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A. V. Tevelev V. E. Kovarskaya D. S. Tatarinova 《Moscow University Geology Bulletin》2012,67(2):93-102
In this work the study results of two detailed sections of the Chenka Formation of the Southwest Crimea are given. Based on the chemical composition of deposits, possible sedimentation settings, and their position in the general structure of the Jurassic-Cretaceous complexes of the Southwest Crimea, as well as the first palynological age datings we obtained, it is proposed that the age of the Chenka Formation deposits is Bathian-Callovian and that they accumulated within the distal part of a large river valley estuary. 相似文献
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E. M. Bugrova 《Stratigraphy and Geological Correlation》2008,16(1):81-91
Benthic foraminifers from borehole sections recovered by drilling in the Yamal Peninsula, West Siberia, characterize the Ceratobulimina cretacea Beds (the upper Campanian-lower Maastrichtian) and the Spiroplectammina variabilis-Gaudryina rugosa spinulosa and Spiroplectammina kasanzevi-Bulimina rosenkrantzi regional zones of the lower and upper Maastrichtian, respectively. The Danian Stage is missing from the sections, which include marine deposits of the Selandian Stage attributed to the Ceratolamarckina tuberculata Beds. Foraminiferal assemblages of the beds include the Siberian endemic species associated with Paleocene foraminifers of the Midway-type fauna of subglobal distribution range. Occurrence of the latter suggests that warm-water surface currents from the North Atlantic reached southern areas of the Kara Sea. 相似文献
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This study of the upper Maastrichtian to Danian sedimentary succession from the northern part of the Romanian Eastern Carpathians (Varniţa section) aims to establish an integrated biostratigraphy based on calcareous nannofossils, organic-walled dinoflagellate cysts (dinocysts) and foraminiferal assemblages, and to reconstruct the depositional environments of the interval. The stratigraphic record across the studied section is incomplete, considering that an approximately 16 m thick strata interval from the top of the Maastrichtian to lowermost Danian cannot be analyzed due to a landslide covering the outcrop. The upper Maastrichtian is marked by a succession of biostratigraphic events, such as the First Appearance Datum (FAD) of the nannoplankton taxon Nephrolithus frequens and FAD of the dinocyst species Deflandrea galeata and Disphaerogena carposphaeropsis, and the Last Appearance Datum (LAD) of Isabelidinium cooksoniae in the lower part of the section. These bioevents are followed by the LAD of the Dinogymnium spp. and Palynodinium grallator dinocyst markers in the top of the Maastrichtian deposits analyzed. In terms of foraminiferal biostratigraphy, the upper Maastrichtian Abathomphalus mayaroensis Zone is documented in the lower part of the studied section. Some bioevents, such as the bloom of the calcareous dinoflagellate genus Thoracosphaera and the FAD of the organic-walled dinocysts Damassadinium californicum, Senoniasphaera inornata, Xenicodinium lubricum and X. reticulatum suggest an early Danian age for the middle part of the section. From the Danian deposits in the Varniţa section, we describe a new organic-walled dinocyst species, Pentadinium darmirae sp. nov., which is until now the only species of the Pentadinium genus discovered in the Paleocene. The occurrence of the global Danian dinocyst marker Senoniasphaera inornata in the top of the section, suggests an age not younger than middle Danian (62.6 Ma) for the analyzed deposits.The palynofacies constituents, as well as the agglutinated foraminiferal morphogroups, used to reconstruct the depositional environments, show that the late Maastrichtian sediments were deposited in an outer shelf to distal (bathyal) environment, followed by a marine transgression during the Danian. 相似文献
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Geochemical and isotopic analyses of the Cretaceous–Paleogene (K/Pg) boundary deposits were conducted at the Caravaca section (External Subbetic, southeast of Spain) in order to evaluate the recovery of the macrobenthic tracemaker community and the bioturbational disturbance. Samples from the infilling material of several lower Danian dark-colored trace fossils (Chondrites, Planolites, Thalassinoides and Zoophycos) located in the uppermost 8-cm of the light upper Maastrichtian strata, as well as samples from the host sedimentary rock of these trace fossils, were analyzed and compared with data from the lower Danian deposits. The values of element ratios indicative of extraterrestrial contamination (Cr/Al, Co/Al and Ni/Al) are higher in the infilling trace fossil material than in the upper Maastrichtian and lower Danian deposits, which suggests a contribution of the ejecta layer. Regarding the isotope composition, the δ13C values are lower in the infilling material than in the Maastrichtian host sedimentary rocks surrounding the traces, while the δ18O are higher in the infilling material. The geochemical and isotopic compositions of the infilling material evidence the unconsolidated character of the sediment, including the red boundary layer. Softground conditions confirm a relatively rapid recovery by the macrobenthic tracemaker community, starting a few millimeters above the K/Pg boundary layer. The mixture of the infilling material of the trace fossils moreover reveals a significant macrobenthic tracemaker activity affecting K–Pg boundary transition sediments that may have significantly altered original signatures. 相似文献
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The Vigny limestones: a record of Palaeocene (Danian) tectonic-sedimentary events in the Paris Basin
Danian marine sedimentation in the Paris Basin occurred between two major erosional phases. The earlier was responsible for the stripping of presumably deposited Maastrichtian sediments and of a variable thickness of Campanian chalk. The later occurred during the late Palaeocene and resulted in the erosion of almost all Danian deposits, which are now limited to small and scattered outcrops. One of these outcrops corresponds to reefal and peri‐reefal limestones of middle to late Danian age, exposed in the quarries of Vigny (NW of Paris). Danian deposits here show intricate relations with the surrounding Campanian chalk. Danian sedimentation was contemporaneous with faulting, which generated signifiant sea‐floor relief and resulted in contrasting depositional areas: topographic highs with coralgal reefs, and depressions where calcirudite channel fill accumulated. Normal faulting occurred along WNW–ESE master faults. The generation of submarine fault scarps gave rise to various types of gravity‐driven phenomena, including the sliding and slumping of large blocks of reefal limestone and the deposition of carbonate debris flows. Along with the redeposition of the Danian carbonates, flows of fluidized and reworked Campanian chalk resulted from the peculiar physical properties of the undercompacted chalks. Erosion and faulting occurred predominantly during the Palaeocene and represent a major episode in the physiographic evolution of the Paris Basin. 相似文献
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Yu. O. Gavrilov O. V. Golovanova E. V. Shchepetova B. G. Pokrovsky 《Lithology and Mineral Resources》2018,53(5):337-348
The paper reports lithological and geochemical data on the stratigraphic interval corresponding to the Paleocene/Eocene Thermal Maximum (PETM) event in the Paleogene section of Eastern Crimea (Nasypnoe section). The section is located on the western continuation of the sublatitudinal profile consisting of 15 PETM sections spanning the area from Crimea to Tajikistan (over 2500 km). It is shown that PETM sediments have the negative δ13C and δ18O isotope excursions and are enriched in kaolinite, which is typical of most sections of this interval around the world. At the same time, the extremely low content of organic matter (OM) in sediments of the Nasypnoe section makes them sharply different from the highly carbonaceous rocks of the PETM interval in Central and Eastern Caucasus, and Central Asian regions. This is correlated with the low contents of many chemical elements in the studied rocks, and their extremely high contents in the highly carbonaceous rocks of the easterly sections. Thus, Eastern Crimea in the end of the Paleocene?beginning of the Eocene was occupied by the low-bioproductive marine paleobasin, whereas the coeval paleobasin in Central Asia was characterized by extremely high bioproductivity owing to the presence of significant amount of phosphorus. 相似文献
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E. A. Lygina L. F. Kopaevich A. M. Nikishin I. V. Shalimov E. V. Yakovishina 《Moscow University Geology Bulletin》2010,65(6):343-354
This work considers the structure and conditions of the formation of deposits of the Simferopolskoe regional stage of the
Crimea. The deposits of this stage include planktonic foraminifera zones Morozovella aragonensis and Acarinina bullbrooki
and nanoplaktonic zones Marthasterites tribrachiatus (the upper part), Discoaster lodoensis, Discoaster sublodoensis (lower
part). The deposits of this interval throughout most of the Crimea represent a nummulitic bank, which formed in shallow warm-water
basin and was isolated carbonate platform. The distribution of rocks of this regional stage, the facial change, and a number
of interruptions are shown in the chronostratigraphic profile. The facial transitions within the carbonate platform point
to variations in the basin’s depth, as well as periodical changes in the relative sea level, which were not only of a eustatic
nature, but were determined by the periodic rise of the Simferopol Uplift. 相似文献
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T. V. Kezina 《Stratigraphy and Geological Correlation》2011,19(3):296-309
The Wuyun deposit of brown coal is situated on the right bank of the Amur River in the People’s Republic of China, 35–60 km
away from the Arkhara-Boguchan brown coal deposit. The Belaya Gora stratotype of the latter and the southwestern flanks of
the Raichikhinsk brown coal field (Russia) have been studied previously when the author analyzed in detail the Danian and
Selandian-Thanetian palynoassemblages from the Upper Tsagayan Subformation. A section of the Wuyun Formation was studied at
the eponymous deposit in 2002 and 2004. Based on new palynological results and analysis of data from earlier publications,
two palynoassemblages distinguished there in the Paleocene coal-bearing succession enable correlation between sections of
relevant deposits on the right and left banks of the Amur River. Data on the taxonomic composition of palynoassemblages are
considered, and their basic and characteristic taxa are figured in paleontological plates. 相似文献
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Gilberto A. Albertão Eduardo A.M. Koutsoukos Marília P.S. Regali Moses Attrep Jr Paulo P. Martins Jr 《地学学报》1994,6(4):366-375
A preliminary integrated study of a Cretaceous-Tertiary (K/T) boundary section in Pernambuco, northeastern Brazil, provides evidence for an extraterrestrial bolide impact in the earliest Danian. A non-graded, nodular carbonate mudstone/wackestone bed is interpreted as a slump or a mud Flow deposit, induced by a tsunami event or by a gravity mass movement during a sea-level lowstand, the former possibly generated by the K/T boundary Yucatán impact. This bed overlies marlstones deposited in an upper bathyal environment and marks the top of the Cretaceous. Nearly all known latest Maastrichtian planktonic foraminifera are recovered from the Cretaceous strata. Iridium shows a marked peak in a thin hemipelagic claystone layer, about 75 cm above the K/T boundary, deposited in a middle to deep neritic environment. The claystone overlies alternating beds of finegrained limestones and marlstones and a 50 cm-thick graded bioclastic packstone, which rests upon a marly limestone breccia of the lowermost Danian. Abundant reworked Cretaceous and rare lowermost Danian microfossils (e.g. E. edita, E. eobulloides, E. fringa, G. irregularis, P. eugubina, P. cf. pseudobulloides, W. claytonensis and W. hornerstownensis ) have been recovered from these strata. These lowermost Danian beds record the sudden appearance of abundant shock-metamorphosed quartz grains, with several sets of intersecting deformation lamellae and microtektite-like microspherules. This suggests that these deposits were formed by an additional tsunami caused by a second impact event in the earliest Danian, near or at the boundary between the Palaeocene P α and P 1a foraminiferal zones. Impact-derived material has not been found in the uppermost Cretaceous beds. 相似文献
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Two distal Cretaceous–Paleogene (K/Pg) boundary sections in the Central Apennine region (Italy) have been studied: Bottaccione Gorge and Contessa Highway. Geochemical and carbon isotope analyses on the infilling of trace fossils and on the host sedimentary rocks were performed to determine paleoenvironmental conditions during the Cretaceous–Paleogene transition. Major and trace element contents were measured in a 63 cm-thick interval at Bottaccione Gorge (from 22 cm below to 41 cm above the K/Pg boundary) and in a 72 cm-thick interval at Contessa Highway (from 43 cm below to 29 cm above the K/Pg boundary). Even though the K/Pg ejecta layer is now depleted at these sections due to continuous oversampling, the uppermost Maastrichtian and lowermost Danian deposits record the paleoenvironmental conditions prior to and after the K/Pg event. We used redox-sensitive element ratios (V/Al, Cr/Al, Co/Al, Ni/Al Cu/Al, Zn/Al, Mo/Al Pb/Al and U/Mo) and detrital element ratios (K/Al, Rb/Al, Zr/Al and ƩREE/Al) as proxies of certain environmental parameters, used for paleoenvironmental reconstruction. In general, similar values for elemental ratios are registered within Maastrichtian and Danian deposits, which supports similar paleoenvironmental conditions prior to and after the K/Pg event as well as the rapid reestablishment of the pre-impact conditions (i.e., oxygenation, nutrient availability, and/or sedimentary input). An enrichment in certain redox-sensitive elements above the K/Pg at the Bottaccione Gorge section suggests lower oxygenation, as also evidenced by the tracemaker community. Carbon isotope composition data from the infilling material of trace fossils furthermore reveals values similar to those of the host rocks at the corresponding depth, which supports an active infilling by nearly contemporaneous bioturbation during sediment deposition. 相似文献
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This is the first record of a representative of the organic-walled dinoflagellate cyst genus Palynodinium from the New Zealand region. Previously, Palynodinium grallator has been reported from two sites in offshore Tasmania during Ocean Drilling Program, Leg 189. The new species Palynodinium minus is found consistently in latest Maastrichtian? and earliest Danian strata (latest Haumurian–earliest Teurian) in two sections located along the mid-Waipara and Grey rivers, North Canterbury, South Island. It occurs in a narrow stratigraphic interval at the Cretaceous–Paleogene transition and is potentially a stratigraphically important index species in the region. Its range coincides with that of the global earliest Danian index fossil Carpatella cornuta and a basal Danian acme interval of Trithyrodinium evittii, and is correlated to ca. 65.5–65.2 Ma. Its highest occurrence is at the base of an acme interval of Palaeoperidinium pyrophorum. It has only been recorded from sections composed of siliciclastic shelf sediments, suggesting that it might have had a palaeoecological preference for relatively near-shore environments. 相似文献
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The composition and origin of the Bedenekir Formation deposits of Mountainous Crimea are detailed on the basis of our work results and analysis of both published and unpublished data. 相似文献
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Uranium is significantly enriched (up to two orders of magnitude) in the Danish Cretaceous-Tertiary boundary beds relative to the underand overlaying sediments. Both the predominant oxic and some anoxic deposits have a high uranium content. To investigate the geochemical behaviour of the element, a series of sections was analysed for uranium by means of the delayed-neutron counting technique. Uranium contents in the carbonate rocks from different parts of the Danish Sub-basin are generally low but show slight regional trends. Experiments that involve cold acid extractions suggest that uranium is associated with the non-carbonate residues. The uranium distribution with depth in the offshore drill core from the Central Graben area (North Sea) suggests that the element is associated with clay in the Danian part. Cretaceous-Tertiary boundary beds from Stevns Klint and other localities in the Danish sub-basin have anomalously high uranium contents compared with the values for chalk. Uranium is not correlated with iron, non-carbonate carbon or aluminium. The highest uranium values within boundary sections are not found in the lower part of the sections as is the case for iridium. The only boundary beds that show typical anoxic depositional affinity have a total uranium accumulation that is one order of magnitude lower than that found in the oxic sections. High amounts of uranium within Cretaceous-Tertiary boundary beds are suggested to be related to diagenetic processes such as compaction and dehydration. Uranium is thought not to cause the extinctions at the Cretaceous-Tertiary boundary because of the relatively low contents found at the actual extinction level. 相似文献
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L. R. Distanova 《Moscow University Geology Bulletin》2007,62(3):184-189
The article is dedicated to multidisciplinary studies of organic matter (OM) in Eocene deposits. In the Ciscaucasia region, the mean content of organic carbon in the Kumian deposits is high. A decrease in quality is partly related to the approaching of the displacement source. In the investigated regions of Ciscaucasia and Crimea, hydrogen sulfide contamination of the water column in Eocene basins did not exist. Eocene carbon deposits are characterized by increased and high OM oil source potential. A sharp increase in primary biological production is likely to be related to endogenous processes. 相似文献
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W. Stinnesbeck G. Keller J. de la Cruz C. de León N. MacLeod J. E. Whittaker 《International Journal of Earth Sciences》1997,86(3):686-709
Limestone breccia deposits in southern Mexico, Guatemala and Belize have recently been interpreted as proximal to distal ballistic fallout deposits, generated by a bolide impact that struck Yucatan at K/T boundary time. We review the age, lithology and the depositional environment of five K/T boundary sections in the South Petén area of Guatemala (Caribe, Aserradero, Chisec, Actela, Chemal) in order to evaluate the nature and origin of K/T limestone breccia deposition. The sections are located 500?km south of the proposed impact site at Chicxulub and trend in an east–west direction from the Guatemala/Mexico border to southern Belize. In four of the five sections examined, a breccia unit up to 50?m thick overlies reef-bearing shallow-water limestones of late Cretaceous (Campanian-Maastrichtian) age. Rhythmically bedded limestones, marls and siltstones of early Danian age overlie the breccia and were deposited under middle-to outer-neritic conditions. The breccia consists of differently coloured layers of shallow-water limestones. Clast size generally decreases upsection to thin layers of predominantly rounded clasts, and these fine-grained rudstones grade into grainstones at the top. In at least one section (EI Caribe) diagenetically altered glass spherules are present in the uppermost layers of the grainstone. These glass spherules are of stratigraphic position and chemical composition similar to black and yellow glass from Beloc, Haiti and Mimbral, Mexico, which some workers have chemically linked to melt glass within the breccia of the Chicxulub cores. We suggest that breccia deposition in Guatemala may have been multi-event, over an extended time period, and related to the collision of the Yucatan and Chortis plates as well as related to a major impact or volcanic event at the end of the Cretaceous. 相似文献
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Lithology and Mineral Resources - The composition and depositional environments of the Tithonian(?)–Berriasian deposits in the Tonas River basin (Central Crimea) are considered. The paper... 相似文献
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R. R. Gabdullin I. V. Shalimov N. V. Badulina T. I. Nigmadzhanov A. V. Sergienko T. A. Konovalova 《Moscow University Geology Bulletin》2017,72(5):305-313
A stratigraphic scheme for dividing the Triassic–Neogene deposits of the central Crimea by suites has been proposed. The division is based on the generalization of our own results and the analysis of the published and unpublished data. 相似文献