鏡铁山铁礦区的礦石礦物組成和条带構造的成因

引言本文根据地质部甘肃局634队的材料,结合室內研究写成。准备从矿石矿物組成和条带構造的成因,来簡略地探讨鏡铁山鉄矿床的成因問題。一矿床地質特点簡述镜铁山鉄矿是我国西北未来的巨大钢铁基地的矿石来源地,位於酒泉南面的祁連山中。經过我們的研究初步确定了这个矿区的矿床分属於兩个不同成因类型:樺树溝式的正常淺海相沉积矿床,並略受区域变質作用,和珠龙关式的火山-沉积矿床。

Recognition of the distribution of Cambrian source rocks and its significance for exploration in Tarim Basin

Due to the importance of the marine source rocks to the exploration in the Tarim Basin, this paper present a new distribution of the Cambrian source rocks distribution based on the study of tectonic-paleogeography, geochemitry of typical wells and new seismic data. It is shown that the source rocks are mainly mudstones and shales from the Middle-Lower Cambrian in the eastern Tarim and from the Lower Cambrian in the western Tarim. However, the source rocks are sparse in the Lower Paleozoic carbonate rocks. With logging calibration, the source rocks thickness is less than 100 m and 40 m in the eastern and western Tarim, respectively. By the seismic data interpretation, the Cambrian source rock distribution is not full of the basin, but mainly distributed in three areas of the Mandong and Manxi Depressions, and southwestern margin of the Tarim, while sparse source rocks in basement uplifts. Controlled by Precambrian palaeo-uplift and weak extension in the Cambrian Tarim, the source rocks are mainly developed in four tectonic setting：inter-platform basin and inner-platform depression, and the possibly passive margin slope and plate margin rift.