The so-called North China includes the middle and lower reaches of the Yellow River and the vast areas of Haihe River and Luanhe River basins. Quaternary strata in this area are mainly distributed in the North China Plain, which is composed of the river terraces, deltas, Bohai beaches and marine terraces of the above rivers and their tributaries, as well as some intermountain fault basins and valleys on both sides, including some intermountain fault basins and valleys in Taihang Mountain, Luliang Mountain, Yanshan Mountain and Yinshan Mountain areas. In the North China Plain and some intermountain basins, Quaternary deposits reached a great thickness. During the Quaternary period, due to the development of differential ascending and descending movements between mountain areas and adjacent plains and intermountain basins, the mountain dew of Quaternary deposits in mountain areas in various periods was good. However, the early Quaternary deposits in plain and basin areas are buried underground, which are relatively intact and have good continuity. The main genetic types of Quaternary deposits in North China are alluvial deposits, proluvial deposits, lacustrine deposit deposits, aeolian deposits, glacial deposits, glacial deposits and marine deposits. These deposits have clear lithofacies characteristics and contain a large number of fossils.

These characteristics are very beneficial to the study of Quaternary strata in North China. North China is the region with the earliest and highest degree of Cenozoic geological research (including Quaternary strata research) in China. For decades, many geoscientists at home and abroad have done a lot of research on Quaternary strata in this area and established standard stratigraphic profiles. The study of North China has laid a good foundation for the study of Quaternary strata in China.

1. Lower Pleistocene

(1) Nihewan Formation

The typical area of Nihewan Formation is located in the Sanggan River Valley Basin of Hebei Province and Nihewan Village of Yangyuan County. Nihewan Formation is dominated by lacustrine deposits, with fluvial deposits at the bottom and basin edge. The thickness of sediments may exceed 6m in the center of the basin, which has not been exposed to the end. Nihewan Formation is dominated by grayish green, grayish blue, grayish white clay, sandy clay and marl. In some places, there are mottled sand and sandy clay layers in the upper part, such as light red, light yellow and gray black. In some places, swamp peat layers are developed; There are sand and gravel layers at the bottom and the edge of the basin. The fine clay layer has complete large horizontal bedding; The gravel layer has obvious cross bedding. It is rich in freshwater mollusk fossils, fish fossils and abundant mammalian fossils. Brackish water foraminifera fossils have been found in some horizons. The above characteristics show that the Nihewan Formation is mainly deposited by large freshwater lakes, and seawater may invade in some periods. This set of sediments is concentrated in some large rift lake basins in Fen and Wei graben, such as Yanqing Huailai Basin, Yuxian Yangyuan Basin, Datong Basin, Fen River Valley Basin, Weihe River Valley Basin and Sanmenxia area in the middle reaches of the Yellow River.

The early Pleistocene long-nosed three-toed horse-true horse fauna was found in the stratum of Nihewan Formation, so it was compared with Villafrancian and became the standard stratum of Quaternary lower Pleistocene in China and the world.

The main representatives of Nihewan fauna (i.e. long-nosed three-toed horse-real horse fauna) are as follows:

long-nosed three-toed horse (Proboscidipparion sinensis), Weng's corner antelope (Spirocherus wongi)

Eguus sanmeniensis, China antelope (Gazella sinensis)

Elaodon. Smotherium sp.) Canis Chihliensis

Palaeoloxodon namadicus, China Raccoon (Nyctereutes sinensis)

Paracamelus gigas, Hyaena sinensis

Bubu's bighorn deer ( Eucladoceros boulei) Megantereon Nihowanensis

Four Ding Shi zokor (Myospalax tingi) unlike deer (Elaphurus bifurcatus)

Bison Palaeosinesis in China

In addition, The Nihewan Formation also contains a large number of mollusk fossils, among which the following are common: Limnaea, Pianorbis, Corbicula, Lamprotula and Cuneopsis.

There are still many problems in the Nihe Formation, which need to be further studied. According to the data obtained in some recent work, it is briefly introduced as follows:

① The lower part of the Nihewan Formation is directly covered on the Pliocene red soil layer with three-toed horses. In the profile (Figure 13-6) found in Hongya Village, Yuxian County, west of Hulu River in the south of Yangyuan-Yuxian Basin, it was suggested in 1975 that 1.7m of the bottom of the red clay gravel layer containing three-toed horses was moraine, which was designated as "Hongya Glaciation". Therefore, it is suggested that the Quaternary boundary should be pushed below the red soil layer of Hippies. This suggestion has not been adopted.

② At present, the systematically measured section of Nihewan Formation is Haojiatai Section. Actually, it is only a stratum exposed more than 1 meters above the surface, and it cannot represent all the Nihewan Formation with a thickness of more than 6m

Figure 13-6 Luanshi Luantagou Section in Hongya Village, Yuxian County, Hebei Province

1-Mesozoic volcanic rocks; 2-Lower Tertiary; 3— Upper Tertiary Hippies, 4— Lower Pleistocene F (Nihewan Formation) Gray-green marl and sandy clay

Haojiatai section is located in the southeast corner of Xiaodukou, Huashaoying Township, Yangyuan County (Figure 13-7), on the lacustrine platform cut by Sanggan River and Huliu River, 147m higher than Sanggan River, with a total stratum thickness of 113m m. The upper part is interbedded with grayish yellow sandy clay and variegated clayey silt; The lower part is grayish green and grayish white sandy clay containing more calcium or marl interbedded with grayish yellow gravelly clayey silt.

③ Xiashagou section in Nihewan Village is a place where abundant fossils are found, which contains most mammalian fossils of Nihewan fauna. Xiashagou section corresponds to the upper part of Nihewan Formation. It was located at the junction of lacustrine plain and the foothills during Nihewan period, thus forming a set of alternating fluvial and lacustrine sediments of sand, gravel and sandy clay. The section * * * is 43.6m thick (Figure 13-8).

figure 13-7 haojiatai section in Yangyuan, Hebei province

1-loess; 2-calcium tuberculosis; 3-sand; 4— Sandy clay; 5— Mudstone; 6— marl; 7— Gravel lens body; 8-invertebrate fossils; 9— vertebrate fossils

Figure 13-8 Xiashagou section of Nihewan, Yangyuan, Hebei Province

1— Loess; 2-staggered sand layer; 3-sand; 4— Gravel; 5-clay; 6 monocalcium tuberculosis; 7-invertebrate fossils; 8-vertebrate fossils

Figure 13-9 Measured profile of marine layer in Quaternary Nihewan on the east side of Sanli Yuxian-Xuanhua Highway in the southeast of Dongyaozitou, Yuxian County, Hebei Province (according to Wang Pinxian et al.)

④ At present, it is equivalent to this layer, and brackish water foraminifera fossils have also been found in the warm springs of Huailai Basin. It is likely that the Sangyuhe fault basin was connected with seawater at some time in the early Pleistocene. At this time, seawater can invade the basin along a certain channel, bringing in some foraminifera. Under the special conditions of desalting brackish water, a mutant foraminifera appeared and propagated for a period of time. The section where marine fossils are found is located in Sanli, southeast of Dongyaozitou, Yuxian County, on the east side of Yuxian-Xuanhua Highway (Figure 13-9). There is only one genus and one species of foraminifera in Shanxi, but there are many foraminifera, accounting for 9% of the microfossils. There are 6 genera and 11 species of brackish water ostracods in the remaining 1%. There are also Pisidium, which can live in fresh water, brackish water and brackish water, and the land snails.

(2) Sanmen Formation

This is a set of fluvial-lacustrine deposits of Lower Pleistocene which can be compared with Nihewan Formation. Sanmenxia is located in a faulted basin in the middle reaches of the Yellow River, bounded by Zhongtiaoshan in the north, Qinling in the south, Fenweihe Valley in the west and Sanmenxia Valley in the east. In this basin, gravel and marl layers of river and lake facies with a total thickness of about 2-9 m are accumulated, and many outcrops and faces can be seen along the banks of the river valley (Figure 13-1). In the past, this stratum was generally called "Sanmen System". In 1959, according to the Quaternary geological site meeting in Sanmenxia, the original "Sanmen System" was divided into five layers. According to the opinions of most people, the ③ and ④ layers were lower Pleistocene series, called Sanmen Formation, ① and ② belonged to the upper part of Pliocene series, and the fifth layer was temporarily classified as middle Pleistocene series. It is briefly described as follows:

⑤ The sand and sandy clay layers are mixed with gravel layers, which are distributed in the lower part of the second and third terraces of the Yellow River.

denudation discontinuity

④ brownish red sandy clay layer mixed with clay, sand and gravel layer. The clay content is high, containing muddy snail fossils, which are often eroded after deposition and are not widely distributed. 6m thick < P > ③ Gravel, interbedded gravel and sand. To the center of the basin, it becomes a fine sand and silt layer with clay. Gravel has a high degree of roundness, mainly composed of quartzite, Shi Ying sandstone and mammalian fossils with obvious cross bedding and rich clam shells. 7-1m thick < P > Upper Pliocene:

② Sandy clay layer with gravel layer or clay sand layer, brownish red in color, solid in lithology and poor in gravel sorting, containing Hipparion richthofeni I.. 2-24m thick

① Bottom conglomerate layer, grayish white composed of quartzite, Shi Ying sandstone, limestone, schist and extrusive rock, with poor gravel sorting, slightly angular and hard calcareous cementation. 1-9m thick

unconformity

The lower complex stratum is the Paleogene Pinglu Formation

Three sections (according to Jia Fuhai) in Sanmenxia area in Figure 13-1

A-Shanxi Pinglu Huangdi River; B— Dongpogou, Sanmenxia City; C— section and histogram of Yaotougou in Sanmenxia

Before liberation, Yang Zhongjian found Minomys orientalis in the gravel layer in the lower part of Dongyan village, which was a fossil of early Pleistocene in Europe. Bian Meinian found the jawbone of a swollen deer on the sandy surface of fenglingdu. After liberation, many mammalian fossils were found. Except for some unknown strata, Bubu deer, vole, deer, rhinoceros, hyena and so on were found in the sand layer of Hougou, Zhangyu, from which Platycodon peii may have been produced. Flat-fronted elephant, Sanmen horse, beautiful black deer (Rusaelegans), Bud deer and Euctenoceros tetroceros antelope were collected in Linyi, Shanxi. This indicates that it belongs to Nihewan fauna. It is also found in Sanmen Formation that the sporopollen data of the turtle (Clemmys sp) now living in South Asia prove that it was a forest and grassland environment at the time of deposition, and the temperate climate was slightly wetter than it is now, belonging to the interglacial climate.

In North China, most strata of Nihewan Formation and Sanmen Formation suffered from structural changes, strata tilted and fractures occurred. It can be proved that the neotectonic movement after the early Pleistocene is very intense. This period of tectonic movement is called "Sanmen Movement" in North China. < P > After the "Sanmen Movement" and "Yuanmou Movement" of the early Pleistocene, most of the fault basins in the central fault depression sedimentary area no longer preserve the paleogeographic features of the lake basin. Except for a few basins with inherited lakes, most of them become valleys of river valleys. Alluvial deposits in different periods have developed or there are other genetic types of deposits in between. In the central fault depression area, in addition to the alluvial layer in the valley, due to the change of climate in the direction of drought, a thick loess layer has developed in the northern region. Loess can be covered on different genetic types of sediments and topography, and its distribution area is beyond the scope of the central fault depression sedimentary area, which is a sedimentary layer with the main feature of reflecting climate zoning.

2. Middle Pleistocene

The Middle Pleistocene in North China used to be called Zhoukoudian Formation. Since the discovery of the Lantian ape-man, the Xiehu Formation, which produced Lantian man's fossils, has also become a standard site, and because the Lantian Gongwangling man's fossils are older than the Peking ape-man, the age of the lower part of the Xiehu Formation may be earlier.

(1) The standard site of Xiehu Formation is on the third and fourth steps of Yuanshang and Bahe River in Lantian, Shaanxi. There are two main types of sediments, namely, gravel layer and red soil alluvial by rivers. The former is distributed along the Bahe River, especially on the right bank of Bahe River. The gravel layer is about 4 meters thick in Choushui River, Angou and Gongwangling, and gradually becomes thinner to the northwest, and even pinches out. The latter is distributed in the loess plateau and the ⅲ and ⅵ terraces of Bahe River. According to vertebrates, buried soil and denudation surface, it can be divided into upper and lower parts:

The lower part of Xiehu Formation is in loess plateau area, which is yellow-brown loess sandy soil with large calcareous nodules. The colors of A and B layers of buried soil are not obvious, and the occurrence is basically the same as that before Quaternary. In addition, in the lower layer of loess plateau, there is a set of brown sandy soil and clayey deposits with horizontal bedding, which are in unconformity contact with the underlying strata and may be the product of ancient gullies in loess plateau. There are gravel, sandy and red clayey layers distributed in Bahe terrace, which are in unconformity contact with the underlying Tertiary, and the gravel layer is nearly horizontal, and it is displaced and fractured in the area damaged by neotectonics.

The upper layer of Xiehu Formation is brownish red or reddish brown loess sandy soil, and calcareous nodules are often integrated into a network, sometimes connected into strips. The buried soil layers A and B are bright in color, and the surface is undulating, with an inclination angle of about 1. The lower layer is also loess-like soil, which is rich in calcium and plate-like, and the buried soil layers A and B are light in color. The stacking range is small.

In Lantian area, the "Lantian Ape Man" fossil was found in two places, one is Gongwangling and the other is Chenjiawo Village. They belong to the upper and lower parts of the Xiehu Formation respectively (Figure 13-11).

According to the comparison of profiles in different parts of the Xiehu Formation, the Xiehu Formation has the following characteristics:

① River facies sediments are deposited in the lower part of the Xiehu Formation, and ancient gullies are deposited in Yuanshang; ② The upper part of Xiehu Formation is mainly soil-like deposit; ③ The color of the buried soil in the upper part of Xiehu Formation is bright, with sporadic calcareous nodules; The color of the buried soil in the lower part is light, and the calcareous nodules are tabular; ④ The occurrence of the upper and lower parts of the Xiehu Formation on the loess plateau is inconsistent, with an inclination of 1-15 in the upper part and nearly horizontal in the lower part, with a denudation surface between them; ⑤ The fossils in the upper part of Xiehu Formation are close to those of Peking Man, while Gongwangling fauna is between Nihewan fauna and Zhoukoudian fauna, and closer to the latter; ⑥ The age of the gravel layer in the lower part of Gongwangling may belong to the Middle Pleistocene or the Early Pleistocene. There have also been some controversies about the genesis of the gravel layer. One view is that it is current deposition, while others suggest that it is moraine layer, and it is called "Gongwangling Ice Age". It seems that detailed work should be done to establish the "Gongwangling Ice Age".

fig. 13-11 Shuizigoukou profile, the fossil origin of Lantian Man in Gongwangling, and the columnar contrast map of Lantian Xiehu Formation (simplified by Jia Lanpo et al., 1964)

(2) Zhoukoudian Formation was once the standard site of Middle Pleistocene in North China, and it was a cave accumulation in Zhoukoudian, Fangshan District, Beijing. In Zhoukoudian area, there are many fissures and caves. The Zhoukoudian Formation refers to the cave accumulation in the first place of Zhoukoudian, the origin of Peking Man, and its sedimentary lithology is difficult to compare with that outside the cave. However, it contains extremely rich mammalian fossils. The mammal fauna of Zhoukoudian Formation is called the Chinese Ape-Puffed Deer Fauna, which is the standard fauna in northern China.

List of fossils from the first site in Zhoukoudian:

Peking Man (Sinant