新疆西南天山伽师砂岩型铜矿床古环境分析

Paleoenvironmental analysis of Jiashi sandstone-type copper deposit in the Tianshan， southwest Xinjiang

中文关键词: 岩性岩相  古环境分析  滨海潟湖  伽师砂岩型铜矿床

英文关键词: lithology petrography  paleoenvironmental analysis  coastal lagoon  Jashi sandstone-type copper deposit

中文摘要:

      伽师砂岩型铜矿床位于新疆西南天山砂岩型铜成矿带中段，是该带最大的砂岩型铜矿床。通过矿床及外围实测剖面测量、路线剖面调查，及岩性、岩相鉴定，结合区域岩性、岩相及古环境分析，推断古近系早期到晚期由于陆壳的持续抬升与局部间歇性海侵、海退，其成矿环境表现了滨海潟湖及局部夹有河流三角洲相变规律。其含铜矿层应为滨海潟湖-三角洲环境的产物。至古近系始新世（45 Ma），在印度板块碰撞俯冲的背景下，陆壳持续抬升，至新近纪中新世（21 Ma）完全变为陆相沉积，随着近南北向持续挤压隆升，形成西南天山古近纪推覆构造带，致使含矿层位发生褶皱以至于南翼发生倒转的构造样式。据此来推动新疆伽师地区铜矿资源的进一步开采，并对研究区古环境分析提供更为有力的的论证。

英文摘要:

      Jiashi sandstone-type copper deposit， located in the middle of the Tianshan sandstone-type copper metallogenic belt of southwestern Xinjiang， is the largest sandstone-type copper deposit in this region. Based on peripheral measured section， route section survey， lithology and lithofacies study， combined with analysis of regional lithology， facies and palaeo-environment. It is inferred that facies transition law of coastal lagoon and the local river delta of the metallogenic setting in the early to late Paleogene is caused by the continuous uplift of the continental crust and the intermittent transgression and regression of the local sea. The copper-bearing layer should be the product of the coastal lagoon and delta environment. During the Eocene （45 Ma） of the Paleogene， the continental crust was constantly uplifted associated with the collision and subduction of the Indian Plate， and transformed into continental sendimentation in the Miocene （21 Ma） of the Neogene. With the continuous extrusion and uplift in the near north-south direction， the Paleocene thrust tectonic zone in the southwest Tianshan was formed， resulting in the folding of the ore-bearing layers and the inversion of the tectonic style of the southern flank. So as to promote the further exploitation of copper resources in Jiashi area， Xinjiang， and provide a more powerful demonstration of paleoenvironment analysis in the study area.