Calcareous nanoplankton of Cretaceous sediments of Bahchisaray area of the South-Western Crimea

2019 ◽  
pp. 57-69
Author(s):  
M. A. Ustinova ◽  
R. R. Gabdullin
Keyword(s):  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Calcareous Nannoplankton ◽  
The South ◽  
Calcareous Nanoplankton ◽  
Cretaceous Deposits

The calcic nannoplankton of the Cretaceous deposits of the Bakhchsarai region of the South-Western Crimea was studied. In the Lower Cretaceous, it is extracted from the Rezan and Biasala Formations, in the Upper Cretaceous — from the Belogorsk, Prokhladnoye and Kudrino Formations. The age of the enclosing sediments by calcareous nannoplankton has been specified. In the Rezan Formation, the nannoplankton zone is not singled out; in the Biasala Formation, apparently, part of the NC5 zone is present. In the Belogorsk Formation, the UC3 zone, subzone b, is allocated (partially), in the Kudrino Formation — the UC20 zone, and the UC20b subzone. Upper and lower boundaries of the zones are not traced.

Le Cretace des environs de Chabrieres (Basses-Alpes)

1963 ◽  
Vol S7-V (3) ◽  
pp. 333-344 ◽  
Author(s):  
Gerard Thomel
Keyword(s):  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Transitional Zone ◽  
Upper Jurassic ◽  
Lower Zone ◽  
The South ◽  
Erosion Surface ◽  
Cretaceous Deposits

Abstract The results of lithologic and paleontologic study of Cretaceous rocks of the Vocontian facies demonstrate that the massive upper Jurassic limestones are separated from Valanginian (lower Cretaceous) deposits by an erosion surface. Two series distinguishable in the Valanginian include a lower zone of marls and limestone containing a Berriasian fauna, and an upper zone of marls and limestones, less compact than those below, containing an upper Valanginian fauna. The Hauterivian is represented by a transitional zone of marls and limestones overlain by blue fossiliferous marls. The passage to the Barremian (lower Cretaceous) is transitional, marked by a zone resembling the thick-bedded Barremian limestones in which two members are recognized --thick-bedded limestone with interbedded schistose marl and fossiliferous marls and limestones with Emericiceras and Acrioceras in the lower part, and Holodiscus above. The uppermost Barremian bed is corroded, corresponding to an interruption in sedimentation. This surface is directly overlain by lower Albian-upper Aptian black marls, glauconitic in the upper part. Blue marls with Pervinquieria represent the Vraconian (upper Cretaceous). The Cenomanian, sparsely fossiliferous, is represented by blue marly limestones, sandstones and glauconitic sandy limestones. The Chabrieres Cretaceous series resembles the neritic facies to the south and the surrounding Vocontian domain. Sedimentation in the area is a result of slow uplift and subsidence, especially in the Valanginian.

scholarly journals A Cretaceous dinoflagellate cyst zonation for NE Greenland

2019 ◽  
Vol 157 (10) ◽  
pp. 1658-1692 ◽  
Author(s):  
H. Nøhr-Hansen ◽  
S. Piasecki ◽  
P. Alsen
Keyword(s):  
North Sea ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Barents Sea ◽  
The South ◽  
Norwegian Sea ◽  
Dinoflagellate Cyst ◽  
The North ◽  
Northern North Sea ◽  
First Time

AbstractA palynostratigraphic zonation is for the first time established for the entire Cretaceous succession in NE Greenland from Traill Ø in the south to Store Koldewey in the north (72–76.5° N). The zonation is based on samples from three cores and more than 100 outcrop sections. The zonation is calibrated to an updated ammonite zonation from the area and to palynozonations from the northern North Sea, Norwegian Sea and Barents Sea areas. The palynozonation is primarily based on dinoflagellate cyst and accessory pollen. The Cretaceous succession is divided into 15 palynozones: seven Lower Cretaceous zones and eight Upper Cretaceous zones. The two lowermost zones are new. The following five (Lower Cretaceous) zones have already been described. Two of the Upper Cretaceous zones are new. The zones have been subdivided into 20 subzones, 11 of which have been described previously and one of which has been revised/redefined. Nine subzones (Upper Cretaceous) are new. More than 100 stratigraphical events representing more than 70 stratigraphic levels have been recognized and presented in an event-stratigraphic scheme.

scholarly journals Facies changes in the Cenomanian (Cretaceous) of the northwestern Elbe Valley near Dresden (Saxony, Germany)

2017 ◽  
Vol 67 (1) ◽  
pp. 135-144 ◽  
Author(s):  
Karl-Armin Tröger
Keyword(s):  
Upper Cretaceous ◽  
The South ◽  
The West ◽  
The North ◽  
Near Shore ◽  
Bohemian Cretaceous Basin ◽  
Early Late ◽  
Rich Fauna ◽  
Cretaceous Deposits

Abstract The Upper Cretaceous of the Elbe Valley in Saxony and the erosion outliers west of it mark an Upper Cretaceous NW-SE-running strait between the Westsudetic Island in the NE and the Mid-European Island to the west. This street connected the NW-German-Polish Basin in the north and the Bohemian Cretaceous Basin (and adjacent regions of the Tethys) in the south. However, post-Cretaceous erosion north of Meißen removed any Upper Cretaceous deposits but erosion outliers at Siebenlehn and especially north of the Forest of Tharandt proof the presence of a marly through silty belt in this area. Three transgressions (base of uppermost Lower to Middle Cenomanian, base of Upper Cenomanian and base of the geslinianum Zone in the mid-Upper Cenomanian) have taken place. The sedimentation was influenced by the topography of the mentioned islands and by movements at structural lines in the Proterozoic and Palaeozoic basement. During the early Late Cenomanian, a marly-silty sedimentation (Mobschatz Formation) in the north existed besides sandy sedimentation in the south (Oberhäslich Formation). The transgression at the base of the geslinianum Zone caused the final submergence of island chains between Meißen, Dresden and Pirna, and a litho- and biofacies bound to cliffs and submarine swells formed. A silty-marly lithofacies, a mixed sandy-silty lithofacies (Dölzschen Formation) and a sandy lithofacies in the south (Sächsisches Elbsandsteingebirge) co-existed during the latest Cenomanian. The first mentioned biofacies yields a rich fauna mainly consisting of oysters, pectinids, rudists, and near-shore gastropods accompanied by echinids and, in some cliffs, teeth of sharks. The Pennrich fauna (Häntzschel 1933; Uhlig 1941) especially consists of the very common serpulids Pyrgopolon (P.) septemsulcata and Glomerula lombricus (formerly Hepteris septemsulcata and G. gordialis).

The Auk Field, Block 30/16, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 227-236 ◽  
Author(s):  
Nigel H. Trewin ◽  
Mark G. Bramwell
Keyword(s):  
North Sea ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
The South ◽  
Well Control ◽  
Western Margin ◽  
The North ◽  
Fault Block ◽  
Definition Of ◽  
Central North Sea

AbstractThe Auk field is located in Block 30/16 at the western margin of the Central Graben. Oil is contained in a combination stratigraphic and structural trap which is sealed by Cretaceous chalk and Tertiary claystones. An oil column of up to 400 ft is contained within Rotliegend sandstones, Zechstein dolomites, Lower Cretaceous breccia and Upper Cretaceous chalk. Production has taken place since 1975 with 80% coming from the Zechstein, in which the best reservoir lithology is a vuggy fractured dolomite where porosity is entirely secondary due to the dolomitization process and leaching of evaporites. Both Rotliegend dune slipface sandstones, and the Lower Cretaceous breccia comprising porous Zechstein clasts in a sandy matrix, also contribute to production. Poor seismic definition of the reservoir results in reliance on well control for detailed reservoir definition. The field has an estimated ultimate recovery of 93 MMBBL with 13 MMBBL remaining at the end of 1988.The Auk field is situated in Block 30/16 of the Central North Sea about 270 km ESE from Aberdeen in 240-270 ft of water (Fig. 1). The field covers an area of about 65 km2 and is a combination of tilted horst blocks and stratigraphic traps, located at the western margin of the South West Central Graben. The Auk horst is about 20 km long and 6-8 km wide, with a NNW-SSE trend. It is bounded on the west by a series of faults with throws of up to 1000 ft, and the eastern boundary fault has a throw of 5000 ft in the north reducing to zero in the south (Fig. 2). The horst is a westward tilted fault block in the north which grades into a faulted anticline in the south. The Auk accumulation is largely contained within Zechstein dolomites and is ultimately sealed by Cretaceous chalk which overlies the base Cretaceous erosion surface. An E-W cross-section of the field is illustrated by Fig. 3. Auk was the first of the alphabetical sequence of North Sea sea-bird names used for Shell/ Esso fields.

The calcareous nanoplankton in the Upper Paleocene deposits from Bakhhisaray region (South-Western Crimea)

2018 ◽  
pp. 35-41
Author(s):  
M. A. Ustinova ◽  
R. R. Gabdullin
Keyword(s):  
Species Composition ◽  
Calcareous Nannoplankton ◽  
The South ◽  
Shelf Sea ◽  
Calcareous Nanoplankton ◽  
Upper Paleocene

The calcareous nannoplankton of the Upper Paleocene and Eocene deposits from Bakhchisaray region of the South-Western Crimea was studied, it comparison with the coeval complexes studied earlier was made and zones were identified. Kacha Formation corresponds to zones NP6–NP8 (?), Bakhchsarai Formation — to NP12 zone, Simferopol Formation — to zones NP13–NP14. According to the species composition, it was found that the calcareous nannoplankton lived in the normal-salt shelf sea, in the tropical belt.

IV.—The Cenomanian Overlap

1902 ◽  
Vol 9 (11) ◽  
pp. 495-497
Author(s):  
A. J. Jukes-Browne
Keyword(s):  
Central Europe ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Cretaceous Deposits

That the Upper Cretaceous deposits overlap those of the Lower Cretaceous series, and extend over much larger areas throughout the whole of western and central Europe, are facts which have long been familiar to all European geologists. There has, however, been a tendency, especially in France, to imagine that the subsidence to which the overlap is due took place at one particular epoch, namely, the Cenomanian, and that this subsidence was so rapid and profound that it caused the Upper Cretaceous Series to be sharply marked off from the subjacent strata by the so-called ‘Cenomanian transgression.’

scholarly journals TOPONYMS OF CRETACEOUS DEPOSITS IN WESTERN KAZAKHSTAN TERRITORY (in the context of Aktobe region)

2021 ◽  
Vol 2 (446) ◽  
pp. 22-30
Author(s):  
A. G. Abdullina ◽  
A. M. Sergeyeva ◽  
K. T. Saparov ◽  
G. Zh. Shumakova ◽  
A. Ye. Yeginbayeva ◽  
...  
Keyword(s):  
Physical Properties ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Geological Structure ◽  
Western Kazakhstan ◽  
West Kazakhstan ◽  
Terrain Features ◽  
Selection Of ◽  
Cretaceous Deposits

The article deals with the occurrence of Cretaceous deposits in the territory of Aktobe region and geographical ground of their reflection in local toponyms. Aktobe region is characterized by the complexity of the terrain in West Kazakhstan. Terrain features are influenced by its geological structure and terrain-forming factors. The map presents a selection of toponyms including the words ak, bor, saz, kum, shagyl which correspond to the formations of lower Cretaceous and upper Cretaceous deposits widespread in the western part of the region. The percent of oronyms, hydronyms and oikonyms in the toponyms of 141 names selected in the study area was analyzed with subsequent representation on the diagram. The analysis of the names of Aktolagay, Akshatau, Belogorka, Aktau, Akzhar, etc., indicating the reflection in toponyms of such physical properties of rocks as composition, color and the rate of their frequency is carried out, the results are presented in a table. The map shows the position of geographical features corresponding to the outcropping Cretaceous beds and photos of the area are provided.

THE BARROW ISLAND OILFIELD

1967 ◽  
Vol 7 (1) ◽  
pp. 130
Author(s):  
J. C. Parry
Keyword(s):  
Production Rate ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Seismic Refraction ◽  
Upper Jurassic ◽  
Northwest Coast ◽  
The South ◽  
Primary Methods ◽  
Reservoir Characteristics

Barrow Island lies 35 miles off the northwest coast of Australia, 800 miles north of Perth, and has an area of 90 square miles. Miocene Trealla Limestone crops out over most of the island. Eocene Giralia Calcarenite is found in some valleys of the crestal region and Quaternary sand covers the island fringes.The Barron No. 1 well was located at the highest point in the sub-surface, as indicated by seismic refraction work, and in the crestal area of a gently dipping surface anticline. It was mapped as having at least 80 feet of vertical closure with an area of 24,000 acres. This well was completed as a new field discovery in August, 1964, with an initial production rate of 985 BOPD from sand in the Jurassic. In February, 1965, Barrow No. 4 was completed as a shallower pool discovery with an initial production rate of 125 BOPD from a Lower Cretaceous sand. By December, 1966, 33 wells had been drilled for a total footage of 155,409 feet.Barrow No. 1 is the deepest well at 9875 feet although it is considered that the sedimentary section may exceed 20,000 feet. The known sequence begins with Upper Jurassic siltstones. These pass upwards into a predominantly sandstone sequence containing minor shale and siltstone, and are followed by the dark-coloured marine shales and siltstones and minor sandstone of Lower Cretaceous age. In the Upper Cretaceous and Tertiary, fossiliferous, micro-crystalline Limestones and calcareous siltstones were deposited.The field contains two petroliferous intervals. The deeper interval is within the Upper Jurassic and contains a number of small irregular pools with good reservoir characteristics, these, however, are not commercial in themselves. The shallower interval contains the widespread "Windalia Sand" which has an average pay thickness of 44 feet and generally poor reservoir characteristics. Drilling is now developing the "Windalia Sand" pool which covers 24,700 acres and contains reserves currently estimated at 114 million barrels recoverable by primary methods. Structure at this pay horizon is a broad north plunging nose truncated at the south by a down-to-the- south fault. One hundred and forty-four development wells will he drilled in 1967.

Transect across the External Pamir thrust belt and Main Pamir Thrust along the Altyn Darya valley, Kyrgyzstan

2021 ◽  
Author(s):  
Jonas Kley ◽  
Thomas Voigt ◽  
Edward R. Sobel ◽  
Johannes Rembe ◽  
Chen Jie
Keyword(s):  
Cross Section ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Hanging Wall ◽  
Lower Jurassic ◽  
Late Triassic ◽  
Thrust Belt ◽  
The South ◽  
Late Neogene ◽  
Basal Detachment

<p>The ca. 35 km long, N-S-trending Altyn Darya valley in Kyrgyzstan exposes a nearly complete cross-section of the External Pamir thrust belt (EP), extending from the active Pamir Frontal Thrust in the north to the Main Pamir Thrust (MPT) and some distance into its hanging-wall. The EP comprises a northward imbricated stack of Carboniferous to Late Neogene rocks. From north to south, young clastics of the Alai Valley foreland basin are overthrust by an intensely folded and thrust-repeated frontal stack of Upper Cretaceous to Paleogene limestone, shale and evaporite. Lower Cretaceous red sandstones first emerge above north- and south-verging thrusts forming a triangle zone whose core comprises spectacular isoclinal folds in Upper Cretaceous strata. Towards the south, another thrust imbricate of Lower Cretaceous is overthrust by Late Triassic-Jurassic sandstones and mafic volcanics which are themselves overthrust by an internally deformed, Carboniferous to Triassic succession of, from bottom to top, greywacke and shale, limestone, volcanoclastic conglomerates, variegated sandstone-shale and pink conglomerates. The Carboniferous units in the south are truncated by the MPT which emplaces a succession of greenschist, marble and chert overlain by a km-thick sequence of metamorphosed and deformed, pillow-bearing lavas of Carboniferous age. Structural geometries and fault preference indicate that the basal detachment of the EP deepens southward very gently, stepping down from a detachment in Upper Cretaceous shale to another one near the base of the Lower Cretaceous and eventually a third one in Triassic shale. Cross-section balancing suggests minimum shortening of 75 km for units in the MPT´s footwall. The displacement on the MPT is poorly constrained due to eroded hanging-wall cutoffs, but must exceed 15 km. The basal detachment cuts into basement no earlier than 100 km from the present thrust front, too far south to link up with the top of the Pamir slab.</p><p>The stratigraphic succession exposed in Altyn Darya can be readily correlated with less deformed and less metamorphosed transects in westernmost China (Qimgan and Kawuke), some 250 km to the east. A marble-greenschist sequence similar to that carried on the MPT in Altyn Darya has been identified there as a tectonic nappe of the Karakul-Mazar unit, emplaced from the south already in an Upper Triassic to Lower Jurassic (Late Cimmerian) event. If the correlation is correct, then the MPT had a Mesozoic precursor structure extending over much of the E-W striking segment of the Northern Pamir.</p>

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