(Institute of Geology and Paleontology, Tohoku University, Sendai, Japan, 980-77)

Biogeographic analysis of the Permian-Triassic ammonites in East Asia shows that the ancient land in the southern part of the northern highlands, as the remnants of the Zaochifeng structural belt in the southern part of the northern highlands and northeastern Japan, is located in the equatorial Tethys region, and was adjacent to the South China landmass of China and the Xingkai Lake landmass in the Middle and Late Triassic. This practice, especially between the southern part of the northern highlands and Xingkai Lake, lasted at least until the Middle Triassic.

Chrysanthemum stone; Palaeogeography; Permian; Triassic; North plateau; Southeast Asia

1 Introduction

The northeastern margin of the Asian continent and related island arcs are mainly composed of accretionary complexes from late Paleozoic to Mesozoic. Together with them, there are several small plots with pre-Mesozoic basement, such as Xingkai Lake and brea in the Russian Far East in the northeast of China, and the southern part of the northern highlands in the northeast of Honshu (Figure 1). From Permian to Triassic, there are several large landmasses in the East Tethys Sea: China-Korea landmass, South China landmass (Yangtze and Cathaysia) landmass and Indo-China Peninsula landmass. Most of the above small plots are located near the edge of large plots and may be part of them. From Permian to Triassic, there are different opinions on the location of these discontinuous continents, which will be discussed later.

Figure 1 Schematic diagram of some East Asian landmasses

SKP was originally the land in the subduction zone of the northern margin of Gondwana continent in the early Paleozoic, including Waagenoceras and Daubichites, but there was no endemic genus of equatorial Tethys.

Fig. 2 Partial geographical distribution map of Early-Middle Permian ammonites (according to Ehiro, most of the 27 genera are Pacific Tethys ammonites, and there is no Arctic ammonites (Table 4), among which Tethys is distributed in 23 genera, Pacific Ocean in 20 genera and Arctic in 8 genera. Of the 2 1 Middle Triassic ammonites in coastal areas, 14 belongs to the southern part of the northern highlands. Therefore, in the Early-Middle Triassic, the ammonite fauna in the southern part of the northern highlands was closely related to the southern coastal areas. On the other hand, there are only six Middle Triassic ammonites in the south of the northern highlands, South China and Siberia.

Distribution of Triassic ammonites in Table 4

Note: 1— Iran; 2- Timor Island; 3- South China; 4- North Highland South; 5- Southern coastal areas; 6- Siberia; 7- Nevada-Idaho. The triangle represents ammonites that are not found in the northern highlands.

There are few ammonites in the Upper Triassic strata in the southern part of the northern highlands, but these ammonites are all worldwide. Triassic ammonite-producing rock formations in southwestern Japan include early Triassic Iwai Formation, Taho limestone and Kamra Formation, as well as rock formations in northern highlands and southern areas. Zohoin Group of Middle Triassic; Late Triassic Nabae group, Kochigatani group, Tanoura group and Nakijin group. The ammonites in these Triassic strata are worldwide, and there are no molecules close to the Japanese Arctic ammonites in the Pacific Tethys or Tethys.

4 Inferring the Permian-Triassic paleogeography of East Asia from the ammonite paleogeography.

There are two opinions about Permian paleogeography in the southern part of the northern highlands. According to the similarity of coral animals, it is considered that the paleogeographic position of the southern part of the northern highlands is close to South China or Indo-China Peninsula in China. The molecules in Kawamura and Machiyama areas are similar. The biogeographic views of species and terrestrial plants are very different. According to Ozawa. Cathaysian flora can be divided into two sub-regions: South China and North China. Asama strata containing Daubichites and Waagenoceras are different from those in south China and northern highlands, because Jilin and Inner Mongolia have no Middle Permian auxiliary Celtic bodies found in equatorial Tethys, and Breya landmass belongs to the southern Arctic far away from south China and northern highlands.

With regard to Triassic biogeography, Nakazawa Tomohide [27] thinks that molluscs in the southern part of the northern highlands are related to Siberia to some extent, because the middle Triassic bivalve Daonella densisulata and the middle Triassic ammonites belong to some species of Hollandites, Ussurites, Sturia and Balatonites which are common in the southern part of the northern highlands in Siberia. But in any case, these ammonites are worldwide, and the early-middle Triassic ammonite fauna in the northern highlands lacks arctic ammonite molecules, which are mainly composed of the above-mentioned Pacific-Tethys molecules. In the Early-Middle Triassic, judging from the ammonite fauna, the southern part of the northern highlands should belong to the Pacific Ocean or Tethys region, but not to the Arctic region. It can be concluded that the southern part of the northbound highland is at a low latitude, and the geographical positions of South China, the southern part of the northbound highland and Xing 'an are similar, especially the latter two are more closely related, at least until the Middle Triassic (Figure 4).

The paleogeographic reconstruction of the northern highland south and Xingkai Lake blocks is consistent with the conclusion of paleomagnetic research [4 1], and it is considered that the Permian paleolatitude in the southern coastal area is 1.0 ~ 16.7, and the early Triassic paleolatitude is 24.2.

Thanks to Professor K.Ishizaki of Northeastern University and Professor Brian F.Glenister of the University of Iowa for reviewing the manuscript. This research was partially supported by the Research Fund of the Ministry of Education, Culture, Sports, Science and Technology of Japan (C:07640593).

(translated by Xu, Xiang Jiao)

refer to

[1] K.Asama from Maiya, Japan. I. Tokyo, 1967, 10, 139~ 153.

K.Asama K. and M.Murata M. Permian plants in Setamai, Japan. Bull. Natural Science. Tokyo, 1974,17,251~ 256.

[3]Y.Bando. Triassic strata and ammonite fauna in Japan. Science Representative of Northeastern University, Series 2, 36, 1964, 1~ 137.

[4]Y.Bando and M.Ehiro. Study on the Lower Triassic ammonites in Asanuma Formation, Towamachi, Miyagi Prefecture, northeastern Japan. Journal of palaeogeography, N.S., 1982, 127, 375~385.

[5]Y.Bando and S.Shimoyama. Late cassiterite ammonites from Beishenshan block. Japan, N.S., 1974, 94, 293~3 12.

[6]M.Ehiro. A new kainite (Triassic ammonite) from Rifu Formation in northeastern Japan. Saito Ho-on Kai Mus.Res.Bull， 1992，60， 1~6。

[7] M. Ehiro. Spathian ammonoids Metadagnoceras and Keyserlingites, from the Osawa Formation in the south of the Ki-takami block in northeastern Japan. Japan, N.S., 1993, 17 1, 229~236.

[8] M.Ehiro cephalopod fauna of Nakadaira Formation (Lower Permian) in the south of Kitayama block in northeastern Japan. Japan, n.s.,1995,79, 184~ 192.

[9]M.Ehiro. Permian ammonite fauna of Kitakami block in northeastern Japan-biostratigraphy and paleogeography. The ancient world, 9. ISP'94, Guiyang), 1997.

[10]M.Ehiro. Permian Cephalopods from Kurosawa, Kesennuma City, south of Kitayama Block in northeastern Japan. Paleontological Studies, 1( 1997, submitted).

[1 1]M.Ehiro and S.Kanisawa. Formation and evolution of the northern and southern ancient lands during Paleozoic, with special reference to the geodynamics of East Asia (IGCP-32 1). Japan's contribution to IGCP, 1996: Geological development in Asia-Pacific region and its influence on the evolution of Gondwana continent. IGCP· Nath. Japan communication (editor. ). IGCP· Nath. Japan Telecom, Shizuoka, 1996, 43~50.

A preliminary study on the fauna of Cathaysia. Acta Palaeontologica,1985,24,344 ~ 349.

[13] Fang, Yin. Discovery of Early Permian bivalve fossils in the East of Hainan Island, and on the glacial origin of Nanlong complex. Journal of Paleontology. China Academy of Sciences, 1995, 34, 30 1~3 15.

[14] Permian stage name. Permian and Triassic and their boundaries. Logan and hill (editor. Mem, a Canadian social petroleum geologist. , 1973,2.

[15]B.F.Glenister, W.M.Furnish, Z.Zhou and M.Polahan. Cephalopods of Lower Permian in Thailand. Journal of Paleogeography,1990,64,479 ~ 480.

[16]T.Ishibashi, K.Hasegawa, Y.Sato, K.Kamada and M.Murata. Ammonites from the rice wells in the south of the north block-part 1. Osawa formation (lower Triassic), abst. 143 Reg. Paleogeographic Society of Japan,1994,37.

[17]K.Ishii. Comparison of (Odonata) fauna between Inner Mongolia-Jilin Province and Japan. Pre-Jurassic Geology of Inner Mongolia, China. Report of the Sino-Japanese Cooperation Research Group, 1987~ 1989. Ishii, Liu, Shi Chuankang, Huang (editor. ). Osaka, osaka city university. , 199 1, 189~ 199.

[18]T.Kawamura and H.Machiyama. Late Permian coral reef complex in the northern and southern Shenshan terrane of Japan. Sed.Ge-ol。 , 1995,99, 135~ 150.

[19] T.Kimura. Geographical distribution of Paleozoic and Mesozoic plants in East and Southeast Asia. Historical biogeography and plate electronic evolution in Japan and East Asia. A.Taira and M.Tashiro (editors. ). Terra Science Publishing Company in Tokyo, 1987, 135~200.

20 L. d. kiparisova. Paleobiological basis of Triassic stratigraphy in Ussurilan. Part 1. Cephalopods. ，N.S .， 196 1，48， 1~278。 [Russian]

[2 1]H.Koizumi, K.Mimoto and N.Yoshihara. Permian ammonites from Sakagawa Kwai, Kochi Prefecture, southwestern Japan. Spirited spirits are anxious, 1994, 43, 29~33. [Japanese].

[22]G.V.Kotlyar, Y.D.Zakharov, G.S.Kropatcheva, G.P.Pronina, I.0.Chedija and V.I.Burago. Evolution of the latest Permian biota. Midian stage in the Soviet Union. Soviet Academy of Sciences, Leningrad, 1989[ Russian].

[23] X. Liang. Early Permian cephalopods in northwestern Gansu and western Inner Mongolia. Journal of Paleontology. China Academy of Sciences, 198 1, 20,485 ~ 500.

[24] X. Liang. Some early Permian ammonites from Jilin and Inner Mongolia. Journal of Paleontology,1982,21,645~657.

[25] M. Minato and M. Kato. Waagenophyllidae.Jour.Fac.Sci FAC. Sci. Hokkaido University, 1965, ser. ⅳ12,1~ 241.

[26]K.Nakamura and J.Tazawa. Endemism of Permian brachiopod fauna in Japan. In: Pre-Cretaceous Mountains in Japan. K. Ishikawa, S. Shui Gu, I. Yuan, S. Hada and A. Yao (Editor. Osaka city university, Os-aka, 1990, 3 13~320.

[27]K.Nakazawa. The relationship between Tethys and Japan in Permian and Triassic from the perspective of bivalve fossils. In: Shallow Tethys 3. T.Kotaka, J.M.Dickins, K.G.McKenzie, K.Mori, K.Ogasawara and G.D.Stanley (Editor. Saito Ho-on Kai, Sendai, 199 1, 3~20.

[28] Permian ammonites from devon island and Melville Island in Canadian Arctic Islands. Hello. Parion , 1970,44,77~97.

[29]W.W.Nassichuk. Permian ammonites and nautilus, southeast eagle plane of Yukon. Hello. Goodbye. , 197 1,45, 100 1~ 102 1.

[30]W.W.Nassichuk. Permian ammonites in the Arctic region of the world. Permian in northern Pangaea, 1 Volume: Paleogeography, Paleoclimate, Stratigraphy. P.A.Scholle, T.M.Peryt and D.S.Ulmer-Scholle (Editor. ). Berlin springer Publishing House,1995,210 ~ 235.

[3 1]W.W.Nassichuk, W.M.Furnish and B.F.Glenister. Permian ammonites in the Canadian Arctic. Canadian Geological Survey, Bull. , 1965, 13 1, 1~56.

[32]T.Nishida and Y.Kyuma. Upper Carboniferous and Lower Permian ammonite fauna in Japan. Newslet.Co-op.Res.Gr.C/P boundary, 199 1, 1, 123~ 128.

[33]Y.Onuki and Y.Bando. On the Yinai Group of Lower Triassic and Middle Triassic. Pale-ont institute of geological control. , Northeastern University,1959,50, 1~69.

[34] T.Ozawa. Permian (Odonata) biogeographic region in Asia and its tectonic significance. Historical biogeography and plate tectonic evolution of Japan and East Asia. A.Taira and M.Tashiro (editors. ). Terra Science Publishing Company in Tokyo, 1987, 45~63.

[35]J.P.Smith, Permian ammonites in Timor. ，Jaarb。 ，Jaarg。 , 1927, 1, 1~9 1.

[36]J.Tazawa. Middle Permian brachiopod biogeography in Japan and adjacent areas of East Asia. Pre-Jurassic Geology of Inner Mongolia, China. Report of the Sino-Japanese Cooperation Research Group, 1987~ 1989. Ishii, Liu, Shi Chuankang, Huang (editor. Osaka city university, Osaka, 199 1, 2 13~230.

37 e.t.tozer. Triassic ammonites: geography and stratigraphic distribution. Chrysanthemum: the evolution, classification, lifestyle and geological use of a major fossil group. Mr. house and old J. R. ). Academic Press, London, 198 1, 397~43 1.

[38]Y.D.Zakharov. Lower Triassic ammonites in East SSSR. Soviet Academy of Sciences, Moscow, 1978[ Russian].

[39] Permian cephalopods and Tethys Permian stratigraphic problems in Y.D. Zakharov and A. m. pavlov. Primorye areas. Comparison of sporopollen deposits in eastern Soviet Union. Y.D. zakharov and Y.I. Onopliyenko (Editor. ). Far East Science Center of Soviet Academy of Sciences, Vladivostok, 1986, 5 ~ 32[ Russian].

[40]Y.D.Zakharov and A.N.Sokarev Permian-Triassic paleomagnetism of Eurasia. In "Shallow Tethys 3" edited by T.Kotaka, J.M.Dickins, K.G.McKenzie, K.Mori, K.Ogasawara and G.D.Stanley, Jr. Saito Ho-on Kai, Sendai, 199 1, 3 13~323.

[4 1] Zhou. The first discovery of ammonite fauna in China. Journal of Paleontology. China Academy of Sciences,1978,26, 130~ 148.

Zhu Sheng. Early Permian ammonite fossils from Honggemiao, Abuga Banner, Inner Mongolia. Stratigraphic palaeogeography,1988,21,65~78.