四川盆地西北部中侏罗统沙溪庙组物源:碎屑锆石U-Pb年代学的证据  

Study on U-Pb age and provenance of detrital zircons from sandstones of the Shaximiao Formation,northwestern Sichuan Basin

作　　者：陈伟伟[1,2] 牟传龙 王启宇 姚升阳 任鹏 CHEN Weiwei;MOU Chuanlong;WANG Qiyu;YAO Shengyang;REN Peng(Shandong University of Science and Technology,Qingdao 266590,China;Chengdu Center,China Geological Survey(Geosciences Innovation Center of Southwest China),Chengdu 610218,China;Key Laboratory of Sedimentary Basins and Petroleum Resources,Ministry of Natural Resources,Chengdu 610218,China;Chengdu University of Technology,Chengdu 610059,China;China University of Geosciences,Wuhan 430074,China)

机构地区：[1]山东科技大学,山东青岛266590 [2]中国地质调查局成都地质调查中心(西南地质科技创新中心),四川成都610218 [3]自然资源部沉积盆地与油气资源重点实验室,四川成都610218 [4]成都理工大学,四川成都610059 [5]中国地质大学,湖北武汉430074

出　　处：《沉积与特提斯地质》2024年第3期613-629,共17页Sedimentary Geology and Tethyan Geology

基　　金：中国地质调查局项目(DD20221661);中国石油天然气股份有限公司西南油气田分公司项目(XNS川西北矿JS2022-101)。

摘　　要：通过对沙溪庙组三个砂岩样品进行碎屑锆石U-Pb定年,结果显示,其年龄区间呈现为五个年龄组,分别为2660~2300 Ma,1905~1738 Ma,1690~1442 Ma,866~811 Ma和298~160 Ma。通过与周边区域不同地块(体)锆石年龄对比并综合区域相关地质资料,发现2660~2300 Ma和1905~1738 Ma两个年龄组的碎屑锆石主要来自南秦岭造山带与扬子板块北缘,少量来自碧口地体和松潘-甘孜地体;1690~1442 Ma,该年龄组碎屑锆石来源于武关岩群、武当岩群及碧口杂岩;866~811 Ma,该组碎屑锆石主要来源于扬子克拉通北缘、碧口岩群及南秦岭造山带;298~160 Ma,碎屑锆石主要来自南秦岭造山带和晚三叠世的松潘-甘孜地体。以上证据表明,沙溪庙组物源主要来自南秦岭造山带及松潘-甘孜褶皱带,扬子克拉通则贡献较少,且南秦岭已于沙溪庙组之前隆升结束,阻挡了来自北秦岭及华北板块南缘的物质输入。The U-Pb dating of detrital zircons from three sandstone samples of the Shaximiao Formation reveals five age groups:2660~2300 Ma,1905~1738 Ma,1690~1442 Ma,866~811 Ma,and 298~160 Ma.By comparing the ages of zircons from different blocks(or bodies)in the surrounding areas and combining relevant regional geological data,it is found that the detrital zircons with ages of 2660~2300 Ma and 1905~1738 Ma are mainly from the southern Qinling orogenic belt and the northern margin of the Yangtze Plate,and slightly from the Bikou terrane and the Songpan-Ganzi terrane.Detrital zircons with ages of 1690~1442 Ma come from the Wuguan Group,the Wudang Group,and the Bikou complex.Detrital zircons with ages of 866~811 Ma are mainly derived from the northern margin of the Yangtze Craton,the Bikou Group,and the South Qinling orogenic belt.Detrital zircons with ages of 298~160 Ma mainly come from the South Qinling orogenic belt and the Late Triassic Songpan-Ganzi terrane.Evidences show that the sediment provenance of the Shaximiao Formation is mainly derived from the South Qinling orogenic belt and the Songpan-Ganzi fold belt,and partly from the Yangtze Craton.The uplift of the South Qinling ended before the sedimentation of the Shaximiao Formation,thus blocking the sediment input from the North Qinling and the south margin of the North China Plate.

关 键 词：川西北 碎屑锆石 U-PB定年 物源分析 沙溪庙组 

分 类 号：P597[天文地球—地球化学]