| 松辽盆地南部钱家店铀矿床姚家组砂岩地球化学特征及地质意义 |
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| 引用本文： | 夏飞勇,焦养泉,荣辉,吴立群,朱强,万璐璐.松辽盆地南部钱家店铀矿床姚家组砂岩地球化学特征及地质意义[J].地球科学,2019,44(12):4235-4251. |
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| 作者姓名： | 夏飞勇 焦养泉 荣辉 吴立群 朱强 万璐璐 |
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| 作者单位： | 1.中国地质大学构造与油气资源教育部重点实验室, 湖北武汉 430074 |
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| 基金项目： | 国家重点研发计划项目2018YFC0604202国家青年科学基金项目41502105中国石油辽河油田分公司重大项目LHYT-KTXMGLB-2010-JS-13848中央高校基本科研业务费专项资金G1323511660 |
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| 摘 要： | 沉积物的地球化学成分在沉积岩物源分析及构造背景的研究中具有重要的作用.对研究区4口钻孔中的姚家组砂岩进行了详细的岩石学和地球化学研究，结果显示，砂岩碎屑颗粒石英含量最高，长石次之，岩屑含量最低，平均值分别为42%、37%和21%，具有锆石+钛磁铁矿+石榴子石的重矿物组合，反映源岩以酸性岩浆岩或变质岩为主，Dickinson判别图解表明物源主要来自于大陆物源区；姚家组砂岩的稀土元素以轻稀土富集、重稀土平坦、中度铕负异常为特征.砂岩CIA值为52.02~60.16，平均值为56.69，反映了干燥气候背景下弱的化学风化作用.源岩属性判别图解表明源岩为再旋回的古老沉积物及长英质火山岩.主量、微量和稀土元素的构造背景判别图解综合表明姚家组砂岩物源区为被动大陆边缘构造环境，结合区域构造演化，认为姚家组砂岩的物源为华北克拉通北缘燕山陆内造山带发育的火山-沉积岩系.
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| 关 键 词： | 钱家店铀矿床 姚家组砂岩 地球化学特征 源区风化 物源 构造背景 |
| 收稿时间： | 2019-03-13 |
Geochemical Characteristics and Geological Implications of Sandstones from the Yaojia Formation in Qianjiadian Uranium Deposit,Southern Songliao Basin |
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| Abstract: | The geochemical composition of sandstones in sedimentary basin plays an important role in the study of sedimentary provenance and tectonic settings. In this paper, detailed petrography and geochemical analyses were carried out on the sandstones of the Yaojia Formation from 4 drilling cores in the study area. All sandstone samples have the highest content of quartz (Q), followed by feldspar (F), and the lowest amount of lithic fragments (L), with an average of 42%, 37% and 21% respectively, featuring with heavy mineral assemblage of zircon-titanium magnetite-garnet, which suggests an acidic or metamorphic source. Dickinson discrimination diagrams show provenance mainly from continental block provenance. The REE distribution patterns are uniform, with LREE enrichment, flat HREE, and moderate negative Eu anomalies (average 0.63). Chemical index of alteration CIA (52.02-60.16, average 56.69) of the sandstones displays that they have experienced low grade of chemical weathering and alteration under arid paleoclimate condition. The discrimination diagrams for provenance attribute indicate a mixed source material composition of old sedimentary rocks and felsic igneous rocks. Based on major elements, trace and rare earth elements tectonic setting discrimination diagrams, suggested that source materials of the Yaojia Formation sandstones were from passive margin environment, and its provenances were from Yanshan intracontinental orogenic belts of the northern margin of Huabei Craton. |
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