3-D paleotemperature modeling of the geothermal regime of sedimentary basins: Example of the Lunskaya depression,Sakhalin Island

The task of 3-D modeling of the thermal field of a sedimentary basin during sedimentation is considered. The aim of the modeling is to determine the temperature at any point of the basin at a given moment of geological time. The mathematical model is based on a system of equations of thermal conductivity for a heterogeneous layered medium with dynamic boundaries. The conditions of the continuous temperature and thermal flow are given at the boundaries of the adjacent layers. The temperature values, which are determined by the values of the secular course of the earth temperature, are given at the upper boundary coinciding with the sedimentation surface. The thermal flow value is considered to be given at the lower boundary. The medium is approximated using a vertical triangle prism, which is accepted in algorithms of interpretation of the gravitation field and characterized by random upper and lower basements and given values of the thermal physical parameters. The equations of thermal conductivity are solved on the basis of potential theory. The precision of this algorithm is demonstrated by calculation of a test example. The thermal evolution of the sedimentary complexes and dynamics of the major zone of oil formation are reconstructed and possible errors of paleotemperature interpretations caused by ignored 3-D modeling medium are determined on the example of the sedimentary basin of the Lunskaya depression of Sakhalin.     

Geological characteristics and origin of the Hadamengou gold deposit in Inner Mongolia,China

The Hadamengou gold deposit is located in the western segment of the northern margin of the North China Craton (NCC). It is hosted by Archean metamorphic rocks of the Wulashan Group. The main ore types include gold-bearing quartz vein type, gold-bearing quartz-potassic feldspar vein type, and gold-bearing altered rock type. Gold mineralization is closely related to K-feldspathization. Hydrogen and oxygen isotope data indicate that ore-forming fluids were dominated by magmatic water mixed with minor meteoric water. Sulfur and lead isotope data indicate that metallogenic materials were mainly supplied by the magmatic and Archean Wulashan Group. The gold mineralization was mainly formed during the Early Indosinian tectonic movement, which drove ore-forming fluids to the favorable depositional environment. The northern margin of the NCC is a prospective area for gold exploration. Gold deposits hosted by or related to alkaline intrusions have become one of the most important mineral exploration targets in northern China.     

S-101与S-57分类编码对比分析(二):属性

地理要素的分类编码是人类认知地理信息世界的成果,也是人类对地理信息世界再认知的入口和关键。在海洋地理信息领域,S-101数据标准即将替代现行S-57 ENC标准,分类编码方案也将会相应改变。先对S-57到S-101的属性变化内容进行整体描述,再从地理要素属性、元要素属性、图示表达属性三方面内容,对新旧两套分类编码中的属性内容进行对比分析,为涉海人员消化吸收新标准提供一定的参考。