Basalts and picrites from a plume-type ophiolite in the South Qilian Accretionary Belt, Qilian Orogen: Accretion of a Cambrian Oceanic Plateau?

Abstract

'Basalts and picrites from a plume-type ophiolite in the South Qilian Accretionary Belt, Qilian Orogen : accretion of a Cambrian Oceanic Plateau? ', Lithos.,[278][279][280][281] Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT

Petrogenesis of the Fe–P–REE mineralized Shangzhuang ultramafic intrusion in the Lajishan tectonic belt, South Qilian Belt: Implications for mantle metasomatism and tectonic setting

“…The numbers indicate the degree of crustal contamination. Data source: Cambrian picrite in the regional Yongjing terrane from Y. Zhang et al (); metamorphosed basaltic rocks from the Hualong Group from T. Wang et al (); Xiashitang intrusion from Z. Zhang (). The calculated parameters of Sr (ppm), 87 Sr/ 86 Sr ( i ) , Nd (ppm), and εNd ( t ) are 320, 0.716, 27 and −10.8 for the upper crust and 348, 0.709, 11 and −7.6 for the lower crust, respectively [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…The extent of crustal contamination can be estimated using εNd ( t ) versus 87 Sr/ 86 Sr ( i ) by assuming that the rock compositions observed are products of a mixing of mantle‐derived magma and crustal contaminant. The Sr–Nd isotopic compositions of the regional Cambrian picrite in the Yongjing terrane (Y. Zhang et al, ) were used as the mantle‐derived end member, and the average compositions of the upper crust and lower crust (Goldstein & Jacobsen, ; Vervoort et al, ) were used as the possible crustal contaminants. Modelling results indicate that less than 10% crustal contaminants to the mantle‐derived magmas can yield Sr–Nd isotopic compositions of the Shangzhuang intrusion (Figure ).…”

A paired metamorphic belt in a subduction‐to‐collision orogen: An example from the South Qilian–North Qaidam orogenic belt,NWChina

“…540–510 Ma, the South Qilian ocean was opening and separated the Qaidam and the Qilian Blocks. Seamount/oceanic plateaus resulting from hot spots were constructed on the South Qilian ocean crust (Yan et al., ; Zhang, Song, et al., ). The initiation of southward subduction of the South Qilian oceanic crust led to the formation of intra‐oceanic arc (Fu, et al., ).…”

Detrital zircon record of rivers' sediments in the North Qilian Orogenic Belt: Implications of the tectonic evolution of the northeastern Tibetan Plateau

“…Zircons with ages ranging from 775 to 520 Ma are consistent with the timing of the opening and spreading of the Qilian Ocean, which was part of the Proto‐Tethys Ocean (Song, Niu, Su, Zhang, et al, ; Song, Niu, Su, & Xia, ; Figure c). The spreading of the Qilian Ocean was accompanied by extensive volcanic activity in the NQOB, as reflected by the diabase swarms in the Liugouxia area, which date to 738–604 Ma (single‐grain zircon ages; Mao et al, ), the Zhulongguan basalts, which date to 600–580 Ma (SIMS U–Pb age; Xu et al, ), and the plume‐type ophiolite in the Lajishan area, which dates to 525 Ma (according to LA‐ICP‐MS U–Pb dating; Zhang et al, ). Moreover, ages falling in this range have also been identified from the Devonian strata of the NQOB (Xu et al, ), which indicates that the NQOB experienced strong extension‐related magmatism at that time (Figure ).…”

“…Li, Li, et al () also proposed that the Qilian Ocean is part of the Proto‐Tethys Ocean during the Early Paleozoic. Given the results from river sediments (Kang, Chen, Li, Bao, & Zhang, ) and Lajishan plume‐type ophiolite (Zhang et al, ) found within the CQB, the CQB is considered to have been a palaeo‐oceanic plateau. Based on the study of river sediments, we find that the age groups and age spans in the CQB are similar to those in the NQOB (Kang et al, ; Li et al, ).…”