铀矿地质2026，Vol.42Issue(3)：403-416,14.DOI:10.3969/j.issn.1000-0658.2026.42.030
胡力海洼陷主含矿层层间还原流体地球化学特征及其对铀矿化的控制作用
Geochemical Characteristics of Interlayer Reducing Fluids in the Lower Member of Yaojia Formation-Qingshankou Formation of Hulihai Sag and Their Controlling Effect on Uranium Mineralization
摘要
Abstract
To clarify the geochemical characteristics of interlayer reducing fluids in Qingshankou Formation and the lower member of Yaojia Formation in Huliha sag and their control on uranium mineralization,the ore host sand bodies in gray sandstone of the target layer were studied by testing the acidic hydrocarbon decomposition and vitrinite reflectance(Ro),and a comprehensive analysis was conducted in combination with the previous zircon U-Pb dating results of diabase and the current measured borehole geothermal data.The study area is a fault-depression type double-faulted asymmetric sag,developed with multiple sets of high-quality source rocks.The NE-trending normal faults penetrating the basement controlled the uranium orebodies which present the characteristics of"zonal distribution,lateral development,multi-layer occurrence,and superimposed location",and the reducing fluids supplied by the underlying source rocks served as the key driving force for uranium mineralization.Geochemical analysis of acidic hydrocarbons in the ore hosting sandstones reveals that their components are dominated by methane with low heavy hydrocarbon content and a dryness coefficient ranging from 0.59 to 0.99(mainly wet gas),which confirms that the interlayer reducing fluids originate from the hydrocarbon expulsion generated from deep source rocks.Ro values was used to quantitatively calculating the paleotemperature,and the paleotemperature of the target layer was estimated from 58.1 to 136.6℃by the Ro values from 0.36%to 1.11%,which indicate that the source rocks are mainly in the stage of low-maturity-maturity hydrocarbon generation and have sufficient hydrocarbon generation potential.Diabase dating and geothermal data were combine to analyze the driving mechanism of fluid activity,and interlayer reducing fluids was found driven by tectonic thermal events related to the intrusion of diabase in the Paleogene Eocene(39 Ma,47 Ma),which generally show a heat transfer and fluid migration pattern from deep to shallow.The interlayer reducing fluids control the unique distribution pattern of uranium metallization through the dual effects of creating a reducing environment to form a reduction barrier and constructing a temperature-increasing hydrothermal system to accelerate the activation and enrichment of uranium elements.This study clarifies the genesis,driving mechanism and ore-controlling effect of interlayer reducing fluids in Qingshankou Formation and the lower member of Yaojia Formation in Hulihai sag,providing an important geological basis for the uranium prospecting and exploration in Hulihai sag and the similar fault-depression area.关键词
胡力海洼陷/还原流体/地球化学/铀矿化/姚家组下段/青山口组Key words
Hulihai Sag/reducing fluids/geochemistry/uranium mineralization/the lower member of Yaojia Formation/Qingshankou Formation分类
天文与地球科学引用本文复制引用
武飞,何春生,唐国龙,卢天军,郭恒飞,宫天琦,高屹,蔺鹏飞,胡鑫垚,蔡建芳,姜山,宁君,张亮亮,王常东,黄笑,郝晓飞,马树松..胡力海洼陷主含矿层层间还原流体地球化学特征及其对铀矿化的控制作用[J].铀矿地质,2026,42(3):403-416,14.基金项目
中国核工业地质局铀矿地勘费项目"松辽盆地通辽市—大庆地区铀矿资源调查评价与勘查"(编号:202212)和"内蒙古通辽市科尔沁区余粮堡—科左中旗宝德勒地区铀矿资源调查评价"(编号:202212-3)联合资助. （编号:202212）
