| The East Kunlun area has been built into a national integrated exploration area of Qimantag copper nickel polymetallic ore,because of its superior metallogenic geological conditions,numerous metallogenic facts and huge potential mineral resources.Xiaozaohuo area in East Kunlun is located in the south margin of Qaidam Basin.The eastern part of Qimantag integrated exploration area belongs to the "structural knot" interweaved by North Qilmantag magmatic arc,Qimantag ophiolite melange belt and North Kunlun composite magmatic arc.However,the area is largely covered by Quaternary deposits,and poorly known in metallogenic geotectonic background.Likewisely,of the progress in mineralization prediction carried out by chemical exploration and remote sensing is little.The key problems of regional structure location are unknown in the basic and mineral geology research,and the distribution characteristics of strata and magmatic rocks are unclear,which restrict the metallogenic prediction research and prospecting deployment in this area.This paper attempts to carry out the research on the geological background and prediction of mineralization in Xiaozaohuo area by geophysical means.The research updates indicate that the mineralization in East Kunlun area is closely related to plate tectonics.From the analysis of tectonic evolution,the dominant types of deposits in East Kunlun area are magmatic copper nickel sulfide deposit and skarn type iron polymetallic deposit;on this basis,the typical deposits are selected and the geological characteristics of the typical deposits are analyzed.Using1:50000 bouguer gravity anomaly data and 1:50000 magnetic survey ?T pole data,comparatively carried out the edge recognition of gravity NVDR-THDR,wavelet decomposition of gravity,first derivative of gravity vertical,modulus of gravity total horizontal gradient,edge recognition of magnetic measurement NVDR-THDR and multi-data processing method of magnetometry vertical first derivative.The geophysical response characteristics of the materials in the region are extracted and guided by plate tectonic evolution,the distribution characteristics of the three major metallogenic geological backgrounds,including the main strata,structures and magmatic rocks,are studied and found out,and the shallow "bedrock geological map(<100m)" is drawn in the area of Xiaozaohuo.The geological geophysical response characteristics of summer Xiarihamu and Haxiyatu deposits are studied.Based on the study of metallogenic geological background,the metallogenic prediction of the target area is carried out by combining the geological geophysical information.The main knowledge obtained are:1.The fault structure of Xiaozaohuo area in East Kunlun is divided into four phases,the faults in the study area are divided into four phases chronologically,near East-West to north margin of Qimantag,Kunbei fault and a series of sub faults derived from near east-west direction,northwest fault with right-hand feature,north-east fault with left-hand feature and north-west fault.The near East-West secondary faults on both sides of Kunbei fault are closely related to mineralization.2.The exact location of the Qimantag north margin fault and Kunbei fault in Xiaozaohuo area of East Kunlun is confirmed.The north margin of Qimantag fault is the Cenozoic heavy deposition of Qaidam.The north margin of Qimantag and Kunbei fault are divided into two parts: the early Jurassic syenite porphyry and the upper Triassic Erlashan Formation in the northwest,and the ophiolite melange belt in the southeast.The south of Kunbei fault is a large number of Jinshuikou Rock Group.The marble formation in the group is an important orebearing layer of skarn type deposits in this area.3.The geological geophysical comprehensive metallogenic prediction marks of magmatic molten nickel cobalt deposits and skarn type iron and polymetallic deposits are established.Both types of deposits have geophysical characteristics of high weight,high magnetic,high polarization and low resistance,but they have essential differences.The high,medium high magnetic,high polarization and low resistance characteristics of magmatic melt away deposits are the direct reaction of rock(ore)bodies.The high gravity of skarn type deposits is the response characteristics of Jinshuikou Group.The characteristics of high magnetic,high polarization and low resistance are generally the display of contact zones(skarn belts),and contact zones are divided into inner and outer zones.In this area,the metallogenic prediction of skarn type deposits should be distinguished.4.By the geophysical forward calculation,it is determined that ?T window value of the tmagnetic anomaly 150 n T and the residual gravity anomaly of 0.5m Gal is extracted.The oreforming favorable information in the area is extracted by the window value,and the metallogenic prediction research is carried out by combining the geological geophysical information,and three target areas of skarn type deposits are delineated.No geophysical information was found related to the underlying ultrabasic rock mass. |
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