What are the biota types?

1. Marine biota (1) Guang Hai to deep-sea biota.

Distributed from East China Sea to South China Sea in China. The main biota are planktonic foraminifera, calcareous ultramicro, dinoflagellate and benthic foraminifera, ostracods, bivalves and gastropods. There are hundreds of foraminifera in the Paleocene and Eocene in the East China Sea, including the planktonic foraminifera belt from Pl to P 1 1, the discontinuous planktonic foraminifera belt from P 12 to P2 1, many benthic foraminifera associated with calcareous nannofossil belts, and some dinoflagellates and ostracods. There are planktonic foraminiferal zones and corresponding calcareous nannofossil zones in Oligocene (P 18-P22) and Miocene to Pliocene (N4-N2 1) in Taiwan Province Province, the Pearl River Estuary and the South China Sea. This kind of biota is rich in plankton and benthos, which is a biota of seawater with normal salinity and can be used for global stratigraphic correlation. Several species of benthic foraminifera coexist with the fauna in western North America, which is a mystery of biological distribution to be solved. The oxygen isotope staging of foraminifera from Miocene to Pliocene to Quaternary in the South China Sea has achieved the results of global climate stratigraphic correlation.

(2) Large foraminiferal fauna in shallow water

Macroforaminifera (i.e. currency insects) fauna in Paleocene and Eocene were found in Gamba Dingri zone south of Gangdise Mountain and south of Gangdise Mountain, which formed the limestone facies of currency insects, and were rich in macroforaminifera, mollusks, corals and other benthic organisms, belonging to the typical Tethys shallow sea biota. The Eocene monetary insect fauna in the East China Sea and Taiwan Province Province is also well developed, but most of them are sandy limestone facies, and the species are much less than those in southern Tibet. In Taiwan Province Province, Penghu, Xisha and Beibu Gulf, Miocene Middle Cretaceous fauna is a kind of warm shallow-sea fauna widely distributed all over the world, and it is a reef-building organism that forms Middle Cretaceous limestone or chalk. From Pliocene to Quaternary, some large foraminifera species and corals formed reef limestone, which was found in Taiwan Province Province, Penghu and Xisha, but its scale has been greatly reduced.

(3) Bay-lagoon biota

Found in western Tarim. Except some planktonic foraminifera from the late Paleocene to the early Eocene, there are mainly benthic foraminifera and oyster mollusks, belonging to the same paratethys biota as Central Asia. Miocene foraminifera transformed into a monotonous bay-lagoon fauna. From Pliocene to Quaternary, there may be residual wandering basins in Tarim, and a few biological residues can adapt to high salinity water.

(4) Marine biota in continental basins.

This special type of biota is widely distributed in the inland of China, which is rare in the world. It is found in Cretaceous strata in Songliao basin, Erlian basin and Sichuan basin. The first two areas have fish, golden algae and dinoflagellate, while the latter area has monotonous foraminifera. There are known foraminifera in Jianghan basin and Subei basin, and Paleogene foraminifera in Maoming and Sanshui basins of Guangdong Province. Eocene foraminifera and calcareous nannofossils in Shahejie, North China Plain are particularly famous. Foraminifera and marine ostracods from Neogene to Quaternary are often combined. They are not only distributed in the North China Plain (including the Beijing Plain), Sanggan River and Wei Fen Graben, but also in Inner Mongolia, Tarim, Qaidam and even Ali, which is thousands of meters above sea level. Their distribution has caused a long discussion at the source, and there is no conclusion so far. This biota is different from the marine sandwich biota in coastal areas and coastal areas, because it is far away from the sea in the region and the passage with the sea is difficult to determine. There are several possible sources, such as seawater tracing, bird carrying and wind belt, and the specific transmission mode needs to be studied. The ancient water system in the eastern basin is likely to spread upstream, and there may be wandering residual basins in the Neogene and Quaternary in the western basin. Under the above background, the wind belt and bird-borne mode are not excluded.

2. Terrestrial biota

Here are mainly mammals and flora, and briefly describe their ecological types.

The evolution of Paleogene and Neogene fauna can be divided into two stages: Paleocene to Early Miocene and Middle Miocene to Pliocene. The fauna from Paleocene to early Miocene is a transitional fauna from local (or indigenous) fauna to intercontinental fauna, and the fauna from middle Miocene to Pliocene is the fauna of the whole northern border or northern region. Within the scope of China, there are differences between the two stages of fauna.

(1) Fauna from Paleocene to Early Miocene from local to intercontinental transition

This change is manifested in the gradual and phased change from the dominance of local elements to a large-scale regional or intercontinental region, with a large number of molecules, but always maintaining the indigenous characteristics at the project and family level. There are more than 65,438+00 orders, more than 65,438+00 families and more than 65,438+000 species of Paleocene mammals in China, with Bemalambdidae as the representative in the early stage and Archaeolambdidae as the representative in the late stage, which is difficult to compare with another well-studied Paleocene fauna in North America, especially in the early Paleocene. There are early and late fauna in South China, and only late assemblage in North China (Inner Mongolia), but there are no southern dominant components such as Archaeopteryx. It can be seen that there was a difference between North China and South China at that time, but the fauna composition of the two regions has yet to be discovered. Eocene fauna has increased to 17 orders, with more than 90 families and hundreds of species. Several genera can be used to compare the level of families. However, it is difficult to compare the animals before and after the Middle Eocene with those in South Asia, and it was not until the late Middle Eocene and the late Eocene that the genus * * * was obvious. The Eocene fauna in China has obvious Asian characteristics: the early Eocene represents oriental apes, Asian apes and gerbils, the early Middle Eocene represents Lo-phiolestes, Protitan and Tamquammys, and the late Middle Eocene represents Rhinotitan. In the late Eocene, anthrock-eryx and Pappocricetodon were the representatives, and cork algae, Dianomys and Sinosminthus were the representatives. Taking the fauna in the late Eocene as an example, the nature of fauna in the north and south is obviously different: ungulates, rodents and rabbits are the main animals in the north, such as cork animals, Gigantamynodon, Desmatolagus, Lophiomeryx and so on. In the Middle Eocene, there were other genera and species of mesothelidae and amphibian rhinoceros. The fauna in South China is dominated by odd-hoofed, cloven-hoofed carboniferous animals and carnivores, such as Gigantomynodon, Cadurcodon, Indricotherium, Schizotherium, Bothriodon, Anthracotherium and Gu Jian Toothed Tiger, and there are also some residual types in the Middle Eocene. Oligocene fauna is mainly distributed in the north, especially in the northwest to Inner Mongolia, and is rarely found in the south except in eastern Yunnan. In the early Oligocene, there were Karakoromys decessus, Ordolagus and so on. In the late Oligocene, it was represented by Dzungariotheriumturfanense, Yindirtomys grangeri and Tachyoryctoides obrutchewi. In Oligocene fauna, giant rhinoceros, rodents, rabbits and small insect-eating mammals increased greatly. Early Miocene mammals were found in Lanzhou, Gansu, Xining basin, Qinghai and Junggar basin, Xinjiang. Taking the Xie Jia fauna in Xining as an example, among the four fossils of 10 genus 14, only Eucricetodon (archaea hamster) and Brachypotherium (Brachypotherium rhinoceros) can be compared with the international ones, belonging to the Oba aquitaine-Bourdigarh period. Most of them are Oligocene remnants, and most of them are Asian indigenous types. The "Zhangjiaping Fauna" in Lanzhou in the early Miocene also includes more than a dozen genera and species, mainly large mammals, most of which are remnants; It is worth noting that some of these genera and species are distributed in South Asia and Central Asia, including elephants that have just migrated from Africa to Asia, indicating that the Qinghai-Tibet region has not yet formed a huge barrier. It can be seen that in the early Miocene, although some species were more advanced than Paleogene fauna, they still retained the local color of units above genus.

(2) Mammal fauna from the middle Miocene to Pliocene.

This stage has been extremely modern, and more than 80% of the subjects have continued to modern times. Compared with South Asia, Africa, Europe and America, a large number of fossils have appeared, such as North American horses entering Europe and Asia in the west, and African long-nosed dragons entering Europe and Asia and North America in the east. A large number of new families have emerged, among which the appearance of primates, higher apes or apes is of special significance. Forest Australopithecus (forest Australopithecus) and Siva Australopithecus (= Rama Australopithecus, that is, Siva Australopithecus or Rama) in Asia and Africa are important links in the evolution of ancient humans. Hippie fauna is the most widely distributed in this area, with dozens of locations in North China, Northwest China, South China, North Tibet and South Tibet, indicating that forests, grasslands or forest-grassland environments were widely developed in most areas of China in Neogene. Of course, the west becomes dry and the east becomes wet. The north-south differentiation of the fauna in the eastern region also clearly shows that the three-toed horse fauna is dominant in the north and Tibet; In addition to Australopithecus fauna, there are many saber-toothed elephants (Gu Jian Tooth Elephant) and saber-toothed elephants (Saber-toothed Elephant) in Yunnan and Guangxi, and the latter is the representative molecule of Quaternary southern fauna. The middle and lower reaches of the Yangtze River are transitional areas. According to the evolution and chronostratigraphic sequence, Miocene to Pliocene can be divided into five periods, each represented by endemic genera and species (National Stratigraphic Committee, 2002; Wang Naiwen and He Xixian, 2005).

(3) Modern terrestrial animals in the world

From north to south, it is divided into: northern region or Palaearctic boundary, whose southern boundary extends from North Africa, Turkey, Central Asia and Kunlun-Qinling Mountains to North America, and its interior is divided into Europe-Siberia region, Palaeo-Mediterranean region (including northwest China) and East Asia region (or East region, including North China, Northeast China, North Korea and Japan, etc.). ), Canada and Sonoran (basically the United States and Mexico). Central China or the old world, including Madagascar, South Asia, South China-Southeast Asia-Irian and other regions; Central and South America or the New World; South China or South China, including Australia, New Zealand and Patagonia. This global pattern of ancient animals was formed in Neogene, which broke through the range of Paleogene native animals and strengthened the global communication between animals. Among them, the boundary between the northern and southern animal areas in China is the boundary between the northern and central areas. This boundary swung from north to south in the Quaternary, forming the so-called "Huaihe River Transition Zone". The success of animal communication on land is attributed to the contraction and disappearance of the continental marine barrier, among which the animal communication between Europe and Asia benefits from the large-scale contraction of the Deputy Tethys or Ponty Sea and the large-scale contraction and disappearance of the Turkish Gulf or Strait connecting the Ponty Sea with the Arctic Ocean. The communication between Asia and the United States mainly depends on the multiple connections of Bering Continental Bridge; The communication between Europe and North Africa is related to the formation period of the Gibraltar Strait Continental Bridge. There may be another transmission mechanism between animals other than mammals. For example, Nida fish school in Eocene in eastern North China can be compared with similar fish schools in western North America, but no fossil remains passing through Bering land bridge have been found. This situation is quite similar to that of Paleocene Silicosigmoilinacalifornica in the East China Sea, and this benthic animal is also consistent with its counterparts in western North America. They are likely to communicate through the ecological environment of floating islands with warm current in the north equator.

(4) Paleogene and Neogene terrestrial flora types.

According to the analysis of large-scale plant fossils and sporopollen assemblages, there are 3 flora types or flora regions in Paleogene and 4 flora types or flora regions in Neogene, which clearly reflect the nature and evolution of paleoclimate zones.

The three types or flora of Paleogene are: northeast-north China-Altay region, south China-northwest-northern Tibet region and south Tibet-Guangxi-Taiwan Province province, which are subtropical-warm temperate warm and humid flora, subtropical arid and semi-arid flora and tropical warm and humid flora respectively.

Belonging to the first category are: northeast paleocene Lizigou wood fossil group, early Eocene Gucheng Formation sporopollen assemblage, middle Eocene Jijuntun flora, late Eocene to Oligocene Baoquanling Formation, Fraxinus mandshurica Formation and Yanghe Formation, late Eocene Xikaitian Formation sporopollen assemblage, Oligocene Fraxinus mandshurica Formation sporopollen assemblage, north China Oligocene Kaidifang Formation sporopollen assemblage and Altai Paleocene flora. Their common feature is that evergreen deciduous broad-leaved trees occupy a prominent position. Especially the Altay flora in northern Xinjiang has not been paid attention to in the past. The floristic composition of its 2 1 plant fossils is the same as that of Shennongjia in Hubei, Tianmu Mountain in Zhejiang and Jiangnan in modern times, and the diameter of some leaves is 30 cm, indicating its subtropical nature. Although the flora of the same period has not been found in the vast area of Mongolia, it can be inferred that there was a vast warm and humid zone from northern Xinjiang to northeast China in the middle latitude of East Asia at that time. The sporopollen properties of plants in North China are different from those in Northeast China. The early Eocene sporopollen assemblage of Kongdian Formation in North China Plain contains ephedra powder, and the "Bailuyuan Flora" in Wei Fen area from late Eocene to Oligocene consists of several Palibinia species, all of which indicate arid climate conditions. It can be seen that North China is the transition zone between the humid area in the north and the arid area in the south.

Belonging to the second type, the Paleocene "Chashan 'ao Flora" from the middle and lower reaches of the Yangtze River to Nanling in South China is characterized by a variety of Palibinia, and ephedra plants are common in the Paleocene pollen spectrum in this area. Casuarina and Ephedra from Eocene to Oligocene are distributed westward in the "Geru Flora" in western Sichuan, southward in the third member of Tubuxin Formation in Sanshui Basin in northern Guangdong, and northward in Weifen area and western Shandong. Palibinia flora extends to Central Asia, Turkmenistan and other places, and goes directly to the Isle of Wight in England through central and southern Europe. With the transformation of Neogene South China into humid climate zone, and the occupation of the vast area from Central Asia to the Mediterranean by Tethys Sea or Ponty Sea, the giant arid zone in the southeast and northwest of Neogene suddenly collapsed and Palibinia became extinct.

The third type is Changchang flora in Hainan in the middle Eocene, Nadu flora and Gongkang flora in Youjiang area in the late Eocene-Oligocene, and Qiuwu flora in the middle Eocene in southern Tibet. These flora were all located in the tropical humid area at that time, among which the flora of Hainan and Youjiang were close to the newly born South China Sea, and the flora of Qiuwu in southern Tibet was formed on the coast of Tethys and has not disappeared yet.

The four types or flora of Neogene are Northwest China, North China-Northeast China, South China and Qinghai-Tibet-South China Sea-Taiwan Province Province.

There are few Neogene plants in northwest China, but in Xie Jia Formation in the early Miocene, Xianshuihe Formation in the middle and late Miocene and Linxia Formation in Lanxi, and even in Baode Formation in the late Miocene in Shanxi, the dominant components of sporopollen assemblage are Chenopodiaceae and Artemisia, and the typical sporopollen assemblage of Shizigou Formation in the Pliocene in Qaidam area is Artemisia, Ephedra powder and Chenopodiaceae. The Xie Jia Formation in the early Miocene still contains a lot of pollen from Ulmaceae and Pinaceae, and even a few tropical and subtropical molecules. From the middle and late Miocene to Pliocene, with Chenopodiaceae and Artemisia as the background, aquatic plants gradually decreased and mountain conifers gradually increased, reflecting the strengthening of drought trend.

There are abundant Neogene plants and sporopollen fossils in North China-Northeast China. The most famous is the Miocene Shanwang flora and sporopollen assemblage in Shandong Province. The flora of Shanwang contains 130 species, of which Acer and Carpinus are the most, followed by Acer, Carya, Juglans and Hamamelis. Sporopollen spectrum contains some evergreen broad-leaved trees and mountain conifers, and this flora is defined as mixed flora. The sporopollen assemblage of the interlayer flora of Xiaguantao Formation in North China Plain and Hannuoba basalt in the border area of Shanxi and Hebei is dominated by conifers, accompanied by deciduous broad-leaved trees, showing the nature of mountain flora with lower temperature than that in eastern North China. However, the flora of Laoliangdi in eastern Inner Mongolia is dominated by deciduous broad-leaved trees, which is closer to the Neogene flora in Northeast China. The Pliocene flora in North China is still different from the east and the west, and the sporopollen flora in Yaoshan Formation in Shandong Province still shows similar properties to the Shanwang flora, but the Yushe flora in early Pliocene and the Taigu flora in late Pliocene in Shanxi Province show the characteristics of the northern broad-leaved mixed forest. The most famous flora of Neogene in Northeast China is the Qiu Li ditch flora in Dunhua, Jilin. The 19 fossil found reflects the vegetation of Miocene mesophyte mixed forest, which is similar to Shanwang flora in Shandong, but contains 8 species of conifers and cypresses, reflecting that the paleotemperature is lower than Shanwang flora. The lack of Pliocene plant pollen data in Northeast China is related to the extensive development of basalt.

There are few abundant Neogene flora in southern China. The most important is the Miocene Zhangpu flora in Fujian, including Liquidambar formosana, Syzygium, Gynostemma pentaphyllum, Magnoliaceae, Gymnospermum and so on. It belongs to the subtropical rainforest vegetation in the tropical flora. The sporopollen assemblage of Pliocene Fotan Formation in western Fujian is rich in mountain conifers, with less thermophilic components and more herbs, reflecting the low temperature of mountain vegetation. From Miocene to early Pliocene, the Toupi Formation in Jiangxi Province was dominated by Quercus pollen flora, which contained many genera of beech, Liquidambar formosana, Hedysarum, Myrica rubra and Tilia, belonging to evergreen broad-leaved deciduous mixed forest vegetation, but there were also a large number of Chenopodium herbs, reflecting a slightly cooler and drier subtropical climate. The Quercus-Cladosporium assemblage in Nanfeng, Jiangxi Province may belong to the upper part of the scalp formation in the early Pliocene, while the Quercus-Cyclobalanopsis assemblage in Ji 'an belongs to the Huangqiao formation in the late Pliocene, which reflects the vegetation of evergreen broad-leaved and deciduous broad-leaved mixed forest in warm and humid climate, and Chenopodium is less likely to reflect the expansion of forest vegetation. The sporopollen of Liangshuijing Formation in late Miocene in Sichuan is mainly angiosperms and ferns, while the sporopollen of Yanyuan Formation in late Pliocene is mainly Polypodiaceae and monospores, which still belongs to humid climate vegetation, and does not show any characteristics of drying and cooling, which also reflects that the Qinghai-Tibet Plateau at the edge of this area has not obviously uplifted at this time. In a word, South China here is a subtropical humid climate zone in Neogene.

The Qinghai-Tibet South China Sea (including Taiwan Province Province) was a tropical or tropical-subtropical humid flora extending several Qian Qian meters from east to west in Neogene. The tropical vegetation in eastern Yunnan (south of Nanling to Taiwan Province Province) has obvious properties, such as Xiaolongtan and Duotang flora in eastern Yunnan, Nankang flora in Hepu, Guangxi, and Shidi flora in Taiwan Province Province. The Miocene flora in the eastern part of the western section, such as Jinggu, Jianchuan and Lincang flora in western Yunnan and Mangkang flora in eastern Tibet, undoubtedly has the characteristics of tropical vegetation, but the Tengchong flora in Pliocene has been transformed into evergreen deciduous broad-leaved mixed forest, reflecting the evolution trend of Miocene tropical vegetation to warm temperate vegetation. Miocene Wu flora in Gangdise belt of central Tibet is a tropical mountain vegetation dominated by Quercus alpina, and its nature is evergreen leatherleaf shrub. The Pliocene Gaelic flora in southern Tibet and the flora on the northern slope of Xixiabangma are deciduous broad-leaved forest and evergreen leatherleaf shrub, respectively, which should reflect the enhancement of vertical zonation in Pliocene tropical mountains and the subtropical arid environment in Neogene. In short, most areas of Qinghai-Tibet changed from a tropical area with flat landforms to a tropical-subtropical area with alternating plains and mountains in Neogene, but there was no alpine and arid plateau environment.