麻山群孔兹岩系地层新见

<正> 黑龙江省东部出露一个较为独特的地质构造单元,前人曾赋以“老爷岭台背斜”、“佳木斯隆起”及“佳木斯中间地块”等名称。地块总体呈南北向展布,向北向东分别越黑龙江和乌苏里江进入俄罗斯远东南部,周围均被加里东期及其后侵入的花岗岩所包围。地块内主要出露两套变质岩系,一为麻山群,构成该地块的主体,另一“黑龙江群”。张贻侠等认为,该地块是一个由异地的龙江地体和基本为原地的麻山地体在晚元古代末(600—750

Discoveryof the khondalite series in the Mashan Group

Systematic investigation of geology has revealed that tectonic style of the earlier defor-mation of the Mashan khondalite series is a group of complex folds in the direction of E-W, and that the sillimanite-garnet-cordierite gneisses and garnet-sillimanite schists in this region belong to the same horizon but are not at the different position in sequence, which has been divided into the Mashan and Liumao (or Longjiang) Formations respectively by the previous researchers. According to the representative associations of metamorphic rocks and the space relationships between them discovered in the field, five lithological members are distinguished from bottom to top in the strata of the Mashan Group, i. e., sillimanite schists, quartz schists-felsic gneisses, graphite schists, phosphorous marbles and calc-silica-tes, and leptites members, which represent a transgression sequence deposited on a stable continental shelf.