| 蔡厚安,李伟,张磊,杨国龙,肖文进,尹艳广,王广磊.西南天山喀拉多维岩体年代学、岩石地球化学及其地质意义[J].矿产勘查,2025,16(5):969-978 |
| 西南天山喀拉多维岩体年代学、岩石地球化学及其地质意义 |
| Geochronology, petrochemistry and significance of the Karadovi pluton in southwestern Tianshan |
| 投稿时间：2025-02-14 |
| DOI：10.20008/j.kckc.202505003 |
| 中文关键词: 喀拉多维 岩石地球化学 石英正长斑岩 新疆中图分类号:P618.6文献标志码:A文章编号:1674-7801(2025)05-0969-10 |
| 英文关键词: Karadovi petro-geochemistry quartz syenite porphyry Xinjiang |
| 基金项目:本文受2024年度新疆维吾尔自治区重点研发专项“环塔里木砂(砾)岩型铜矿典型矿床解剖研究(2024B03011-2)”和中国地质调查局项目(DD20160001)联合资助。 |
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| 中文摘要: |
| 西南天山分布着一条重要的碱性侵入岩与稀有稀散金属成矿带，带内岩体的研究程度不高。本文以喀拉多维岩体为例，通过锆石 U-Pb年代学和元素地球化学研究等方法，揭示了区内碱性岩地质特征、成岩时代、岩石成因、形成环境及其地质意义。同时，本文对区内稀有稀土以及有色金属矿勘探也有一定的借鉴意义。研究结果表明，喀拉多维岩体为碱质不饱和的富碱性酸性侵入岩，总稀土元素含量较高，∑REE为 164.14×10-6~483.23×10-6，平均值为 283.05×10-6；高场强元素(HFSE)相对于大离子亲石元素(LILE)具有明显的富集，显著亏损 Sr、P、Ti元素，具有明显的负 Eu异常。稀土元素球粒陨石标准化图解呈现轻微右倾的海鸥式形态，轻稀土较重稀土元素富集。岩体是源区物质在部分熔融过程中，具有特定微量元素组成的岩浆经过分异形成的。岩体的 LA-ICP-MS U-Pb同位素年龄为(277±1.6)Ma，这一时期，西南天山地区发生大规模岩浆事件；该岩体应属于塔里木大火成岩省(TLIP)晚期岩浆作用产物。从其产生的构造背景来看，其属于同碰撞阶段后造山阶段的过渡性产物，且发育于板内环境。岩体与围岩接触带的矽卡岩 Nb、 Ce、W、Sn、Au相对富集，在南疆地区两大板块缝合带，寻找这种与基性—超基性岩和碱性岩组合相关的稀有稀土及 Au多金属矿具有较好的前景。 |
| 英文摘要: |
| There is an important alkaline intrusive rock and REE metallogenic belt distributed in the south.western Tianshan. The research of the plutons in the belt is weak. Taking the Karadovi pluton as an example, thispaper reveals the geological characteristics, diagenetic age, petrogenesis, formation environment and geological sig.nificance of the alkaline rocks in the area through methods such as zircon U-Pb geochronology and elemental geo.chemistry research. At the same time, this paper also has certain reference significance for the exploration of rareearth and non-ferrous metal minerals in the area. The research results show that the Karadovi pluton is an alkali-unsaturated alkaline-rich acidic intrusive rock. The total rare earth element content is relatively high, with ∑REEranging from 164.14×10-6 to 483.23×10-6, and the average value is 283.05×10-6. High-field-strength elements(HFSE) are significantly enriched relative to large-ion lithophile elements (LILE), with significant depletion of Sr,P, and Ti elements, and obvious negative Eu anomalies. The chondrite-normalized REE diagram shows a slightlyright-inclined seagull-like shape, with light rare earth elements more enriched than heavy rare earth elements. Thepluton was formed by the differentiation of magma with specific trace-element compositions formed during the par.tial melting of source-area materials. The LA-ICP-MS U-Pb isotopic age of the pluton is (277±1.6) Ma. During thisperiod, large-scale magmatic events occurred in the Southwestern Tianshan region; this pluton should belong to theproduct of the late magmatic activity of the Tarim Large Igneous Province (TLIP). From the perspective of its tec.tonic setting, it is a transitional product of the post-syn-collision stage to the orogenic stage and develops in anintra-plate environment. The skarn in the contact zone between the pluton and the surrounding rocks is relativelyenriched in Nb, Ce, W, Sn, and Au. In the suture zone of the two major plates in southern Xinjiang, there is goodprospecting potential for finding rare earth and Au polymetallic minerals related to the combination of mafic-ultramafic rocks and alkaline rocks. |
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