(1. Institute of vertebrate paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing100044; 2. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037)
The origin of 1 Lushi sequential names
Lushi step name comes from Lushi Formation, a stratigraphic unit with the same name in Lushi Basin, Henan Province. In June, 5438 +065438+2000 10, Qiu Zhanxiang, Wang Banyue, Qiu Zhuding and Tong Yongsheng proposed that Lushi Stage could be the next stage name of Miocene in China, and reported it to the National Stratigraphic Committee.
2 Lu's hierarchical lateral position
Lushi Formation in Lushi Basin overlaps with old strata, and the bottom boundary is difficult to determine. Therefore, it is suggested that the stratotype profile be moved to Liguanqiao Basin at the junction of Hubei and Henan. Liguanqiao basin, which spans Hubei and Henan provinces, is an east-west fault basin. Paleogene is developed in the basin, which constitutes the main body of basin sedimentation, with a thickness of nearly 2 km, Lushi stage is quite thick, and the thickness is nearly 1 km, including the upper member of the original Yuhuangding Formation, Dacangfang Formation and Hetaoyuan Formation, with relatively rich mammalian fossils. Therefore, it is suggested that the stratotype section is located in Liguanqiao Basin, and the large concave section near Qingtangling in the northeast of Xijiadian Town, danjiangkou city (Figure 1, Figure 2). This part is highly studied. Although the Hetaoyuan Formation in the upper Lushi Stage is missing, its bottom boundary is connected with the Lingcha Stage in the middle and lower part of the Lower Eocene.
Figure 1 Mesozoic-Cenozoic stratigraphic distribution map and main section position of Lushi period in Liguanqiao basin.
Stratigraphic profile of Lushi boundary.
3 Lushi boundary stratotype profile
Da 'ao-Pangwan section is located near Qingtangling, Xijiadian Town, danjiangkou city City, Hubei Province, and the stratum is well exposed. The boundary between the lower middle part of the Lower Eocene Lingcha Stage/the upper Eocene-the lower Eocene Lushi Stage is between the 7th and 8th floors. This part is described from top to bottom as follows (quoted from Xu Yuxuan et al., 1979, with modifications).
Research Report on Major Dating Strata in China (2006 ~ 2009)
Research Report on Major Dating Strata in China (2006 ~ 2009)
On the Yangnvquan-Zhanggou section on the east side of the boundary section, a mammal fossil similar to the Middle Eocene type (Department of Geology, China Geo University, field location No. : 84003) is found in 15 layer, which may be equivalent to 10 layer in Dawa-Pangwan section of stratotype section (Figure 3). Therefore, the eighth layer of glutenite above the early Eocene fossil layer in Daao-Pangwan section can be regarded as the bottom boundary of Lushi period.
In the middle of Yuhuangding Formation, there are mammals in the late period of Lingcha, such as Hunan beast (undetermined species) (see Hunan beast. ), Mongolian gerbil in Turpan (1978), Mongolian gerbil (Exmus mini Wible et al., 2005), Mongolian gerbil in Hubei (Li et al., 1982), Li's Henan mouse (Hohomys lii Hu, 1995), and Asian crested beast. 1976), Allosaurus (heterothoryphodon xuae Tong xuae et al., 2000) and Danjiang (Danjiang duck pingiwang, 1995), etc. However, fossils similar to typical Lushi mammals were found in the upper part of Yuhuangding Formation, which were produced in the middle and upper mudstone of Yangnvquan-Zhanggou section 15 layer. Some people call it Zhanggou Fauna. Mammalian fossils include: Progressive Subcrown Odonata (1990), Subcrown Odonata sp., Small Gobi Horn (1990), and Early Crown Odonata. Primus Cheng et Ma, 1990), Yimeng beast (Yimegia sp.), Coriolis rhinoceros? (Forstercooperia？ Species), Zhang Gou began to claw beast (? Iomolops? Cheng et Ma, 1990) (Department of Geology, China Geo University, field station number: 84003). The fossil layer is about 140 m from the bottom of the upper member of Yuhuangding Formation, and its horizon may be equivalent to the 10 layer of Daao-Pangwan section. This fauna has two characteristics. First, the species of Dentopods account for 50%, which is similar to the typical species of Lushi period in morphology, but looks primitive. Second, there are genera in the middle and early Early Eocene, but they appear to be more progressive, such as Asiocoryphodon progressivus. Therefore, the researchers (,Ma,, 1990) think that the age should be the middle Eocene or the early and late Eocene. Therefore, the lower boundary of Lushi Stage is located between the middle and upper parts of Yuhuangding Formation, in the 8th layer of Daao-Pangwan section, or in the 1 1 layer of Yangnvquan-Zhanggou section. Yangnvquan-Zhanggou section can be used as an auxiliary section of Lushi stage bottom boundary, which is described as follows:
Research Report on Major Dating Strata in China (2006 ~ 2009)
Research Report on Major Dating Strata in China (2006 ~ 2009)
(1) Specific data is missing in the original text.
Fig. 3 Auxiliary section of Lushi boundary stratotype
4 Lushi stage bottom boundary definition
The boundary between the Middle Eocene and the Lower Eocene, that is, the boundary between Lutetian stage and Ipri stage, has not been finalized internationally, but the preferred profile of GSSP is Gorrondatxe beach profile in the western Pyrenees, and the Agost profile in Murcia province (Fortuna) between Basque country and Betic Cordilleras is bounded by the horizon where planktonic foraminifera Hantkenina first appeared, and its age is about (48.6. This is quite different from the traditional continental stratigraphic division. In North America and Asia, continental strata are well developed and well exposed, and the boundary between Middle Eocene and Lower Eocene is traditionally located between Bridgerian /Wa-satchian strata (North America) or Lushi/Lingcha strata (Asia). The boundary of the Bridgerian /Wasatchian strata in North America is in the C22r polar belt, with an age of about 50.4 Ma(Prothero D R, 1998). That is to say, the lower strata of Bridgean stage in North America should be equivalent to the upper part of Ipsian stage. In China, there has not been a systematic and multidisciplinary comprehensive study on the strata that produce mammalian fossils, including paleomagnetic strata. Therefore, only genera (such as Mesonyx, Uint-atherium, etc. ) is similar to the mammal fauna of North America. Accordingly, the lower boundary of Lushi stage should be in the upper part of the lower Eocene Ipri stage, and Lushi stage should include the upper part of the lower Eocene Ipri stage-the Middle Eocene Rudite stage.
The changes of terrestrial mammals and marine biota may be different in time. From North America and China, the Eocene mammal fauna changed between Bridgerian /Wasatchian Strata and Ashantou Strata (Lower Lushi Stage) /Lingcha Stage, that is, it appeared in the Upper Ipri Stage of the Lower Eocene. For example, the composition of ungulates in Ashantou period and Lingcha period is obviously different (Figures 4 and 5). Among the ungulates in the early Eocene, odd ungulates accounted for about 65,438+0/3, and ancient ungulates accounted for the majority. But in the early Middle Eocene, there were at least 6 families of ungulates, and ungulates accounted for about 60% of ungulates. The ancient ungulates declined obviously, the genus and species were relatively single, and the number of individuals decreased greatly.
Fig. 4 Pie chart of early Eocene ungulates in China.
Fig. 5 Pie chart of classification of ungulates in early Eocene in China.
Mammals that first appeared in Lushi stage are: Iconapterodus, Sinosinopa, Neoryctes, Eodendrogale, Lushius, Lushilagus, Strenulagus, Dituberolagus, Dawsonolagus, Asiomys, Orientocylindrodon, Tamquammys、Virio-somys、Tsinlingomys、Chuankueimys、Yuomys、Saykanomys、Stelmomys、Boromys、Zoyphiomys、Hydento-mys、Palasiomys、Raricricetodon、Primisminthus、 hydHarpagolestes，Lunania，Helaletes，Hyrachyus，Aktauchyus，Schlosseria，Lophialetes，Yimeng-ia，Breviodon，Teleolophus，Telmatherium，Metatelmatherium， Desmatotitan，Hyotitan，Arctotitan，Acroti-tan，Protitan，Microtitan，Dolichorhinoides，Gnathotitan，？ Triplop us, Teilhardia, Forstercooperia, Litolo-phus, Gobiohyus, etc. Most of them only exist in Lushi stage. The main feature of Lushi mammals is the richness and diversity of exotic ungulate fossils.
Also extinct in this period are Hapalodectidae, Pantolambdodontidae, Didymoconidae, Metacoryphodon, Advenimus in rodents, and some ancient genera in Podopoda, such as? Homogalax, Heptodon, etc.
In a word, during the period of continental deposition, the characteristics of mammal fauna were the prosperity of odontopods and the appearance of a large number of ancient comb-toed rodents. Extinct species such as Lei Shou and Chiroptera account for a large proportion of the fauna, which is quite different from the mammals in Lingcha period of the Lower Miocene and Yuanqu period of the Upper Miocene.
5. Sequence, characteristics and correlation of biostratigraphy in Lushi stratigraphic types.
Yuhuangding-Shimiao section in the same basin (Zhou Shiquan et al.,1979; Xu Yuxuan et al., 1979), supplemented the above-mentioned boundary stratotype section (Dawa-Pangwan section) and auxiliary section (Yangnvquan-Zhanggou section) without Lushian upper fauna. On this profile, Lushi Stage is 2258 meters thick, including Yuhuangding Formation, Dacangfang Formation and Hetaoyuan Formation. The lower member of Lushi Stage (i.e. Dacangfang Formation) is reddish brown gravelly mudstone, often with grayish white glutenite interlayer, while the upper member (i.e. Hetaoyuan Formation) is grayish green, grayish black, reddish brown mudstone and grayish white marl, with grayish black conglomerate at the top. Mammalian fossils are produced in both the lower and upper segments, and the upper segment is more abundant. The outline is described from top to bottom as follows.
Research Report on Major Dating Strata in China (2006 ~ 2009)
Research Report on Major Dating Strata in China (2006 ~ 2009)
Research Report on Major Dating Strata in China (2006 ~ 2009)
Research Report on Major Dating Strata in China (2006 ~ 2009)
Research Report on Major Dating Strata in China (2006 ~ 2009)
Research Report on Major Dating Strata in China (2006 ~ 2009)
Mammalian fossils of different horizons were found around the Yuhuangding-Shimiao section, which can be compared with the corresponding horizons on the section. Gobiatherium is a Gobi beast found in the upper layer of Yuhuangding Formation in Jiajiazhai. Species, but the fossil horizon is difficult to be directly compared with the boundary layer profile (Daao-Pangwan profile) and auxiliary profile (Yangnvquan-Zhanggou profile) in the west of the basin, which may be equivalent to the upper part of Yuhuangding Formation. Asian crown teeth and heterocrown teeth were found in Yuhuangding Formation in Dahupo, Xichuan, which are equivalent to the lower middle section of Yuhuangding Formation in stratotype profile and auxiliary profile. There are groupers in the upper part of Dacangfang Formation near taoyuan village West Highway in Xichuan nuclear area. , Chinese family. , odontidae. , Lei Shou-like (compared with the ancient ape species. ) and Chiroptera. (the genus and species are undetermined) (? Lo-phialetidae indet。 ) (Wang Jingwen, 1988, identified as Yimeng mountain species. ), a little new rhino? (Caenolophus？ (Xu, Yan et al., 1979). 46 species of mammalian fossils were found in the lower part of the Walnut Garden Formation in Beishipigou, taoyuan village, Xichuan nuclear area: Icnapteronodonqii, Neoryctes qinlingensis? Preliminary batidaceae (species undetermined) (? Archaeopteridae ), Dendrolimus punctatus, Shiqian Nostoc flagelliforme, Liuhe Lushi Nostoc flagelliforme, Danjiang Lushi Rabbit? (Luxi Lagos? Danjiang), desert rabbit (undetermined species) (Shamolagus sp.), elegant twin-humped rabbit (Dituberolagus venustus),? Rat race (? Echinomyiidae ), Li Guan Bridge Oriental Cylindrical Rat (ori-entocylodon liguangqiaoensis), True Rat (undetermined species) (see Pareumys sp.), Sticky Bran (undetermined species) (see Mysops sp.), Long-eared Bat (Tamquammys dispinorum), Viriosomys jingweni, Young mouse in Qinling Mountains (Tsinlingomys youngi), Sichuan gibbon (Chuankueimys xichuanensis), gerbil (Saykanomys cf.bohlini), yellow mouse (Stelmomys parvus), blunt-toothed bat (Eoboromys obtusus), Eoboromys brachblastus, China rare rat, Zoypomys Grandis, Hydentomys cryblophus, gerbils and ancient cone-toothed rat. (Raricricetodon？ Trapezius), lungflower, Protopterosaur (unknown species), Protopterosaur. , Shipigou Protopterosaur (Protopterosaur? Shiqian), mucro Sparus, Henan Schizothorax (Sarkastodon? Henan), Spinibarbus Luxi, Zhong Jian Xichuan (Spinibarbus Xichuan), Lei Shou (unidentified species) (original salamander? Species), Tapestry with Flat Ridge (Lophialetes expeditus), Tapestry with Rock Perch in Taoyuan, Tapestry with Short Ridge (Breviodon minutus), Tapestry with Full Ridge in Danjiangkou (Telelophus Danjiangkou), Tapestry with Sichuan Ridge (Pachylophus xui), Amphibian Rhinoceros An (undetermined species), Protosaurus (Primordial lizard).
It can be seen that there are mainly three fossil horizons in the Lushi period in Liguanqiao Basin: the bottom is the upper part of Yuhuangding Formation in the east of Zhanggou Village, Huangying Township, danjiangkou city, and the Zhanggou fauna is mainly composed of strange hoofed animals, accounting for 57. 1%, which is similar to other lower Lushi mammals; Another feature is that the content of archaic type is relatively high, accounting for 42.9%, indicating that it is older than other lower Lushi mammals. Six species of mammals were found in the upper part of Dacangfang Formation near taoyuan village West Highway in Xichuan nuclear area, with relatively broken fossils. Xu Yuxuan and others (1979) think that the fossil horizon should be higher than that of the Western Zhou Dynasty in Xintai, Shandong. The third fossil layer is located in the lower part of Walnut Garden Formation in Beishipigou, taoyuan village, and is rich in fossils, with 10 orders, 22 families and 46 species. It can be regarded as a lower fauna in the upper continental stage.
Although there are abundant microfossil data in the surrounding basins, there is a lack of systematic microfossil research in Liguanqiao basin, so it is impossible to introduce microfossil data from the surrounding basins into the above sections or compare them. According to mammalian fossils, Lushi mammals can be divided into two types: (1) Lower Lushi fauna, namely Ashantou type; (2) Il Ding Man Ha type in the Upper Lushi stage.
The characteristic of Ashantou-type mammal fauna is that odontosaurus accounts for a considerable proportion in the fauna, among which primitive tapirs account for the majority, and tapirs unique to Asia account for the majority. Among the original tapirs, there are other tapirs, such as helaletids and deperetellids. Lei Shou is a kind of large strange hoof, which is quite prosperous in Inner Mongolia and rarely found in other areas. Aliens began to appear. There are few cloven-hoofed animals of the genus goby. Among the ancient ungulates, true dinosaurs with crowned teeth and horned mammals such as Evanta and Gobi are often found. Except Mongolonyx, a large Chinese mammal in Inner Mongolia, there are only Mesonyx-type Chinese mammals in other regions. Among the rodents, most of them are primitive comb-toed rodents endemic to Asia, and occasionally there are affiliated rodents.
The characteristics of the upper Lushi-type mammal fauna are that the ungulates are still dominant, and the original species of amphibian rhinoceros and rhinoceros of life family appear, but the species and quantity of swamp tapirs are obviously reduced, while tapirs and Dai tapirs are obviously differentiated, and it is often found that rhinoceroses appear. Bifidobacterium type, Gobi pig type and Carboniferous animal type appeared in cloven-hoofed animals. Among the ancient ungulates, the horned beast was almost extinct, and the crested beast was quite specialized. Rodents are mainly primitive comb-toed rodents, with primitive rodent-shaped suborder species, and rabbit-shaped rodents have been preliminarily differentiated. Among Ding Man mammals, tapirs, Lei Shou, medium mammals and primitive comb-toed rodents seem to have reached their peak.
Up to now, there is no systematic and multidisciplinary stratigraphic study of continental continental continental facies in China, and there is also a lack of microfossils associated with mammalian fossils, and volcanic ash has not been found in known strata. Therefore, the correlation between continental facies and international marine facies and continental strata is mainly based on the comparison between mammalian fossils and continental strata in North America (table 1). For example, Mesonyx, Uintatherium, Thinocyon, Hyrachyus and Helatetes found in the lower Lushian are also found in the corresponding Bridgerian strata in North America, and the morphology of Kuanchuanius in the lower Lushian is also very similar to Trogosus mainly distributed in Bridgerian in North America. Therefore, the Lower Lv Xian Formation is compared with the Bridger Formation in North America. Eomoropus and Forstercooperia belong to the same genus as the early Indosinian strata in North America, which have been found in the upper strata of Lu in China, and there are also specimens suspected to be classified as Triplopus and Harpagolestes in the early Indosinian strata in North America. On this basis, the upper strata of Lushi stage are compared with the early strata of Ewintan in North America.
The age of the stratigraphic boundary of the North American continent is also uncertain. For example, in the Wasatchian/Bridgerian mammalian era in North America, the traditional data was ~ ~50 Ma, and some people thought it was earlier, maybe ~ ~52 Ma, during the C22r inversion period. The age data of Wasatchian/Bridgerian in Plaute Luo (1998) is 50.4 Ma, because the latest tuff age data in the Green River Basin infer that the age of the Wasatchian/Bridgerian North American mammal stage boundary should be after the C23n forward stage (50.55±0.43)Ma (Smith, Singer and Carroll, 2003), which is different from that of the previous stage. Age of Bridgean/Ewantan mammalian stage boundary in North America (46.5 Ma? ) is even more uncertain. Although the age of the boundary between Wasatchian/Bridgerian and Bridgerian/Uintan continental strata in North America is controversial and uncertain to some extent, the age determination of each period is based on paleomagnetism and isotopic age. The correlation between marine and continental strata is equivalent to the Ypre-sian, Lutitian and Bartonian stages of Eocene in the international stratigraphic table, which has not been completely solved. Therefore, to solve the boundary problem of Eocene in China, it is necessary to strengthen the comprehensive study of continental strata in China.
Table 2 shows the correlation of Paleogene continental strata in China.
Table 1 Lushi stage and international marine and continental stratigraphic correlation table
Table 2 Comparison Table of Paleogene Continental Strata in China
Take the exam and contribute.
Guan Shaozeng. 1984. discussion on the early tertiary ostracods in liguanqiao basin, Henan province and the ontogeny of cyprinids in Henan province. Acta microflora, 1 (1): 90 ~ 99.
Jin Meng. 1990. A new species of Diptera and related strata. Journal of Vertebrate Paleontology, 28 (3): 206 ~ 2 17.
Tong Yongsheng. 1989. Middle and late Eocene mammals in China. Journal of Paleontology, 28 volumes, 5 issues: 663 ~ 682 pages.
Tong Yongsheng. 1997. Middle Eocene small mammals in Liguanqiao, Henan Province and Yuanqu Basin, Shanxi Province. Paleontology of China, New Species C No.26, page 256.
Tong Yongsheng, Wang Jingwen. 1980. Division of Upper Cretaceous-Lower Tertiary in Tantou, Lushi and Lingbao areas of Henan Province. Vertebrate Paleontology and Paleoanthropology,18 (1): 21~ 27.
Tong Yongsheng, Zheng, Qiu Zhuding. 1995. Zoning of Cenozoic mammals in China. Journal of Vertebrate Paleontology, 33 (4): 290 ~ 3 14.
Wang Jingwen, 1988. A new genus of Ceratophyllum from Middle Eocene. Journal of Vertebrate Paleontology, 26 (1): 20 ~ 34.
Xu Yuxuan, Yan Defa, Zhou Shiquan, et al. 1979. Division of red beds in Liguanqiao basin and study on mammalian fossils. Collection of essays on Cretaceous-Eogene red beds in southern China in Nanxiong, Guangdong, Science Press, 4 16 ~ 432.
Zheng Jiajian, Zhai, et al. Early tertiary strata in lunan basin, Yunnan province Essays on Stratigraphic Paleontology, 7: 22 ~ 29.
Zhou Mingzhen, Li Chuankui, Zhang Yuping. 1973. Late Eocene mammalian fossils from Henan and Shanxi. Vertebrate Paleontology and Paleoanthropology,11(2):165 ~181.
Zhou Mingzhen, Tao Qi. 1982. Middle Eocene mammalian fossils from Xintai, Shandong Province. Vertebrate Paleontology and Paleoanthropology, 20 (4): 302 ~ 3 13.
Zhou Shiquan, Han Shijing, Zhang Yongcai. 1979. Some views on the division of "red beds" in Liguanqiao Basin, Henan Province. Geological science, 1: 43 ~ 55.
Bogren W A, Kent D V, swisher C C, Aubrey M P, 1995. A review of Cenozoic geochronology and chronostratigraphy. SEPM, Specification Press, 54: 129 ~2 12
Krishtalka L, Stucky R K, West R M et al., 1987. Biogeochronology of Eocene in North America (Wasatchian to Duchesnean). Cenozoic Mammals in North America: Geochronology and Biostratigraphy, 77~ 1 17. Berkeley: University of California Press
Prot Luo registered trademark, 1995. Geochronology and magnetostratigraphy of Paleogene North America L and mammalian "age": update. SEPM, specification publishing, 54:305~3 15
Prot Luo registered trademark, 1995. Geochronology and magnetostratigraphy of Paleogene North America L and mammalian "age": update. SEPM, specification publishing, 54:305~3 15
Prot Luo registered trademark, 1998. Chronology, climatology and paleogeography background of mammalian evolution in North America. I terrestrial carnivores, ungulates and ungulates mammals. New york: Cambridge University Press.
Tao Qi, 1987. Middle Eocene Alsato Fauna in Inner Mongolia. Ann Carnegie Conservatory of Music. ,56( 1 ): 1 ~73
40Ar/39Ar geochronology of Eocene Gelinhe Formation in Wyoming, 2003. American Bulls, 1 15:549 ~565
Woodburne M O，Swisher C C， 1995。 L and mammalian high-resolution geochronology, intercontinental coverage and diffusion, sea level, climate and variation. SEPM special issue, 54:335~364
Woodburn m.o. , 2004. Late Cretaceous and Cenozoic Mammals in North America: Biostratigraphy and Geochronology, 345 pages, new york: Columbia Press.
Zdanski o, 1930. Die altterti？ Ren s? China's largest stratigraphic scientist. North Carolina legislature, 6(2), 87 pages.