Devonian to Permian plate tectonic cycle of the Paleo-Tethys Orogen in southwest China (II) Insights from zircon ages of ophiolites, arc/back-arc assemblages and within-plate igneous rocks and generation of the Emeishan CFB province | |
Jian, P (Jian, Ping); Liu, DY (Liu, Dunyi); Kroner, A (Kroener, Alfred); Zhang, Q (Zhang, Qi); Wang, YZ (Wang, Yizhao); Sun, XM (Sun, Xiaomeng); Zhang, W (Zhang, Wei) | |
刊名 | LITHOS
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2009 | |
卷号 | 113期号:3-4页码:767-784 |
关键词 | Zircon age Ophiolite Arc/back-arc Within-plate igneous rocks Paleo-Tethys Emeishan CFB province |
ISSN号 | 0024-4937 |
英文摘要 | New SHRIMP zircon ages for ophiolites, arc/back-arc assemblages and within-plate igneous rocks constrain the evolution of the Paleo-Tethys Orogen of southwest China. Ophiolites represent remnants of the Paleo-Tethys ocean, which was divided by the Simao terrane into two tracts, the main ocean in the west (current position) and a branch in the east. The main ocean has been inferred to originate from Gondwana break-up in the Early Devonian, and the heritage is preserved as the Changning-Menglian ophiolite (SSZ-type). The oceanic branch is represented by the Ailaoshan (NMORB-type)-Jinshajinag (EMORB-type) ophiolites. Zircons from a diabase and a plagiogranite of the Ailaoshan ophiolite yielded (206)Pb/(238)U ages of 382.9 +/- 3.9 Ma and 375.9 +/- 4.2 Ma. The age of a cumulate gabbro from the Jinshajiang ophiolite is 343.5 +/- 2.7 Ma. A metagabbro of the Changning-Menglian ophiolite yielded a crystallization age of 267.1 +/-.1 Ma. We interpret the ages of the Ailaoshan and Jinshajiang ophiolites to represent sea-floor spreading in the branch ocean, whereas the age of the Changning-Menglian ophiolite reflects closure of the main ocean. Arc/back-arc assemblages (zoned mafic-ultramafic complexes and arc volcanic rocks) are records of convergent plate boundary magmatic activity. Rocks of the Gicha complex (back-arc rift) yielded zircon ages of 306.2 +/- 4.6 Ma for a tonalite, 301.0 +/- 2.9 Ma for a microgabbro, 297.1 +/- 2.0 Ma for a plagioclase hornblendite, and 281.3 +/- 1.7 Ma for a diabase. A gabbro and a tonalite of the Banpo complex (plutonic arc) yielded identical ages of 285.6 +/- 1.7 Ma and 285.8 +/- 2.0 Ma. A basalt of the Yaxianqiao volcanic arc was dated at 266.2 +/- 2.2 Ma. Within-plate igneous rocks were also dated. Two amphbolite xenoliths in the Jinshajiang ophiolite melange, derived from low-Ti continental flood basalts, have zircon ages of 439.3 +/- 3.5 Ma and 403.7 +/- 3.1 Ma, which we interpret to represent the inception of continental rifting prior to the opening of the branch ocean. The small Dalongkai differentiated mafic-ultramafic intrusion reflects post-orogenic extension and is characterized by superimposed arc and within-plate geochemical signatures. Zircons from a plagioclase pyroxenite of this intrusion yielded an age of 245.6 +/- 1.4 Ma. These new results, combined with geological and geochemical data, allow the reconstruction of a Devonian to Permian plate tectonic cycle in which generation of the Emeishan CFB province correlates with Paleo-Tethys orogeny in time. This study provides evidence for cyclic continent-ocean-continent development via multiple orogenesis, as well as temporal constraints on the dynamic relationship between plate tectonics and generation of a large igneous province. (C) 2009 Elsevier B.V. All rights reserved. |
学科主题 | 火成岩岩石学 |
WOS关键词 | CONTINENTAL BREAK-UP ; PLUME-LITHOSPHERE INTERACTION ; VOLCANIC RIFTED MARGIN ; COAST RANGE OPHIOLITE ; SW CHINA ; MANTLE PLUME ; FLOOD BASALTS ; GEOCHEMICAL EVIDENCE ; SPREADING RIDGES ; NORTH-ATLANTIC |
WOS研究方向 | Geochemistry & Geophysics ; Mineralogy |
语种 | 英语 |
出版者 | ELSEVIER SCIENCE BV |
WOS记录号 | WOS:000272787200027 |
内容类型 | 期刊论文 |
源URL | [http://119.78.100.197/handle/2HKVOGP0/39031] ![]() |
专题 | 中国地质调查局 |
作者单位 | Jilin Univ, Fac Appl Technol, Changchun 130022, Peoples R China |
推荐引用方式 GB/T 7714 | Jian, P ,Liu, DY ,Kroner, A ,et al. Devonian to Permian plate tectonic cycle of the Paleo-Tethys Orogen in southwest China (II) Insights from zircon ages of ophiolites, arc/back-arc assemblages and within-plate igneous rocks and generation of the Emeishan CFB province[J]. LITHOS,2009,113(3-4):767-784. |
APA | Jian, P .,Liu, DY .,Kroner, A .,Zhang, Q .,Wang, YZ .,...&Zhang, W .(2009).Devonian to Permian plate tectonic cycle of the Paleo-Tethys Orogen in southwest China (II) Insights from zircon ages of ophiolites, arc/back-arc assemblages and within-plate igneous rocks and generation of the Emeishan CFB province.LITHOS,113(3-4),767-784. |
MLA | Jian, P ,et al."Devonian to Permian plate tectonic cycle of the Paleo-Tethys Orogen in southwest China (II) Insights from zircon ages of ophiolites, arc/back-arc assemblages and within-plate igneous rocks and generation of the Emeishan CFB province".LITHOS 113.3-4(2009):767-784. |
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