地学前缘 ›› 2020, Vol. 27 ›› Issue (5): 151-170.DOI: 10.13745/j.esf.sf.2020.5.42

• 地质过程与成矿作用示踪的成因矿物学 • 上一篇    下一篇

辽西赤峰—朝阳金矿带早白垩世以来的隆升剥蚀及启示意义

申俊峰,李胜荣,徐渴鑫,王业晗,张士全,许元全,何泽宇,迟雷,吴晋超   

  1. 中国地质大学(北京) 地球科学与资源学院, 北京 100083
  • 收稿日期:2020-04-25 修回日期:2020-05-20 出版日期:2020-09-25 发布日期:2020-09-25
  • 作者简介:申俊峰(1962—),男, 博士,教授,矿物学、岩石学、矿床学专业,主要从事成因矿物学与找矿矿物学研究。E-mail:shenjf@cugb.edu.cn
  • 基金资助:

    国家重点研发计划项目(2016YFC0600106)

Uplifting and denudation of the ChifengChaoyang gold ore zone in western Liaoning Province since the Early Cretaceous and the implication

SHEN Junfeng, LI Shengrong, XU Kexin, WANG Yehan, ZHANG  Shiquan, XU Yuanquan, HE Zeyu, CHI Lei, WU Jinchao   

  1. Uplifting and denudation of the ChifengChaoyang gold ore zone in western Liaoning Province since the Early Cretaceous and the implication
  • Received:2020-04-25 Revised:2020-05-20 Online:2020-09-25 Published:2020-09-25

摘要:

华北克拉通于中生代遭受严重破坏的观点已被地学界广泛接受。其北缘的辽西地区赤峰—朝阳金成矿带之岩浆作用和成矿作用被认为是克拉通破坏事件的典型响应。在区域地质和矿床地质调查的基础上,选择该矿带的金厂沟梁金矿区和排山楼金矿区,分别针对与成矿时间一致的西对面沟岩体(成岩时间128 Ma)和大石头沟岩体(成岩时间128~126 Ma)进行了矿物组合、结晶温度、氧逸度和侵位深度研究。采用黑云母全铝压力计获得两个岩体结晶压力平均值分别为97 MPa和145 MPa,按照地壳密度2.7 g/cm3估算了两个岩体的侵位深度分别为3.67 km和5.48 km。根据以上估算结果并结合前人研究成果,认为早白垩世以来赤峰—朝阳金成矿带剥蚀深度应该在3.67~7.70 km范围,平均值5.27 km。此外,在收集和综合对比分析华北地区隆升剥蚀资料的基础上,认为自早白垩世以来华北地区总体剥蚀深度范围为2.0~10.0 km,主要集中在2.0~6.0 km,平均值约5.60 km。这一认识对于华北地区进一步找矿具有重要参考意义。

null

关键词: 黑云母, 压力计, 剥蚀深度, 辽西, 华北地区

Abstract:

The viewpoint that the North China Craton (NCC) in eastern China underwent Mesozoic lithospheric destruction has been widely accepted. The ChifengChaoyang gold mineralization zone in western Liaoning Province is a typical ‘destruction’ zone of the north margin because the magmatism and metallogeny of the mineralization zone were a fundamental response to the NCC destruction. Based on the investigation of regional and deposit geologies we studied the two plutons—the Duimiangou intrusive (solidification in 128 Ma) and Dashitougou pluton (solidification in 128-126 Ma) from the Jinchanggouliang and Paishanlou gold mineralization districts, respectively—in terms of mineral assemblage, crystallization temperature, oxygen fugacity, and crystallization pressure. Specifically, we estimated the crystallization pressure of biotite (equal to the crystallization pressure of the pluton) and its average value to be 0.97 kbar and 1.45 kbar, respectively, by Al-in-biotite barometric measurement. We also computed the emplacement depths of the Duimiangou and Dashitougou plutons to be 3.67 km and 5.48 km, respectively, using the above crystallization pressures and a crustal density of 2.7 g/cm3. Combining with the previous data, we estimated the denudation depth in the ChifengChaoyang gold mineralization zone to be 3.67-7.70 km, averaging at 5.27 km. In addition, we compiled the crustal exhumation data on the NCC for comparison. We found that since the early Cretaceous, the total crustal exhumation of the NCC ranged between 2.0-10.0 km; but it is more concentrated between 2.0-6.0 km, averaged at 5.60 km, with varying denudation depths. All above results are very important for the Mesozoic gold prospecting in the NCC.

Key words: biotite, geobarometer, crustal exhumation, western Liaoning Province, North China Craton

中图分类号: