Gcol. Paläont. Mitt. Innsbruck, ISSN 9378-6870, Bd. 15,1-12, 1988

THE HISTORY OF LAND IN THE DURING THE WITH SPECIAL REFERENCE TO THE FLORAS OF EURASIA

I.A. Dobruskina, Moscow

With 2 charts and 7 figures

Abstract: Triassic period is a period of reconstruction ("perestroyka") in the kingdom. During the Triassic Paleophytic plant assemblages gradually changed to Mesophytic ones. The greatest break in the plant life took place in the middle of the Triassic and "perestroyka" itself occurred during the late and the first half of the Triassic, i.e. during about 60 millions of years. Late Permian and Lower Triassic stage of development of plants may be characterized as the last stage of the Paleophytic. Reconstruction continued during Ladinian-Karnian stage which may be considered as the first stage of Mesophytic. "Normal" Mesophytic begins from Norian (middle Mesophytic) and continues during the and Lower (late Mesophytic). The reconstruction in floral composition was accompanied by the reconstruction of the paleogeographical zo- nation. The great isolation and f ractionality of the Paleozoic Phytochoria were replaced by more simple zona- tion, similar to the recent one. Zusammenfassung: Während der Trias erfuhr die Pflanzenwelt eine grundlegende Änderung. Die paläophy- tische Florenvergesellschaftung wurde von der mesophytischen abgelöst. Der stärkste Florenschnitt erfolgte in der Mitteltrias, wobei sich die Änderung in der Pflanzenwelt bereits während des Oberperms und der Untertri- as vollzog, d.h. während eines Zeitraums von ca. 60 Mill.J. Die oberpermische und untertriadische Entwicklungsstufe der Pflanzen kann als spätes Stadium des Paläo- phytikums charakterisiert werden. Der Umbau erfolgte während des Ladins und Karns, was als erstes Stadium des Mesophytikums aufgefaßt werden kann. Das eigentliche ("normale") Mesophytikum beginnt mit dem Nor (mittleres Mesophytikum) und setzt sich bis in den Jura und die Unterkreide (spätes Mesophytikum) fort. Die Änderung der Florenvergesellschaftung war begleitet von einer Änderung der paläogeographischen Zo- nierung. Die starke Isolation und Zonierung der paläozoischen Phytochoria wird von einer einfacheren Zonie- rung, ähnlich der heutigen, abgelöst.

1. Introduction redbeds and the quantities of clastic rocks reach 70% (RO- NOV & KHAIN, 1961). Many tectonic events occurred in The Triassic period is in many respects a time of great the Triassic, although they are explained in various ways changes. In fact some researchers even consider it to be by different geologists. A number of them believe that rift- unique because of the significance of these events zones began to form in the early Triassic or in the late part (TRÜMPY, 1982). Itis with the Triassic that the of the Permian in Laurasia, and that one of these riftzones era began, a time when great changes took place in both the was responsible for the origin of the Atlantic during plant and animal kingdoms. During the Triassic the Paleo- the Triassic. In other words Pangea had begun to break up phytic flora which had been in existence since the origin of during the Triassic. Other geologists think that Pangea did land plants in the early Paleozic disappeared and was re- not form until the Triassic (see TRÜMPY, 1982). A third placed by a different flora, the so-called Mesophytic flora point of view is that Eurasia was formed during the Triassic (KRYSHTOVICH, 1957). In addition thephytogeograph- (BELOV et al., 1982). ic zonation which developed during the Mesophytic is very close to that of the present day. The Triassic is thought to Significant floral changes occurred during the Trias- have been one of the warmestperiods in history when sic and here I briefly summarize them and attempt to relate the average temperature is estimated by paleoclimatolo- them to tectonic events of the period. Detailed discussions gists to have been 20° higher than at present (FRAKES, of this material has been presented elsewhere in Russian 1975). Triassic deposits contain conspicuous quantities of (DOBRUSKINA, 1978,1980,1982). 2. Flora stages of the Triassic study of Korvuntchana flora which consists principally of conifers (DOBRUSKINA, 1984, MOGUTCHEVA, Three floral stages have been recognized in the Triassic 1984), the correlation of this flora with Voltzia flora of (DOBRUSKINA, 1978, 1982, chart 1 in present paper). western and China (DOBRUSKINA, 1985 - chart The first is in the lower part of the Triassic (the Scythian 2) and the correlation of volcanics of the Tunguska basin and Anisian) and is so closely related to the Paleophytic with the volcanics of the Kuznesk basin, Verkhojanie and that it is generally referred to as the late Paleophytic (Post- Taymyr (MOGUTCHEVA, 1982). paleophytic of MEYEN, 1970). As shown in chart 1 the very provincial Permian floras were replaced during this During the first floral stage only one new family of time by most widespread floras which contained many land plants appeared, the Pleuromeiaceae (DOBRUSKI- forms that were close or identical to Permian genera. It was NA, 1982,1985 b). After its sudden appearance the family also characterized by the origin and expansion of a new rapidly spread throughout most of the world. family of lycopsids, the Pleuromeiaceae. The second floral The presence of the Voltzia flora in China, the exis- stage, the early Mesophytic, occurs in the Ladinian and tence of common forms of conifers and lycopsids in the Carnian and was a transitional stage from the Paleophytic floras of , China and and the uni- to the Mesophytic. The Scytophyllum flora with its pro- form development of the early Triassic floras of Siberia nounced meridional zonation is characteristic of this stage and China indicates that the fragmented floras of the late (DOBRUSKINA, 1982). The third floral stage or the mid- Paleozoic had been replaced by a single flora which al- dle Mesophytic occurs in the Norian and Rhaetian stages lowed the exchange of plants between them. At the very of the Triassic, together with the Early and Middle Juras- beginning of the Triassic there was no barrier between the sic. The Triassic portion of the stage is characterized by the Atlantic and Cathaysian plant kingdoms, and as a result a Lqjidopteris flora with its more modern type of biogeo- united European-Sinian floristic area developed. The bar- graphical zonation. The beginning of the Middle Meso- rier between this area and the Siberian area had now be- phytic is actually the real beginning of the Mesophytic come much less significant than it was in the Permian. with the domination of Cycadophyta, Ginkgophyta and There is some question about what geologic events are Dipteridaceae (KRYSHTOFOVICH, 1957). (The late connected with it. Mesophytic includes late Jurassic and early Cretaceous As shown in figure 1 the southern boundary of the floras and is not discussed here). Angarian floristic area of the Permian (MEYEN, 1970, fig. g) coincides with the zone of the Variscean uplifts First floral stage which extended from the to the Donetz basin. The northern part of Urals separated the East-European area The late Paleophytic began during late Permian time and from the Angara area. From this point of view it is not im- was marked by (1) the extinction of many of the plants portant, if the isolation of the three phytogeographical which had dominated the late Paleozoic plant assemblag- kingdoms was caused by high mountains, marine basins, es, and (2) the beginning of the expansion of those plant or by the separation of plates. But it is significant that by groups that had been in the background. These changes late Tatarian time this barrier did not exist and the Tatari- probably were caused by the increased aridity which oc- na flora extended in a wide belt between the Angara area in curred following the great regressions of the during this the north and the Atlantic and Cathaysian areas in the south time. In western Europe the late Paleophytic lasted from (DURANTE, 1983). It occupied the eastern European part the Zechstein to the middle of the Triassic during the time of the Angarian kingdom and the northern part of Cathay- of the Voltzia flora, a flora which was closely related to the sia where its traces are known in northern China at Nan- Zechstein flora and contained practically no new plant shan and adjacent areas. But at the same time the isolation groups. In , Siberia and northern China the of the Atlantic and Cathaysian kingdoms continued. In the late Paleophytic lasted from the Upper Tatarian (DU- early Triassic (figs 1 and 2) this barrier disappeared and the RANTE, 1980) to the middle of the Triassic during the floras of the west and of the east of European-Sinian areas time of the analogues of the Voltzia flora and during the became similar. time of the Korvuntchana flora of Siberia. So, the role of Variscids as a barrier disappeared by New data confirm the traditional point of view (Res- the end of the Permian, or when the joining of the Cathay- olutions, 1981), that the Korvuntchana flora of Siberia sian plate to the rest of Eurasia had been completed by this arose at the very beginning of the Triassic and lasted un- time, and the barriers between the west and east ceased to til Middle Triassic time. This conclusion is based on a exist either at the beginning of the Triassic or possibly in TRIASSIC LAURASIA KINGDOM GONDWANA PHYTOCHORIA SIBERIA AREA EUROPEAN-SINIAN AREA KINGDOM

Hettangian I Thaumatoptehs flora Thaumatopteris flora Sinemurian

Rhaetian O Lepidopteris flora Lepidopteris flora

Norian

Carnian Scytophyllum flora Scytophyllum flora Dicroidium flora Ladinian rv Korvunchana, Anisian flora / Pleuromeia Pleuromeia Voltzia flora flora Olenekian flora Induan Voltz. Tatarina flora Upper Zechstein Gigantopteris Glossopteris Permian flora flora flora

Corda i tes flora Flora with I Mixed Lower I arborescent Permian I lepidophytes, Tingia flora Calamites Gangamopteris I flora I and ferns flora

T-V T-K F-E Pe. north south north ' south East Siberian province pr. pr. european PERMIAN area ATLANTIC CATHAYSIAN GONDWANA PHYTOCHORIA Angara area KINGDOM KINGDOM KINGDOM ANGARA KINGDOM

' Chart 1 : The stages of development of the floras at the Paleophytic-Mesophytic transition Phytochoria in the Permian, after MEYEN (1970); Gondwana kingdom, after RETALLACK (1977) Abbreviations: T-V: Taymyr-Verkhoyansk count; T-K: Taymyr-Kuznetsk count; F-E: Far East pro- vince; Pe.: Pechora province; Voltz.: Voltziopsisflora; Thinn.:*Thinnfeldia"callipteroidesiiora Fig. 1: Distribution of floras and phytogeography in the lower part of the Lower Triassic (Induan stage): 1 - NovayaZemlya, 2-4 - Petchora basin, 5 - Kuznetsk basin, 6-15 - Tunguska basin, 16-19 - Tay- myr peninsula, 20-21 - Olenekian coast, 22-29 Verkhoyansk range, western slope, 30 - Vilyuy syneclise, 31 - Northern China, 32-33 - Southern China Fig. 2: Distribution of floras and phytogeography in the Olenekian and Anisian: 1-6 - central part of the German basin, 7-11 - marginal parts of the German basin, 12-15 - the Alps and , 16-21 - southern part of Moscow syneclise, 22-23 - northern part of Moscow syneclise, 24 - southern Priuralye (Fore-Urals), 25-26 eastern Predkavkazye (Fore-), 27 - northern Caucasus, 28-29 - Pricaspian depression, 30-33 - southern Mangyshlak, 34 - Darvaz, 35 - southern Ferga- na, 36 - Kuznetsk basin, 37-47 - Tunguska basin, 48-50 - Taymyr peninsula, 51-53 - Olenekian coast, 54 - Verkhoyansk range, western slope, 55-Southern Mongolia, 56-59-Northern China, 60-62-Southern China, 63-Japan, 64-66 - Soviet Primorye, 67-68 Central , 69 - Salt Range Russian platform Western Europe and adjacent areas Siberia Northern China Southern China

Marls w th Upper formations Pu to rana Voltzia in R ecoaro with Pleuromeia Ermaying Yunningzheng Lingwen horizon Voltzien- in Mangyschlak Anisia n Röt sandstone

Formations with Soiling Dvurogiy Pleuromeia and Heshankou Upper Dongchuan Hardegsen horizon single conifers Olenekia n

Lower part of Ust-Berezovka Korvunchan a formatio n Tutonchana Shischienfen g Liujiakou Lower Dongchuan Buntsandste n formation of horizon Indua n without pia its Pechora basin

Coalbearing Zechstein Tatarian stage Sunjiakou Changhsing formations Uppe r Permia n

Chart 2: Correlation of plant-bearing deposits of Western Europe, USSR and China at the Permian-Triassic transition

the upper part of the Lower Triassic. Any continental re- flora. This distribution suggests several questions: What constructions showing ocean basins between Angara and prevented the and Glossophyllacea from Cathay sia at the end of the Permian and in the Triassic are migration to the west and to the east in the middle of the doubtful. In fact the basins could be present only in pre- Triassic? What prevented the Dipteridaceae and Cycado- late Tatarian time. carpidiaceae from migrating from Japan to China, the Ben- nettitales to Japan, the Czekanowskiales to theFarEast? In other words, it seems that the new groups were fixed to the Second floral stage places of their origin during this stage and only the Sphe- The beginning of the second stage is marked by the abrupt nopsida (Neocalamites, Equisetites) seem to have had no disappearance of the Pleuromeia flora and the appearance barriers and became widely distributed all over Eurasia. of the Scytophyllum flora. The Sq/thophyllum flora is The disappearance of the Pleuromeiaceae at the be- the next stage of the development of the Voltzia flora and ginning of the second stage may be easily explained by the Korvuntchana floras The geological and botanical chang- appearance of the new groups of plants. But what caused es at the boundary between the first and second stages are such a sudden appearance of the new groups? different from those that occurred at the boundary be- Tectonic activity at the boundary between the first tween the Permian and the Triassic. The second stage is and second floral stages is more significant in the Far East characterized by the appearance of several new groups of (Akiesi tectonic phase) and it is here where florogenesis plants including the Dipteridaceae, Bennettitales, Czeka- was most active in the middle of the Triassic. In northern nowskiales and Cycadocarpidiaceae, by the expansion of China less different formations occur in the first half of the the Cycadophyta, by the wide distribution of the Peltas- Triassic than in its second half; the boundary between the permaceae and Glossophyllaceae. During the Ladinian two halves corresponds to the Middle Triassic. There is an and Carnian the last two families were present only in the important unconformity in western Eurasia at the end of Middle Asian sector (fig. 3) i.e., at the position of the Mid- the Anisian (MO VSCHOVICH, 1981). Could the tectonic dle Eurasian zone of the later Permian with its Tatarina activity have been responsible for the unconformity of the Fig. 3: Distribution of floras and phytogeography in the Ladinian and Carnian: 1 -4 - central part of the German basin, 5-6 - marginal parts of the German basin, 7-9 - the Alps, Carpathians, Balkans, 10-12 - Svalbard, 13 - Donets basin, 14-15 - NovayaZemlya, 16-20 - Pechora basin, 21 -23 -southern Priuralye (Fore- Urals), 24-26 - eastern Predkavkazye (Fore-Caucasus), 27-30 - depression of the eastern Urals, 31-33, Middle Asia, 34 -Taymyr peninsula, 35 - Olenekian coast, 36 - Verkhoyansk range, 37 - Semeytau mountains, 38-48 - Mongolia, 49-71 - Northern China, 72-76 - Southern China, 77 - Japan, 78 - Southern Primorye, 79 - Sarawak, 80 - India florogenesis? Perhaps florogenesis occurred gradually of the Carnian and Norian or to the boundary of the lower during the first half of the Triassic and the tectonic activity and middle Norian as it is in the west of Eurasia) this mo- in the middle of the Triassic only accentuated the differ- ment was characterized by the extinction of those plant ences between the floras of the two parts of the Triassic. At groups which came from Tatarina flora and Zechstein flo- that time some new meridional barriers appeared and those ra and by the distribution of the new Mesophytic groups that had existed in the Paleozoic and the first half of the Tri- which originated in the middle of the Triassic. assic disappeared. To judge by paleogeographical maps But if the Scytophyllum flora and the Lepidopteris these new barriers (the boundaries of the sectors) appear to flora are partly coeval (especially in the east) then a distinct be connected with marine basins. If this is thecase it is clear boundary between the second and the third stages does not why they did not obstruct the migration of the Sphenopsida exist. In this case the transition between the Scytophyllum which lived along shorelines. In connection with the paleo- and Lepidopteris floras was gradual and that change did geographical changes at the end of the Triassic the boun- not take place simultaneously in different parts of Eura- dary between the Eastern Asian and Middle Asian sectors sia. moved toward the west. The floras of China, and Ja- pan now became more similar. The clearness of the sectori- al boundaries became less and the differences in the floras 3. Conclusion of the various sectors at the end of the Triassic and in the Ju- rassic as well as nowadays can be explained by their dis- If we consider the history of the Triassic florawhe n we ana- tance from the sea (although the history of the distribution lyze the paleomagnetic reconstructions of continents for of plants must not be forgotten). the second half of the Triassic (fig. 7), we see that (1) an ocean between Cathaysia and Angarida (KHRAMOV, 1982, BELOV et al., 1982) seems to be doubtful, (2) an Third floral stage ocean between Indochina and the rest of Eurasia (GO- RODNITSKI et al., 1978) also seems doubtful because the The third stage is marked by the disappearance of the Scy- Norian-Rhaetian floras of Indochina as well as tetrapods tophyllum flora (i.e. Danaeopsis-Bernoullia flora) and are similar to the European ones, and the Ladinian-Carnian appearance of the Lepidopteris flora (Dictyophyllum- floras of Sarawack are similar to the coeval floras of the rest Clathropteris flora). However, there is some question of South-Eastern Asia, (3) the position of in about the position of the boundary as the Chinese geolo- the northern hemisphere (TOZER, 1982) is strange be- gists think that these two floras are partly coeval with the cause it has a typical Middle Triassic Gondwana flora. The Scytophyllum flora being distributed in the north and the distribution of the floras of the first half of the Triassic is Lepidopteris flora in the south of that country (KIMURA, better in modern paleogeographic reconstruction (fig. 5) 1984). At present there is no sufficient evidence to clarify than in paleomagnetic reconstruction (fig. 6). this situation. Therefore the stratigraphical position of every locality in China must be carefully evaluated. In B y the beginning of the Triassic the extinction of the fig. 3,1 show all localities with Scytophyllum flora of the dominants of the Paleophytic kingdom was completed Ladinian-Carnian and all localities with Lepidopteris flo- (MEYEN, 1970). It took place in the four Paleozoic plant ra of the Norian-Rhaetian (fig. 4). It was done because kingdoms and was probably initiated by the increasing most of the Scytophyllum flora is Ladinian-Carnian and aridity during the great regression. At the beginning of the most of the Lepidopteris flora is Norian-Rhaetian. Scyto- Triassic the barriers between the three northern kingdoms phyllum floras east of Asia occur in terrestrial grey beds disappeared - the mountains were leveled and/or the isolat- and Lepidopteris floras in coal bearing deposits of sea ed plants were combined in the united Eurasia. We can shores, shallow water and islands. Does it really corre- judge about it because a single great community of plant spond to the situation that the origin of the coal bearing for- assemblages developed in all Eurasia, especially in the Eu- mations began in the Norian or in some places it began ear- ropean-Sinian area. lier - now it is not clear. But the outlines on the paleogeo- graphical and climatological maps depend on the answer Some paleophytic plants survived in hot and arid to this problem. conditions during the firsthalf of the Triassic together with the new plant groups formed the Mesophytic plant king- Thus the position of the boundary between the sec- dom in the middle of the Triassic. During the first half of ond and third stages is still not clear. If the Lepidopteris the Triassic when conditions were unfavourable for the flora changed to Scytophyllum flora everywhere at the "normal" plants we see the explosion and world-wide ex- same time (and that moment corresponded to the boundary pansion of the peculiar Lycopsids, the Pleuromeiaceae. Fig. 4: Distribution of floras and phytogeography in the Norian-Rhaetian: 1 -3 - central part of the German basin, 4-13 - marginal parts of the German basin, 14-15 - the Alps, Carpathians, Bal- kans, 16 - Donets basin, 17 - Pricaspian depression, 18-20 - eastern Predkavkazye (Fore-Caucasus), 21 - eastern Urals, 22 - Turgay basin, 23 - Zakavkazye (Transcaucasus), 24-28 - Iran, 29 -Afghanistan, 32-34 - Middle Asia, 35-36 - Taymyr peninsula, 37 - the northeast of the USSR, 38 - the mountainous Altay, 39-41 - Northern China, 42-66 - South- ern China, 67-68 - Japan, 69-70 - Soviet Primorye, 71-74 - Korea, 75-76 - Viet Nam, 77 - Thailand, 78 - Cambodia + / ; • 2 ; k 3 ;

Fig. 5: Distribution of floras of the first half of the Triassic in modern paleogeographic reconstruction: 1 -fam. Pleuromeiaceae, 2 - Korvuntchana flora, 3 - Voltzia ana Dicroidum floras.

+ i : • 2 ; A3 ;

Fig. 6: Distribution of floras of the first half of the Triassic on the paleomagnetic reconstruction map of KHRAMOV, 1982 10 X /; •Zi Y 3 ;

Fig. 7: Distribution of floras of the Ladinian and Carnian on the paleomagnetic reconstruction map of KHRAMOV, 1982: 1 - northern non-tropical floras, 2 - tropical floras, 3 - southern non-tropical floras

Glossophyllaceae, the Equisetaceae, and the Pleuromeia- Relatively high humidity was present at that time only in ceae. Coexistence of the dying and flourishing groups is the Siberian area as indicated by the abundance of ferns the most important feature of the Scytophyllum flora, the and Sphenopsidae in the Korvuntchana flora (MO- first stage of Mesophytic. The absence of the former and GUTCHEVA, 1973). But at the end of this stage when the abundance of the latter is the characteristic feature of great quantities of conifers migrated into the Siberian area I the next stage of Mesophytae, which continued from the can suggest that climatic conditions in all Eurasia had be- end of the Triassic into the middle part of the Jurassic. come more arid. However, abundant ferns and Sphenopsi- During the second half of the Triassic theclimate be- dae were still present only in the Siberian area (ibid.). came colder and more differentiated: in the lower Ladinian The absence of barriers, the similarity in climatic in the very north of Siberia there lived such southern forms conditions, and the great new transgression resulted in con- as Anomozamites, Vittaephyllum, and Macrotaeniopte- ditions that were again favourable for the distribution and ris (MOGUTCHEV A, 1981); in the Carnian and later they evolution of "normal" plants. We can judge about this be- are absent at such higher latitude. The southern boundary cause of the extinction of Pleuromeiaceae and of the good of the Siberian area in the Ladinian-Carnian corresponded development of "normal" plant assemblages as the Scyto- with the boundary of the -Japan and Iran-Viet- phyllum flora throughout Eurasia. After the tectonic nam belts in the Norian-Rhaetian. It means that the more movements indicated by the unconformities of the end of cold-resistant floras extended to the south, a tendency the Anisian or between the Anisian and Ladinian and also which continued into the Jurassic. At the same time the dif- after the change of the formations in the middle of the Tri- ferences between the Boreal and Tethys fauna grew. It is assic came the culmination of the Mesophytic flora. To- important to note that this cooling was not very significant; gether with the appearance of the new groups (Dipterida- during all Mesozoic it was actually very warm. There was ceae, Cycadales, Bennettitales, Cycadocarpidiaceae, etc.) an abundance of tropical Cycadales and Bennettitales pre- came the gradual extinction of the last representatives of sent at this time in the European-Sinian area. The warmth the Paleophytic flora - most of the Peltaspermaceae, the

11 of the first half of the Triassic may be compared only with and China. - In: KOBAYASH, T., the warmth in the Eocene on the eve of the next glacial TORIMAYA, R. & HASHIMOTO, W.: Geology epoch. and palaeontology of Southeast Asia, 25,325-350, Univ. Tokyo Press. Acknowledgments KRYSHTOFOVICH, A.N. (1957): Palaeobotany. - Gos- toptechisdat, 1-650 (in Russian). The author is greatly indebted to Prof. S .R. Ash for his help MEYEN, S.V. (1970): Permian floras. - Trans. Geol. Inst. in preparing the manuscript for publication. USSR Acad. Sci., N 208,111-157 (in Russian). MOGUTCHEVA, N.K. (1973): The Lower Triassic flora of Tunguskabasin. - Trans, of SNJJGGIMS.N 154, References Nauka, Moscow (in Russian). BELOV, A.A., MOSSAKOVSKI, A.A., SOKOLOV, MOGUTCHEVA, N.K. (1981): A new found of the Mid- S.D.,) SHVOLMAN, V.A. (1982): Late Paleozoic dle Triassic flora in Eastern Siberia. - Collection of and early Mesozoic development of the mediterra- scientific papers SNIIGGIMS : S tratigraphy and pa- nean - central-asiatical branch of Tethys. - In: The laeontology of Siberia, N 287,43-48, Novosibirsk problems of geodynamics of the Caucasus, Nauka, (in Russian). 21-30, Moscow (in Russian). MOGUTCHEVA, N.K. (1982): The Permian-Triassic DOBRUSKINA, I.A. (1978): The relations in thedevelop- boundary in the Tunguska syneclise. - In: The boun- ment of the flora and fauna during the transition daries of the great divisions of the Phanerozoic of from the Palaeozoic to Mesozoic. - In: The pro- Siberia. Collection of scientific papers SNIIG- blems of stratigraphy and historical geology, Nau- GIMS, Novosibirsk, 115-120 (in Russian). ka, 127-139, Moscow (in Russian). MOGUTCHEVA, N.K. (1984): New Triassic plants of DOBRUSKINA, I.A. (1980): The stratigraphical position Middle Siberia. - In: New species of ancient inverte- of the Triassic plant-bearing beds of Eurasia. - brates and plants of oil-bearing provinces of Sibe- Trans. Geol. Inst. USSR Acad. Sci., N 346,1-156 ria, SNIIGGIMS, 50-55 (in Russian). (in Russian). MOGUTCHEVA, N.K. & DOBRUSKINA, I.A. (1986): DOBRUSKINA, I.A. (1982): Triassic floras of Eurasia. - Buntsandstein conifers in the Korvunchana flora. - Trans. Geol. Inst. USSR Acad. Sci., N 365,1-196 In: Biostratigraphy of the Mesozoic of Siberia and (in Russian). the Far East. - Trudy Institute Geologii i Geophysiki DOBRUSKINA, I.A. (1984): Triassic conifers as the basis (Sibirskoye Otdelenie AN SSSR), vyp. 648,72-76 for stratigraphical correlation. - Geobios, N 17, (in Russian). fase. 6,861-863. MOVSCHOVICH, E.V. (1981): Main problems of Trias- DOBRUSKINA, I.A. (1985 a): Correlation of the Lower sic stratigraphy of Precaspian depression (to 150th Triassic plant-bearing beds of Siberia and China. - anniversary of discovery of the Triassic). - Bull. Albertiana,N3,21-23. Mosk. o-va ispytatelei prirody, otd. geol., t. 56, vyp. DOBRUSKINA, I.A. (1985 b): Questions of systematics 5,58-69 (in Russian). of the Triassic lycopsids. - Palaeontological Jour- Resolutions of the third interdepartmental regional strati- nal, N 3,90-104 (in Russian). graphical meeting on Mesozoic and Kainozoic of DURANTE, M.V. (1980): The relations of the Upper Per- Middle Siberia, 1981,1-91, Novosibirsk (in Rus- mian flora of Nanshan with the coeval Angara flo- sian). ras. - Palaeontological Journal, N 1, 125-135 (in RONOV, A.V. & KHAIN, V.E. (1961): The Triassic litho- Russian). logical formations of the world. - Sovietskaja geolo- DURANTE, M.V. (1983): Existence of an Upper Permian gia, N1,27-48 (in Rusian). mixed Cathaysio-Angarian flora in Nanshan (North TOZER, E.T. (1982): Marine Triassic faunas of North China). - Geobios, N16, fase. 2,241-242. America. Their significance for assessing plate and FRAKES, A.L. (1979): Climates through Geologic Time. - terrane movement. - Geol. Rdsch., 71, 3, Elsevier, 1-130. 1077-1104. GORODNITSKI, A.N., ZONENSHEIN, L.P. & MIR- TRÜMPY, R. (1982): Das Phänomen Trias. - Geol. LIN, E.G. (1978): Reconstructions of the position Rdsch., 71, 3, 711-724. of the continents in Phanerozoic (after the palaeo- magnetic and geological data). - Moscow, Nauka, Author's address : 1-122 (in Russian). Dr. Inna A. Dobruskina, Geological Institute, USSR KHRAMOV, A.N. (1982): Palaeomagnetology. - Nedra, Academy of Sciences, Pyzhevski per. 7,109017 Moscow, 1-312, Leningrad (in Russian). USSR KIMURA, T. (1984): Mesozoic floras of East and South- , with a short note on the Cenozoic floras of received: May 19,1988 accepted: October 25,1988

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