Palynological characteristic of the border cretaceous and paleogene deposits in the Sourth of Trans-Ural region (bh 9, Troizk)

Author(s):  
Olga B. Kuzmina ◽  
◽  
Natalia K. Lebedeva ◽  

The Upper Cretaceous and Paleogene sediments exposed in Borehole 9 (Troizk, Chelyabinsk Area) in the south of the Trans-Ural Region (Western Siberia) are studied by palynological methods. The BH9 has uncovered the Fadyushinskaya and Gan’kino formations of Upper Cretacious age and the Talitsa, Serov, Irbit, Chegan and Kurtamysh formations of Paleogene age. Nine dinocysts assemblages and nine spores and pollen assemblages were revealed. The Campanian, Maastrichtian, Late Paleocene, Low-Middle Eocene and Early Oligocene age of the sediments were substantiated.

1964 ◽  
Vol S7-VI (4) ◽  
pp. 545-553 ◽  
Author(s):  
Fernand Touraine

Abstract The Sainte-Victoire mountain in southern France has been considered the overturned southern limb of the Vauvenargues anticline, but the structure east of the Delubre fault is complicated by an oblique fold. The western margin is concealed by transgressive Tortonian (middle Miocene) beds covering the plateau of Beaumettes. The anticline probably is upper Cretaceous. Folding was renewed in the upper Lutetian (middle Eocene), and resulted in overturning and thrust faulting of the south limb. Subsequent normal faulting compartmented the mass, resulting in selective differential movement of blocks as horsts and grabens. The term piano keys structure is given to this type of structure.


1998 ◽  
Vol 135 (1) ◽  
pp. 101-119 ◽  
Author(s):  
IVAN S. ZAGORCHEV

The Paril Formation (South Pirin and Slavyanka Mountains, southwestern Bulgaria) and the Prodromos Formation (Orvilos and Menikion Mountains, northern Greece) consist of breccia and olistostrome built up predominantly of marble fragments from the Precambrian Dobrostan Marble Formation (Bulgaria) and its equivalent Bos-Dag Marble Formation (Greece). The breccia and olistostrome are interbedded with thin layers of calcarenites (with occasional marble pebbles), siltstones, sandstones and limestones. The Paril and Prodromos formations unconformably cover the Precambrian marbles, and are themselves covered unconformably by Miocene and Pliocene sediments (Nevrokop Formation). The rocks of the Paril Formation are intruded by the Palaeogene (Late Eocene–Early Oligocene) Teshovo granitoid pluton, and are deformed and preserved in the two limbs of a Palaeogene anticline cored by the Teshovo pluton (Teshovo anticline). The Palaeocene–Middle Eocene age of the formations is based on these contact relations, and on occasional finds of Tertiary pollen, as well as on correlations with similar formations of the Laki (Kroumovgrad) Group throughout the Rhodope region.The presence of Palaeogene sediments within the pre-Palaeogene Pirin–Pangaion structural zone invalidates the concept of a ‘Rhodope metamorphic core complex’ that supposedly has undergone Palaeogene amphibolite-facies regional metamorphism, and afterwards has been exhumed by rapid crustal extension in Late Oligocene–Miocene times along a regional detachment surface. Other Palaeogene formations of pre-Priabonian (Middle Eocene and/or Bartonian) or earliest Priabonian age occur at the base of the Palaeogene sections in the Mesta graben complex (Dobrinishka Formation) and the Padesh basin (Souhostrel and Komatinitsa formations). The deposition of coarse continental sediments grading into marine formations (Laki or Kroumovgrad Group) in the Rhodope region at the beginning of the Palaeogene Period marks the first intense fragmentation of the mid- to late Cretaceous orogen, in particular, of the thickened body of the Morava-Rhodope structural zone situated to the south of the Srednogorie zone. The Srednogorie zone itself was folded and uplifted in Late Cretaceous time, thus dividing Palaeocene–Middle Eocene flysch of the Louda Kamchiya trough to the north, from the newly formed East Rhodope–West Thrace depression to the south.


2001 ◽  
Vol 49 (3) ◽  
pp. I
Author(s):  
Robert S. Hill

The macrofossil record of the plant family Cunoniaceae in Australia is summarised and reviewed where necessary by using detailed studies of the morphology of extant genera. Eleven of the 26 Cunoniaceae genera are represented in the Australian macrofossil record and include leaves and leaf fragments, foliar cuticle and reproductive structures, and range from Late Paleocene to Quaternary in age. Macrofossils show that some genera had a different or more widespread distribution in Australia during the Cenozoic, with two genera (Weinmannia and Codia) having become extinct from the continent. Changes in climate, including increasing cold, frost, dryness, seasonality, or some combination of these, or a reduction in vegetation disturbance regimes (e.g. volcanism, uplifting, landslips), may be implicated in the regional or continental extinctions demonstrated by the macrofossil record. Many extant genera (Schizomeria, Vesselowskya, Callicoma, Ceratopetalum, Acsmithia, Codia) had evolved by the Early Oligocene or earlier (Eucryphia, Late Paleocene; Ceratopetalum, Middle Eocene), perhaps with generic diversification more or less complete by the end of the Early Cenozoic or earlier. A Cretaceous origin of the family is possible, and may account for its widespread distribution on Southern Hemisphere landmasses, although long-distance dispersal events are required to explain some modern geographic disjunctions.


2001 ◽  
Vol 49 (3) ◽  
pp. 301 ◽  
Author(s):  
Richard W. Barnes ◽  
Robert S. Hill ◽  
Jason C. Bradford

The macrofossil record of the plant family Cunoniaceae in Australia is summarised and reviewed where necessary by using detailed studies of the morphology of extant genera. Eleven of the 26 Cunoniaceae genera are represented in the Australian macrofossil record and include leaves and leaf fragments, foliar cuticle and reproductive structures, and range from Late Paleocene to Quaternary in age. Macrofossils show that some genera had a different or more widespread distribution in Australia during the Cenozoic, with two genera (Weinmannia and Codia) having become extinct from the continent. Changes in climate, including increasing cold, frost, dryness, seasonality, or some combination of these, or a reduction in vegetation disturbance regimes (e.g. volcanism, uplifting, landslips), may be implicated in the regional or continental extinctions demonstrated by the macrofossil record. Many extant genera (Schizomeria, Vesselowskya, Callicoma, Ceratopetalum, Acsmithia, Codia) had evolved by the Early Oligocene or earlier (Eucryphia, Late Paleocene; Ceratopetalum, Middle Eocene), perhaps with generic diversification more or less complete by the end of the Early Cenozoic or earlier. A Cretaceous origin of the family is possible, and may account for its widespread distribution on Southern Hemisphere landmasses, although long-distance dispersal events are required to explain some modern geographic disjunctions.


A study of rock-samples collected at 26 stations and continuous seismic profiles taken over a distance of 2000 km in the eastern part of the English Channel reveals the existence of a large flat-floored Tertiary syncline which forms an easterly extension of the Hampshire Basin of Southern England. The newly delineated basin, which is here referred to as the Hampshire—Dieppe Basin, forms part of the well-known Palaeogene Anglo-Paris-Belgian depositional basin. The total thickness of Palaeogene strata in the eastern part of the basin is about 380 m and the youngest beds present are probably of Upper Eocene age. Upper Cretaceous strata are exposed around the edges of the basin; the thickness of the Chalk varying from about 250 m in the south and east to 420 m in the northwest. The basin is bounded to the northeast by the Weald—Artois anticline and a strong flexure, the Bembridge—St Valery line, which is a continuation of the Isle of Wight monocline, controls the position of much of its southwestern boundary. To the south of the Hampshire-Dieppe basin lies the Baie de la Seine Tertiary syncline. Here, freshwater limestones of presumed Oligocene age overlie a Middle Eocene marine sequence. Lithologies and microfaunas of the samples are described and related to those of sequences of similar age on nearby land, and some conclusions are drawn about the palaeogeography of the area. The geological structure of the area is elucidated, the paths of faults and fold axes are traced and a geological map is presented.


1992 ◽  
Vol 6 ◽  
pp. 12-12
Author(s):  
Marie-Pierre Aubry

Calcareous nannoplankton diversity varied greatly during the Paleogene. From extremely reduced values (~10 species) in the early Paleocene (circa 66.4 to 66 Ma, age estimates from Berggren, Kent and Flynn, 1985) following the terminal Cretaceous extinctions, diversity increased progressively throughout the late Paleocene and early Eocene and reached a maximum (~120 species) in the early middle Eocene (circa 52–48 Ma). This was followed by a step-like decrease until the early Oligocene (circa 35 Ma) when minimal values (~37 species) were reached once again. After a stable low during the remainder of the early Oligocene, a moderate, increase occurred near the early/late Oligocene boundary (circa 30 Ma).Temperature has been regarded as the most important factor controlling the distribution of the calcareous nannoplankton following the characterisation of five temperature-controlled assemblages of living Coccolithophoridae in the Atlantic Ocean. Studies relative to variations in diversity in the calcareous nannoplankton throughout the Mesozoic and Cenozoic and among the extinct late Paleocene to Pliocene group Discoaster, and to changing biogeographic patterns during the Cenozoic have revealed an apparent relationship between composition of calcareous nannofossil assemblages and temperature as deduced from isotopic studies. This relationship, which is currently used to infer Paleogene climatic and oceanographic evolution from quantitative analyses of calcareous nannofossil assemblages, is however not a simple one as indicated by the fact that maximum diversity during the Paleogene (i.e., the early middle Eocene) did not occur during (but subsequently to) the warmest time (i.e., the latest Paleocene-earliest Eocene).Diversity changes in the Paleogene calcareous nannoplankton are strikingly similar to diversity changes in the Paleogene planktonic foraminifera, which have been shown to reflect fluctuations in nutrient availibility as indicated by oxygen and carbon isotopes. The parallel evolution in the two groups thus suggests that trophic levels in the photic zone played an important role in the Paleogene diversification of the calcareous nannoplankton. In the present day ocean, the calcareous nannoplankton (Coccolithophoridae) dominate the phytoplankton under oligotrophic conditions and tropical waters are characterized by highly diversified associations with strong vertical specific stratification. Only few species occur under meso- and eutrophic conditions, and there is no vertical stratification. Extremely low diversity during the earliest Paleocene followed by increasing diversity through the Paleocene and earliest Eocene is interpreted as reflecting the change from an essentially mesotrophic to an oligotrophic ocean, increased rates of speciation resulting from niche partitioning occasioned by increased oligotrophy, leading to strong vertical stratification of species in the photic zone. Decrease in diversity from middle Eocene to early Oligocene reflects, on the other hand, progressive eutrophication of the ocean as a result of climatic deterioration.


Author(s):  
Zinaida V. Pushina ◽  
Galina V. Stepanova ◽  
Ekaterina L. Grundan

Zoya Ilyinichna Glezer is the largest Russian micropaleontologist, a specialist in siliceous microfossils — Cenozoic diatoms and silicoflagellates. Since the 1960s, she systematically studied Paleogene siliceous microfossils from various regions of the country and therefore was an indispensable participant in the development of unified stratigraphic schemes for Paleogene siliceous plankton of various regions of the USSR. She made a great contribution to the creation of the newest Paleogene schemes in the south of European Russia and Western Siberia, to the correlations of the Paleogene deposits of the Kara Sea.


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