关键词: 晚古生代, 沉积相, 岩相古地理, 东北地区

Abstract:

 The mapping units of lithofacies palaeogeography map were strictly selected in accordance with the principles of isochronous comparison. On the basis of the sections measured in field survey and the detailed study of fine sedimentary microfacies, we have identified the marine facies（shallow marine subfacies, half deep marine subfacies）and delta facies（delta front: underwater distributary channel, estuary dam and the former delta）sedimentation in outcrop profile in northeast China. Based on the outcrop point measurement, from point to line and from line to plane, the paleoenvironments has been analyzed. On the basis of fine division in the field profile microfacies and combined with regional geological data, the maps of stratigraphic thickness, sandstone thickness, mudstone thickness, carbonate rocks thickness, the ratio of sandstone in the formation, the ratio of mudstone in the formation, the percentage of rocks, etc. have been plotted. On the basis of quantitative analysis and combining the principle of advantages of phase，the lithofacies palaeogeography map of Middle Permian in Northeast region was drawn. In this region mainly developed delta facies, carbonate platform facies, neriticbathyal phase. Delta facies mainly distributed in the west, northeast, and southeast; the ancient land mass nearby is the main source system；the carbonate platform is mainly in the northwest and east of the work area；the neriticbathyal phase is widely distributed.

Key words:  Late Paleozoic, sedimentary facies, lithofacies paleogeography, northeast region of China