Evolution of a Permian intraoceanic arc-trench system in the Solonker suture zone, Central Asian Orogenic Belt, China and Mongolia

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	Evolution of a Permian intraoceanic arc-trench system in the Solonker suture zone, Central Asian Orogenic Belt, China and Mongolia
	Jian, P (Jian, Ping); Liu, DY (Liu, Dunyi); Kroner, A (Kroener, Alfred); Windley, BF (Windley, Brian F.); Shi, YR (Shi, Yuruo); Zhang, W (Zhang, Wei); Zhang, FQ (Zhang, Fuqin); Miao, LC (Miao, Laicheng); Zhang, LQ (Zhang, Liqao); Tomurhuu, D (Tomurhuu, Dondov)
刊名	LITHOS
	2010
卷号	118 期号:1-2 页码:169-190
关键词	CAOB Proto-arc crust Ophiolite Forearc melange Plate convergence Zircon dating
ISSN号	0024-4937
英文摘要	The identification of a fossil arc-trench system from the ophiolite-decorated Solonker suture zone in the southernmost Central Asian Orogenic Belt (CAOB) enables us to constrain the timing of pre-subduction extension (ca. 299-290 Ma), subduction initiation (ca. 294-280 Ma), ridge-trench collision (ca. 281-273 Ma) and slab break-off (ca. 255-248 Ma) in the Permian. A fraction of proto-arc crust (ca. 45 km long, up to 8 km wide) is preserved as a volcanic-plutonic sequence and is juxtaposed against a wide (ca. 30-80 km) forearc melange. This proto-arc crust comprises two distinct magma series, island arc tholeiite (IAT) and mid-ocean ridge basalt (MORB), both of which have strong supra-subduction zone (SSZ) geochemical signatures. Zircons from a gabbro and a plagiogranite yielded weighted mean (206)pb/(238)U ages of 284.0 +/- 4.0 and 288.0 +/- 6.0 Ma. The forearc melange consists of numerous ophiolite fragments and continental margin-derived olistoliths/blocks that predate the ophiolite. The olistoliths are best represented by a gabbroic block (291.8 +/- 2.3 Ma) that contains granite xenoliths (312.6 +/- 1.8 and 313.6 +/- 3.1 Ma). Other dated blocks include a trondhjemite (323.9 +/- 2.7 Ma), a gabbro (296.6 +/- 1.7 Ma) and a tonalite (294.9 +/- 2.4 Ma). Small bodies of diabase, andesite and diorite in the forearc melange exhibit a wide variety of geochemical signatures. We dated zircons from an N-MORB-like diabase (274.4 +/- 2.5 Ma), an E-MORB-like diabase (252.5 +/- 2.3 Ma), a transitional sanukitoid/adakite (andesite, 250.2 +/- 2.4 Ma), a sanukitoid (high-Mg diorite; 251.8 +/- 1.1 Ma) and an anorthosite (252.2 +/- 1.7 Ma). The N-MORB-like diabase contains ca. 301-394 Ma zircon xenocrysts suggesting assimilation of trench sediments when a spreading ridge intersected a trench. The other dated rocks simultaneously formed near the Permian/Triassic boundary and captured abundant zircon xenocrysts (ca. 269-295 Ma; ca. 301-495 Ma; and ca. 923-2501 Ma). Our new formation ages constrain a magmatic episode in response to slab break-off beneath a fossil forearc in a young post-collisional setting, and the youngest xenocryst ages (ca. 269-273 Ma) may define the maximum depositional age of trench sediments. (C) 2010 Elsevier B.V. All rights reserved.
学科主题	构造地质学
WOS关键词	SETOUCHI VOLCANIC BELT ; COAST RANGE OPHIOLITE ; INNER-MONGOLIA ; NORTH CHINA ; CONTINENTAL GROWTH ; CHEMICAL CHARACTERISTICS ; TECTONIC IMPLICATIONS ; GEOCHEMICAL EVIDENCE ; MAGNESIAN ANDESITES ; BAJA-CALIFORNIA
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000280010200013
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/39190]
专题	中国地质调查局
作者单位	Mongolian Acad Sci, Inst Geol & Mineral Resources, Ulaanbaatar 210351, Mongol Peo Rep
推荐引用方式 GB/T 7714	Jian, P ,Liu, DY ,Kroner, A ,et al. Evolution of a Permian intraoceanic arc-trench system in the Solonker suture zone, Central Asian Orogenic Belt, China and Mongolia[J]. LITHOS,2010,118(1-2):169-190.
APA	Jian, P .,Liu, DY .,Kroner, A .,Windley, BF .,Shi, YR .,...&Tomurhuu, D .(2010).Evolution of a Permian intraoceanic arc-trench system in the Solonker suture zone, Central Asian Orogenic Belt, China and Mongolia.LITHOS,118(1-2),169-190.
MLA	Jian, P ,et al."Evolution of a Permian intraoceanic arc-trench system in the Solonker suture zone, Central Asian Orogenic Belt, China and Mongolia".LITHOS 118.1-2(2010):169-190.