Regional geophysical prospecting has covered the whole area (Figure 1- 1). From 1956 to 1985, the aerial survey team of the Ministry of Geology and Metallurgy carried out aeromagnetic scanning. In some areas, aerial surveys of1:200,000 or1:250,000 were carried out on the basis of aerial surveys. 1979~

Figure 1- 1 schematic diagram of the working degree of the study area.

199 1 year, the geophysical team of Shandong Geological Bureau conducted a gravity survey of1∶ 200,000 in Luxi area, and established a database.

After 1980, aerial geophysical exploration improved the accuracy of measurement and positioning, obtained rich geophysical information in weak magnetic field, and found some new structures and concealed rock masses. The characteristics of aeromagnetic field show that the Tan-Lu fault zone is a large-scale and long-term active fault zone. Because of its long-term activity, the structure in the area has developed, and with many magmatic intrusions and hydrothermal activities, the accumulation of volcanic materials and the intrusion of deep basic rocks have appeared in some areas. Long-term hydrothermal process provides good conditions for the activation, migration and low-pressure spatial enrichment of gold and silver.

1.2.2.2 regional geochemical survey

Since 1950s and 1960s, the Geological Bureau of Shandong Province has conducted a survey of1∶ 200,000 heavy sand and river sediments in this area. From the late 1980s to the mid-1990s, the Shandong Dispatching Team and the Eighth Institute of Geology and Mineral Exploration of Shandong Province re-measured1∶ 200,000 stream sediments and heavy sand in this area. There are four combined abnormal zones of Au, Ag, Cu, Pb and As in Yishu fault zone, namely Yinan-Gegou, Mazhan-Yishui, Juxian-Daokou and Junan-Linshu combined abnormal zones, and the Au is generally 2.15×10-9 ~ 4.52× 65438. At the same time, the Geological Survey Institute of Shandong Province and the Eighth Geological and Mineral Exploration Institute of Shandong Province carried out the investigation of heavy sand and river sediments in some areas1∶ 50,000. In 200 1 year, Shandong Geological Survey Institute carried out a survey of1∶ 50,000 river sediments in Sucun-Gaofuzhuang area, covering an area of 400 km2, and delineated a number of combined anomalies dominated by gold. This river sediment survey provides geochemical basis for the general survey of gold deposits in this area.

Through1∶ 200,000 regional geochemical scanning surface and1∶ 50,000 geochemical exploration work, the distribution, dispersion and enrichment laws of 45 elements such As Au, Ag and As in the study area are further identified, local anomalies are explained, geochemical characteristics are discussed, and basic geochemical metallogenic background information is provided, which provides a basis for general survey and prospecting.

1.2.2.3 remote sensing geological work

1993, the Remote Sensing Center of Shandong Geological Bureau compiled1:200,000 and1:500,000 image maps by using the 4.7.3 synthetic band TM satellite photos, and completed the image interpretation. In 2002, Shandong Geological Survey Institute entrusted Shandong University of Science and Technology to interpret the remote sensing image of Longquan Station-Tongjing-Cuijiayu area1∶ 50,000, and found that the Yishui-Tangtou main fault was obviously dislocated by the NE-trending fault.