河南省三川幅1:50000地质图数据库

1:50000 Geological Map Database of Sanchuan Map-sheet, Henan Province

河南省三川幅(I49E013014)1:50000地质图数据库的数据源采用实测和数字填图方法获得,野外数据采集过程中实施构造–岩性填图,注重特殊地质体及非正式填图单位的表达,共采集薄片66件,全岩岩石化学样品180件,同位素测年样品19件,化学分析样品21件。图幅主要成果有:在陶湾群层型剖面上发现多门类、时限短的微体化石,确定陶湾群为奥陶纪;在陶湾群发现碱性火山岩夹层,指示奥陶纪在华北板块南缘发育伸展性盆地;确定宽坪岩群四岔口岩组、谢湾岩组内的绿片岩为板内火山岩,指示宽坪岩群主体形成于伸展性盆地;在图幅区南部填绘出志留纪碱长花岗斑岩岩墙群,限定了秦岭洋关闭的时代不晚于志留纪;将晚中生代侵入岩划分为5个侵入期次;厘定了栾川断裂带存在早古生代、早中生代、晚中生代3期活动;在区内新发现震旦纪冰积物。该数据库的数据内容分为基本要素类、综合要素类和对象类,数据量约为63.5 MB,充分反映了本图幅区的地质矿产成果资料,对该区矿产勘查与开发、地质灾害防治、秦岭造山带研究与地质科普等提供基础数据支撑。

The 1:50000 Geologic Map Database of Sanchuan Map-sheet(I49E013014),Henan Province(also referred to as the Database)was established using data obtained through practical measurement and digital mapping.The structural and lithologic mapping was conducted during field data acquisition,focusing on the presentation of special geological blocks and informal mapping units.The samples collected in the field included 66 samples for microscopic petrography identification,180 samples for whole-rock petrochemical analysis,19 samples for isotopic dating,and 21 samples for chemical analysis in total.In this study,the main achievements obtained in this map-sheet are as follows.The Taowan Group was found to have occurred during the Ordovician according to multiple taxonomic classifications and short age ranges found in its stratotype section.Alkaline volcanic intercalations were found in the Taowan Group,indicating that an extensional basin developed on the southern margin of the North China Plate in the Ordovician.The greenschists in the Sichakou Formation and Xiewan Formation of the Kuanping Group were determined to be intraplate volcanic rocks,indicating that the main part of the Kuanping Group was formed in an extensional basin.The dike swarms of Silurian alkali-feldspar granite porphyry were found in the southern part of the map-sheet by mapping,restricting the closure era of the Qinling Ocean to a time not later than the Silurian.The intrusions of the late Mesozoic were divided into five intrusive stages.The Luanchuan fault zone was determined to have undergone three stages of activities in the early Paleozoic,early Mesozoic,and late Mesozoic.Furthermore,Sinian glacial sediments were newly discovered in the map-sheet.The Database consists of data on feature classes,complex classes,and object classes,with a data size of about 63.5 MB.It fully reflects the geological and mineral achievements of the map-sheet,and will provide basic data for mineral exploration and exploitation and prevention and control of geological hazards in the map-sheet,research on the Qinling Orogenic Belt,and the popularization of geoscience.