古地理学报 ›› 2018, Vol. 20 ›› Issue (6): 1068-1085. doi: 10.7605/gdlxb.2018.06.079

• 岩相古地理学及沉积学 • 上一篇    下一篇

贺兰山地区中晚三叠世物源分析及其时空演化过程*

李蒙1,2, 赵红格1,2, 李文厚1, 任战利1, 卓鱼周1, 付星辉1   

  1. 1 西北大学地质学系,陕西西安 710069;
    2 大陆动力学国家重点实验室,西北大学,陕西西安 710069
  • 收稿日期:2018-01-10 修回日期:2018-05-23 出版日期:2018-12-01 发布日期:2018-11-27
  • 通讯作者: 赵红格,女,1975年生,博士,教授,主要从事沉积盆地分析及油气地质研究。E-mail: zhaohg-75@sina.com
  • 作者简介:李蒙,男,1989年生,博士研究生,主要从事沉积盆地物源研究及沉积学研究。E-mail: limengdzxr@sina.com。
  • 基金资助:
    *国家自然科学基金项目(编号: 41330315,40902032),国家科技重大专项(编号: 2011ZX05023-001-002),中国地质调查局矿产资源调查评价项目(编号: 121201011000150014)和西北大学大陆动力学国家重点实验室科技部专项项目(编号: BJ08133-14,BJ081334-2)联合资助

Provenances of the Middle-Late Triassic in the Helan Mountain and its temporal-spatial evolution

Li Meng1, 2, Zhao Hong-Ge1, 2, Li Wen-Hou1, Ren Zhan-Li1, Zhuo Yu-Zhou1, Fu Xing-Hui1   

  1. 1 Depertment of Geology,Northwest University,Xi'an 710069,Shaanxi;
    2 State Key Laboratory of Continental Dynamics,Northwest University,Xi'an 710069,Shaanxi;
  • Received:2018-01-10 Revised:2018-05-23 Online:2018-12-01 Published:2018-11-27
  • Contact: Zhao Hong-Ge,born in 1975,is a professor and director of Ph.D. candidate. She is mainly engaged in analysis of sedimentary basins and oil and gas geology. E-mail: zhaohg-75@sina.com.
  • About author:Li Meng,born in 1989,is a Ph.D. candidate at Northwest University. He is mainly engaged in research of sedimentology and provenance analysis. E-mail: limengdzxr@sina.com.
  • Supported by:
    Co-Funded by the National Natural Science Foundation of China(Nos. 41330315,40902032),National Science and Technology Major Project(No.2011ZX05023-001-002),Mineral Resources Survey and Evaluation Project of the China Geological Survey(No.121201011000150014),and special project of the Ministry of Science and Technology of the State Key Laboratory of Continental Dynamics,Northwest University(No. BJ08133-14,BJ081334-2)

摘要: 系统分析物源的时空演化过程,必将为判断当时的盆地构造背景和盆地属性提供佐证。文中运用重矿物分析方法,结合砾石岩性组成、地层厚度变化及沉积相分布规律,对贺兰山地区中晚三叠世沉积物源进行系统分析。结果表明: 贺兰山地区中晚三叠世沉积物具有多源、混源以及上下层段时空演化差异明显的特点。中三叠世纸坊期物源主要来自盆地西北部和西部;晚三叠世延长期T3y1T3y2段沉积时期,物源主要来自盆地西北部、西部、南部;T3y3T3y5段沉积时期,盆地东部物源开始出现,并分布于贺兰山汝箕沟沟口至鬼头沟一线,此时汝箕沟—香棒子沟一带是沉积混源中心。西部物源主要为阿拉善地块之上的沉积地层,但西部南段受南部物源控制,与西部北段的物源岩性有较明显不同;西北部物源主要是孔兹岩带、前寒武纪变质岩及古生代岩浆岩;东部地区物源可能为现今银川地堑及其东部的沉积地层。贺兰山地区中晚三叠世物源时空演化的转折期,主要在纸坊期至延长期T3y1段沉积时期之间和延长期T3y2段至T3y3段沉积时期之间,2次明显的物源演化反映了贺兰山盆地构造动力学机制的重大转变。

关键词: 贺兰山, 三叠系, 重矿物, 物源时空演化

Abstract: Combined with conglomerate composition,strata thickness and sedimentary facies,heavy mineral compositions were firstly used to study the provenances of the Middle-Late Triassic in the Helan Mountain. Results showed that the provenance of the Middle-Late Triassic sediments in the Helan Mountain were characterized by multiple and mixed sources,and were varied greatly. Sediments of the Middle Triassic Zhifang Formation were mainly from northwest and west. However,sediments of the Late Triassic Yanchang Formation changed. During deposition of the lower two members T3y1 and T3y2,sediments were mainly derived from the northwest,west and south. During deposition of the upper three members T3y3 to T3y5,eastern sources appeared,which were distributed in the Ruqigou to Xiangbangzigou. The western provenance was mainly in the sedimentary strata on the Alxa Block. Sediments of northwestern part were mainly from the Precambrian metamorphic rocks and Paleozoic magmatic rocks in the Paleoproterozoic Khondalite Belt,which was different from the southwestern part. Sediments in its eastern part were sourced from the sedimentary strata of Yinchuan graben and areas to its east. Provenance transformation of the Middle-Late Triassic strata in the Helan basin occurred twice: One from the Zhifang to Yanchang formations T3y1,and the other from the T3y2 to T3y3.These two prominent transitions suggested significant transformation of the dynamic mechanism in the Helan basin.

Key words: Helan Mountain, Triassic, heavy mineral, temporal-spatial provenance evolution

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