Description Of Outcrops Research Articles

An optimized potential field geological modeling method for a high-level radioactive-waste geological disposal repository

A three-dimensional geological model that incorporates spatial information efficiently and intuitively is an important basis for the planning, construction, and utilization of high-level radioactive waste (HLW) disposal geological repository sites. However, traditional modeling methods cannot describe extremely complex geological contexts accurately due to the sparsity of effective data. This paper proposed a cokriging gradient interpolation method based on integrated potential fields that combines relationship and orientation data from outcrop descriptions, contour lines, boreholes, and stratigraphic contacts. A multi-stratigraphic sequence was constructed via a curve/surface tracking algorithm, and optimal geological interfaces were screened using universal cokriging equations. The geological modeling for a HLW disposal repository shows that under different data completeness conditions, this method can reveal the spatial distribution of geological structures (including fault networks and intrusive bodies), achieve better approximations for complex geological environments, and provide strong support for HLW repository roadway planning.

From clays to pottery: Role of geomaterials in the social - technological development of the Messina territory (Sicily, Italy) and archaeological-historical information on the main kilns

This contribution is intended to answer the question of why in teaching approaches it is important to speak about territory? The answer to the question is driven by the consideration that the territory, including the established human activities, encompasses the history, the events and the culture of the people who populated it. On this regard, it should be noted that the relationship between natural elements and human activities that refer to a given territory has a dynamic character since both influence each other and help to write the history of that place. In this framework, the proposed method is used as an interdisciplinary approach to the theme of clay minerals. These latter are hydrous aluminium phyllosilicates, with variable amounts of iron, magnesium, alkali metals, alkaline earths. They are the main constituents of soils, and have been used by humans since ancient times in agriculture and manufacturing. For this reason, clays played a basic role for the human civilization process since its earliest periods. Clays are recognized amongst the most important rock products, both as raw material and in the form of pottery, bricks, tiles, terra-cotta and many other tools for daily use. This is particular evident in Sicily, where, since ancient times, the availability of local clay sources favoured the diffusion of clay-artefacts and related workshops found over the territory. This paper makes reference to a lecture addressed to university students and includes: i) the description of the main mineralogical features and properties of clay minerals; ii) a brief discussion on the role played by clays in terms of clay-artefacts production in the historical and cultural evolution of the Messina territory; iii) a description of local clay outcrops; iiii) a presentation of the main kilns over the Messina territory, and in particular of unpublished archaeological information on the S. Pier Niceto kilns. The proposed approach aims to increase the interest of students towards the significant aspects that affected the social-economic growth of the Messina’s territory and on the importance that geo-materials had in the technological evolution of its civilization process.

Virtual mapping and analytical data integration: a teaching module using Precambrian crystalline basement in Colorado's Front Range (USA)

Abstract. The COVID-19 pandemic hindered the ability to conduct field geology courses in a hands-on and boots-on traditional manner. In response, we designed a multi-part virtual field module that encompasses many of the basic requirements of an advanced field exercise, including designing a mapping strategy, collecting and processing field observations, synthesizing data from field-based and laboratory analyses, and communicating the results to a broad audience. For the mapping exercise, which is set in deformed Proterozoic crystalline basement exposed in the Front Range of Colorado (USA), student groups make daily navigational decisions and choose stations based on topographic maps, Google Earth satellite imagery, and iterative geological reasoning. For each station, students receive outcrop descriptions, measurements, and photographs from which they input field data and create geologic maps using StraboSpot. Building on the mapping exercise, student groups then choose from six supplements, including advanced field structure, microstructure, metamorphic petrology, and several geochronological datasets. Because scientific projects rarely end when the mapping is complete, the students are challenged to see how samples and analytical data may commonly be collected and integrated with field observations to produce a more holistic understanding of the geological history of the field area. While a virtual course cannot replace the actual field experience, modules like the one shared here can successfully address, or even improve on, some of the key learning objectives that are common to field-based capstone experiences while also fostering a more accessible and inclusive learning environment for all students.

Activity-educational aspects of geological excursions

The purpose of this article is to discuss the educational tour as a form of educational process in the activity-the educational aspect of the geological excursion in the study of rock outcrops career «Borok» of Novosibirsk as a geological object of interest for educational tours and training-practical work. To write the article, we used methods of comparative analysis, generalization, field geological observations, sampling, cross-section sketches, descriptions of outcrops, including working with a mountain compass and methods of conducting a training geological-geographical and geoecological route, drawing up a map of the territory, laboratory studies of rocks. The absolute advantage of the Borok quarry is its location, as well as optimal conditions for a thorough inspection and description of rock outcrops. Branched dikes and veins are visible in the walls of the quarry, as well as the overlap of igneous Paleozoic rocks with sedimentary later deposits. Dumps of various Intrusive igneous, dike rocks and pegmatites, hydrothermal veins with ore minerals are of educational interest during excursions. The Borok quarry cooperates with schools, colleges, and Universities in Novosibirsk and is a platform for educational excursions to the production site and a place for training practices, as well as a venue for educational Olympiads in Geology and Geoecology. On the example of one of the production facilities of the city of Novosibirsk - the stone quarry «Borok», the possibilities of organizing and conducting geological excursions in order to study the geological structure of the territory, consolidate theoretical geological and geoecological knowledge, acquire skills in educational and practical work and analyze the results obtained are demonstrated.

Origin of the penecontemporaneous sucrosic dolomite in the Permian Qixia Formation, northwestern Sichuan Basin, SW China

Abstract The characteristics, formation time, and origin of the sucrosic dolomite reservoirs in the Permian Qixia Formation of northwestern Sichuan Basin are analyzed. Core and outcrop description and microscopic analysis of the sucrosic dolomite samples are carried out. It is found that the dolomite has typical features different from other kinds of dolomites: (1) This dolomite is generally medium-coarse in crystal size, and often associated with very finely to finely crystalline dolomite and cave-filling dolomite. (2) Typical identification marks of eogenetic karstification are developed at the top of the upward-shallowing sequence. (3) The medium-coarse crystalline sucrosic dolomite is cut by the early diagenetic karst fabric, and is characterized by dolomite with dissolution edge, dolomite vadose silt in pores, and transgression clay filling between the medium-coarse dolomite crystals. The medium-coarse crystalline sucrosic dolomite was formed earlier than the eogenetic karstification. The sucrosic dolomite with occasional cloudy core and clear rim has bright cathodoluminescence, high inclusions temperature, significant negative skewness carbon and oxygen isotopic compositions, and rare-earth element (REE) pattern similar to seawater, indicating it experienced two periods of dolomitization, evaporative concentration reflux-infiltration and penecontemporaneous seawater circulation hydrothermal fluid dolomitization. The study results not only update the understanding on the dolomitization time of Qixia Formation, demonstrate that the sucrosic dolomite can be formed in the penecontemporaneous stage when seawater reflux superimposed with hydrothermal fluid effects, but also show that the taphorogenesis in the Dongwu period began in the Early Permian. Moreover, the dolomite controlled by the grain bank migration and terrain in the slope break appears in bands of large scale, this knowledge provides basis for expanding the exploration field of this type of reservoirs.

Calcretes and travertines from the Palaeocene Itaboraí Basin as evidence of the early evolution of the Southeastern Brazil Continental Rift

AbstractThe Itaboraí Basin, located in Rio de Janeiro state, is the smallest segment of the Southeastern Brazil Continental Rift, and the first to open, during the Palaeocene. Numerous studies focused on its fossiliferous content, but few systematically approached its depositional and diagenetic processes and products. A detailed description of the basal sedimentary deposits that remained after nearly fifty years of exploitation for cement production allowed an interpretation of the initial tectono‐sedimentary conditions responsible for the formation of the Basin. The macroscopic and petrographic description of outcrops and well core samples of the calcretes and travertines that correspond to the initial basin infill was integrated with stable isotope geochemistry. The calcretes were separated into different facies (powdery, nodular, massive, platy, laminated and brecciated), and classified according to morphogenetic stages. Their main microscopic features include nodules, contraction cracks, vadose pisoliths, rhizocretions, infiltrated clays, corroded grains, expanded micas and clay aggregates with bimasepic–plasmic microfabric. The travertines exhibit diverse forms of abiotic calcite crystal aggregates (plumose, lamellar to prismatic‐radial, spherulitic) and a minor proportion of microbial microcrystalline precipitates (bacterial shrubs). Tectonically active periods, characterized by intense fault movements associated with humid climate, promoted hydrothermal activity, formation of travertines and modification of the alluvial deposits and calcrete facies by ascending fluids. During periods of tectonic stability under arid to semi‐arid climate, the exposed alluvial and hydrothermal deposits were influenced by pedogenetic processes. Sulphide‐rich carbonate hydrothermal breccias occur in the main fault zone at the southern border. The characterization of extremely active pedogenetic and hydrothermal processes during opening and early evolution of the Itaboraí Basin is essential to the understanding of the initial evolution of the Southeastern Brazil Continental Rift. Additionally, some isotopic and petrographic similarities of the Itaboraí carbonates with the vast South Atlantic Aptian Pre‐Salt lacustrine deposits may offer an interesting contribution to the understanding of that important petroleum province.

Outcrop and thin section scale descriptions of Silurian carbonates within the Hiawatha National Forest, Mackinac County, Upper Peninsula, Michigan, USA

Silurian carbonate outcrops within the southern part of the St. Ignace District of the Hiawatha National Forest (Mackinac County, Michigan) were examined to develop a local description of the exposed geology. The bedrock geology consists of the Manistique Group (dominantly the Cordell Formation) and the Engadine Group (Rockview Formation, Rapson Creek Formation, and Bush Bay Formation). Building on observations and differentiation from previous investigations, outcrops were selected to describe the macroscopic characteristics of these formations in attempt to develop a local description that would be more useful compared to confusing regional descriptions for researchers and forest officials. In Mackinac County, the Cordell Formation is a dark-to-light gray, chert-rich dolostone with abundant corals, stromataporoids, brachiopods, and echinoids. The Rockview Formation is a dark gray-to-white, chert-poor dolostone with microbiolite laminations, and brachiopod molds. The Rapson Creek Formation is a light gray-to-white, chert-free dolostone with abundant stromatoporoids. The Bush Bay Formation is light reddish brown to white in color, chert-poor, crystalline dolostone with abundant echinoids, brachiopods, and corals.

The response to the rebuttal on the revised stratigraphy of the Bida Basin, Nigeria: New observations.

The late Cretaceous Bida Basin lithostratigraphy was carried out in order to establish a correlation between the northern (Bida area) and the southern part (Lokoja area) of the basin. The detailed fieldwork carried out over four years involved field description and mapping of outcrops in the entire basin. The study showed that the basin is underlain by mainly continental sedimentary rocks with minor occurrence of marginal/shallow marine to freshwater flood-plain deposits. The basin fill is characterised mostly by several cycles of amalgamated and/or stacked alluvial fans of the Bida/Lokoja Formation directly overlying the Basement Complex. The study revealed that the Lokoja/Bida Sandstone is overlain directly by the oolitic/pisolitic ironstone of the Agbaja/Sakpe Formations, which, in turn, is succeeded by fine to medium grained, grey and white sandstones, siltstones, grey clays, carbonaceous silts and shales, and ubiquitous concretionary ironstone bands of the Patti/Enagi Formation. Given the current detailed investigation, this study suggests that contrary to the rebuttal published, the Agbaja Ironstone is not the youngest formation in the basin. This study further revealed that the sequence of rocks and fossils used to define the Patti Formation and its probable age do not exist on Mount Patti in Lokoja, rather they are found along excavated road sections, quarries and boreholes around the Ahoko Village. Based on the detailed field work and sedimentological investigations, this study hereby proposes that the name ‘Patti Formation’ be changed to ‘Ahoko Formation’.

Sequence stratigraphic investigation of the Early Miocene Formations in the Zagros Folded belt using wireline well logs analysis

Based on the available core sample description and wireline log analysis, sedimentary facies, microfacies and lithofacies interpretation are evaluated to determine the large scale architecture in the Early Miocene formations, from close to the contemporaneous Lower Miocene depositional margin of the Zagros basin, as represented in outcrop sections, to productive oil field within the Kirkuk embayment equivalents ca. 100 km to the south-west and west. Sequence stratigraphic methods of sedimentary log interpretation and log correlation are used to construct a model of the overall regressive and transgressive or combined transgressive to regressive character of each of the formations, thus providing an indication of the gross reservoir stacking patterns over this distance. Based on outcrop descriptions and wireline log data the Dhiban Formation is interpreted as a lowstand system tract (LST) of a third order depositional sequence, lying between the Euphrates Formation regressive parasequence set that could represent a highstand systems tract (HST) of a third order sequence and the transgressive parasequence set (third order transgressive systems tract, TST) of the lower part of the Jeribe Formation. Several higher order transgressive and regressive cycles are evident within the Dhiban Formation in the subsurface sections. The transgressive cycles within the Dhiban formation are associated with the carbonate layers. Yellowish grey, friable anhydrite is recognized in the Dhiban Formation at outcrop, and thick anhydrite of low gamma ray and high density readings was identified in the subsurface sections. This lowstand evaporite system filling the basin centre can be confirmed as the relevant model for the mixed carbonate-evaporite basin at the scale of a third order cycle.

Sedimentologi Batugamping Formasi Jayapura di Sepanjang Lintasan Dewarebru, Mamei-Waibron, Jayapura

The Pleistocene of the Jayapura Formation limestones well cropped out at Dewarebru Section, Mamey-Waybron, Jayapura Regency. Detailed descriptions of rock outcrops and petrography analysis of selected limestone samples is used to find out the limestone sedimentology characters. This Jayapura limestone was divided onto four limestone facies, including lithoclastic rudstone, bioclastic packstone, bioclastic grainstone and bioclastic wackesone rock facies. The rocks was deposited in a fore slope talus forming submarine alluvial fan, furthermore the rocks was deposited in a local slope on the back reef environment.Keywords: Limestone, petrography, stratigraphy, sedimentology, Jayapura

Lower to middle pleistocene coastal dune fields formation in the western mediterranean (Western Eivissa, Balearic archipelago): Chronology and landscape evolution

Abstract Colluvial and aeolian successions in coastal environments are useful indicators of geomorphological changes that occurred during the Quaternary. Pleistocene aeolian deposits interbedded with colluvial deposits and palaeosols in areas of Cap Negret, Punta de sa Pedrera, Cala Bassa and Cala Compte, western coast of the island of Eivissa (western Mediterranean) are studied here. These deposits span almost continuously along 14 km of the coast, covering an area of approximately 22 km2. We present a sedimentological and stratigraphical description of these Pleistocene outcrops. Five major sedimentary facies involving the succession of aeolian, colluvial and edaphic environments are described. Carbonate sandstones, breccias, conglomerates and fine-grained deposits are the main components of these sequences. Optically stimulated luminescence (OSL) dating of aeolian levels indicates that deposition took place from the Lower to Middle Pleistocene. The sedimentological and chronological analysis of these deposits allows reconstructing of the coastal Pleistocene environmental history from Marine Isotopic Stage (MIS) 22 to MIS 6. Results show that the main controls on Lower to Middle Pleistocene coastal landscape evolution on Western Eivissa are changes in the average wind direction over time, modulated by the interaction with coastal relief orientation. The main episodes of aeolian activity identified and dune formation in the Western Mediterranean can be linked to periods of low sea level.

Morphology and features of Cambrian oncoids and responses to palaeogeography of the North China Platform

The Cambrian strata in the North China Platform are fully exposed. A wide variety of carbonate oncoids with different shapes occur in the Xuzhuang and Zhangxia formations (Miaolingian Series) from six Cambrian sections in the study area. A comprehensive study involving outcrop description, microscopic observation, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and carbon and oxygen isotope analysis is conducted to determine the facies, morphology, internal structure, and geochemical properties of the oncoids. The oncoids are divided into six types based on their morphology and internal structure. Microscopic and ultrastructural observations reveal typical microbial fossils (Girvanella) and microbially-related sediments (framboidal pyrite), indicating the biogenicity of the oncoids. Additionally, the XRD and carbon and oxygen isotope analysis results suggest that the formational environments of these oncoids are different due to terrestrial influences. Statistical data on the oncoids from the six sections show that there are obvious differences in the types of oncoids and the proportions of different varieties in each section. The spatial differences in the oncoid morphologies are associated with different palaeogeographic settings. The rough oncoid growth patterns developed in nearshore environments were influenced by terrigenous debris and steep terrain, whereas the delicate oncoid growth patterns developed in offshore environments were less affected by terrestrial factors and were featured by more stable depositional processes related to microbial mats.

3D stratigraphic architecture, sedimentary budget, and sources of the Lower and Middle Triassic strata of western Canada: evidence for a major basin structural reorganization

This study focuses on the Lower–Middle Triassic Montney, Sunset Prairie, Doig and Halfway formations from the foreland basin of the Canadian Cordillera (Alberta and British Columbia). Based on core and outcrop descriptions, the correlation of 400 wells, and on mineralogical analyses, this study interprets the basin-scale, 3D-stratigraphic architecture of these formations and discusses the controls on its evolution. Well correlation highlights four sequences (1–4) interpreted to occur in two second-order cycles (A and B). In this work, the Early Triassic Montney Formation and the early Middle Triassic Sunset Prairie Formation are interpreted to consist of three third-order sequences (1–3) related to the first second-order cycle (cycle A). The Middle Triassic Doig and Halfway formations are interpreted to consist of a fourth sequence (4) related to a second second-order cycle (cycle B). Integration of the stratigraphic surfaces with previously published biostratigraphic analyses emphasizes a major time gap of c. 2 myr between these two cycles, interpreted to record a major reorganization of the basin. Mineralogical analyses suggest that during cycle A, sediments were delivered from the east (Canadian Shield); whereas in cycle B, additional sources from the west (proto-Canadian Cordillera) occurred. This study shows that the stratigraphic architecture evolution was affected by the structural heritage of the basin and continental geodynamic evolution. This study provides a large-scale understanding on the controls of the stratigraphic architecture of the Lower and Middle Triassic strata, suggesting local and regional controls on the reservoir extension and unconventional play configuration within these strata.

The Tumey Giant Injection Complex, Tumey Hill, California (USA)

Abstract The Tumey Giant Injection Complex (TGIC) is a regionally developed sandstone intrusion complex emplaced into the deep-water Kreyenhagen Shale (Eocene) in the San Joaquin Basin, Central California. Detailed geological mapping, stratigraphic reconstruction and outcrop description, supported by structural analysis, allowed the architectural characterization of the TGIC. The complex is described as two main stratigraphically constrained intervals: (1) a lower interval (250 m thick) emplaced into clay-rich mudrock, consisting dominantly of sills with stepped and multilayered geometry; and (2) an upper interval (200 m thick) characterized by injection breccia and large wing-like intrusions ( c. 600 m width × 100 m high) emplaced within predominantly biosiliceous mudrock strata. The intrusions in both intervals were derived from turbiditic channel fills intensely modified by sand fluidization. Sandstone intrusions and fractures affecting host strata are dominantly oriented sub-parallel to the basin axis striking between NW–SE and N–S, mainly dipping to NE and forming asymmetric saucer-shaped intrusions, suggesting structurally driven hydraulic fracturing and sand emplacement. The absence of a deep aquifer and potential sand sources underlying the complex suggests a lateral contribution of fluid flow. The TGIC occurs at a scale similar to injection complexes recognized in the subsurface and is a valuable reservoir analogue for hydrocarbon accumulations associated with sand injectites.

Facies, petrophysical and geochemical properties of gravity-flow deposits in reservoir analogs from the Itararé Group (late Carboniferous), Paraná Basin, Brazil

Abstract Since many reservoirs do not allow direct observation due to their depth and/or difficulty of sampling, studies of analogs have been commonly used as a tool to understand the spatial distribution of reservoir properties. The Parana Basin is 1.6 million km2 large and has two known petroleum systems. However, there are only 124 irregularly distributed wells drilled in the basin, among which 22 contain gas or oil shows and 10 have sub commercial accumulations. The Permo-Carboniferous Itarare Group, due to the exploration history, is the best exploratory target in the basin because it has thick intervals of sandstones with moderate to good reservoir quality and also because it often lies directly on gas-prone source rocks of the Devonian Ponta Grossa Formation. In order to increase knowledge about Itarare Group reservoirs, as well as to better understand its heterogeneities, this study aims to integrate petrophysical data with facies and facies associations using both outcrop and cores from shallow wells in southeastern Parana Basin. By doing this it is expected to fill a gap of quantitative data in previous studies on reservoir analogs in the Itarare Group. Cores and outcrops were analyzed in sandstones in order to integrate surface and subsurface data, and to understand the lateral continuity according to stratigraphic correlations. Equipment such as gamma-ray spectrometer, portable x-ray fluorescence, and a minipermeameter were used for the acquisition of quantitative data. Sedimentological description of cores and outcrops as well as thin section description were also carried out. The facies with the greatest reservoir potential are medium to fine-grained, massive (Sm) and normally-graded (Sg) sandstones. In one outcrop locality (Rio dos Cedros), the Sg facies presents the best reservoir properties such as secondary porosity of 32% and average permeability of 1439 mD. The geochemical data allowed evaluating the gamma-ray variation in relation to chemical elements, such as iron oxide. In outcrop, API radiation is higher in relation to the cores, as well as Al2O3 and Fe2O3. These values are related to the large amount of intraclasts and cementation by iron oxides-hydroxides. Despite in the great amount of iron presents in the Rio dos Cedros samples, the porosity is mainly secondary, generated by the feldspars dissolution. The correlation between the cores and outcrops allowed the evaluation of the influences of mass transport deposits in the petrophysical properties of sandstones. In cores, sandstones interbedded with these deposits have high permeability, but it is not possible to evaluate its lateral continuity. In outcrops it was possible to observe that these deposits affect lateral continuity, permeability and porosity. We conclude that the best reservoir facies in the Itarare Group will be associated with sites within the basin that are away from the slope region and the influence of mass-transport processes.

Seismic imaging of complex geometry: Forward modeling of sandstone intrusions

Sandstone intrusions form large bedding-discordant sandstones that intruded into finer grained, less permeable host strata. They form naturally sand-propped hydraulic fractures that constitute a connected network of permeable conduits through which fluids escape to the Earth's surface. Saucer-shaped sandstone intrusions are among the largest volume intrusions and are commonly resolved on seismic data. Outcrop analogues of seismically-resolved saucers-shaped intrusions reveal that many attendant intrusions, in particular dikes, are undetected in seismic data. Seismic forward modeling of a detailed outcrop description of a saucer-shaped intrusion demonstrates that intrusions steeper than 45° are undetected and that up to 40% of the entire volume of sandstone intrusions is not seismically imaged. Wedge geometry – associated with discordant contacts between different lithologies – causes constructive and destructive amplitude interference, creating imaging artefacts of sandstone thickness and geometry. Comparison of the outcrop seismic models with 3D seismic data from Volund oilfield demonstrate both the similarity of the saucer-shaped intrusions and the distribution and quantity of dikes that may be undetected (ca. 78%) using subsurface data. Lack of detection of dikes has direct implications on the valuation of upward migration of fluids and an overestimation of seal capacity. This therefore has major implications when using seismic data to evaluate waste sequestration or to execute hydrocarbon or groundwater exploration and production.

Facies analysis and paleosol characterization of Urucuia group in the Sao Domingos - GO region

The Sanfranciscana basin is a wide intracratonic basin sub-divided in Abaeté sub-basin and Urucuia sub-basin which includes four Groups of Neo Paleozoic to Neo Cretaceous ages, among them there is the target of this study, the Urucuia Group (Upper Cretaceous). The Urucuia Group has the largest rock volume and areal distribution of the basin. Its rocks constitute two Formations, the basal named Posse overlaid by Serra das Araras Formation. In a continental environment where there is a few fossil contents, the paleosol study can bring important information about climatic and geomorphologic conditions, and biological activity being possible to do an environmental reconstruction. Therefore, this project aims to elaborate a paleoenvironmental model to the Upper Cretaceous of the Sanfraciscana basin through facies analysis and paleosol characterization. The fieldwork was accomplished in the outcrops of the Urucuia Group situated near to São Domingo (GO) town. Outcrop descriptions, photographic registration, and sample collection to laboratory analysis were the methodology applied. The outcrop description was made by the identification of lithologies, textures, sedimentary structures, paleocurrents, fossil content, bed geometry, as well as paleosol macromorphologic description.

Geophagic Clayey Materials of Sabga Locality (North West Cameroon): Genesis and Medical Interest

Geophagia, the deliberate ingestion of clayey materials, is a complex eating behaviour with obscure etiology and numerous health/medical problems. Geological, mineralogical and geochemical studies were carried out on Sabga geophagic clayey materials located within a trachyte Bamenda mountain, about 16 km east of Bamenda town (North West Cameroon), in order to define the genesis, and its medical interest. Four (04) samples were characterized by different techniques: description of outcrops and pits, particle size distribution by laser dispersion, X-ray diffraction, Fourier transform infrared spectrometry, Scanning electron microscopy and bulk chemical analyses. The main clay minerals were smectite (49-60%) and kaolinite (4-6%). The other major minerals are quartz (19-34%), feldspar (6-12%), goethite (3-6%), and hematite (1-3%). The average particle diameter varied from 2 to 9 μm. Results from the different analytical techniques point out a meteoric weathering of feldspar as petrogenetic origin of geophagic clayey materials. Smectite and kaolinite, which are the main desirable minerals components of the geophagic clayey materials, were geochemically derived from surrounding trachytes. However the presence of crystalline silica (quartz) up to 2% limits the application of some Sabga geophagic clayey materials for pharmaceutical clays. The high radioactive (Th, U), carcinogenic (Cr, Cu, Pb, Ni) and teratogenic (or birth defects) (Cu, Zn, Pb) elements contents in some Sabga geophagic clayey materials implied some pretreatment.

ГЕОЛОГІЧНІ/ГЕОТУРИСТИЧНІ ОБ'ЄКТИ ЗАКАРПАТСЬКОЇ ОБЛАСТІ ЯК ВІДОБРАЖЕННЯ ГЕОЛОГІЧНОЇ ІСТОРІЇ КАРПАТ

Consideration is given to description of important geological objects (observation points) of the southern slope of the Carpathians as reflections of sedimentary, paleogeographic and paleogeodynamic history of the Carpathians formation. Method. Standard method of geological description of outcrops, elements of sedimentological analysis of structural and textural features of rocks, and micropaleontological method are used. Results. A number of key geological objects that reflect the important stages of the geological evolution of the Carpathians in the Transcarpathian region near highways is described. These objects (the observation points in the article) can be represented as geotourist ones. In the first location which is in Yablunytsa Pass, an outcrop of Oligocene "striped" Holovets Limestone; further, along the Trostyanets Stream – Jurrassic pillow-lavas in the front of the Burkut Nappe; along the Kamyanyi Potik Stream – Jurassic- Early Cretaceous volcanogenic-sedimentary succession of the Kamyanyi Potik Nappe; along the Kosivka River – Eocene marls of the Marmarosh Massif sedimentary cover and the Inner Carpathian flysch of the Monastyrets Nappe; in the area of Novoselytsya village in the basin of the Luzhanka River – the Jurassic-Paleogene deposits of the Pieniny Klippen Belt; along the riverbed Tereblya in Zabrid village – Cretaceous-Paleogene deposits of the Marmarosh Klippen Zone are traced. Scientific novelty. The characteristic of a number of geological objects of the Transcarpathian region is supplemented and detailed and their brief description as reflections of sedimentary, paleogeographic and paleogeodynamic history of the Carpathians is presented. These objects reflect subsequent geological events: the birth of the Carpathian sedimentary basin; the formation of sub-oceanic and oceanic crust of the Outer Carpathian Flysch Basin; the formation of Inner Eastern Carpathian nappes and their destruction due to the formation of Early Cretaceous olistostrome of the Maramorosh Klippen Zone; ForeMarmarosh and Pieniny Klippen Belt accretionary prisms growing; and the final Oligocene stage of the Outer Carpathian Basin development. In addition, the range of Paleocene-Eocene paleogeographic elements such as (from the East to the West): (a) the passive margin of the Tisza-Dacia – (b) the deep-water Inner Carpathian Flysch Basin – (c) the Pieniny active edge of the Alcapa Terrane is demonstrated. The route of the geological tour described in the article is recommended to get acquainted with the main features of Geology, Geodynamics and processes of formation of the Carpathians. It can be used for further development of geotourism in the Carpathians.

Section of the Paleocene-Eocene in the region of the Ak-Kaya Mountain (Central Crimea) and its geohistorical interpretation

«Вестник Санкт-Петербургского университета. Науки о Земле» — научно-теоретический рецензируемый журнал, обобщающий результаты исследований в области геологии, гидрогеологии и геохимии, петрологии и экологии, ландшафтного планирования и геоморфологии, экономической и социальной географии.