Research And Application Of Micro Motion Exploration In The Middle And Lower Reaches Of The Yangtze River

In this study,H/V spectral ratio method is used to study the distribution map of sedimentary layers in the middle and lower reaches of the Yangtze River is obtained.We use spatial autocorrelation(SPAC)method to obtain the shallow S-wave velocity structure near the mining area,and predict and estimate its mineral exploration prospects.According to the results of H/V method,the sedimentary layer in the He Huai basin is relatively thicker,and the predominant frequency of the basin is 0.05-0.1Hz.There is no obvious lateral variations in the impedance interface between bedrock and sedimentary layer in this area.The sedimentary thickness of the margin of Jianghan Basin is more than 3500 m,which shows that the thickness of the central sedimentary layer in Jianghan Basin is relatively deeper.In the Middle-Lower Yangtze Metallogenic Belt,the basement in Tongling,Anqing and Luzhou mining areas and their adjacent region is Kongling-Dongling type,which is composed of a set of metamorphic core complex,and the sedimentary cover is volcanic rock.The predominant frequency is 0.05-0.1Hz.The sedimentary thickness gradually thinned from 3800 m in the west to 2100 m in the East.We speculate that the reasons leading to the uneven distribution of sedimentary layer thickness in this area may be that the basement of the study area is uplifted gradually,and the degree of denudation is different in different parts.However,according to the results of H/V spectral ratio method,we can see that after a long period of geological denudation and artificial mining,most areas of the metallogenic area in the middle and lower reaches of the Yangtze River still have thick sedimentary layers,which may have good exploration prospects in the future.The SPAC results reveals that the depth of the interface between the loose sediments and the volcanic rocks in the study area near the Lu Zong mining region in the middle and lower reaches of the Yangtze River is about 600 m,and the average depth of the interface between the volcanic rock section and the intrusive complex section is about 1000 m.This indicates that the thickness of volcanic rock section in the study area is small.The results show that the mineral content of 0-1000 m in the study area is poor and there is little exploration potential.According to the results of H/V spectral ratio and well logging data,the thickness of the intrusive rock is more than 2000 m.Tourmaline is developed in the interior of the intrusive rock,which is distributed in black gray clumps and clusters.Carbonate minerals,anhydrite and chalcopyrite are associated with electricity,which may have better exploration potential.The results of this study show that H/V spectral ratio method and spatial autocorrelation play an important role in shallow exploration.In the future,with the maturity of these two technologies,they will have broad application prospects in the study of basin sedimentary mechanism,exploration of geothermal resources,evaluation of landslide hazards and so on.