北京怀柔地区上新世-更新世地层

本文运用岩石地层学、年代学、古地磁学、孢粉学、生物学和矿物学等综合分析方法对HR88-1钻孔资料进行了详细研究,确立了北京怀柔地区晚新生代地层层序,并阐明了自上新世晚期至更新世末期不同阶段的沉积物类型和地质演化史。

STUDIES ON THE PLIOCENE SERIES AND PLEISTOCENE SERIES IN HUAIROU, BEIJING

Huairou area is located at the contiguous area of the northern margin of North China aplain and Yanshan Mountain range. The Cenozoic strata are fairly developed in this region. It abounds in natural resources. Different kinds of fossils in these strata are abundant. It will be greatly significant to study all of the above. In order to study the strata in this area, a lot of useful work has been done. A special drill numbered HR88-1 had been carried out in 1988. Now we have a great deal of information, it is very important to use comprehensive method to study the Late Cenozoic strata. For this reason, we have systematically studied on the sediments, minerals, assemblages of polen and spore and so on. Based on the principles and methods of Palaeomagnetism, Chronology, Palaeobotany and Stratigraphy, the sequence of strata in this region has been established. Pleistocene series ranging from the surface of the ground to the depth of 370 meters cart be subdivided into three parts. It consists of sand, silt, clay and gravel with multi colors. Upper Pleistocene series formed during 0.15—0.01Ma B. P. is called Malan Formation named after the standard stratum of Late Pleistocene in North China. The name for Middle Pleistocene series is taken from Zhoukoudian Formation which is also typical in North China. The middle part deposited from 0.73 Ma B. P. to 0.15 Ma B. P. Lower Pleistocene series is named after Nihewan Formation which has different meaning from the classical one in Yangyuan Basin, Hebei Province. This part formed about 2.48 Ma B. P. to 0.73 Ma B. P. Pliocene series ranges from the depth of 370 meters to 505.27 meters in drill HR88-1, it is composited with brown, red gravel, sand and clay. We give it the name Huairou Formation which formed during late period of Gauss Normal Polarity Epoch.