Study on the geochemical characteristics of ocean-ridge and oceanic-island volcanic rocks in the Nan-Uttaradit zone, northern Thailand  

作　　者：SHEN Shangyue FENG Qinglai YANG Wenqiang ZHANG Zhibin Chong pom Chong lakmani 

机构地区：[1]State Key Laboratory of GPMR, China University of Geology, Wuhan 430074, China [2]Institute of Regional Geology, Yunnan Bureau of Geology and Mineral Resources, Yuxi 653110, China [3]Suranaree University of Technology, Thailand

出　　处：《Chinese Journal Of Geochemistry》2010年第2期175-181,共7页中国地球化学学报

基　　金：by the National Natural Science Foundation of China(Grant Nos. 40372105 and 40772143)

摘　　要：Field investigations and laboratory integrated research as indicated that ophiolite mélange in the Nan-Uttaradit zone, northern Thailand, consists of fragments of tectonites such as metamorphic peridotite (extremely silicified serpentinite), cumulates (pyroxenolite, gabbro, and gabbro-diorite), ocean-ridge basalt, oceanic-island ba-salt and radiolarian silicalite, and it was formed during D3-P. The rock series, rock types and petrogeochemical characteristics of metamorphic tholeiites in the Nan area of the Nan-Uttaradit zone are similar to those of ocean-ridge basalts (C1) in China's Ailaoshan zone. As for the Hawaiites in the Nan area of the Nan-Uttaradit zone, their major elements, REEs and trace elements are similar to those of oceanic-island basalts in China's Jinshanjiang zone (P11). In the Uttaradit area of this zone the metamorphic alkaline basalts show transitional petrogeochemical characteristics between ocean-ridge basalts and oceanic-island basalts, which were still formed in oceanic-island environments. The above-described basalts are all oceanic volcanic rocks and they are the most important part of the Paleo-Tethys oceanic crust in the Nan-Uttaradit zone.Field investigations and laboratory integrated research as indicated that ophiolite melange in the Nan-Uttaradit zone, northern Thailand, consists of fragments of tectonites such as metamorphic peridotite （extremely silicified serpentinite）, cumulates （pyroxenolite, gabbro, and gabbro-diorite）, ocean-ridge basalt, oceanic-island basalt and radiolarian silicalite, and it was formed during D3-P. The rock series, rock types and petrogeochemical characteristics of metamorphic tholeiites in the Nan area of the Nan-Uttaradit zone are similar to those of ocean-ridge basalts （C0 in China＇s Ailaoshan zone. As for the Hawaiites in the Nan area of the Nan-Uttaradit zone, their major elements, REEs and trace elements are similar to those of oceanic-island basalts in China＇s Jinshanjiang zone （Pll）. In the Uttaradit area of this zone the metamorphic alkaline basalts show transitional petrogeochemical characteristics between ocean-ridge basalts and oceanic-island basalts, which were still formed in oceanic-island environments. The above-described basalts are all oceanic volcanic rocks and they are the most important part of the Paleo-Tethys oceanic crust in the Nan-Uttaradit zone.

关 键 词：岩石地球化学特征 洋岛玄武岩 火山岩 洋脊 泰国 放射虫硅质岩 微量元素 蛇绿混杂岩 

分 类 号：P588.14[天文地球—岩石学] P588.13[天文地球—地质学]