218
IS 2
UT 000474771100036
BP 1246
EP 1261
DI 10.1093/gji/ggz219
ID 61189
ER

EF