Age and tectonic setting of volcanic rocks of the Dashizhai Formation from Xinkaiba, Balinyouqi area, Inner Mongolia

作者：Guan QingBin^*; Liu ZhengHong; Bai XinHui; Li PengChuan; Wan Le; Li ShiChao

来源：Acta Petrologica Sinica, 2016, 32(7): 2029-2040.

• Balinyouqi area
• Dashizhai Formation
• Zircon U-Pb dating
• Zircon Hf isotopes
• Geochemistry
• Subduction

Zircon U-Pb chronological, geochemical and in situ Hf isotope research have been undertaken on the basaltic andesites of the Dashizhai Formation in Xinkaiba, Balinyouqi area, southeast part of the Central Asian Orogenic Belt in Inner Mongolia, China. The basaltic andesites, which yield age of similar to 280Ma (the Early Permian), display an enrichment in large ion lithophile elements (Sr, Ba, Rb and K) and depletion in high field-strength elements (Nb, Ta and Ti), exhibited the transitionary geochemical features of island arc volcanics. The results of geochemistry and different sources of Hf isotopes (depleted mantle and ancient crust), indicate the magma originated from the subduction sediment melt and fluid metasomatism peridotite which from the mantle wedge. A comparative study on the basaltic andesites of the Dashizhai Formation, in Dashizhai area, indicates that basaltic andesites from Balinyouqi area are formed under the island arc-active continental margin environment in a subduction tectonic setting. It's demonstrated that the ocean crust was subducting from south to north and Paleo-Asian Ocean wasn't closed in Early Permian.

• 出版日期2016-7
• 单位吉林大学