[18] Fusulinids from Member 1 are mostly represented by Reitlingerina bradyi, a species of wide stratigraphic range from the Bashkirian of the Upper Carboniferous to the Permian inclusive. Additionally we encountered several poorly preserved, likely Triticites tests chiefly ranging from the uppermost Kasimovian to the Gzhelian (Late Carboniferous).
[19] A significantly richer fusulinid assemblage was found at the base of Member 2. It includes 9 genera and 18 species. Most of the encountered species are endemics and their identification with the known forms is difficult. The species of Triticites and Rauserites are most similar to that of the uppermost Kasimovian Triticites quasiarcticus-Tr. acutus Zone and of the lowermost Gzhelian Rauserites rossicus-R. stuckenbergi Zone. One of the three species Rugosofusulina (R. uralica) was described by Mikhailova [1967] from the lowermost Gzhelian in the Northern Urals. Two other, which assignment to Rugusofusulina is doubtful, resemble "Triticites arcticus" and Rugosofusulina scaphulaeformis described by G. P. Zolotukhina from the upper zone of the Kasimovian in the southern East European Platform. The Schwageriniformis species indicate the same age. For instance, Sch. perstabilis is characteristic of the Kasimovian and Gzhelian of the Caspian syneclise [Scherbovich, 1969]. The rest forms were described by Bensh [1969, 1972] from the upper Kasimovian beds of the southern Gissar and southern Fergana region. However, according to V. I. Davydov (personal communication), in southern Fergana the Schwageriniformis forms referred by Bensh to the Kasimovian, were recorded in the lower part of the Uchbulak Horizon together with the Gzhelian ammonoids [Popov et al., 1989].
[20] Based on the reported data the age of the discussed assemblage can be roughly estimated as the latest Kasimovian and earliest Gzhelian. According to the general development of Triticites and Rauserites, it is similar to the association derived from the isolated limestone outcrop located on the slope downward from the base of the above-discussed section (Sample RL). Among its forms Rauserites rossicus, the index species of the Gzhelian lower zone, occurs. The concurrent fusulinids more likely confirm the early Gzhelian age of the sediments than contradict it. We are not aware to what part of the described section the R. rossicus-bearing limestone corresponds. Most likely it is close to the base of Member 2. If so, the assemblage from its lower part is Gzhelian as well. In that case the question of the presence of the Kasimovian sediments in the section remains open. True, the upper portion of Member 2 contains the Kasimovian-like fusulinids, as Schwageriniformis (Tumefactus), Montiparus (?), and Pulchrella. However, these identifications are not quite reliable owing to a poor preservation of the forms. Additionally all of them have traces of redeposition.
[21] Member 3 lacks fusulinids. They occur in the middle of Member 4 and are represented there by Schwageriniformis acutatus, the new species similar to the forms encountered by V. I. Davydov in the uppermost Gzhelian of Darvaz and the Chios Island, Greece (personal communication). Although the species differs in lesser number of whorls and accordingly in smaller size, its Gzhelian age is beyond question. Fusulinids from the upper portion of Member 4 are also estimated as Gzhelian. The species Triticites shikhanensis, Rauserites erraticus, R. elongatissimus, and R. postarcticus are characteristic of the lower zone of the Gzhelian in the East European Platform and the South Urals. However, the concurrent occurrence of Jigulites cf. formosus suggests the successive, Jigulites jigulensis Zone of the Gzhelian.
[22] Marls of Member 5 are barren of fusulinids. Ruzhenzevites ferganensis encountered immediately above, at the base of Member 6, is known in Central Asia in the uppermost Gzhelian, beginning at the beds correlated with the Daixina sokensis Zone of the East European sections [Bensh, 1972; Davydov, 1986]. Anderssonites and Ultradaixina first occur in the upper portion of Member 6. The former is characteristic of the lower zone of the Asselian in a great deal of East European sections but first occurs in the uppermost Gzhelian Ultradaixina bosbytauensis Zone. Precisely this zone is indicated by the latter genus that is represented by the new subspecies of the index form and by the Indo-Chinese species described by Deprat [1914] as Fusulina kozui, which is transitional between the typical Ultradaixina and the genus Likharevites.
[23] The assemblage of Member 7 differs from the previous one in a greater number of diverse Anderssonites forms and in the Likharevites first occurrence. The species L. esetensis and L. paranitidus are known in the South Urals and northern Fergana region, where they are associated with the beds underlying the Asselian. This fact and the presence of Ultradaixina bosbytauensis distincta indicate that the discussed assemblage should be referred to the U. bosbytauensis Zone, i.e. it is still Gzhelian. It is not therewith improbable that the uppermost part of Member 7 is referred to the Asselian.
[24] Member 8 is undoubtedly of Asselian age, which is evidenced by the finding of Sphaeroschwagerina at its very base. Despite a small (under 6 m) thickness of the bed, three significantly distinct fusulinid assemblages can be recognized in it. The first one in addition to few Sphaeroschwagerina includes Praepseudofusulina kljasmica, Ruzhenzevites subcylindricus, R. zaladuensis zaladuensis and R. zaladuensis brevis. The former species is characteristic of the uppermost Gzhelian and the lower zone of the Asselian in the East European Platform and Darvaz. R. subcylindricus was described from the Asselian of the southern Fergana region. Both subspecies of Ruzhenzevites were recorded in the Asselian part of the Zaladou Formation in the Ozbak-Kuh Mountains, eastern Iran.
[25] The second assemblage mainly includes numerous Likharevites gracilis and scarcer L. kokpectensis and Anderssonites pseudoanderssoni. L. gracilis is the new species and it is hard to judge of its age. However, it is similar to the form described as Paraschwagerina acuminata uralensis from the lower half of the Asselian in the Nikol'skii section of the South Urals [Rauzer-Chernousova and Scherbovich, 1949]. L. kokpectensis is known from the Caspian and southern Fergana sediments correlated with the middle zone of the Asselian in the Urals [Bensh, 1972; Scherbovich, 1969].
[26] The latter assemblage recorded in Member 8 is typical just for that zone. This is evidenced by the occurrence of numerous Sphaeroschwagerina, namely, Sph. shamovi, Sph. moelleri, and Sph. pavlovi, and of characteristic species of Pseudoschwagerina and Likharevites.
[27] The dolomitic Tighe-Maadanou Formation lacks faunal remains. Its late Asselian-Sakmarian age is indicated by the position in the section above the beds bearing the middle Asselian fusulinids. Recall that limestones of the Zaladou Formation grade into the dolomites.
Powered by TeXWeb (Win32, v.2.0).