Zircon U-Pb dating and petrogeochemical characteristics of the gabbro in the Xiaokelehe area,northern segment of the Great Xing'an Range
The formation mechanism of Early Cretaceous extensional environment in the Great Xing'an Range is uncertainty yet.In this paper,zircon U-Pb geochronology and pedogeochemical characteristics of the gabbro in the Xiaokelehe area,northern segment of the Great Xing'an Range were studied.Zircon U-Pb dating show that the gabbro was formed in the late Early Cretaceous(123.7±0.9 Ma).Results of petrogeochemical analysis show that the samples are low in Si and high in Mg.The fractionation between light and heavy rare earth elements in the samples is weak.The samples are enriched in large-ion lithophile elements(e.g.,Ba,Sr,and U),depleted in high-field-strength elements(e.g.,Th,Ti,and Zr),and shown weak Eu positive anomalies(δEu=1.03～1.27).It was concluded that the fractional crystallization and crustal contamination during the formation of the Xiaokelehe gabbro were weak,and the magma was derived from the lithospheric mantle source that had previously been metasomatized by slab-derived fluids.Combined with the regional tectonic evolution data,it was concluded that the late Early Cretaceous Xiaokelehe gabbro was formed in an extensional environment caused by the subduction of the Paleo-Pacific Plate.
northern segment of the Great Xing'an RangeXiaokelehegabbropetrogeochemistryextensional environment
万方数据
维普
