Wyniki wyszukiwania - BazTech

1

Foraminiferal and palynological organic matter records of the Upper Badenian (Middle Miocene) deposits at Anadoly (marginal part of the Ukrainian Carpathian Foredeep Basin)

Gedl P., Peryt D., Peryt T. M.

Geological Quarterly

|

2016

|

Vol. 60, No. 2

517--536

EN

The Badenian section of Anadoly near Kamyanets Podilskyy (Ukrainian Carpathian Foredeep Basin) consists of the Tyras Fm. (gypsum and Ratyn Limestone) and the Ternopil Mb. of the Kosiv Fm. The latter are 5.3 m thick and are composed of dark grey mudstones with limestone intercalations. This study indicates the occurrence of over 54 species of benthic foraminifers and 10 species of planktonics. Benthic foraminifera are represented mainly by calcareous forms; agglutinated tests are very rare. Planktonic foraminifera appear in the upper part of the succession studied. Five benthic foraminiferal assemblages are recognized: A (Elphidium/Lobatula/Astrononion) B (Hauerinidae), C (Cibicidoides/Lobatula), D (Porosononion) and E (Uvigerina/Bulimina). The foraminiferal record indicates deposition in a shallow subtidal environment (20 m depth) of normal marine salinity and temperate waters followed by gradual deepening of the basin to >50 m. Analysis of foraminiferal assemblages indicates that bottom waters were highly oxygenated during deposition of the lower and middle parts of the Anadoly sequence. During deposition of the upper part of the sequence the oxygenation of bottom water gradually decreased, as expressed by a large decrease in the proportion of oxic species and an increase in dysoxic ones. The same set of samples yielded low amounts of palynological organic matter represented by dominant black opaque phytoclasts; bisaccate pollen grains and dinoflagellate cysts are rare. Taxonomically impoverished assemblages of the latter consist of dominant Polysphaeridium and Cleistosphaeridium placacanthum associated with Lingulodinium machaerophorum and a few other taxa. The taxonomically richest assemblage was found in the topmost sample. These changes were interpreted as indicative for increased salinity in the surface water layer, with its maximum in the middle part of the section; the assemblage from the topmost part is characteristic for normal marine salinity.

2

Foraminiferal and palynological records of the Late Badenian (Middle Miocene) transgression in Podolia (Shchyrets near Lviv, western Ukraine)

Peryt D., Gedl P., Peryt T. M.

Geological Quarterly

|

2014

|

Vol. 58, No. 3

465--484

EN

The Upper Badenian marly shales overlying gypsum and the Ratyn Limestone at Shchyrets, Ukraine, contain moderately to well-preserved benthic (calcareous only) and planktonic foraminifers, and palynofacies dominated by bisaccate pollen grains, presumably transported by wind. Both foraminiferal and dinoflagellate cyst assemblages indicate an open marine environment with normal-marine salinity and cool waters. The palaeodepth was ca. 50 m except for the uppermost part of the section studied, where a distinctive deepening is indicated by the dominance of Uvigerina in benthic foraminiferal assemblages and a high P/B ratio. The water was thermally stratified and the differences between the bottom water and the water column show an upwards-increasing trend. Bulimina and Globocassidulina are the most common and dominant component of benthic foraminiferal assemblages, except for the uppermost part where Uvigerina dominates the assemblage. The composition of benthic foraminifer assemblages and δ13C values of foraminifers indicate nutrient-rich waters and mesotrophic to eutrotrophic environments in surface waters, and low oxygenation at the sea floor in the Ukrainian Carpathian Foredeep Basin during the Late Badenian.

3

Petrographic characteristic of the Middle Miocene sediments in the Ukrainian segment of the Carpathian Foredeep

Kuberska M., Kozłowska A., Lis P.

Annales Societatis Geologorum Poloniae

|

2011

|

Vol. 81, No 3

351-361

EN

The Upper Badenian and Sarmatian strata from thirteen wells situated in the Ukrainian part of the Carpathian Foredeep were petrographically analysed. The studies were performed using a polarizing microscope (standard petrographic analysis, cathodoluminescence studies – CL), SEM and EDS ISIS. Moreover, the XRD was conducted, isotopic ratios of light isotopes of carbon and oxygen in carbonate cements determined, and porosimetric measurements performed on selected samples of sandstones. Claystones, mudstones and sandstones were distinguished among the studied rocks. The sandstones were examined in great detail. The following sandstone varieties were distinguished: unequal-grained, fine-, and rare medium-grained. They are classified as arenites and subarkosic, locally sublithic and quartz wackes. Quartz and feldspars (K-feldspars, plagioclases) are main components of the grain fabric of mudstones and sandstones. Rock fragments (of sedimentary, less common effusive rocks, individual fragments of granitoids and/or metamorphic rocks) occur in the sandstones, too. Micas (mainly muscovite), glauconite, rare bioclasts, fine plant remnants, and accessory zircons are present. The cement is composed of allogenic-and authigenic clay minerals (illite, smectite, chlorites, kaolinite), carbonates (Fe-calcite, dolomite, ankerite), authigenic quartz and, sporadically, authigenic feldspar and anhydrite. Effects of diagenetic processes, mainly of mechanical compaction, cementation, dissolution, and less significant replacement and alteration have been recorded in the sediments studied. The compaction and cementation have almost an equal influence on reduction of porosity and permeability of the analysed rocks. Abundant sandstone packages, however, display very good reservoir properties (porosity amounts to 30%, and permeability is over 200 mD).

4

Dinoflagellate cyst, palynofacies and foraminiferal records of environmental changes related to the Late Badenian (Middle Miocene) transgression at Kudryntsi (western Ukraine)

Gedl P., Peryt D.

Annales Societatis Geologorum Poloniae

|

2011

|

Vol. 81, No 3

331-349

EN

Qualitative and quantitative characteristics of the palynological content of the Upper Badenian strata at Kudryntsi (western Ukraine) indicate that this succession was deposited in variable environments. The basal siliciclastic series shows a very low content of palynological organic matter and palynofacies, which indicate a restricted environment and/or unfavourable conditions for the palynomorph preservation. The presence of dinoflagellate cysts (and composition of their assemblages) in the upper part of organodetrital limestones and the overlying rhodoid limestones indicates a typical shelf environment. Taxonomically variable dinoflagellate cyst assemblages from particular samples reflect gradual environmental changes – from environments of slightly increased salinity of seawater (strata overlying the siliciclastic series) to open marine, more remote environments during deposition of the upper part of the section examined. The gradual deepening of the sea and decrease of salinity is supported also by the succession of foraminiferal assemblages, which undergo gradual changes from Elphidium spp. assemblages, through Miliolidae assemblage, Lobatula lobatula assemblage, Neoconorbina spp. assemblage to Cibicidoides assemblage. The Late Badenian foraminiferal assemblage from Kudryntsi contains two species common for the Sarmatian, i.e. Elphidium reginum and Elphidium koberi, the latter species known so far from the Sarmatian.

5

Diagenesis and reservoir properties of the Middle Miocene sandstones in the Polish segment of the Carpathian Foredeep

Kozłowska A., Kuberska M., Maliszewska A.

Annales Societatis Geologorum Poloniae

|

2011

|

Vol. 81, No 1

87-103

EN

The Upper Badenian and Sarmatian sandstones from eight wells of the Carpathian Foredeep Basin have been studied. The following research methods were used: petrographic analysis with the use of polarizing microscope (staining analysis, cathodoluminescence studies – CL, porosity determinations, fluid inclusion ana- lysis), scanning electron microscope (SEM) investigations and energy dispersive spectrometer studies (EDS ISIS), X-ray diffraction analyses (XRD), isotopic analysis and petrophysical studies. The sandstones are very-fine to medium-grained subarkosic and sublithic arenites and wackes. The main components of the sandstone grain framework are quartz, feldspars (potassium feldspar and plagioclase), lithoclasts (fragments of carbonate rocks, clastic rocks, granitoids, volcanic rocks and quartz-mica schists) and micas (mainly muscovite). Bioclasts (mainly foraminifera), glauconite, ooids, organic matter and accesory minerals are subordinate. Pore spaces between the grains are filled by matrix and by cement (mostly Fe-calcite, quartz overgrowth, dolomite, siderite and kaolinite). The Middle Miocene sandstones show good and very good filtration abilities. Sandstones porosity very often exceeds 20% and permeability is above 100 mD. Primary intergranular porosity is considerably more frequent than secondary intragranular porosity (mainly dissolution of feldspar grains) and intercrystalline porosity (clays microporosity). Effects of the following diagenetic processes can be observed in the sandstones: compaction, cementation, dissolution, replacement and alteration. Primary porosity reduction in sandstones was predominantly caused by mechanical compaction by about 26% and cementation, mainly by calcite, by approximately 35% on the average. Some increase in porosity was caused by dissolution of detrital grains, mainly feldspars, and decay of the soft parts of organisms. Diagenetic and related reservoir properties evolution of the Middle Miocene sand- stones have been accomplished during eo- and mesodiagenesis.