| 王博,张虎军,王福东.关于伊犁盆地南缘水西沟群沉积相的认识[J].矿产勘查,2025,16(S1):1-9 |
| 关于伊犁盆地南缘水西沟群沉积相的认识 |
| Understanding of the sedimentary facies of Shuixigou Group in the southern margin of Yili Basin |
| 投稿时间：2024-11-04 |
| DOI：10.20008/j.kckc.2025S1001 |
| 中文关键词: 伊犁盆地南缘 水西沟群 辫状河三角洲相 河道砂体 |
| 英文关键词: southern margin of Yili Basin Shuixigou Group braided river delta facies channel sand body |
| 基金项目:本文受中国核工业地质局项目“新疆伊犁盆地及周边地区砂岩型铀矿资源调查评价与勘查”(202205)资助。 |
|
| 摘要点击次数: 564 |
| 全文下载次数: 180 |
| 中文摘要: |
| 伊犁盆地作为中国砂岩型铀矿的重要产区，在其南缘相继发现了库捷尔太铀矿床、洪海沟铀矿床、蒙其古尔铀矿床等几个大型、超大型铀矿床，其主要赋矿层位为中下侏罗统水西沟群，但是前人对于该层位属于扇三角洲相还是辫状河三角洲相存在分歧。本研究通过总结分析前人研究成果，对扇三角洲与辫状河三角洲进行全面、细致的对比分析，发现其在形成方式、沉积类型、沉积体形态、沉积微相、沉积韵律、沉积构造、岩性以及岩石结构等多方面存在明显不同，属于两个完全不同的沉积体系。伊犁盆地南缘水西沟群在各方面均符合辫状河三角洲的沉积特征，为冲积扇 -辫状河三角洲沉积体系。在辫状河三角洲演化的晚期，盆地南缘东、西段的沉积相存在时空差异，这可能是由于地形的差异隆升使得盆地西段更早地进入湖退体系，呈现出盆地西段西山窑组下段为三角洲平原相，上段为河流相；而盆地东段西山窑组下段为三角洲前缘相，上段为三角洲平原相的特征。该地区的铀矿体主要发育在三角洲平原和三角洲前缘的分流河道砂体、河流相的厚大河道砂体和冲积扇相的扇中河道砂体中以及三角洲前缘的河口砂坝、席状砂和水下决口扇等沉积微相中。 |
| 英文摘要: |
| As a significant production area for sandstone-type uranium deposits in China，several large to super-large uranium deposits such as the Kujiertai，Honghaigou，and Mengqiguer deposits have been successivelydiscovered along the southern margin of the Yili Basin. The primary host horizon for mineralization is the ShuixigouGroup of the Lower-Middle Jurassic. However，there has been disagreement among previous researchers regarding whether this horizon represents a fan-delta facies or a braided river delta facies. This study comprehensively sum.marizes and analyzes prior research findings，conducting a thorough and detailed comparative analysis between fan deltas and braided river deltas. Significant differences were identified in multiple aspects，including their forma. tion mechanisms， depositional types， depositional body morphology， depositional microfacies， sedimentary rhythms，sedimentary structures，lithology，and rock textures. These distinctions confirm that they belong to twoentirely distinct depositional systems. The sedimentary characteristics of the Shuixigou Group along the southernmargin of the Yili Basin are consistent in all aspects with those of a braided river delta，indicating an alluvial fan-braided river delta depositional system. During the late stage of braided river delta evolution，spatiotemporal differ.ences existed in the depositional facies between the eastern and western segments of the southern basin margin.This is likely attributable to differential topographic uplift，which caused the western segment to enter a lacustrine regression system earlier. Consequently:In the western segment，the lower member of the Xishanyao Formation belongs to the delta plain facies，while the upper member exhibits fluvial facies；in the eastern segment，the lower member of the Xishanyao Formation corresponds to the delta front facies，and the upper member transitions to thedelta plain facies. Uranium ore bodies in this region are primarily developed within:distributary channel sands of the delta plain and delta front facies；distributary channel sands of the delta plain and delta front facies；mid-fan channel sands within the alluvial fan facies；various depositional microfacies of the delta front，including mouth bars，sheet sands，and subaqueous crevasse splays. |
|
查看全文
查看/发表评论 下载PDF阅读器 |
| 关闭 |