~(40)Ar/~(39)Ar Dating and Its Significance of the Ertix Gold Metallogenic Belt in the Altay Orogen, Xinjiang
~(40)Ar/~(39)Ar Dating and Its Significance of the Ertix Gold Metallogenic Belt in the Altay Orogen, Xinjiang
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发表时间：
2004
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通讯作者：
Yan Shenghao
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作者：
Yan Shenghao
额尔提克斯剪切带是目前阿勒泰造山带古生代最重要的金成矿带之一，但在成矿成因和成矿动力学背景方面仍存在争议。通过对鄂尔多斯西北缘马尔卡库里剪切带多兰纳萨伊和赛都两个典型金矿床的野外考察和同位素年代学研究，获得了一组蚀变含金岩的Ar/Ar年代学数据，即多兰纳萨伊矿白云母的高原年龄为292.8±1.0 Ma，等时年龄为293.13±4.84 Ma，赛都矿白云母的高原年龄为289.2±3.1 Ma，等时年龄为291.93±8.37 Ma。表明Ertix带的韧性-脆性剪切和剪切带金矿床主要形成于290 Ma左右。这些年代学资料结合区域地质资料表明，控矿剪切带经历了由深部构造域的韧性变形到浅层构造域的脆性变形的构造演化过程，并与两次岩浆活动相结合，成矿过程主要发生在阿勒泰造山带碰撞后的伸展环境中，与构造岩浆活动晚期有成因关系。
The Ertix shear zone is currently one of the most important gold metallogenic belts in the Paleozoic Altay Orogen, but there remain disputes both in genesis and geodynamic setting of the mineralization. Through field investigations and isotope chronological studies of two typical gold deposits (e.g. Duolanasayi and Saidu) in the Ma'erkakuli shear zone northwest of the Ertix belt, the authors obtained a group of Ar/Ar chronological data of altered auriferous rocks, i.e., a plateau age of 292.8±1.0 Ma and isochronal age of 293.13±4.84 Ma for muscovite from the Duolanasayi deposit, and a plateau age of 289.2±3.1 Ma and isochronal age of 291.93±8.37 Ma for muscovite from the Saidu deposit, suggesting that the ductile-brittle shearing of the Ertix belt and shear zone-hosted gold deposits were chiefly formed at the time around 290 Ma. These chronological data together with regional geology show that the ore-controlling shear zone experienced a structural evolution from ductile deformation in the deeper tectonic domain to brittle deformation in the shallower tectonic domain, and was coupled with two magmatic events, and the gold-forming process mainly occurred during the post-collisional extensional environment of the Altay Orogen and genetically related to the late stage of the tectono-magmatism.