A Detailed Analysis Of Sedimentary Facies Since The Pleistocene In Langfang Basin

The geographic coordinates of Langfang City is116°38′07″-44′06″E,39°28′42″-32′54″N.It is in the east of the middle of Hebei Province, lied betweenBeijing and Tianjin. It is called “the eye of Jingjin Corridor”. Its tectonic is HuabeiPlatform and it is covered by metamorphic rocks which were born from Archean toEarly Proterozoic.Above them are rocks from Middle and Late Proterozoic andPaleozoic Era. During the middle of Cenozoic rifting happened so that thesedimentary thickness of some places reached hundreds of meters. Since NeoceneHuabei Plain entirely went down so an entire rifted basin formed. Moreover, the strataof Quaternary are mainly gray and dust gray lake face.The paper mainly bases on the hole LD-4in Langfang Dishangying. Through thecore of the hole, I can analyze the face-changes of Langfang City during Quaternary,rebuild its sedimentary condition. The hole is located in the north of DishangyingCounty Developing District of Langfang City. Its geographic coordinates is39°36′35.32″N,116°42′54.88″E. the deepness of the hole is256.14m while thedeepness of the core is209.81m. The core recovery percent is81%. We can identify9lithologic characters and6colors in the core of LD-4during Qp3in which silty clay isthe most and the next are clay and fine-sand. In the colors, the most is yellow-grayand gray-yellow. Hence, yellow-grey silty-clay, gray-yellow silty-clay, yellow-greyclay, gray-yellow clay, gray clay and yellow-gray fine-sand appear the most. Theirinterbedded sedimentation forms the sedimentary background of LD-4during Qp3.through analyzing I can know that at that time it was a delta above181.39m and thedelta went lager and lager turned into a lake at last.