中亚大型-超大型矿床找矿中值得重视环形遥感影像

Worthy of giving attention to circular structure in remote sensing image in large or super large deposits exploration in Central Asia

中亚区域多戈壁或浅覆盖,为遥感地质找矿提供了更多机会;中亚成矿域发现较多大型-超大型金铜铁多金属矿床,它们的遥感地质特征受人关注。本研究采用美国陆地卫星7号ETM+数据对乌兹别克斯坦Muruntau巨型金矿床、哈萨克斯坦Kounrad和Aktogai超大型铜矿床、蒙古国Oyu Tolgoi超大型铜金矿床、中国新疆西天山查岗诺尔大型铁矿床等中亚代表性金属矿床进行了遥感地质分析,表明大型-超大型斑岩铜金矿、造山型金矿和火山岩型铁矿均与直径几km至几十km的环形遥感影像关系密切,矿床往往产在环形遥感影像边部。新疆西天山赛里木湖东南部库松木切克发现清晰的环形遥感影像,面积约2.9×2.3km2,"十字形"地质剖面实测证实它是构造-岩浆热穹隆的表现:穹隆核部是蓟县系白云岩和大理岩,翼部为泥盆系复成分碳酸盐岩和细碎屑岩,核部与翼部之间多发育外倾正断层,沿断层硅化和黄铁矿化显著。库松木切克发现的环形遥感影像与航磁异常和Co-Ni-W-Mo-Cu-Zn-Pb-Sb-Ag地球化学综合异常相重合,可能是斑岩-夕卡岩型,或卡林/类卡林型,或MVT等铜、金、铁、铅锌大型矿床找矿重要靶区。我国新疆北部相关大型矿床找矿中值得高度重视环形遥感影像的示矿作用。

There are many Gobi,desert,sand dunes in Central Asia,which provide more chances for remote sensing geological exploration.Some large or super large deposits have been found in Central Asia metallogenic zone and the remote sensing characteristics of them have been attracted great attention.We have analyzed and researched the remote sensing geology of some typical ore deposits in Central Asia by using the ETM＋data from the USA Landsat No.7,such as Muruntau giant gold deposits in Uzbekistan,Kounrad and Aktogai super large-sized copper deposits in Kazakhstan,Oyu Tolgoi super large-sized copper-gold deposits in Mongolia and Chagangnuoer-Zhibo iron deposits in western Tianshan in Xinjiang,and have drawn a conclusion that some famous large or super large porphyry copper and gold deposits and volcanic iron deposits have deep relationship with circular structures several kms to tens of kms in diameter in the remote sensing image,and the deposits are mostly located in the margin of these circular structures.A very clear circular structure in the remote sensing image of Kusongmuqieke in western Tianshan in Xinjiang has been found which has the area of2.9×2.3km3.It has been confirmed as a tectonic-magmatic thermal dome by cross geological section survey.The dolomite and marble are located in the core,and the polymictic carbonate rock and fine grained clastic rocks are located in the marginal part.There are extrovergent normal faults between the core and the marginal part,and silicification and pyrite widely developed along faults.The circular structure found in the remote sensing image of Kusongmuqieke is coincided with the aeromagnetic composite anomaly,as well as the Co-NiW-Mo-Cu-Zn-Pb-Sb-Ag geochemical assemblage anomaly.There may be some very important prospecting targets of porphyry-skarn type,or carlin/carlin-like type,or MVT copper,gold,iron,lead-zinc large deposits.Therefore,the circular structure should be used fully and reasonably in some relatively large or super large mineral deposit exploration in the central and northern areas in Xinjiang.