气候变化领域集成服务门户(CCPortal): The conversion tectonics from spreading to subduction: Paleostress analysis of dike swarms during the subduction initiation in the Oman Ophiolite

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DOI	10.1130/B35202.1
	The conversion tectonics from spreading to subduction: Paleostress analysis of dike swarms during the subduction initiation in the Oman Ophiolite
	Umino S.; Kusano Y.; Yamaji A.; Fudai T.; Tamura A.; Arai S.
发表日期	2020
ISSN	167606
起始页码	1333
结束页码	1343
卷号	132 期号:2021-05-06
英文摘要	We present paleostress analyses of dike swarms intruded during the subduction initiation in the northern Oman Ophiolite to understand the tectonomagmatic environment. Five swarms of subparallel dikes extending WNW-ESE are 1-5 km in width and are spaced every 5 km N-S. Each swarm has a core of 100% sheeted dikes 1-2 km in width, which emanated from the dunitewherlite-clinopyroxenite-gabbronorite-diorite-tonalite complexes below and intruded through V1 and into V2 extrusive rocks. Individual dike strikes are varied but generally subparallel to the overall trend of the swarm. Paleostress analyses indicate subvertical σ1, ~σ2, and subhorizontal σ3 with high magma pressures, resulted in the mutually intrusive, extensional shear dikes and abrupt changes in dike strike at high angles. These occurrences suggest intrusions under a more compressive environment compared to the extensional stress field that formed the N-S-striking sheeted dikes of V1 spreading stage. Most E-W-striking dikes possess both boninitic and tholeiitic geochemistry. The latter resemble the V1 flows and dikes with affinities of mid-ocean ridge basalt. Some tholeiitic dikes strike N-S, which are mutually intrusive to E-W-striking dikes. Tholeiitic dikes are more intensely altered than boninite, suggesting their older ages. Conversion of the stress field from a N-S-running spreading axis to inextensional E-W-running rift zones associated with the change in magma geochemistry agree with the relatively compressive V2 arc above a forced subduction zone, which originated from intraoceanic thrusting caused by the clockwise rotation of a microplate including the future northern ophiolite. © 2019 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184861
作者单位	College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan; Japan Agency for Marine-Earth Science and Technology, Natsushima 2-15, Yokosuka, 237-0061, Japan; Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, Higashi 1-1-1, Tsukuba, Ibaraki, 305-8567, Japan; Division of Earth and Planetary Sciences, Kyoto University, Sakyo-ku, Kyoto, Kyoto, 606-8502, Japan; Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan; Institute of Nature and Environmental Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan; Institute of Liberal Arts and Science, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan
推荐引用方式 GB/T 7714	Umino S.,Kusano Y.,Yamaji A.,et al. The conversion tectonics from spreading to subduction: Paleostress analysis of dike swarms during the subduction initiation in the Oman Ophiolite[J],2020,132(2021-05-06).
APA	Umino S.,Kusano Y.,Yamaji A.,Fudai T.,Tamura A.,&Arai S..(2020).The conversion tectonics from spreading to subduction: Paleostress analysis of dike swarms during the subduction initiation in the Oman Ophiolite.Bulletin of the Geological Society of America,132(2021-05-06).
MLA	Umino S.,et al."The conversion tectonics from spreading to subduction: Paleostress analysis of dike swarms during the subduction initiation in the Oman Ophiolite".Bulletin of the Geological Society of America 132.2021-05-06(2020).