Back arc extension in the Okinawa Trough

Journal Article · Thu Dec 10 04:00:00 EST 1987 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JB092iB13p14041· OSTI ID:5404854

Sibuet, J; Letouzey, J; Barbier, F; Charvet, J; Foucher, J; Hilde, T W.C.; Kimura, M; Ling-Yun, C; Marsset, B; Muller, C; others, and

The Okinawa Trough, lying to the east of China, is a back arc basin formed by extension within continental lithosphere behind the Ryukyu trench-arc system. Middle to late Miocene uplift, associated with normal faulting of the initially adjacent Ryukyu nonvolcanic arc and the Taiwan-Sinzi folded belt, corresponds to the first rifting phase. The timing of rifting is supported by the presence of marine sediments of corresponding age drilled in the northern Okinawa Trough. The rifting occurred after a major early Miocene change in the motion of the Philippine plate with respect to Eurasia and ceased during the Pliocene. A second rifting phase started about 2 m.y. ago, at the Plio-Pleistocene boundary and has continue until the present time. It has proceeded to a more advanced stage in the middle and southern Okinawa Trough than it has farther north. Detailed bathymetric (Sea Beam), seismic reflection and magnetics data collected during the POP 1 cruise of the R/V Jean Charcot reveal the principal features of the extensional processes. The back are spreading phase started very recently in the southern and middle Okinawa Trough, as exemplified by several and echelon and, in some cases, overlapping active, central graben oriented N70/sup 0/ E--N80/sup 0/ E. Some of these depressions are intruded by volcanic ridges of fresh back arc basalt with associated large magnetic anomalies. Transform faults between these en echelon active rifts are not obvious.

• Research Organization: Institut Francais de Recherche pour l'Exploitation de la Mer, Centre de Brest, Brest, France
• OSTI ID: 5404854
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 92:B13; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580203* -- Geophysics-- Geophysical Survey Methods-- (1980-1989)
ASIA
BASALT
CHINA
CONTINENTAL CRUST
CONTINENTAL MARGIN
CRACK PROPAGATION
EARTH CRUST
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGIC SURVEYS
GEOPHYSICAL SURVEYS
IGNEOUS ROCKS
JAPAN
MAGNETIC SURVEYS
OCEANIC CRUST
PLATE TECTONICS
RIFT ZONES
ROCKS
SEDIMENTATION
SEISMICITY
SURVEYS
TECTONICS
VOLCANIC ROCKS
VOLCANISM