漠河盆地西段洛古河泥岩地质特征及时代

Geological characteristics and age of the Luoguhe mudstone in the western section of Mohe basin

摘要: 在漠河盆地西段黑龙江南岸洛古河地区新发现一套以黑色泥岩为主，夹粉砂岩、长石砂岩、凝灰岩的岩石组合，岩石普遍发生糜棱岩化，发育同斜褶皱、a线理、S-C组构、眼球状构造等，将其命名为洛古河泥岩。凝灰岩夹层锆石的LA-ICP-MS U-Pb测年结果为176.3±1.1 Ma，表明洛古河泥岩形成于早—中侏罗世，逆冲推覆于下伏地层上侏罗统漠河组之上，推覆方向总体由北西向南东，洛古河泥岩与上阿穆尔盆地下—中侏罗统具有可对比性，其可能来自于俄罗斯境内的上阿穆尔盆地。

Abstract: We identify a new set of rock assemblage mainly composed of black mudstone interbedded with siltstone, feldspar sandstone and tuff. The rocks are widely mylonitized with isoclinal folds, A lineation, S-C fabric, augen structure and so on.It is named as Luoguhe mudstone.The dating result of zircon LA-ICP-MS U-Pb in tuff interlayer is 176.3±1.1 Ma, indicating that the Luoguhe mudstone was formed in the Early-Middle Jurassic, it thrusted overthrust in Upper Jurassic Mohe Formation.The thrust direction was from NW to SE.The Luoguhe mudstone could be compared with the Lower-Middle Jurassic strata in the Upper Amur Basin and it probably came from the Upper Amur Basin.