Prolonged post-rift magmatism on highly extended crust of divergent continental margins (Baiyun Sag, South China Sea)

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doi: 10.1016/j.epsl.2016.04.001
Author(s): Zhao Fang; Alves, Tiago M.; Wu Shiguo; Li, Wei; Huuse, Mads; Mi Lijun; Sun Qiliang; Ma Benjun
Author Affiliation(s): Primary:
Chinese Academy of Sciences, South China Sea Institute of Oceanology, Guangzhou, China
Cardiff University, United Kingdom
Chinese Academy of Sciences, Institute of Deep-Sea Science and Engineering, China
University of Kiel, Germany
University of Manchester, United Kingdom
China National Offshore Oil Corporation, China
China University of Geosciences, China
Chinese Academy of Sciences, Institute of Oceanology, China
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, Vol.445, p.79-91. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. 50 refs.; illus., incl. sects., sketch maps
Summary: Three-dimensional (3D) seismic, borehole and geochemical data reveal a prolonged phase of post-rift magmatism on highly extended crust of the Baiyun Sag, South China Sea. Two volcanic complexes are identified and described in the context of continental rifting and diachronous continental breakup of the South China Sea. Biostratigraphic data from exploration wells BY7-1 and BY2, complemented by K-Ar datings from core samples, confirm that magmatic activity in the Baiyun Sag occurred in two main stages: (1) a first episode at the base of the Miocene (23.8 Ma); and (2) a second episode occurring at the end of the Early Miocene (17.6 Ma). The relative location of volcanic complexes in the Baiyun Sag, and their stratigraphic position, reveals prolonged magmatism inboard of the ocean-continent transition zone during continental breakup. We suggest that magmatism in the Baiyun Sag reflects progressive continental breakup in the South China Sea, with the last volcanic episode marking the end of a breakup sequence representing the early post-rift tectonic events associated with the continental breakup process. Seismic and borehole data from this breakup sequence records diachronous magma emplacement and complex changes in depositional environments during continental breakup. Abstract Copyright (2016) Elsevier, B.V.
Year of Publication: 2016
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
ODP Ocean Drilling Program
Key Words: 05 Petrology, Igneous and Metamorphic; Baiyun Sag; Boreholes; Cenozoic; Continental margin; Cores; Crust; Depositional environment; Emplacement; Expedition 349; Extension; Geophysical methods; Geophysical profiles; Geophysical surveys; IODP Site U1435; International Ocean Discovery Program; Intrusions; K/Ar; Lava flows; Leg 184; Magmas; Magmatism; Miocene; Mounds; Neogene; North Pacific; Northwest Pacific; ODP Site 1148; Ocean Drilling Program; Pacific Ocean; Plate divergence; Rifting; Seismic methods; Seismic profiles; Seismic stratigraphy; Sills; South China Sea; Surveys; Tertiary; Volcanic features; Volcanism; West Pacific
Coordinates: N183321 N183321 E1163637 E1163637
N185010 N185010 E1163356 E1163356
N193600 N200000 E1151200 E1140000
Record ID: 2016056538
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands