Abstract:

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 belt，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.

Key words: North Bayan Har metallogenic belt, the information computation method, mineral potential mapping, prediction model, gold deposit, 青Qinghai Province