scholarly journals Calpionellid biostratigraphy and microfacies analysis of a Tithonian–Berriasian carbonate succession in the Western Srednogorie (Bulgaria)

2017 ◽  
Vol 46 (1) ◽  
pp. 65-92
Author(s):  
Silviya Petrova ◽  
Polina Andreeva ◽  
Lubomir Metodiev ◽  
Daniela Reháková ◽  
Jozef Michalík ◽  
...  
Keyword(s):  
Carbonate Platform ◽  
Carbonate Sediments ◽  
Marine Environments ◽  
Microfacies Analysis ◽  
Diagnostic Features ◽  
Depositional Settings ◽  
Lithostratigraphic Units

In the eastern part of the Western Srednogorie Unit, around Dragovishtitsa Village, a specific succession of the Gintsi and Glozhene–Slivnitsa formations has provided micropalaeontological evidence for late Tithonian (Chitinoidella, Praetintinnopsella and the base of Crassicollaria zones) and mid-Berriasian (the Elliptica Subzone of the Calpionella Zone) age on the basis of 45 chitinoidellid and calpionellid species. A significant stratigraphic hiatus is documented within the Glozhene–Slivnitsa Formation, since a part of the Crassicollaria Zone, as well as the Alpina+Remaniella subzones of the Calpionella Zone, is absent from the Dragovishtitsa 1 section. The conformably overlying Salash Formation is of mid-Berriasian age (Elliptica Subzone) and is locally characterized by the presence of calcareous sandstones (Dragovishtitsa 2 section). The Salash–Cherni Osam Formation, as well as the clayey limestone unit covering the Slivnitsa Formation, is also of mid-Berriasian age (Elliptica Subzone). The Slivnitsa and Glozhene–Slivnitsa formations, which underlie the Salash–Cherni Osam Formation in the Dragovishtitsa East section, correspond to the Crassicollaria Zone and the Alpina Subzone, respectively. Reworking of calpionellids from the Crassicollaria Zone is documented in the Alpina and Elliptica subzones in all three studied sections. Eight microfacies types are distinguished, which suggests that the carbonate sediments were deposited in a carbonate platform rather than in a pelagic basin environment, althought the upper part of the studied sections reveals an upward-deepening trend. The Slivnitsa Formation is covered by highly diachronous sediments from more distal settings: from mid-Berriasian around Dragovishtitsa Village to the Berriasian/Valanginian transition at the Tri Ushi section to late Valanginian in the Dragoman and Kalotina sections. This fact, together with the significant stratigraphic hiatus within the Glozhene–Slivnitsa Formation, is interpreted here as tectonically controlled. The presence of transitional depositional settings from carbonate platform to deeper-marine environments caused deposition of specific lithostratigraphic units not always corresponding to the diagnostic features of the Glozhene, Salash and Cherni Osam formations.

scholarly journals Aspects of the Cenozoic stratigraphy of the Northern Sulaiman Ranges, Pakistan

1997 ◽  
Vol 16 (1) ◽  
pp. 51-58 ◽  
Author(s):  
R. W. Jones
Keyword(s):  
Carbonate Platform ◽  
Shallow Marine ◽  
Sequence Stratigraphic ◽  
Depositional Settings ◽  
Marine Carbonate ◽  
Stratigraphic Framework ◽  
Lithostratigraphic Units

Abstract. The results of micropalaeontological, nannopalaeontological and palynological analyses of Cenozoic sections from the Northern Sulaiman Ranges in Pakistan are discussed. They are in keeping with previously published results (though in some cases significantly more refined). They enable placement of most of the sampled lithostratigraphic units in a global bio- and sequence-stratigraphic framework. Limestones appear to be associated with essentially transgressive global sequences, shales with essentially regressive sequences. Palaeoenvironmental interpretations indicate a range of depositional settings from continental through shallow marine to basinal. A number of shallow marine carbonate platform sub-environments are recognized over the Palaeocene–Eocene section

Seismite in the Devonian Sultan Formation, Frenchman Mountain, Nevada: Evidence of far-field effect of the Alamo Event

2016 ◽  
Vol 53 (2) ◽  
pp. 93-114
Author(s):  
Jesús Pinto ◽  
John Warme
Keyword(s):  
Carbonate Platform ◽  
Far Field ◽  
Carbonate Sediments ◽  
Impact Event ◽  
Complex Matrix ◽  
Near Surface ◽  
Fault Block ◽  
Southern Nevada ◽  
Salt Pan ◽  
The Alamo

We interpret a discrete, anomalous ~10-m-thick interval of the shallow-marine Middle to Late Devonian Valentine Member of the Sultan Formation at Frenchman Mountain, southern Nevada, to be a seismite, and that it was generated by the Alamo Impact Event. A suite of deformation structures characterize this unique interval of peritidal carbonate facies at the top of the Valentine Member; no other similar intervals have been discovered in the carbonate beds on Frenchman Mountain or in equivalent Devonian beds exposed in ranges of southern Nevada. The disrupted band extends for 5 km along the Mountain, and onto the adjoining Sunrise Mountain fault block for an additional 4+km. The interval displays a range of brittle, ductile and fluidized structures, and is divided into four informal bed-parallel units based on discrete deformation style and internal features that carry laterally across the study area. Their development is interpreted as the result of intrastratal compressional and contractional forces imposed upon the unconsolidated to fully cemented near-surface carbonate sediments at the top of the Valentine Member. The result is an assemblage of fractured, faulted, and brecciated beds, some of which were dilated, fluidized and injected to form new and complex matrix bands between beds. We interpret that the interval is an unusually thick and well displayed seismite. Because the Sultan Formation correlates northward to the Frasnian (lower Upper Devonian) carbonate rocks of the Guilmette Formation, and the Guilmette contains much thicker and more proximal exposures of the Alamo Impact Breccia, including seismites, we interpret the Frenchman Mountain seismite to be a far-field product of the Alamo Impact Event. Accompanying ground motion and deformation of the inner reaches of the Devonian carbonate platform may have resulted in a fall of relative sea level and abrupt shift to a salt-pan paleoenvironment exhibited by the post-event basal beds of the directly overlying Crystal Pass Member.

Effects of microalgal communities on reflectance spectra of carbonate sediments in subtidal optically shallow marine environments

2003 ◽  
Vol 48 (1part2) ◽  
pp. 535-546 ◽  
Author(s):  
F. Carol Stephens ◽  
Eric M. Louchard ◽  
R. Pamela Reid ◽  
Robert A. Maffione
Keyword(s):  
Reflectance Spectra ◽  
Carbonate Sediments ◽  
Marine Environments ◽  
Shallow Marine

scholarly journals Lithostratigraphy and microfacies analysis of Avanah Formation (Middle Eocene) in Gomaspan section northeast Erbil City, Kurdistan region, Iraq

2021 ◽  
Author(s):  
Irfan Sh. Asaad ◽  
Keyword(s):  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
Middle Part ◽  
Petrographic Analysis ◽  
Microfacies Analysis ◽  
Dolomitic Limestone ◽  
Kurdistan Region ◽  
Thin Sections ◽  
Lithostratigraphic Units ◽  
Lagoon Environment

Lithostratigraphy and microfacies analysis of the Avanah Formation (Middle Eocene) were studied in the Gomaspan section in the Bina Bawi anticline, northeast of Erbil city, Kurdistan Region, Iraq. The field observations refer that the formation attains 56 m of medium to thick bedded yellow limestone, grey dolomitic limestone and blue marly dolomitic limestone interbedded with thin beds of blue marl and dark grey shale with an interval of sandy limestone in the middle part and thin to medium bedded limestone interbedded with red mudstone. The petrographic study of 29 thin sections of Avanah carbonates revealed that the majority of the matrix is carbonate mud (micrite) with few microspar. The skeletal grains include benthic foraminifera, dasycladacean green algae, ostracods, calcispheres, pelecypods, rare planktonic foraminifera and bryozoa in addition to bioclasts. Non-skeletal grains encompass peloids, oncoids, intraclasts and extraclasts with common monocrystalline quartz. Based on the field observation and petrographic analysis, three different lithostratigraphic units were identified. They are in ascending order: A-Thick bedded dolomitic marly limestone interbedded with shale. B- Bedded dolomitic limestone interbedded with shale and marl. C- Thin to medium bedded limestone interbedded with red mudstone. Depending on detailed microfacies analysis of carbonate rocks, three main microfacies and 12 submicrofacies are recognized. From the sum of all petrographic, facies, textural analyses, it is concluded that Avanah Formation in Gomaspan section, was deposited in shallow marine environment, semi restricted lagoon, in lower and upper parts and open lagoon environment in the middle part interval.

scholarly journals Stratigraphy and Depositional Environment of Mauddud Formation in Ratawi Oil wells of Southern Iraq

2021 ◽  
Vol 877 (1) ◽  
pp. 012030
Author(s):  
Maha Razaq Manhi ◽  
Hamid Ali Ahmed Alsultani
Keyword(s):  
Deep Sea ◽  
Lower Cretaceous ◽  
Depositional Environment ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Oil Wells ◽  
Oil Field ◽  
Microfacies Analysis ◽  
Thin Sections ◽  
Southern Iraq

Abstract The Mauddud Formation is Iraq’s most significant and widely distributed Lower Cretaceous formation. This Formation has been investigated at a well-23 and a well-6 within Ratawi oil field southern Iraq. In this work, 75 thin sections were produced and examined. The Mauddud Formation was deposited in a variety of environments within the carbonate platform. According to microfacies analysis studying of the Mauddud Formation contains of twelve microfacies, this microfacies Mudstone to wackestone microfacies, bioclastic mudstone to wackestone microfacies, Miliolids wackestone microfacies,Orbitolina wackestone microfacies, Bioclastic wackestone microfacies, Orbitolina packstone microfacies, Peloidal packstone microfacies, Bioclastic packstone microfacies, Peloidal to Bioclastic packstone microfacies, Bioclastic grainstone microfacies, Peloidal grainstone microfacies, Rudstone microfacies. Deep sea, Shallow open marine, Restricted, Rudist Biostrome, Mid – Ramp, and Shoals are the six depositional environments in the Mauddud Formation based on these microfacies.

scholarly journals Bio-Sequence Stratigraphy of Asmari Formation in the Southeast of Norabad (Zagros Basin, SW Iran)

2021 ◽  
Author(s):  
Mohammadsadegh Dehghanian
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
Carbonate Platform ◽  
Reservoir Rock ◽  
Dispersion Pattern ◽  
Asmari Formation ◽  
Level Curve ◽  
Zagros Basin ◽  
Lithostratigraphic Units ◽  
Global Sea Level

Abstract Asmari Formation is the thick sequence of carbonate sediment in the range of Oligocene-Miocene which is deposited in the foreland basins of the Zagros and is considered as the original and most famous reservoir rock of Zagros basin. To study of lithostratigraphic units and sequence stratigraphy of this Formation, the section in the southeast of Norabad was selected. Field study indicated that Asmari Formation possessed the thickness of 401.5m and included 9 lithostratigraphic units. According to the study of microfacies, Stacking pattern and identification of main sequence level, three depositional sequences including two-second order and one-third order sequence were recognized. The sea-level curve in the studied section indicated that it was correspondence to the global sea level curve. These facies deposited in five environmental sedimentations as follow Open Sea Shelf (Fore Barrier), Bar, Lagoon, Back bar shelf, and Shoal. The environment is part of a carbonate platform that has been formed on an open shelf. In addition, according to the Study of foraminifer dispersion pattern the range of Asmari Formation in Norabad was suggested to be Oligocene (Rupelian- Chattian) to lower Miocene (Aquitanian- Burdigalian).

Rock Magnetic and Magnetostratigraphic Study of Chicxulub Crater Impact Breccias and Post-Impact Carbonates in the Yaxcopoil-1 and Santa Elena Boreholes

2020 ◽  
Author(s):  
Jaime Urrutia-Fucugauchi ◽  
Ligia Perez-Cruz ◽  
Elia Escobar-Sanchez ◽  
Miriam Velasco-Villarreal ◽  
Edgar Garcia-Garnica
Keyword(s):  
Oxygen Isotope ◽  
Carbonate Platform ◽  
Magnetic Hysteresis ◽  
Magnetization Vector ◽  
Carbonate Sediments ◽  
Carbon And Oxygen Isotope ◽  
Post Impact ◽  
Chicxulub Crater ◽  
The Impact ◽  
Santa Elena

<p>Chicxulub crater was formed ~66 Ma ago by an asteroid impact at the Cretaceous/Paleogene (K/Pg) boundary on the Yucatan carbonate platform in the southern Gulf of Mexico. The crater is the youngest and best preserved of the three large impact basins, with a ~200 km diameter and multi-ring and peak ring morphology. The crater, covered by post-impact carbonate sediments with thickness up to ~1.1 km, has been investigated by geophysical studies and drilling programs. Initial drilling in Yucatan was carried out by the Pemex oil company, followed by the National University UNAM Chicxulub program, the ICDP Yaxcopoil-1 project and the IODP-ICDP Expedition 364 marine drilling. Here, results of combined paleomagnetic, rock magnetic, petrographic and geochemical studies are used to characterize the sequence and constrain the unit’s emplacement and crater formation. We analyze core samples of suevitic breccias and Paleogene carbonates from the Yaxcopoil-1 and Santa Elena boreholes drilled in the southern sector, inside and to the south of the crater rim marked by the ring of cenotes.  Magnetic hysteresis, low-field susceptibility and coercitivity analyses indicate that main carriers are titanomagnetites and magnetite. Mineralogical and magnetic properties indicate effects of hydrothermal alteration, associated with the high temperature system generated by the impact. Higher coercitivity minerals are also observed in some samples. In the carbonate sections, hydrothermal effects as marked by the geochemical logs decrease upwards from the breccia-carbonate contact. Alternating field and thermal demagnetization is used to investigate the magnetization vector composition and isolate the characteristic remanent components. Magnetic polarities defined from the inclination data show a sequence of reverse to normal, which correlate to polarity chrons 29r to 26r, with impact occurring within 29r chron.  The correlations of the magnetostratigraphy and stable isotopes indicate a hiatus at the basal Paleocene section. In Santa Elena cores, d<sup>13</sup>C values range from 1.2 to 3.5%<sub>0 </sub>and d<sup>18</sup>O values range from -1.4 to -4.8%<sub>0, </sub>with variation trends correlating with the marine carbon and oxygen isotope records for the late Maastrichtian and early Paleocene. The positive carbon isotopes indicate high productivity after the K/Pg extinction event, while the oxygen isotope values are more negative reflecting regional and local effects. Silica contents decrease from high in the suevites to low values in carbonates showing higher variability and then increased contents at the Paleocene-Eocene Thermal Maximum (PETM). The geochemical trends correlate in other elements including iron, titanium, potassium and aluminum that record impact-induced hydrothermal effects and possibly changing depositional conditions. Ca shows an opposite trend, with lower values in the upper suevitic breccias, higher values in the Paleocene carbonates and lower values in the PETM.</p>

Facies variations in the Devonian limestones of eastern South Devon

1977 ◽  
Vol 114 (3) ◽  
pp. 165-193 ◽  
Author(s):  
Colin T. Scrutton
Keyword(s):  
Carbonate Platform ◽  
Upper Devonian ◽  
The Other ◽  
Reef Complex ◽  
Lithostratigraphic Units ◽  
Platform Margin ◽  
Barrier Reefs

SummaryThe Middle and Upper Devonian limestone successions at Torquay and in the Lemon Valley SW of Newton Abbot are described. Lithostratigraphic units are proposed for the Torquay succession. The compositions of the coral faunas in both successions are outlined and contribute, together with the other available faunal evidence, towards a broad internal dating of these limestone sequences. Successions elsewhere in the limestones of eastern South Devon are briefly outlined. On the basis of this evidence facies variations from the margin towards the centre of the carbonate platform in eastern South Devon are demonstrated and interpreted as reflecting the development of barrier reefs along parts at least of the platform margin in Givetian times. The character of the reef-complex, named the Tor Bay Reef-Complex, is briefly compared with Devonian reefs elsewhere.

scholarly journals Dinantian lithostratigraphic units (Belgium)

2002 ◽  
Vol 4 (1-2) ◽  
pp. 69-94 ◽  
Author(s):  
Edouard POTY ◽  
Luc HANCE ◽  
Alan LEES ◽  
Michel HENNEBERT
Keyword(s):  
Carbonate Platform ◽  
The South ◽  
Third Order ◽  
Sedimentary Deposits ◽  
The North ◽  
Rugose Corals ◽  
Lithostratigraphic Units ◽  
Marine Facies ◽  
Sea Level Variations ◽  
Depositional Setting

Six paleogeographic sedimentation areas (s. a.) are recognized in the Namur-Dinant Basin: (1) the Hainaut s. a., (2) the Namur s. a., (3) the Condroz s. a., (4) the Dinant s. a., (5) the Visé-Maastricht s. a., and (6) the southern Avesnois s. a. (only in northern France). Together with the sea-level variations (third-order sequences), local controls influenced the nature of the sedimentary deposits, so the lithostratigraphic successions in each sedimentation area are distinctive. The depositional setting was that of a carbonate platform which evolved from a ramp in the early Tournaisian to a rimmed shelf during the early Viséan and then to a regionally extensive shelf during the middle and late Viséan. Before the Livian, open marine fades were developed to the south, but from the Livian onwards open marine facies were restricted to the north while evaporites developed in the south. This inversion of the normal pattern was probably related to an early phase of Variscan shortening. Dinantian biostratigraphy is mainly based upon foraminifera, rugose corals and conodonts. Fifty formations (including members), 3 groups and 2 informal lithostratigraphic units are briefly described.

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