Prospecting direction and method

Based on the comprehensive analysis of the dynamic evolution of diagenesis and mineralization, mineralization process and denudation and preservation conditions in Jiaodong area, combined with the geological, geophysical and geochemical characteristics of typical deposits, the following points should be paid attention to in further prospecting in Jiaodong area.

1) orogenic gold deposits are still the focus of prospecting. Gold is the absolute dominant mineral in Jiaodong, and we will continue to increase our efforts. (1) Jiaojia gold deposit has a broad prospect. The prospecting direction should still focus on Sanshandao, Jiaojia and Linglong metallogenic belts. At the same time, the exploration of Jiaojia blind ore in Qixia metallogenic belt should be accelerated, and all-round prospecting should be carried out in the depth range of 500 ~ 2000 m in advance on the premise of reasonable methods and technical means and economic feasibility. When prospecting, we should pay attention to analyze and summarize the previous work data in the work area and optimize the target area in combination with geological and geophysical anomalies. In view of the slow dip angle of ore-controlling faults in Jiaojia-style gold deposits, on the basis of common methods such as surface high-precision magnetic survey, controlled-source magnetotelluric sounding profile survey and surface gravity survey, seismic profile can be tried to detect the deep gentle geological body interface. The comprehensive application of various methods can improve the reliability and accuracy of anomaly resolution. ② There is still a certain prospecting space for chronological gold deposits, including Linglong type, Ma Pan type and Jinniushan type. It mainly includes Xiejiagou area, Caojiawa-Jiang Jiayao area, Jiudian-Shiqiao area, Penglai Hudao-Qigou and Daliuhang area, Qixia Majiayao area, Rushan henan village-Xiachu area, Tangjiagou area, Muping Yulindian-Shuidao area and Gaoling-Qiujia area. The basic method of ore prospecting is large-scale mapping in the mining area to find and control ductile-brittle fractures, and pay full attention to the dense fracture zones and small arsenopyrite mineralization veins, limonite veins and timely veins developed on the surface. Geophysical exploration mainly adopts high magnetic combined with electrical method, which can be combined with large-scale mercury gas measurement, and geochemical exploration can appropriately carry out large-scale fine rock measurement (1: 1 thousand or more) to delineate anomalies.

2) The porphyry deposit is expected to make a breakthrough. Porphyry copper deposit is the main target, focusing on the exposed area and concealed area of Weideshan granite in the late Yanshan period. It mainly pays attention to the Mesozoic basin edge, especially the areas where deep faults are developed, such as Weideshan area in Rongcheng, Mashidian area in Haiyang, Battlefield Park area and Sunan area in Laizhou. The existence of exposed or concealed rock strains in the surface porphyry rock mass, the abnormal nesting of Cu, Mo, Pb and Zn, obvious high magnetic anomalies and obvious hydrothermal alteration zoning can be used as powerful prospecting indicators. Remote sensing images with blurred edges, such as rings and irregular ellipses, are helpful to quickly select targets. Mapping of surface altered minerals, geotechnical investigation, surface high magnetic and electrical exploration are more effective methods.

3) Full attention should be paid to medium-low temperature hydrothermal deposits. Carlin-type gold deposit is the main target. In the Dongting-Gaotuan-Dujiaya area in the northern part of Fushan District, Yantai City, a large area of Paleoproterozoic carbonate-bearing mountains are exposed, which are mainly composed of a set of coastal and shallow marine carbonate rocks and terrigenous clastic rocks. Dujiaya gold-silver mine, Xingjiashan molybdenum mine, Wangjiazhuang copper-zinc mine and Longkou gold mine are distributed from bottom to top, and two of them are located in marble and granulite strata. The latter are mainly granulite, schist with marble and banded carbon-containing silicified marble, and large area mineralization is found in exploration. Therefore, attention should be paid to strengthening large-scale mapping in mining areas, improving the research degree of structural and stratigraphic lithologic distribution laws, and paying special attention to the study of interlayer and small-angle shear faults. The development position of hydrothermal alteration zone, limonite mineralization near the surface and pyrite disseminated by veinlets in the middle and deep parts are relatively direct prospecting indicators. When prospecting, in view of the combination anomalies of Au, Ag, As, Sb and Hg in 1: 5000 geochemical exploration, the large-scale geochemical exploration scanning surface of1:000/1:5000 can be carried out first, and on this basis, the prospecting targets can be delineated by combining geophysical exploration and electrical methods. The medium-low temperature hydrothermal vein type Au-Ag-Cu-Pb-Zn deposit should be mainly located in the northeast margin of Jiaolai Basin and Wendeng-Weihai and Rongcheng areas. The former should strengthen the development space of old metamorphic rocks in ductile shear zone and brittle fracture outside the basin margin, and explore the secondary fracture next to the NE-trending fault in the conglomerate area in the basin. The target mineral is mainly gold, taking into account the search for lead, zinc, copper, gold, silver and polymetallic deposits in the basin margin, such as Rushan wellhead and Mashidian area in Haiyang. The latter should pay attention to strengthen the prospecting around the Mi Shan fault zone and Weideshan rock mass. There are secondary and tertiary faults in structure and Jingshan Group and gneiss outcropping area in lithology, which can be used as the key work area for prospecting. The prospecting method is basically the same as this type of gold deposit.