| 王宁,姚征,王喆,王强.陕南下寒武统牛蹄塘组地球化学特征及其地质意义[J].矿产勘查,2025,16(8):1918-1926 |
| 陕南下寒武统牛蹄塘组地球化学特征及其地质意义 |
| Geochemical characteristics and geological significance of the Lower Cambrian Niutitang Formation in southern Shaanxi Province, China |
| 投稿时间：2022-12-04 |
| DOI：10.20008/j.kckc.202508008 |
| 中文关键词: 地球化学 沉积环境 构造背景 牛蹄塘组 陕南地区中图分类号:P59文献标志码:A文章编号:1674-7801(2025)08-1918-09 |
| 英文关键词: geochemistry sedimentary environment tectonic setting Niutitang Formation Southern Shaanxi Province |
| 基金项目:本文受陕西省公益性地质调查项目(20170104、202403)资助。 |
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| 中文摘要: |
| 黑色岩系作为“多元素富集层”和烃源岩，是金属矿产和能源矿产的目标层位。为深入研究陕南地区下寒武统牛蹄塘组黑色岩系沉积-构造环境，本文采集观音庵剖面黑色页岩样品进行了主量、微量和稀土元素地球化学测试分析。研究结果表明，牛蹄塘组黑色岩系不仅有机碳含量高，而且与上地壳相比更富集 V、 Cr、Zn、Mo、Ba等元素，V/(V+Ni)、V/Cr、Ni/Co、δU、Ceanom和 Ce/La等指标均指示牛蹄塘组页岩沉积于缺氧还原的半滞留水体环境，这种滞留环境促进了多金属元素与有机质的富集。稀土配分曲线呈明显的右倾型，具有轻稀土相对富集、重稀土相对亏损特点。La/Sc、Th/Sc、Cr/Zr反映源岩主要来源于上地壳长英质岩石，(La/Yb)-(Ce/La)和(La/Yb)-∑REE图解指示陕南地区牛蹄塘组黑色岩系源岩具有多元性，沉积时陕南地区属大陆岛弧构造背景。 |
| 英文摘要: |
| As a "multi-element enrichment layer" and source rock, the black rock series serve as target hori-zons for both metallic and energy mineral resources. To further investigate the sedimentary-tectonic environment ofthe black rock series from the Lower Cambrian Niutitang Formation in southern Shaanxi, black shale samples werecollected from the Guanyin'an section for geochemical analysis of major, trace, and rare earth elements. The resultsshow that, compared to the upper crust, the black rock series of the Niutitang Formation not only have high organic carbon content but are also enriched in elements such as V, Cr, Zn, Mo, and Ba. Geochemical proxies including V/(V+Ni), V/Cr, Ni/Co, δU, Ceanom, and Ce/La all indicate that the Niutitang Formation shale was deposited in an an-oxic, reducing, semi-restricted aquatic environment. This restricted setting facilitated the enrichment of polymetal-lic elements and organic matter. The rare earth element distribution pattern shows a distinct right-leaning trend,characterized by relative enrichment of light rare earth elements and relative depletion of heavy rare earth elements.Ratios of La/Sc, Th/Sc, and Cr/Zr reflect that the source rocks were primarily derived from felsic rocks of the uppercrust. Additionally, (La/Yb)-(Ce/La) and (La/Yb)-∑REE diagrams reveal a mixed provenance for the Niutitang For-mation black rock series in southern Shaanxi, suggesting that the region was situated in a continental island arc tec-tonic setting during the deposition period. |
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