阿尔金山喀腊大湾铁矿成因再认识--来自元素地球化学的证据

摘要

The Kaladawan iron ore field in Altyn Tagh Mountain,consist of 6 iron deposits as Baba,Babaxi,7914、7915、7918 and 7910,is located within the area defined by the NE striking Altun strike-slip faults to the north and EW striking northern Altun fault.The iron ore-body shaped bedded and bedded-like with an EW-trending and high dip angle,occurred in volcanic rocks of Zhuo’abulake Formation of lower Paleozoic group,where the volcanic rocks is in the southern and the sedimentary rock in the northern.In other words,the iron ore-body is controlled by a special stratohorizon and given lithological criteria.The analysis of the REE contents shows that the iron ore is similar to volcanic rocks and garnet-epi-dosite skarn,but a little similar to tremolite-diopside skarn,and sedimentary rock.The contents of garnet shows that the garnet in Kaladawan iron deposit is either similar to world other skarn-type iron deposit (as andradite-grossular series ) or different each other( the garnet in Kaladawan iron deposit contents more andradite and less grossular than the garnet from world other skarn-type iron deposit ).So the authors achieve that the Kaladawan iron deposit is classified as a volca-nic-sedimentary type and it is latter effected by the skarnization.%阿尔金山喀腊大湾铁矿田位于NE向阿尔金走滑断裂与EW向阿尔金北缘断裂夹持地区，包括八八、八八西、7914、7915、7918和7910共6个铁矿床。矿体呈层状、似层状出露于寒武系卓阿布拉克组火山岩与沉积岩界线的火山岩一侧，走向近EW向，倾角陡立，层位和岩性对铁矿的控制作用明显。通过对铁矿床密切相关的岩石（中基性火山岩、花岗岩、矽卡岩和铁矿石）的稀土元素地球化学分析、结合矽卡岩矿物（石榴石、绿帘石和透闪石）的成分特点研究显示，浸染状铁矿石与石榴石绿帘石矽卡岩及中基性火山岩在稀土元素分布曲线上具更多相似性，与透辉石透闪石矽卡岩及沉积岩关系不大，石榴石端元成分与世界典型矽卡岩型铁矿床有明显差异。因此，可以认为喀腊大湾地区铁矿床属火山沉积型，后期叠加矽卡岩化改造。