Peculiarities of Stratigraphic Distribution and Paleoecology of Jurassic Bivalve Mollusks of the Pre-Сarpathian Foredeep

Pre-Carpathian region is one of the oldest oil and gas producing regions of our country, which is attracting more and more attention of scientists. In the Outer zone of the Pre-Carpathian Foredeep, Jurassic deposits occur at considerable depths (up to 3,000 m), so we obtain almost all geological information about them exclusively during the study of core material selected during drilling. A comprehensive and detailed study of the Jurassic deposits of this zone during exploration drilling in the 1950s contributed to the discovery of the Kokhanivske and Sudovovyshnianske oil deposits and Rudkivske gas deposit, as well as a number of oil and gas manifestations. After that, the interest in the conditions of formation and stratification of Jurassic deposits increased. Researchers have begun to treat them as the promising objects for oil and gas exploration. Jurassic deposits in the Pre-Сarpathian Foredeep fill a single depression – the Stryi Jurassic deflection, covered by a thick layer of Cretaceous and Neogene rocks. The study of their geology and stratigraphy has acquired important applied and scientific significance, because stratigraphic research serves as a basis for clarifying the history of geological development of the region, performing tectonic constructions, reconstruction of paleogeographic and paleoecological conditions, comparison of productive horizons and specification of their stratigraphic position, search for new objects promising for hydrocarbons. Extremely rare finds of paleontological remains (which are not always well preserved) do not allow to unambiguously determining the age of the host rocks. It is still not always possible to clearly stratigraphically distinguish and correlate these rocks due to weak paleontological study and partial uncertainty in the interpretation of the geological structure of these strata. Despite the significant amount of research we have done, there are some debatable issues regarding the completeness of the section of these rocks and the presence of separate stratigraphic units in them. For many years, we have studied in detail and comprehensively bivalve mollusks found in the core of wells drilled in the Outer zone of the Pre-Carpathian Foredeep. As a result, the age of the host strata was specified and confirmed, as well as the thickness of individual stratigraphic units.

Recently Discovered Thick Bentonite Bed Hosted by the Lithothamnium Limestones (Badenian) in the Polish Part of the Carpathian Foredeep: The Evidence for Volcanic Origin

In this paper, we discuss the hypothesis on the volcanic origin of the precursor sediments for a thick (0.6 m) clay bed, hosted by the sequence of lithothamnium limestones of the Pińczów Formation. Combined X-ray powder diffraction, imaging methods (optical and electron microscopy), and chemical analysis were used to document the volcanic markers, which were preserved in the rock studied. The results obtained show that the clay bed discussed is bentonite in origin. This bentonite, which can be called Drugnia Rządowa bentonite, is composed almost entirely of montmorillonite with little admixtures of quartz and biotite. A small amount of calcite is present, but only in the top of the bed. Despite that, the bentonite contains nothing but clay material—it is a model example of entirely altered pyroclastic rock, which retains texture originally developed in volcanic glass fragments and reveals the preserved original features of the precursor fallout pyroclastic deposits (rhyolitic in character). The thick bentonite beds, discovered for the first time within the Badenian lithothamnium limestones of the Pińczów Formation, can be considered as a record of a violent, explosive volcanic event related to the closure of the Outer Carpathian basin and the development of the Carpathian Foredeep.

Hydrogeochemical Characteristics of Geothermal Waters from Mesozoic Formations in the Basement of the Central Part of the Carpathian Foredeep and the Carpathians (Poland) Using Multivariate Statistical Methods

The subject of this study is the chemical composition of potentially geothermal waters of the Mesozoic basement of the central part of the Carpathian Foredeep and the Outer Carpathians regions. The research objectives were: (1) to identify statistically significant differences between the chemical composition of waters from the Cretaceous, Jurassic, and Triassic aquifers, and between the waters of both regions; and (2) the discovery of zones indicating active water exchange—attractive due to the operational efficiency of wells. Knowledge of the chemical composition of water allows for the preliminary identification of areas of interest for the exploitation of water for recreational, healing, and heating purposes. The research methods used were: (1) statistical tests and (2) methods of multivariate data analysis, such as the Kruskal–Wallis test and Principal Component Analysis (PCA). The performed tests and statistical analyses allowed us to draw conclusions about significant differences between the chemical composition of waters from the Cretaceous, Jurassic, and Triassic aquifers, and the basement of the Carpathian Foredeep and the Outer Carpathians. They indicated the existence of a zone with symptoms of active water exchange. Before establishing the fact of active exchange of waters in this zone, further research should be undertaken.

Prospects of Using Hydrocarbon Deposits from the Autochthonous Miocene Formation (Eastern Carpathian Foredeep, Poland) for Geothermal Purposes

There are many oil and gas fields around the world where the vast number of wells have been abandoned or suspended, mainly due to the depletion of reserves. Those abandoned oil and gas wells (AOGWs) are often located in areas with a prospective geothermal potential and might be retrofitted to a geothermal system without high-cost drilling. In Poland, there are thousands of wells, either operating, abandoned or negative, that might be used for different geothermal applications. Thus, the aim of this paper is not only to review geothermal and petroleum facts about the Eastern Carpathian Foredeep, but also to find out the areas, geological structures or just AOGWs, which are the most prospective in case of geothermal utilization. Due to the inseparability of geological settings with both oil and gas, as well as geothermal conditionings, firstly, the geological background of the analyzed region was performed, considering mainly the autochthonous Miocene formation. Then, geothermal and petroleum detailed characteristics were made. In the case of geothermal parameters, such as formation’s thickness, temperatures, water-bearing horizons, wells’ capacities, mineralization and others were extensively examined. Considering oil and gas settings, insights into reservoir rocks, hydrocarbon traps and migration paths issues were created. Then, for evaluating geothermal parameters for specific hydrocarbon reservoirs, their depths were established based on publicly available wells data. Thereafter, the average temperatures for selected reservoirs were set. As the effect, it turned out that most of the deposits have average temperatures of 40/50 °C, nonetheless, there are a few characterized by higher (even around 80 °C) temperatures at reasonable depths.

Sukil River valley — a natural geological laboratory

<p>We present a number of geological objects located along the valley of the Sukil River, which flows within the Ivano-Frankivsk Region in the west of Ukraine. The river crosses a number of structures of the Skyba nappe and the Inner unit of the Ukrainian Carpathian foredeep, which belong to the orogen of the Outer Ukrainian Carpathians. The Outer Ukrainian Carpathians were formed as a result of alpine tectogenesis. They are composed mainly of flysch deposited in Cretaceous-Neogene basins. The foredeep is filled with sediments known as molasses.</p><p>The research objects allow to study many aspects of geology —sedimentation, fold formation, fault formation, formation of mountain systems.</p><p>Many objects in the Sukil River valley are currently being studied using the latest technologies — digital photogrammetry and terrestrial laser scanning  to create virtual geological outcrops.</p><p>Unique samples of Oligocene fish remnants collected during field research are stored in the Natural History Museum of the Precarpathian Professional College of Forestry and Tourism in Bolekhiv which is located on the Sukil River. Here there are also great druses of gypsum from a local quarry. In the same town are the remains of a saltworks which was one of the oldest in the region.</p><p>Objects located in the Sukil River valley have not only scientific but also aesthetic significance. The folds from Bukivets are the object of the international geotourism route "Geocarpathians".</p>