| The study area is located in the middle of the north margin of the north China Block and the eastern margin of the western part of the Yanliao uranium metallogenic belt.At the same time,the area is located in the intersection and complex of the EW-trending Ten-zan-Yin Mountains-Yan Mountains tectonic belt and the NE-trending Greater Khingan tectonic-magmatic belt developed since Mesozoic,which has a good uranium metallogenic geological background.Studies have shown that the volcanic rock-type uranium deposits in the study area are mainly controlled by NE and NW faults and closely related to intermediate-acid subvolcanic rocks.However,the tectonic framework of the study area is not clear,and the distribution of intermediate-acid subvolcanic rocks remains to be determined.Therefore,in this paper,the controllable source audio frequency magnetotelluric survey(CSAMT)and the high precision magnetotelluric survey are carried out in the research area,the relationship between rock layers and physical properties is established,that is,the andesite of Huajiying formation of lower cretaceous is characterized by high-middle resistivity,the TUFF is characterized by low resistivity and weak magnetism,and the basalt is characterized by low resistivity and weak magnetism The tuff of the Upper Jurassic Zhangjiakou formation is characterized by low resistivity and weak magnetic field,while the porphyrite of the late Yan Mountains Anshan is characterized by high resistivity and strong magnetic field.According to the inversion resistivity profile of CSAMT,the strata,rock mass and faults are identified according to the inversion resistivity difference,the tongue-shaped low stopband and the contour gradient variation dense zone According to the t section positive magnetic anomaly,negative magnetic anomaly,positive and negative jump magnetic anomaly and magnetic field feature boundary,the ground high-precision magnetic survey can identify strata,rock mass and faults,20 faults are inferred and interpreted(6 known faults are verified and 14 new faults are inferred),mainly in NE direction,with steep occurrence and deep descent.There are 8 NE-trending,5 SN-trending and 7 NW-trending faults,which cut each other to form a network of faults.The spatial development characteristics of subvolcanic rocks in the study area are basically identified.It is considered that the ANDESITIC porphyrite(Datangtaigou Massif),which occurs as a whole,intrudes into the Zhangjiakou formation and is spatially narrow to the south and wide to the north,deep to the south and shallow to the north,is characterized by fault blocks bounded by faults F45 and F46,the Anshan porphyrite in the study area can be divided into three fault blocks: Nw Fault Block,Intermediate Fault Block and Se Fault Block.The Chuan porphyry occurs as a dike along the F5 fault,showing a wedge-shaped north-narrow south-wide,about 2 km north-south,and an average east-west width of about 600 m,with a high degree of rock fragmentation.Based on the results of controlled-source audio magnetotelluric survey(CSAMT)and high-precision magnetic survey on the ground,combined with the ore-controlling factors in the area and the mineralization characteristics of known anomalies,it is considered that the F14 NW-trending fault in the study area has favorable metallogenic conditions such as structure,contact surface of subvolcanic rocks,surface uranium and polymetallic anomaly display through the front line and the periphery of Coarse Andesite porphyry,which is a favorable metallogenic area in the study area,it is suggested that attention should be paid to uranium and polymetallic ore prospecting in the future. |
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