Study On Protolith Restoration And Sedimentary Environment Of Halahuogete Group, Altan Obo, Alashan Banner, Inner Mongolia

The Mesoproterozoic Halahuogete Formation of Bayan Obo Group, located at Altan Obao in the north of the study area, distributed from west to east. Its total area was approximately 12 square kilometer. The rocks of this Formation, which are black or light black for rich of C, consist mainly of mica quartz schist, quartzite, marble, carbonaceous phyllite. Although the Formation subjected to strong tectonic deformation, the degree of metamorphic rocks generally reached to greenschist and local amphibolite facies.It is proved that the protolithes of Halahuogete Formation are muddy sand and sandy mudstones by the following facts and features: (1) the occurrence of strata and macro geological features in field including horizontal and parallelized bedding, and its blastosedimentary structure;(2) the microscopic characteristics including mineral assemblage, recrystallization and deformation;(3) the results of some programs of protolith restoration.It is revealed that the Halahuogete Formation was formed in passive continental margin of the northern China Platform under condition of hypoxia and anaerobic, and was a product of normal seawater sedimentation, possibly underwent hydrothermal deposition by analysis of the main elements and REE.