萤石是一种重要的战略性非金属矿产资源，主要用于冶金和化学工业，还用于航空、航天、医药、建材、陶瓷和玻璃等工业领域。近年来，随着萤石应用领域的不断扩展，对萤石矿产的需求呈现快速增长的态势。因此，开展萤石矿产的区域成矿规律及找矿预测研究具有重要的现实意义。虽然萤石是我国的优势矿种，但萤石资源分布极不均匀，主要集中于浙江、赣南及内蒙古中东部地区。近期由浙江省地勘单位在阿尔金地区新发现的卡尔恰尔萤石矿床，初步探明CaF₂矿物量2 249×10⁴ t，已达超大型规模。该萤石矿床位于新疆若羌县境内，阿尔金山中段北麓，东距315国道和新建库尔勒—格尔木铁路约170 km，北距若羌县城直线距离约72.5 km。该萤石矿床的发现与评价，取得了引人瞩目的成果，推动了阿尔金地区的萤石找矿工作，打破了西部缺少萤石矿产的格局。卡尔恰尔萤石矿床大地构造位于阿尔金造山带中部地块变质杂岩带阿中微地块（图1）。

图1　卡尔恰尔萤石矿床大地构造位置与矿体分布地质简图（吴益平等，2021）

Fig. 1　Tectonic location and simplified geological map of the Kalqiaer fluorite deposit

   新疆阿尔金卡尔恰尔超大型萤石矿床属新近发现，其矿床类型和成因机制是丞待研究的重要问题。吴益平、张连昌研究员根据实际勘查工作成果，通过对卡尔恰尔萤石矿床地质特征总结，从矿物包裹体特征、氢氧同位素组成等方面探讨萤石方解石脉型成矿流体的性质及来源，为深入研究成矿机制与区域成矿规律，开展阿尔金地区萤石找矿工作提供帮助。

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阿尔金卡尔恰尔超大型萤石矿床成矿流体特征及形成机制探讨

吴益平1 张连昌2,3 周月斌1 朱明田2,3 陈三中1 钟莉1 杨光靖1 闫瑜婉1 刘建锋1

（1. 浙江省第十一地质大队 浙江温州 325006；2. 中国科学院地质与地球物理研究所 北京 100029；

3. 中国科学院大学地球与行星科学学院 北京 100049）

摘　要 新近发现的卡尔恰尔超大型热液脉状萤石矿床位于阿尔金造山带中部，矿体主要沿中奥陶世二长花岗岩及变质杂岩的接触带产出，并受韧性剪切断裂及裂隙构造控制。矿石主要类型为萤石方解石脉型，矿物组成以萤石和方解石为主，含少量石英和钾长石。矿石呈粗晶粒状和伟晶状结构，条带状、团块状和角砾状构造。包裹体研究表明，萤石和方解石中包裹体具有近似特征，均发育发育CO₂包裹体、含CO₂三相包裹体、气液两相包裹体和含子矿物多相包裹体等4种类型的原生包裹体，各类包裹体均一温度为135℃～359℃，盐度为2.07%～7.59%，反映成矿流体为中-中低温低盐度不混溶NaCl-H₂O-CO₂热液体系类型。萤石和方解石流体包裹体氢氧同位素测试，反映该成矿流体来源于岩浆水与大气降水的混合热液。推测岩浆期后初步形成富CO₂、富F热液，在上升过程中淋滤萃取变质杂岩中的Ca质形成成矿流体，后因大气降水加入发生降温降压与流体沸腾作用，在断裂—裂隙构造的有利部位充填—交代形成萤石方解石矿脉。

关键词　超大型萤石矿　矿床地质　流体包裹体　氢氧同位素　成矿机制　阿尔金造山带

Study on fluid characteristics and metallogenic mechanism of the super-large Kalqiar fluorite deposit in Altyn Tagh area

 Wu Yiping¹　Zhang Lianchang^2,3　Zhou Yuebin¹　Zhu Mingtian^2,3　Chen Sanzhong¹　Zhong Li¹

　Yang Guangjing¹　Yan Yuwan¹   Liu Jianfeng¹

(1. The 11th Geological Team of Zhejiang Province, Wenzhou, Zhejiang 325006; 2. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029; 3. College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049)

Abstract

The Kalqiar super-large fluorite deposit discovered recently was located at the middle Altyn Tagh orogen. The ore bodies were distributed in the contact zone of Middle Ordovician monzogranite and metamorphic rock, and controlled by ductile shear zone and fracture structure. The main ore type is fluorite -calcite veins. The mineral composition of ore vein is mainly calcite and fluorite with a small amount of quartz and K-feldspar. The ore show coarse grain texture, block, breccia and banded structure. The inclusion study shows that fluorite and calcite develop CO₂ inclusions, CO₂–bearing three-phase inclusion and gas-liquid two-phase inclusion and multiphase inclusions containing Daughter Minerals; the homogenization temperature is 135 ℃ ~ 359 ℃ and the salinity is 2.07% ~ 7.59%(NaCl)eq. It shows that the ore-forming fluids is an immiscible H₂O-NaCl-CO₂ hydrothermal system with medium to medium-low temperature and low salinity. Determination of hydrogen and oxygen isotopes of fluorite and calcite mineral inclusions show that the ore-forming fluids comes from the mixed hydrothermal solution of magmatic water and atmospheric water. It is speculated that the hydrothermal solution CO₂ and F-rich was initially formed after the magmatic stage, with the addition of atmospheric precipitation, Ca in the metamorphic complex is leached and extracted to form ore-bearing hydrothermal solution. It is suggested that the fluorite calcite vein is formed by filling and metasomatism in the favorable part of fault and fracture structure.

Keywords　Super large fluorite deposit，Deposit geology，Fluid inclusions，Hydrogen and oxygen isotopes，Metallogenic Mechanism，Altyn Tagh orogen