The Palaeobotanist, 28-29: 301-307, 1981. POLLE CLASSOPOLIS: INDICATOR OF JURASSIC A D CRETACEOUS CLIl\fATES V. A. VAKHRAMEEV Geological Institute of the Academy of Sciences, 109017, Moscow, Pyzhewskyper., 7, USSR ABSTRACT Pollen C/assopollis belonging to extinct coniferalean family Cherolepidiaceae are widely spread in the Jurassic and Cretaceous. The material from the USSR provides the most detailed data on the quantitative distribution of the pollen. A low content (1-10%) of Classopollis suggests temperate climatic conditions, whereas a percentage (20-50%) reveals warm subtropical one. The highest content attaining 60-75 % even 90 % (in Oxfordian of the USSR southern regions) testifies to an arid climate. Thus the distribution of the pollen plotted against that of lithological indicators of the climate allows to reveal climatic belts for different epoch of the Jurassic and Cretaceous and to establish climatic fluctuation during this time. Key-words - Palynology, Classopollis, Cheirolepidiaceae, Jurassic, Cretaceous. USSR. ~ <F1R'f.W ij; 'li~-mtfiffu~m ~<'f~.~f.ua- 'f<ml1'llRHf'f7T<T'f)Uf'1~f«'F~<f ~ 'fil<'r it ~-2 Q'F <f,('r gll; ~ I 'fUlT"'l'UTT ij; ~~ f<rcn:Uf <n: «ern mU'F fu:qcr ~ ~ tfi1 ij' ~ «rmrr ij' fi:f<t ~ I ~f<;rn 'fit 'J;[('q" lffifT (1 ij' 10 5lfu!/lCf Q'F) !1fta'tmrr ~r ~lfT Olffif mr ~~ 20 ~. 50 5l"Rr!/lCf Q'F lfq: '3"U1If-'3'l1mrT ~ ~ mr ~I W'FT 60 ~. 70 llRr!/lCf 'A~iff 00 5l"Rr!/lCf Cf'F ~l'J: If[\:fT (<<mrlfCf tfi1 ij; <nllluIT <ffi;rT ij;~• Q;1fulR it) 11J:1S'F;;merrq ~ mT ~ I ~~ 5I""'f>n: 'lUll" (NT "f<'ferrlferT ~-~T 'liT 5l"fu-ferCf~ 'ij,'tfu'F ~cf "liR-!/lf« ij; ferf~'l 'rfT ij; f<~ ~crT 'llfu-GG'cff 'fit OllcrCf 'llB Cfm W 'fil<'r it ~ '3~ijl6jij'1 'fit ~ 'llB it «QTlf'F ~ I (short incurved leaves) and Elatocladus (longer POLLENat the beginningClassopol/isof thebecamePalaeogene.extinct incurved leaves). Isolated shoots of Pagio• The data accumulated during the phyllum and Elatocladus in general habit are last decade confirmed the previous opinion similar to those of extant Araucariaceae. of the author (Vakhrameev, 1970) on The study of epidermis and cones found dependence between content of Classopollis together with some of the above shoots, in miospore assemblages and of palaeo• Krassilov (1975, 1978), showed that they climates. belong to the latter family. Nevertheless, Shoots with male cones yielding the it would be erroneous to insist on belonging Classopollis pollen have different appearance, of all isolated shoots attributed to form• and hence were described under various genera Brachyphyl/um, Pagiophyllum and genera: Cheirolepidium, Frenelopsis, Pseudo• Elatocladus to Cheirolepidiaceae or Arau• frenelopsis, Tomaxiella and partly, Masculo• cariaceae only. Noteworthy is that the strobus. These shoots are most densely pollen of both the families, as well as male covered by tightly adpressed scale-like or cones, are well distinguished from one incurved spine-like leaves. When isolated, another. they are assigned to the form-genera Brachy• Frenelopsis and Pseudofrenelopsis have phyllum (scale-like leaves), Pagiophyllum articulate shoots. In their nodes there are 301 302 THE PALAEOBOTANIST one (PseudoFenelopsis) to three (Frenelopsis) Paleoclimatic reconstructions for the Late short triangular leaves adpressed to the Jurassic compared with the distribution of axis. The male cones born on shoots of lithological indicators of climate and plant this structure yielded Classopollis pollen only remains (Strakhov, 1960; Vakhrameev, (Watson, 1977; Alvin et al., 1978; Dolu• 1964; Sinitsyn, 1966) show that the northern denko, 1978). Thus, these genera belong to part of Eurasia was a belt of temperate• the Cheirolep·diaceae family. warm and humid climate. The Classopollis Especially abundant material on the content does not exceed here 6-10 %. In the Classopollis content in the Jurassic and Lena River Basin and in the north-east of Cretaceous was obtained by Soviet Palyno• the USSR, where the Upper Jurassic is logists who provided the percentage of the represented by coal-bearing deposits, the pollen in miospore assemblages. This en• Classopollis pollen either occurs a<; solitary abled me to draw the curves showing changes grains, or is missing at all. of the Classopollis content throughout Juras• Southwards, in West Europe, the central sic and Cretaceous plotted against latitudinal p:ut of the Russian platform and in the belts crossing the vast territory of the south of West Siberia, the climate was European part of the USSR, West and warmer and its humidity was seemingly Middle Siberia, Kazakhstan, Middle Asia decreasing. The content of Classop0 lfis and the Caucasus. These curves are based pollen in the Upper Jurassic varies here on published data of Alekseeva, Alimov, from 10 to 30-40 %. In Moldavia, Crimea, Barkhatnaya, Blyakhova, Bondarenko, Dani• Caucasus, South Kazakhstan and Middle lenko, Dobrutskaya, Fokina, Ivanova, Asia (a belt of semiarid and arid) hot climate il'ina, Khachieva, Klimko, Kotova, Kosen• is situated; this being evidenced by wide kova, Kuvaeva-Smirnova, Markova, Nes• distribution of gypsum, and locally presence terova, Orlova, Petrosyants, Pogodaeva, of rock salt. The content of Classopollis Perfilieva, Polumiskova, Ponomarenko, pollen is over 50% here. Such a regularity Rovnina, Sakulina, Shramkova, Shugaev• supports the opinion of many workers skaya, Tarasova, Terekhova, Voittsel, Yaro• claiming that the Cheirolepidiaceae producing shenko and some others. Reference to Classopollis pollen were thermophilic. their publications are given in Vakhrameev The second peculiarity in distribution (1970, 1978) and Vakhrameev and Dolu• of Classopol/is pollen is its enormous quan• denko (1976). tities in rocks sediments deposited in the Palynologists from other countries do not belt of semiarid and arid climate. As it has give, as a rule, the percentage of these or been already mentioned, the content of this other pollen genera and species; they only pollen within this belt exceeds 50 % every• mention their frequent or rare occurrence. where, and that in Oxfordian deposits reaches This fact does not enable a construction of 90 %. Such a percentage of Classopollis curves of the quantitative content according pollen suggests that Cheirolepidiaceae sur• to their data. vived well in dry climate, whereas the role Before analysing the above mentioned of other plant groups in vegetation, especially curves and elucidation of their relation to ferns, abruptly decreased with aridity of climatic changes, the spatial distribution of climate up to their complete disappearance. Classopollis over the greater part of Eurasia The Classopollis pollen is related to for the Late Jurassic epoch should be at• mostly shallow-water, near-sea-shore and tempted (Text-fig. 1). This time is particularly deltaic sediments. It is distributed in lacus• favourable for establishing dependencies trine deposits of intermontane depressions between the Classopollis percentage and as well (Karatau ridge in South Kazakhstan, disposition of climatic belts. It is Upper etc.). Text-figure I clearly shows that the Jurassic deposits that yield maximum content of this pollen appreciably decreases amounts of the pollen, and the quanti• from the West Siberian lowland occupied tative distribution of the latter, and hence, by a shallow water sea in the Late Jurassic distribution of conifers producing them in the eastern direction, where Upper (Cheirolepidiaceae) seems very convin• Jurassic and Lower Cretaceous coal-bearing cing. Text figure 1 shows that the Classo• deposits are developed filling some depres• pollis pollen content increases gradually sions (Vilyui, Zyranka, etc.). In the conti• southwards. nental Upper Jurassic of the Transbaikalian VAKHRAMEEV - POLLEN CLASSOPOLIS 303 TEXT-FIG. J - Contents of Classopollis pollen in palynological samples. Symbols: 1- solitary grains 2-from 1 to 2%, 3-frol11 6 to 10%, 4-from 30 to 40%, 5-from 50 to 70%, 6-75 to 90%, 7• land. Land and sea boundaries are given for Oxfordian age (Atlas of Jithologo-paleogeographical maps of the USSR, v. IIf, 1968, and other sources). area, and Bureya depression the Classopollis higher dratned of the forested land. The pollen content does not exceed 1-2 %. The Cheirolepidiaceae played a considerable role same pattern of the Classopollis pollen in the composition of the latter. It is natural content in synchronous near-sea-shore and that the Classopollis pollen content in near• coal-bearing deposits was established by sea-shore sediments increases considerably. Yaroshenko (1965) for the Pliensbachian of This peculiarity of ecology of Cheirolepi• the North Caucasus. The Cheirolepidiaceae diaceae somewhat disturbs the regularity of producing Classopollis pollen seem to have their distribution in climatic zones. avoided swampy overflooded habitats, pre• An opinion that Cheirolepidiaceae were an ferring to grow on drained slopes or pene• analogue to the recent mangrove plants plated uplands. growing in a very narrow shore intertidal This fact is likely to explain an increase of band (Kondratiev, 1970; Hughes & Moody• Classopollis pollen in transgressive portions Stuart, 1967), causes a serious objection. of successions (Upper Jurassic of the Russian This analogy is opposed by considerable platform & West Siberian lowland). The content of Classopollis pollen (50-70 %) in sea, while transgressing over near-sea-shore Upper Jurassic continental deposits in north lowlands covered by moisture-loving vege• and north-east Kazakhstan accumulated at a tation with prevailing