Research On Temporal-Spatial Characteristics Of Geochemical Data In The Middle And Lower Yangtze River And Its Mineralization Indications Based On GIS

As an important basis for geological research,geochemical data of rocks play an important role in indicating element characteristics and studying metallogenic law.The Cu-Fe-Au metallogenic belt in the Middle-Lower reaches of the Yangtze River is an important metallogenic belt in the eastern part of China.Abundant geological research in this area has accumulated a large number of geochemical analysis data of ore-forming rock masses,which have typical characteristics of GIS spatio-temporal data.With the help of advanced GIS spatio-temporal analysis and visualization technology,spatio-temporal concentration of geochemical data of ore-forming rock masses in this area is carried out from the time and space of ore-forming.It is of great practical significance for guiding the prospecting and exploration work in the Middle-Lower reaches of the Yangtze River to analyze the characteristics of the ore-forming core and its temporal and spatial evolution.Based on the collection,collation,analysis and storage of the spatiotemporal data of magmatic rock geochemistry in the Middle-Lower reaches of the Yangtze River,this paper quantifies the spatial aggregation or dispersion of magmatic rock ore-forming bodies in the Middle-Lower reaches of the Yangtze River by means of the analysis algorithm of spatiotemporal aggregation characteristics of GIS,and reveals the spatiotemporal aggregation and evolution characteristics of ore-forming bodies in each mineralization stage;furthermore,it comprehensively uses the spatial division of GIS Analysis of the algorithm,delineate the Middle-Lower reaches of the Yangtze River in various periods of ore prospecting favorable areas.The main work and research results are as follows:(1)Based on the collection of Late Mesozoic diagenesis and mineralization related geological papers published in 1998-2018 in the Middle-Lower reaches of the Yangtze River,the data of magmatic geochemical analysis in this area were extracted,analyzed and sorted out,and the construction of magmatic geochemical database in this area was completed.The database covers the space,time and geochemical element content and other geological information needed for the analysis of magmatic rock geochemical data,forming the magmatic rock's time-space geochemical data set in the Middle-Lower reaches of the Yangtze River in the sequence of the first period(early stage,135-148Ma),the second period(middle stage,127-135Ma),and the third period(late stage,124-126Ma).(2)Based on the constructed magmatic geochemical database in the Middle-Lower reaches of the Yangtze River,and based on the three geological periods of magmatic mineralization and the spatial distribution characteristics of metallogenic rocks,this paper analyzes the clustering trend,scale,core and evolution characteristics of mineralization in the Middle-Lower reaches of the Yangtze River by using the spatial-temporal clustering feature analysis algorithm of GIS.The core of mineralization and accumulation of magmatic rocks in the period and the characteristics of time and space evolution.(3)Based on GIS spatial correlation and neighborhood analysis,the correlation between magmatic rock mineralization and deep faults of the Yangtze River in the Middle-Lower reaches of the Yangtze River is explored.Combined with the scale and core of magmatic rock mineralization,the favorable area of magmatic rock mineralization is delineated,which provides a basis for the prospecting and exploration in the Middle-Lower reaches of the Yangtze River.