中国地质调查局: 江西省大桥幅(H50E023002)1∶50 000地质图数据库

江西大桥幅（H50E023002）1∶50 000地质图数据库是按《1∶50 000区域地质调查技术要求 》（DD 2019—01）和地质行业的统一标准及要求，在充分搜集和利用1∶200 000、1∶250 000等区域地质调查、1∶50 000 矿产调查工作成果资料的基础上，采用数字填图系统 （DGSS）进行野外地质填图和数据库建设，结合 Spot、ETM等多种遥感影像对构造及岩性边界不断验证和完善，最终绘制成图。图件运用造山带填图理论详细填绘了测区新元古代地层单位，图面表达以构造建造为单位，对新元古代地层进行了重新划分，并对内部沉积序列进行了重新厘定，限定了宜丰岩组沉积时代和沉积环境。解体了九岭南缘新元古代花岗岩侵入体，查明了各侵入体岩石类型、矿物成分、结构构造、接触关系等，识别出测区新元古代、晚志留世、早白垩世3期岩浆事件，建立了构造–岩浆演化序列。图幅数据库的数据内容包含有11个沉积（火山）地层单位、7个变质岩岩层单位和3期岩浆事件，以及12 个样品的锆石 U–Pb 年龄数据，数据量为198 MB。该图幅充分反映了九岭南缘地区造山带结构和地质演化过程，是1∶50 000 区域地质调查最新示范性成果，对江南造山带构造演化有重要的科学研究价值，对后续该区域的地质调查工作也具有借鉴意义。

The 1:50 000 geological map database of Jiangxi Daqiao sheet (H50E023002) was developed in accordance with the "Technical Requirements for 1:50 000 Regional Geological Survey" (DD 2019—01) and unified standards and requirements of the geological industry. It is based on the comprehensive collection and utilization of existing data from regional geological surveys at scales of 1:200 000, 1:250 000 and 1:50 000 mineral surveys. Field geological mapping and database construction were carried out using the Digital Geological Survey System (DGSS), with structural and lithologic boundaries continuously verified and refined by multiple remote sensing images such as Spot and ETM before the final map was completed. Applying the orogenic belt mapping theory, the map has mapped the Neoproterozoic stratigraphic units in the survey area in detail. Taking tectonic assemblages as mapping units, it reclassified the Neoproterozoic strata, redefined their internal sedimentary sequences, and constrained the sedimentary age and depositional environment of the Yifeng Formation. It has dismembered the Neoproterozoic granite intrusions on the southern margin of the Jiuling Mountains, clarified the rock types, mineral compositions, textures, structures and contact relationships of each intrusion, identified three phases of magmatic events in the survey area, namely the Neoproterozoic, Late Silurian and Early Cretaceous, and established the tectonic-magmatic evolution sequence. The database of this map sheet contains 11 sedimentary (volcanic) stratigraphic units, 7 metamorphic rock bed units, three phases of magmatic events, and zircon U-Pb age data from 12 samples, with a total data volume of 198 MB. This map sheet fully reflects the orogenic belt structure and geological evolution process of the southern margin of the Jiuling Mountains, and is the latest exemplary achievement of 1:50 000 regional geological surveys. It holds important scientific research value for the tectonic evolution of the Jiangnan Orogenic Belt, and also provides valuable reference for subsequent geological survey work in this region.