CHARACTERISTICS OF SEDIMENTARY FACIES AND ENVIRONMENTS OF THE NORTH-SOUTH ORDOVICIAN STRATA IN THE EASN PART OF NORTH CHINA PLATFORM

North-China Platf orm is one of the largest platforms in Chinas to the west, it goes beyond Helaashan M ountains； to the south,tains, Qinling Mountains, east, it reaches to the Bohai F uniushaa M ouatains it stretches to and Dabieshan Qilianshan Mountains Moun-to the Sea and the East China Seas farther than Yinshan M ouataias.In Early Ordovician, it sate platform. to the north, it extends was a very broad carbo nate platform.