青海北巴彦喀拉成矿带基于GIS金矿资源综合信息预测评价

Prediction and Evaluation of Gold Resources Based on the Multivariate Information in North Bayan Har Metallogenic Belt,Qinghai Province

青海省北巴彦喀拉金矿成矿带位于中央造山带中段可可西里—巴彦喀拉晚印支造山带。矿带出露地层主要为晚古生代复理石—类复理石建造,晚三叠世花岗岩类沿深大断裂零星分布,NW-NWW向断裂发育,控岩、控矿作用明显。微细浸染型金矿床是矿带主攻矿床类型,近年来勘查找矿突破大,发现大场超大型金矿床,彰显巨大找矿潜力。通过收集该成矿带最新基础地质调查、矿产勘查及物化探测量成果资料,建立了基于GIS的空间数据库,然后,利用矿床位置定位预测系统(DPIS),采取找矿标志自建信息量模型、借用信息量模型和专家知识相结合方法,建立了适合本区带微细浸染型金矿预测的找矿标志信息量预测模型,据此开展区带金(锑)矿产多元信息统计预测,圈定38处找矿远景区,其中A类9处,B类16处,C类13处;规划部署重点勘查区3个,接续普查区3个,战略预查区2处。本次预测工作为北巴彦喀拉金矿成矿带进一步勘查找矿提供了新的方向。

In north Bayan Har gold metallogenic belt, one of the most important metallogenic belt in Central Orogenic Belt, is located in the Hoh Xil-Bayan Har late Indo-Chinese epoch orogenic belt.In this bent, the formation of late Paleozoic flysch-flyschschoid facies is the best developed sedimentary strata;late Triassic granitoids distribute along deep faults sporadically;NW-NWW trending faults developed extensively,which controlled the distribution of the intrusive rocks and the gold deposits.The microgranular disseminated gold deposit is the main type of gold deposits in this metallogenic belt, gold prospecting of this type has made some breakthrough recently,such as Dachang super large gold deposit has been found in recent years,and more prospecting achievement is expected.In this paper,by synthesizing the latest information from geology, geochemical prospecting and mineral deposits etc., we build a GIS-based spatial database for the north Bayan Har metallogenic belt in Qinghai Province.Then a new regional exploration geological model of the microgranular disseminated type gold deposit（ ＂Dachang＂ type ） is established, in which the main prospecting symbols including the middle of the Trassic Bayan Har Group, the Trassic middle-acid intrusive rocks,NW-NWW striked linear structures, Au, As, Sb, Hg, Cu, Pb and Zn anomalies, Au-As-Hg-Sb-Cu and Sb-As-Hg combination anomalies, heavy concentrate anomalies of native gold, stibnite, cinnabar,realgar, orpiment, arsenopyrite, galena and sphalerite,placer gold mines,and the smallest prediction areas selecting from the prediction of potential gold resource in China.On such a basis, we established a suitable information quantity model of geological prospecting marks using the self-built and borrow model, combined with a study of the ore-controlling geological conditions and a summarization of metallogenic regularity.And the information anomalies mapping is finished in the study area according to the information computation method of Deposit Position Indicating System （DPIS）.There are 38 prospecting area was delineated and evaluated, including 9 prospecting targets with level A, 16 ones with level B and 13 ones with level C.And three key exploration areas, three fellow exploration areas and two reconnaissance areas are mapped out.Some new prospecting targets are delineated.