摘要
研究区沉积盖层碎屑物组合可以很好地反映沉积环境,构造事件。下白垩统六盘山群李洼峡组长石石英砂岩广泛出露于华北克拉通(鄂尔多斯盆地)西南缘。文章报道了砂岩样品的碎屑锆石定年分析结果,发现碎屑锆石存在四期峰值年龄,反映华北克拉通在2.5 Ga至1.8 Ga期间依次经历了克拉通化(~2.5 Ga)之后的裂解作用、2.2~2.0 Ga期间与裂解作用相关的岩浆事件、1.95~1.85 Ga期间沿着中部造山带及北部孔兹岩系发生的俯冲作用及与之伴生的变质事件,1.8 Ga之后进入后造山期,整个克拉通发生裂解。晚侏罗世开始,研究区快速隆升,沉积上侏罗统芬芳河组巨砾砾岩。晚白垩世至古近纪以来,研究区主要受青藏高原隆升的影响,形成以六盘山断裂带为主的一系列脆性构造变形。
The clastic assemblage of sedimentary cover can well reflect the sedimentary environment and tectonic events in the study area.The feldspathic quartz sandstone of Liwaxia Formation of Lower Cretaceous Liupanshan Group is widely exposed in the southwest margin of Ordos Basin.This paper reports the dating analysis result of the clastic zircon of sandstone samples.It is found that there are four peak ages of the clastic zircon,reflecting that North China Craton has successively experienced the cracking after cratonization(up to 2.5 Ga),the magmatic events related to the cracking during 2.2 Ga-2.0 Ga,the subduction and associated metamorphic events along the central orogenic belt and the northern khondalite series during 1.95 Ga-1.85 Ga.After 1.8 Ga,the whole craton splits into post-orogenic stage.From the Late Jurassic,the study area rapidly uplifts and the Upper Jurassic Fanfanghe Formation boulder conglomerate is deposited.From the Late Cretaceous to the Paleogene,the study area is mainly affected by the uplifting of the Qinghai-Tibet Plateau,forming a series of brittle structural deformation dominated by the Liupanshan fault zone.
作者
徐欢
刘望明
南芷妍
赵明海
XU Huan;LIU Wangming;NAN Zhiyan;ZHAO Minghai(School of Surveying and Testing,Shaanxi Railway Institute,Weinan 714000,Shaanxi,China)
出处
《矿产与地质》
2022年第6期1169-1175,共7页
Mineral Resources and Geology
基金
陕西省教育厅2020年度一般专项科学研究计划项目(20JK0578)资助。
关键词
六盘山群
碎屑锆石
沉积建造
构造演化
鄂尔多斯盆地
Liupanshan Group
detrital zircon
sedimentary formation
tectonic evolution
Ordos Basin
