1∶50 000 Geologic Map Database of the Xiaoshui Map Sheet, Henan Province

The 1∶50 000 geologic map of the Xiaoshui map sheet (I49E016015), Henan Province was prepared by using the digital mapping technology and database building, during which existing geologic and mineral data were fully collected and comprehensively analyzed. The database of this geologic map (also referred to as the Database) is in the format of MapGIS and covers nine stratigraphic units and six stages of magmatic events, which also includes electronic probe data of 70 samples, chemistry testing data of 57 samples, zircon U–Pb dating of 73 samples and whole-rock geochemical data of 147 samples, coming to a total data size of 31.9 MB. Meanwhile, the new mapping theory and methodology based on orogenic belts were adopted to highlight tectonic and lithologic mapping as well as the presentation of special geologic bodies and informal mapping units. In this way, the contents on the map face were expressed in a more scientific, readable and practical manner. In this study, the structure of the North Qinling Orogenic Belt (NQOB) was established, consisting of the Shangnan –Danfeng tectonic belt, Zhu–Xia ophiolitic mélange belt, Qinling microcontinent and Erlangping island arc, a back-arc basin. Following this, it was clear that the Zhu–Xia ophiolitic mélange belt was formed in the early Paleozoic era. Furthermore, the composition and four stages of fold deformations of the Qinling Group were ascertained; the spatial distribution law, protolith and metamorphic era of the high and ultrahigh-pressure rocks in the map sheet area were determined. Thus, revealing that the whole Qinling microcontinent was involved in the early Paleozoic orogen and had undergone great transformation. The achievements of this study have provided new basic geological data for the preparation of the ‘Annals of Geology of Henan Province’ and the projects funded by the ‘Geological Exploration Fund of Henan Province’. Moreover, the 1∶50 000 geologic map of the Xiaoshui map sheet was awarded the ‘Excellent Map Sheet Prize’, among the areas mapped, based on orogenic belts in the national regional geological surveys of China in 2018.

河南省小水幅（I49E016015）1∶5万地质图采用数字填图技术与数据库建设方法编制，研究过程中全面收集并综合分析了已有地质与矿产数据。该地质图数据库（以下简称本数据库）采用MapGIS格式存储，涵盖9个地层单元与6期岩浆事件，同时包含70件样品的电子探针数据、57件样品的化学测试数据、73件样品的锆石U-Pb定年数据以及147件样品的全岩地球化学数据，总数据量达31.9 MB。同时，研究采用基于造山带的新型填图理论与方法，突出构造与岩性填图，强化特殊地质体与非正式填图单元的表达，使图面内容更具科学性、可读性与实用性。本研究构建了北秦岭造山带（North Qinling Orogenic Belt，NQOB）的构造格架，其由商丹构造带、朱夏蛇绿混杂岩带、秦岭微地块以及作为弧后盆地的二郎坪岛弧组成。据此明确了朱夏蛇绿混杂岩带形成于早古生代时期。此外，研究厘清了秦岭群的组成与四期褶皱变形演化过程，查明了图幅区内高压-超高压岩石的空间分布规律、原岩性质与变质时代。据此揭示了整个秦岭微地块均卷入早古生代造山作用并经历了显著改造。本研究成果为《河南省地质志》的编纂以及河南省地质勘查基金资助项目提供了全新的基础地质数据。此外，该小水幅1∶5万地质图在2018年全国造山带型区域地质调查项目中获评“优秀图幅奖”。