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Implications of brecciation in Pennsylvanian Atoka Bank complex carbonates, Eddy County, New Mexico

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Eren M.

Annales Societatis Geologorum Poloniae

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2023

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tom Vol. 93, No. 4

345--352

EN

The Pennsylvanian Atoka bank carbonates were deposited on the northwest shelf of the Delaware Basin in Eddy County, New Mexico, forming a stratigraphic trap for natural gas. Brecciation is common in the core samples of some wells. This paper describes the brecciation in the phylloid algal limestones and discusses its origin. In the core samples, brecciated dark areas, consisting of irregularly shaped fragments, are seen together with internal sediment-filled pores, characterized by light gray coloured areas. Detailed examination of the core samples reveals that the brecciated dark areas correspond to open space areas between phylloid algal colonies, on the basis of comparison with the well-preserved primary rock texture in the cores. Brecciation is mainly due to the selective dissolution of phylloid algae that produced phylloid algal moulds, later filled by sandy internal sediments under subaerial conditions. The subsequent compaction of the limestone caused the rock to break up and formed a breccia in situ. The sandy internal sediment prevented the moulds from collapse as well as breccia formation in the pore-filling area, owing to its loose character. Overall, the brecciation process, including the dissolution of phylloid algae and breakage of the rocks, significantly improved the reservoir quality, whereas the internal sediment reduced the reservoir quality, for it reduced the porosity.

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The earliest Cretaceous carbonate platform destroyed by volcanism from the Ukrainian/Romanian Carpathians – reconstruction based on microfacies

86%

Iwańczuk J. , Krobicki M. , Feldman-Olszewska A. , Hnyłko O.

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tom nr 1-2 (72-73)

31--31

EN

There is a unique tectonostratigraphic unit called Kaminnyi Potik occur in the Ukrainian-Romanian Carpathian transborder zone. In the Ukrainian part numerous outcrops of this unit can be observed in many streams near Rachiv city, but its most spectacular occurrence is in the Chyvchyn Mountains. The whole complex consists of volcanogenic-sedimentary rocks and is divided into two Berriasian formations: Chyvchyn and Kaminnyi Potik. In the section of the Chyvchyn Formation, at the base, there are pillow lavas (basalts and andesites/trachyandesites) and volcano-sedimentary breccia with clasts of lava, coral limestones and radiolarites (submarine debris flows), and peperites as well. The Kaminnyi Potik Formation is made up of fine-grained hyaloclastic and carbonate debris flows of a flysch character (including organodetrital limestones with fragments of: corals, bryozoans, echinoderms bivalves and foraminifera), which overlying breccias and coral limestones of the Chyvchyn Formation. The profile ends by thin-bedded cherty limestones. The thin sections analysis revealed the following microfacies: oolithic-echinoderm packstone/grainstone; coral lithoclastic quartz packstone/grainstone; oolithic-lithoclastic wackestone/packstone; lithoclastic-echinoderm packestone; lithoclastic packestone; radiolarian echinoderm packestone; radiolarian wackestone; radiolarian-calpionellid wackestone and mudstone. Pyroclastic material is often present in the matrix. The ooids observed in the thin sections and the remains of fauna such as corals, echinoderms and bivalves suggest that the original material came from a carbonate platform that was sheltered by a coral reef. As a result of volcanic eruptions and possibly accompanying earthquakes, the platform has been destroyed and its traces are visible in clasts. Sedimentological character of submarine debris flows, (e.g. fractional graiding, mixture of shallow-water fauna and lithoclasts with deep-marine microfauna (radiolarians and calpionellids) and hyaloclastic material present in the matrix document short-term episodes of a catastrophic nature, leading to the redeposition of shallow-water sediments to the deeper parts of the basin.

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Oxygen isotope analysis of shark teeth phosphates from Bartonian (Eocene) deposits in Mangyshlak peninsula, Kazakhstan

86%

Pelc A. , Hałas S. , Niedźwiedzki R.

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tom Vol. 42, iss. 1

53--61

EN

We report the results of high-precision (±0.05‰) oxygen isotope analysis of phosphates in 6 teeth of fossil sharks from the Mangyshlak peninsula. This precision was achieved by the offline preparation of CO2 which was then analyzed on a dual-inlet and triple-collector IRMS. The teeth samples were separated from Middle- and Late Bartonian sediments cropping out in two locations, Usak and Kuilus. Seawater temperatures calculated from the δ18O data vary from 23–41oC. However, these temperatures are probably overestimated due to freshwater inflow. The data point at higher temperature in the Late Bartonian than in the Middle Bartonian and suggest differences in the depth habitats of the shark species studied.

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The margins of the Early Jurassic Trento Platform (Southern Alps)

86%

Riva A. , Gianolla P. , Caggiati M.

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tom nr 1-2 (72-73)

59--59

EN

Examples of Lower Jurassic carbonate platform margins are rare, probably due to the scarcity of good outcrops. One of the major palaeogeographic units of the Mesozoic Tethys, the Trento Platform, however, shows two different margin types facing the Belluno and the Lombardian basins. While the western margin, facing the Lombardian Basin, is showing an ooidal unit with frequent mud mounds (Massone Oolite), the eastern margin was poorly characterized, mainly due to difficult stratigraphic definition and problematic accessibility of outcrops. The eastern platform margin characteristics are strictly controlled by tectonic activity and the type of carbonate factory; the differences between the eastern and the western margin could be linked to windward-leeward position of the platform margin, more protected to the west than to the east. Subsidence increased since Late Triassic, due to the opening of the Alpine Tethys, defining shallow water areas, dominated by subtidal and peritidal muddy carbonates, and deeper basins, such as the Belluno and Lombardian Basin. More than 500 m of mud-dominated carbonates developed until Early Sinemurian, when major switch in the carbonate factory occurred. The Hettangian-Early Sinemurian margin is usually not well exposed and is strongly dolomitized and appears to be a tectonically controlled escarpments. Since Late Early Sinemurian, the carbonate factory changed and led to a huge production of peloids and ooids, promptly shed in the surrounding basin: in the Eastern Trento Platform we recognize a 400/500 m thick wedge of Sinemurian to Pliensbachian ooidal calcarenites pinching-out towards the basin, with scattered bioconstructions made of calcareous sponges across the margin. This wedge pinches out also towards the platform interior, showing that the ooids were poorly preserved on the platform top. The preserved slope shows an angle of about 20-25°. In the western margin, the resedimented ooids are more limited, probably due to the limited size of the marginal carbonate factory. In the Late Pliensbachian, probably in the Margaritatus zone, a drowning phase affected part of the eastern carbonate platform, switching to encrinitic calcarenites, while in the western one carbonate production continued until Bajocian. These encrinites are extremely thin on the platform top, but a resedimented wedge in the proximal basin highlights the position of the topographic margin. The margins of the Trento Platform is a rare example of Early Jurassic carbonate platform margin that can be used as a reference for coeval carbonate platform depositional systems.

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Wpływ węglanów litu, strontu i baru na fazę belitu tworzoną przy temperaturze 1200°C

72%

Ghorab H. Y. , Abbas M. , Arafa A. , Hassan H. E.

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tom R. 28, nr 6

428--437

PL

Worcowy belit został przygotowany poprzez wypalenie kalcytu i kwarcu w stosunku molowym 2 przez 1,5 godziny w temperaturze 1200°C. Zidentyfikowano odmiany polimorficzne belitu utworzone przy dodatku Li2CO3 z 1% Li2O jako topnika i domieszki oraz SrCO3 i BaCO3 w ilościach równoważnych 8% SrO i 8% BaO jako mineralizatorów. Utworzone odmiany polimorficzne zbadano za pomocą dyfraktometrii rentgenowskiej z analizą Rietvelda oraz zbadano pod skaningowym mikroskopem elektronowym. Stwierdzono, że odmiany β i γ równie często powstają w belicie z domieszką strontu, a w obecności baru pojawia się również α’. Rozkład Li2CO3 do Li2O jest opóźniony przez węglany strontu i baru z powodu wzrostu ciśnienia parcjalnego CO2 i w konsekwencji stopiony materiał jest stabilizowany. Konieczne są dalsze badania w celu wyjaśnienia wpływu ciśnienia parcjalnego CO2 węglanów na polimorfizm krzemianu dwuwapniowego.

EN

A reference belite is prepared from burning calcite and quartz at mole ratio = 2, for 1.5 hours at 1200°C. Belite polymorphs formed in the presence of Li2CO3 with 1% Li2O, as a fluxing and doping agent, in addition to SrCO3 and BaCO3 with amounts equivalent to 8% SrO and 8% BaO, as mineralizers, were identified. The thermal behavior of the belite mixes and of the pure carbonates was recorded for temperatures up to 1300°C. The polymorphs formed are defined by means of X-ray Rietveld analysis, and examined under a scanning electron microscope. It is found that the β and γ polymorphs are equally formed in the belite doped with strontium, and in the presence of barium, the α’ appears as well. The decomposition of Li2CO3 to Li2O is depressed by strontium and barium carbonates due to the increase in the partial pressure of CO2 and consequently the melt is stabilized. Further research is needed to explain the effect of CO2 partial pressure of the carbonates on the polymorphism of belite.

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Application of Nasicon and YSZ for the construction of CO2 and SOx potentiometric gas sensors

58%

Pasierb P.

Materials Science Poland

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2006

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tom Vol. 24, No. 1

279--284

EN

Solid-state potentiometric CO2 and SOx sensors were fabricated using Nasicon (Na3Zr2Si2PO12) or YSZ (ZrO2 + 8 mole % of Y2O3) solid electrolytes, with fused carbonates or sulphates as sensing electrodes and Na2Ti6O13-Na2Ti3O7 two-phase systems or porous platinum as reference electrodes. A comparison of the performance and long-term stability of the prepared sensors was made. More stable behaviour of CO2 sensors was observed for cells prepared from Nasicon while SOx sensors with YSZ used as the solid electrolyte displayed a better performance. The sensing mechanism and long-term stability of the investigated cells was discussed in terms of the possible reactivity of solid electrolytes with the electrode materials and the formation and modification of "ionic-bridges" at the solid electrolyte-electrode interface.

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Cyanobacterial flora and water characteristics of paddy fields of Udaipur [India]

58%

Kapoor K. , Leenta A.

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nr 1