东昆仑西段拉陵灶火沟地区变质侵入体的年代学与地球化学特征及其地质意义OA

In the Laling Zao Huo Gou area of the western segment of the Eastern Kunlun Mountains,a newly identified set of granitic metamorphic intrusions was discovered within the Jinsui Kou Group of the Paleopro-terozoic.The lithology is predominantly composed of eye-shaped hornblende monzogranite.Through studies in petrology,zircon LA-MC-ICP-MS U-Pb isotopic dating,and petrogeochemistry,the author explores the petro-genesis,formation age,and tectonic significance of these metamorphic intrusions.Petrogeochemical studies in-dicate that these metamorphic intrusive rocks exhibit high silica content(SiO2=65.52%-75.31%),high total alka-li content(K2O+Na2O=6.82%-8.81%),elevated Al2O3 content(12.17%-14.22%),and a δ value of 1.89-2.54,classifying them as the high-K calc-alkaline series with an A/CNK ratio of 1.37-1.68,displaying characteristics of S-type peraluminous granite.The rare earth element(REE)distribution pattern shows a right-leaning trend with relative enrichment of light rare earth elements and a distinct negative Eu anomaly(δEu=0.173-0.52).The mid-ocean ridge granite-normalized trace element spider diagram reveals a right-leaning trend,with deficits in Nb and Ta and enrichments in Rb,K,and Th.The CaO/Na2O ratio of the rocks ranges from 0.35 to 0.91,averag-ing 0.61,while the Rb/Sr ratio is relatively high,ranging from 0.6 to 2.83,averaging 1.77,indicating that the granites in the region are derived from the upper crustal source,likely formed by the melting of sandy clastic sedimentary rocks with minor mud components.The LA-MC-ICP-MS zircon U-Pb weighted age of this meta-morphic intrusive suite is(865.8±3.9)Ma(MSWD=0.24),belonging to the early Neoproterozoic.Based on pre-vious studies of chronology and regional tectonic evolution in the eastern Kunlun region,and through the tecton-ic discrimination criteria discussed in the paper,it is concluded that the Laling Zao Hui Gou rock suite formed in a post-collisional tectonic setting,representing magmatic activity under the early Neoproterozoic continental convergence and collision environment in the western segment of the eastern Kunlun orogenic belt.Based on comprehensive data,it is believed that there was a land collision and assembly event in the early Neoproterozoic in the East Kunlun region,which is basically consistent with the formation of the global Rodinia supercontinent.In other words,the metamorphic intrusion in the Lalingzaohuogou area of the East Kunlun is a response to mag-matic activity in the East Kunlun block during the aggregation of the Rodinia supercontinent.