Zircon SHRIMP U-Pb dating and its implications of post-collisional volcanic rocks in Santanghu Basin, Xingjiang.

新疆三塘湖盆地广泛出露哈尔加乌组地层,主要为陆相中性喷发岩夹火山碎屑岩。火山岩锆石SHRIMP U-Pb年龄为319.6±9.8Ma(MSWD=4.8)。地球化学分析表明,哈尔加乌组火山岩高钾富碱,属于高钾钙碱性系列;LREE强烈富集、大离子亲石元素(LILE)强烈富集、大多数高场强元素(HFSE)明显高于MORB,没有Ti的负异常和P的正异常,Nb、Ta负异常明显,基本没有Eu、Ce的异常,Ti/Y(467～494)、Nb/Y(0.41～0.43)值高。判别图解投入板内火山岩和岛弧火山岩区域,整体显示板内火山岩的特征又携带岛弧火山岩的地球化学痕迹。ε_(Nd)(t)值(+5.90～+6.31...Haerjiawu Formation is dominated by intermediate extrusive rocks and pyroclastic rocks, and widely developed in Santanghu Basin, Xingjiang. The zircon SHRIMP U-Pb dating of volcanic rocks in Haerjiawu Formation is 319.6 +/- 9.8Ma (MSWD = 4.8). Using geochemical analysis, the volcanic rocks are characterized by high content of K and alkali-rich, belonging to high-k calcalkaline series. Light rare earth elements (LREE) and large ion lithophile elements, (are strongly enriched. The contents of most high field strength elements (HFSE) are obviously higher than MORB All the samples have obviously negative anomaly in Nb, Ta and without Ti, P, Eu or Cc anomaly, high ratios of Ti/Y (467 similar to 494) and Nb/Y (0.41 similar to 0.43). The discrimination diagrams show volcanic rocks belong to with-plate setting with the signature of arc volcanic rocks. Positive epsilon(Nd) (t) (+5.90 similar to +6.31) and high Mg(#) (0.54 similar to 0.57) indicate the depleted mantle-related source, while high ((87)Sr/(86)Sr)(i) (0.70397 similar to 0.70464) relative to depleted mantle and the ratios of La/Nb (3.12 similar to 3.39) and Nb/U (5.86 similar to 9.80) show participation of crustal material. Combining with regional geology, the volcanic rocks in Haerjiawu Formation generated in a post-collisional and extensional transformation setting and originated from melting of crustal components and arc volcanic components by upwelling of asthenospheric mantle.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000264895900005&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701SCI(E)中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)1003527-5382