Anticlinal Folds Research Articles

Neostructural zoning of the Russian part of the Greater Caucasus megavault, the Eastern segment (advanced studies for engineering survey)

The use of the orotectonic method made it possible to detail significantly the previously proposed schemes of neotectonic zoning of the Eastern segment of the Greater Caucasus megavault. In the Russian part of the segment, the zones of the North-Eastern and Central uplifts are traced. Within the North-Eastern zone, Western, Eastern and Southern subzones are distinguished, differing in their structure and orientation of the main structures. Block structures predominate in the Western and Southern subzones, and folded ones in the Eastern subzones. Among the anticlinal folds, there are folds with eroded arches, as well as folds that are partially preserved. The zone of the central uplifts includes the subzones of the side and main ridges, separated by the subzone of the axial troughs. The trough subzone crosses the entire Eastern segment of the megavault and includes the Northwestern group of differently oriented grabens and the eastern Bezhtino-Samur suture-depression zone with longitudinal grabens. This zone and its subzones are limited by the largest faults and reverse faults. Most regional and local structures are separated by active faults, which may be dangerous for the stability of engineering structures. The obtained original data, which is not available in standard materials on geological surveying for a given area, is useful for construction design and geoecology.

Recognition of crustal extension in the Basin and Range Province: A history

The Basin and Range Province of the western United States has inspired or augmented many important geological ideas but is most famous for the concept of crustal extension. Acceptance of the concept was a slow process. Prior to the recognition of plate tectonics, extension was unexpected and hard to understand; when mapping of the region began in the 1860s, mountain ranges were assumed to be the products of crustal compression due to contraction of the Earth. The first mapping suggested that ranges are anticlinal folds, but the idea of uplift along vertical range-bounding faults arose shortly thereafter. There was recognition starting in the 1880s that at least some faults were normal-sense rather than vertical, which implied extension, but there were decades of dissent by geologists who still promoted the anticlinal-folding idea, thought that inclined faults were reverse faults, or believed that the basins and ranges were created by water or wind or glacial erosion rather than tectonics. Normal faulting gradually became widely accepted, but comprehension of its meaning was hindered by apparent thrust faults in parts of the province that suggested contractional deformation. These faults would later be interpreted as low-angle normal faults, and crustal extension became widely, though not universally, accepted in the 1960s as magnetic anomalies confirmed seafloor spreading. Roughly a century elapsed between the first geologic mapping and general acceptance of crustal extension. A parallel evolution of thought occurred in Africa as a consensus arose that rift valleys were products of extension. "Even those who have more sympathy with man’s endeavor than with the affairs of Nature may take an interest in the Science of Tectonics…. as a rule, the knowledge of the structure of a mountain chain comes as the reward of glorious struggle, both physical and mental." —Edward Battersby Bailey, Tectonic Essays (1935, p. 1)

Structure Analysis Gunung Benau Karst Area by Using mSTA and FFD, North Kalimantan, Indonesia

Abstract The formation of Gunung Benau is associated to the geological structural process. This study uses remote sensing using DEMNAS data resampled at 10 meters. The DEMNAS data will be modeled using the modified Segment Tracing Algorithm (mSTA) and Fault Fracture Density (FFD) approaches. Surface geological mapping methods involve observations, descriptions, direct measurements, and field data recording of data appearances and geological conditions on the Gunung Benau. The structure which found in Gunung Benau is a shear joint with syncline and anticline folds and nine faults identified. The mSTA’s main lineament directions, Northeast-Southwest and Southeast-Northwest, are consistent with the area’s geological structure. The FFD shows that the highest density values occur in the central region of Gunung Benau, where faults are extensively exposed.

Geophysical evaluation and petrophysical assessment of the Abu Roash "F" Member: A probable unconventional oil reservoir in Heba Field, eastern Abu Gharadig Basin, Egypt

This study investigates the geophysical properties of the Abu Roash F Member (AR/F) as a potential unconventional oil reservoir in Heba Field, located in the eastern region of the Abu Gharadig Basin (Egypt). Analysis of seismic data reveals the influence of Late Cretaceous dextral wrenching tectonic activity, evidenced by the presence of ENE-WSW anticlinal folds and intersecting NW-SE as well as WNW-ESE extensional faults throughout the study area. This tectonic regime is believed to have played a significant role in the formation of micro-fractures within the AR/F carbonate, which can enhance the reservoir's potential by improving its permeability and porosity. Petrophysical assessment identifies favorable reservoir zones within specific depth intervals across multiple wells. These zones exhibit promising reservoir quality, characterized by low shale volume (below 0.20), which indicates a cleaner reservoir rock with less clay content. Additionally, the high total porosity (ranging from 0.20 to 0.25) and moderate effective porosity (ranging from 0.15 to 0.20) suggest that a substantial portion of the rock's pore space is available for storing hydrocarbons. The low water saturation (between 0.40 and 0.50) further supports the presence of hydrocarbons, as it indicates that the pores are not predominantly filled with water. Furthermore, the high hydrocarbon saturation (ranging from 0.50 to 0.60) confirms the significant presence of hydrocarbons within the reservoir. The quantitative assessment of these petrophysical properties across all analyzed wells further confirms the good reservoir quality and potential of the AR/F Member. The integration of seismic and petrophysical data provides a comprehensive understanding of the reservoir characteristics, highlighting the AR/F Member as a significant oil reservoir in the eastern border of the Abu Gharadig Basin, particularly in Heba Field. This study's findings complement the existing knowledge of oil-bearing formations in the region, suggesting that the AR/F Member could be a valuable addition to the basin's hydrocarbon resources. The results underscore the importance of further exploration and development of the AR/F Member to fully realize its potential as a major contributor to the area's oil production.

Hydrocarbon composition and properties of oils of the Apsheron Peninsula and their connection with geological mode of occurrence

Hydrocarbon accumulations in the Lower Pliocene Productive Series of Apsheron Peninsula have formed owing to subvertical hydrocarbon migration from the underlying Maykop and Diatom source formations. This concept has been substantiated by the recent studies based on the molecular-isotopic characteristics of organic matter, oil and gas. The most notable feature of the Apsheron oils is the stable predominance of paraffin-naphthene HCs in all oil fractions, and this is true for all the fields considered. Meanwhile two geological features had major influence on formation of the composition and properties of Lower Pliocene oils in Apsheron Peninsula. In structures unaffected by tectonic erosion more mobile light components of oils happened accumulated in upper stratigrafically younger horizons due to natural fractionation of hydrocarbons on their upward migration routes. In anticlinal folds with washed out crestal part physical and biochemical degradation has caused the loss of light hydrocarbons, first of all of methane fraction, and in this way weighting up of oils. From top to bottom, towards the basal PS suites the distillate fractions show reduction in the light ends (gasoline and naphtha), which is predictably accompanied by an increase in the amount of bottoms. Compositional variation in oil hydrocarbons laterally and through the section of the peninsula is graphically demonstrated on the basis of gasoline, ligroin, kerosene and diesel cuts of oil. In terms of elemental composition, the deeper the stratigraphic occurrence of the reservoir, the more the whole oil is enriched in sulphur- and nitrogen-containing polar compounds. Keywords: oil; hydrocarbon composition; Apsheron Peninsula; the Productive Series; Lower Pliocene.

Advanced Geostatistical Techniques for Building 3D Geological Modeling: A Case Study from Cretaceous Reservoir in Bai Hassan Oil Field

A 3D Geological model was generated using an advanced geostatistical method for the Cretaceous reservoir in the Bai Hassan oil field. In this study, a 3D geological model was built based on data from four wells for the petrophysical property distribution of permeability, porosity, water saturation, and NTG by using Petrel 2021 software. The geological model was divided into a structural model and a property model. The geological structures of the cretaceous reservoir in the Bai Hassan oil field represent elongated anticline folds with two faults, which had been clarified in the 3D Structural model. Thirteen formations represent the Cretaceous reservoir which includes (Shiranish, Mashurah, U.kometan, Kometan Shale, L. Kometan, Gulneni, Dokan, Mauddud, Jawan/Mud, Batiwah, Shuaiba, Garagu, L.Sarmord). According to the property model, the model for each petrophysical property was constructed based on core data and CPI. By using the geostatistical method, the property model was constructed. The Mauddud Formation is considered one of the most promising hydrocarbon reservoirs in the Bai Hassan oil field based on the results of the property model, where the ratio of water saturation is around 30%, the porosity value is reaching up to 31%, and the net to gross ratio is averaging at 70%.

Multiscale resistivity mapping from an intracontinental hydrothermal mineral system, Adelaide Rift Complex, Australia

Porphyry mineral systems provide a significant source of critical minerals for modern society, that are predominantly formed in subduction related settings from magmatic hydrothermal fluids derived from an underlying reservoir. However, in post-subduction settings the processes that entrain and focus magmatic hydrothermal fluids throughout the crust, from source to deposit are often poorly constrained. In this paper, we have undertaken a magnetotelluric (MT) survey in an intracontinental tectonic setting across the Adelaide Superbasin, which is a Neoproterozoic passive margin formed during rifting of the supercontinent Rodinia. This region contains the Burra magmatic copper deposit, along with numerous sedimentary-hosted copper deposits. Systematic three-dimensional modelling was undertaken, initially at regional-scale, with 55 km gridded long-period AusLAMP data over a 500 × 500 km area, followed by infilled 10 km gridded broadband MT data, at the district-scale, centred over an area of copper deposits in the Adelaide Rift Complex. The modelling reveals an elongated zone of low electrical resistivity (∼100 Ω.m), in an otherwise resistive crust, at lower crustal depth (20–40 km) that is contiguous with the regional lineament of the Adelaide Rift Complex and copper and gold mineralisation. A narrow zone of low resistivity (∼100 Ω.m) branches through the upper crust (5–20 km) to the surface, that is remarkably aligned with the Burra magmatic mineral system, in an otherwise quite resistive crust (∼1000 Ω.m). Additionally, in the upper crust a zone of low resistivity (1–10 Ω.m at a depth of 5–8 km) extends from the Burra magmatic copper deposit southwards, constrained by anticlinal folding from the ∼500 Ma Delamerian Orogenic deformation of the Adelaide Rift Complex and spatially aligned with the Kapunda sedimentary-hosted copper deposit. We argue that the low electrical resistivity signature encapsulates a whole-of-lithosphere magmatically-hosted copper system, that is further mobilised by low-temperature fluids by mapping the footprint of ore-forming fluids from the source to associated mineralisation. Where later basin wide fluid recycling in a permeability enhanced basin, via neo-tectonism along pre-existing structures/trends, has likely remobilised copper, from a prior magmatic event, with copper being leached in chloride-rich saline fluids at low temperatures.

Exploring for structurally concealed Carlin-type mineralization: A case study from the northern Shoshone Range, Nevada, USA

This study integrates results from previous studies with new reconnaissance-scale mapping of rock types, structures, and hydrothermal alteration at Goat Ridge and Tenabo to provide a district-scale cross section and palinspastic restoration of an area in Nevada with high potential for Carlin-type mineralization in the footwall of a dismembered thrust fault. Reinterpretation of legacy drill data in light of recent advances in the understanding of Cenozoic normal faulting in the area with the expected stratigraphy of the Roberts Mountains autochthon allows for deciphering whether previous drill holes piercements of faults are the Roberts Mountains thrust or are tilted normal faults that down-dropped the deep-water siliciclastic rocks of Roberts Mountains allochthon onto the coeval carbonate rocks of the Roberts Mountains autochthon. A cross-sectional reconstruction shows that ∼11.1 km (120 %) of extension was accomplished along one set of faults that initiated at 60-70°and tilted 40°E. Previously underappreciated Mesozoic folds are present, which likely formed with horizontal fold hinges. Because of Cenozoic normal faulting and associated tilting, the hinge lines currently plunge at moderate angles and are offset as they step across each crosscutting fault. The anticlinal fold hinges produced the modern exposures of lower plate rocks in the range. The Eocene paleogeologic map that results from a plan-view structural restoration shows that the hinge lines of the original folds trended northwest-southeast in the southern half of the range but turned northward toward the northern end of the range.Mineralization in the range includes silver-dominated polymetallic veins/lodes, weak porphyry-type, Carlin-type, and siliciclastic-hosted gold deposits of uncertain origin. Porphyry-style and silver-dominated polymetallic vein mineralization is associated with ∼39–40 Ma granodiorites, with the silver-dominated polymetallic veins interpreted as the distal veins around weakly mineralized and/or deeply buried porphyry system(s), probably of the quartz monzonitic-granitic porphyry Mo-Cu subclass of porphyry molybdenum deposits. Crosscutting relationships demonstrate that at least one of “upper plate” gold deposits is Eocene, but a Miocene age cannot be ruled out for the other gold deposits.

Structural Interpretations for Zubair Formation in Kumait oil field, Using 3D Seismic Reflection Data, Southern-East Iraq

This study deals with the interpretation of structural 3D seismic reflection of the Kumait oil field in southern Iraq within the administrative boundaries of the Maysan Governorate. Synthetic seismograms are prepared by using available data of the Kt-1 oil field by using Petrel software to define and pick the reflector on the seismic section of the Zubair Formation, Which represents the Cretaceous Age. The study shows that the Kumait structure is an anticline fold. It is thought to be a structure trap caused by the collision of the Arabian and Iranian plates and trending in the same direction as driving factors in the area, which are from the northwest to the southeast, and the overall trend of strata is north and northeast. Seismic structure interpretation results show the top of the Zubair Formation and several structure closures. The stratification Phenomenon of the study area was clear evidence of the existence of closures which are probable to be hydrocarbon traps.

Myauchan Ore Field (Northeastern Asia), an Example of Weakly Eroded Ag–Pb–Zn Volcanoplutonic Mineralization

Abstract —The Myauchan ore field located in the Omsukchan zone of the Okhotsk–Chukotka Volcanic Belt is described. The Korennoe and Malyutka Ag–Pb–Zn ore occurrences forming this field are localized at the center of anticlinal fold of NW strike made up of Upper Triassic carbonate-terrigenous deposits intruded by stock-like bodies and dikes of Upper Cretaceous andesite, monzodiorite, granite-porphyry, and rhyolite-porphyry. Sulfide–carbonate–fluorite–quartz veins and vein–veinlet zones with arsenopyrite, pyrite, sphalerite, galena, chalcopyrite, and Ag-tetrahedrite are localized both in intrusions and in terrigenous strata. The field bears As–Sb–Ag–Pb–Au–Bi–Cu–Zn–W mineralization. Study of fluid inclusions and REE and ore element patterns show that the field ores formed from chloride solutions with the participation of surface waters in hydrothermal-magmatic system under epithermal conditions. The ores were deposited from solutions with TDS = 0.5–9.0 wt.% NaCl equiv. in the temperature range 106–287 ºC. The ores containing ca. 70 ppm Ag and up to 1.2% Pb formed through boiling-off of solutions enriched in iron salts. The ores with Ag < 7 ppm and Pb ≤ 25 ppm were generated from diluted hydrothermal solutions with predominant sodium salts and potassium admixture. Mineralization of the Myauchan ore field marks the upper level of the Ag–Pb–Zn ore system similar to the Gol’tsovoe deposit.

A SYNTHESIS OF THE GEOLOGY AND PETROLEUM GEOLOGY OF THE IRANIAN PORTION OF THE SOUTH CASPIAN BASIN AND SURROUNDING AREAS

The South Caspian Basin, the northern Alborz Mountains, the Gorgan plain and the Moghan plain constitute the northernmost and youngest petroleum system in Iran. This region was part of the Paratethys realm from Oligocene to Pliocene time. The Oligocene – Miocene Maikop/Diatom Total Petroleum System of the South Caspian Basin produces major volumes of hydrocarbons in Azerbaijan and Turkmenistan, and the Iranian sector of the basin has consequently undergone exploration due to its generally similar geology. The 20 km thick, dominantly Cenozoic sedimentary cover in the basin is reduced to less than 3 km in the northern foothills of the Alborz Mountains, and scattered surface oil seepages in the latter region are believed to be generated by Cretaceous and Miocene source rocks. In the Moghan plain to the southwest of the South Caspian Basin, anticlinal folds of Oligo‐Miocene Zivar Formation sandstones may be prospective for hydrocarbon exploration. Mud volcanoes in the Gorgan plain and in adjacent offshore regions at the SE margin of the South Caspian Basin are associated with hydrocarbon seepages, and appear to be sourced by Cretaceous and Cenozoic shales and mudstones. Major structural features in the southern part of the South Caspian Basin include Cenozoic mud diapirs, folds and gravity structures.

Delineation of Subsurface Structural Geology in Buzrgan Oil Field Using 2D Seismic Interpretation

This study focuses on the structural picture interpretation of Buzurgan oil field in the Maysan province of southern Iraq. Using 2D seismic data, Synthetic traces are created by selecting reflectors on the seismic section using the Petrel software and the well (BU-1) data currently available. The reflectors represented Paleocene to middle Miocene, which are L-Fars-Kirkuk-Jaddala-Aaliji. A thrust fault that solely impacts the L-Fars formation is dividing the research region into two blocks that are each affected by the examined reflectors. The fault system extends from northwest to southeast. The structural interpretation of depth maps reveals that some anticline folds were localized roughly surrounding well locations were marked on all maps.

The Messinian reservoir in El-Tamad oil field, Nile Delta, Egypt: Seismic interpretation and 3D modeling

El-Tamad Field, the first oil discovery in the onshore Nile Delta, is one of the promising areas in the Nile Delta for oil and gas. Therefore, thirty seismic lines, core data, and real-time flowline resistivity measurements of the Messinian Qawasim Formation were analyzed to characterize and model the reservoir in El-Tamad Field. The structure model shows that there are three main faults in the investigated area; F1 fault is a major growth fault trending E-W with a downthrown to the north, F2 trending NW-SE with a downthrown northeast, and the NE-SW trending F3 fault with a downthrown southeast. The depth-structure contour map on the reservoir's top shows that there is a rollover anticline fold formed at the downthrown side of the major growth fault. The petrophysical model illustrates that effective porosity increases towards both of southeastern and southwestern parts, while water saturation decreases in the southeastern part of the field, and the net-to-gross increase towards the center. Penetrating more vertical and sidetrack wells along the line connecting wells 1, 3, and 4 in El-Tamad Field, especially in the crest of the anticline fold that was recorded in the area is highly recomended. The spatial variation of the reservoir quality was attributed to the depositional setting, where many branches of larger distributary channels (sand facies) accumulated within a muddy estuary (shale facies) on the front of a bay-head delta.

Relationship between structural style and the petroleum system in the siba gas field, southern Iraq

The Siba gas field is the only non-associated gas field in southern Iraq, located in an area primarily for oil production. The study aimed to identify the reasons for gas generation and accumulation in the field's Lower Cretaceous Yamama reservoir and the source of the gas. The study focuses on seven wells from the field, namely Siba-1, 4, 5, 6, 7, 8, and 9, and the structural and tectonic settings of the field were studied by interpreting seismic data. Geometric analysis showed that the Siba field is a non-cylindrical, asymmetrical, open, anticlinal fold. The anticline is northeast-southwest-trending with two culminations, of which the northeastern one is the higher by about 100 m. The Siba field overlies deepest parts of the Mesopotamian foreland basin, almost adjacent to the Zagros orogenic front, where burial depth and thermal conditions were ideal for organic-matter maturation and increased pore pressures that lead to hydrocarbon migration from Middle Jurassic source rocks to the Lower Cretaceous Yamama Formation reservoir. The geochemical parameters of oils from the Yamama Formation are like those of oils from Sargelu Formation in adjacent fields, indicating that the Middle Jurassic Sargelu Formation is the most likely source of Siba hydrocarbons. Vitrinite reflectance and thermal analyses of oils from the Yamama reservoir (0.87% R0; 128.1 °C) and from the Sargelu Formation (1.36% R0; 156.96 °C) show that only the Sargelu Formation had the right burial depths and temperatures in this area during Miocene deformation to source Yamama hydrocarbons in the Siba field. Although the anhydrites of the Upper Jurassic Gotnia Formation form a prominent regional seal separating Jurassic source rocks from Cretaceous reservoirs, structure-contour maps and seismic analyses indicate that many faults and fractures, mostly related to Miocene deformation, penetrate Gotnia anhydrites. Hence, the study interprets that these faults, as well as facies changes on the margin of the Gotnia basin, seriously impaired the Gotnia seal, allowing the vertical migration of hydrocarbons from the Middle Jurassic Sargelu Formation into the Lower Cretaceous Yamama reservoir in the Siba field.

Geochemistry of Neoproterozoic Nagod Limestones from the Girgita Mine, Bhander Group, Madhya Pradesh, India

Vindhyan limestone of the Bander Group (Late Neoproterozoic) in the Maihar area, Satna district, is a part of an anticlinal fold and it forms an outlier in the study area. Geochemical analysis reveals that the proportion of Rare Earth Elements (REEs; La-Lu) in limestones varies between 14.8 ppm and 49.5 ppm. The Eu and Ce anomalies (normalized against Post Archean Australian Shale; PAAS) range from ~ 0.53 to 0.69 and ~ 0.57 to 1.07, respectively. The results of this study revealed that the limestones were principally controlled by the admixture of detrital materials, i.e., (i) The low values of REEs (ii) high values of Y/Ho (iii) positive correlation between REEs and Si, Al, Ti, V, Co, Ni, and Nb, and (iv) slightly negative correlation between CaO and REEs. Further, the variations in Ce anomaly may be due to the influx of detrital materials and positive Ce anomaly was attributable to the shallow marine depositional condition. The distribution of REEs (Chondrite normalized values) illustrates different patterns in the Nagod limestone due to the degree of differentiation in terms of LREEs and HREEs and Eu anomaly. The variations in elemental concentrations and the REE patterns revealed the mixing of detrital materials in the Nagod limestones.

NEW DATA ON PROMISING OIL AND GAS OBJECTS OF THE YAMNA SUITE OF THE PALEOCENE IN THE SOUTH-EASTERN PART OF THE SKІBA AND KROSNO COVERS OF THE UKRAINIAN CARPATHIANS

Thick sandstones of the Yamna suite are widespread throughout the Skіba cover, as well as in the south-eastern part of the Krosno cover. The research area is bounded by the Limnytsia River in the northwest and the Ukrainian-Romanian border in the southeast. Several promising structures comprising the Yamna sandstones (Brusturanska, Yanovetska, and Voronenkivska) are identified in this area. Among them, according to the number of positive indicators of oil and gas potential, the Voronenkivska structure (Nadvirna district of Ivano-Frankivsk region, near the settlements of Voronenka, Yablunytsya, Polyanytsya) is the most promising, localized in the Zelemyanka slice. The structure is divided by faults into four tectonic blocks and stretches for 8 km. Under the Oligocene rocks, crumpled into the anticlinal fold of the north-western extension, Paleocene-Eocene deposits are inferred according to the geological models, which contain thick sand strata of the Vyhoda (Middle Eocene) and Yamna suites of the total thickness over 300 m. Oil manifestations are documented in the Oligocene deposits on the surface. Potentially promising horizons may be in the depths range 1500-1800 m. The article extends the previous work devoted to the assessment of the oil and gas prospects of the Yamna suite of the Paleocene of the north-western part of the Skуba cover of the Ukrainian Carpathians. 4.2 million tons of oil were recovered from the Yamna sandstones of the Paleocene, which are characterized by good reservoir properties, in the fields localized in the north-western part of the Skiba cover. The Yamna sandstones in this sector of the Carpathians are also common in the Krosno cover. The uneven distribution of industrial oil potential between these two parts of the Carpathians is explained by lithological changes or the influence of structural and geochemical factors. A study of stratigraphy and reservoir properties of the Yamna sandstones, common in the deposits of the Skіba and Krosno covers, suggests that they comprise satisfactory reservoirs for hydrocarbons. Promising areas and structures have been identified and described.

PROSPECTS FOR OIL AND GAS POTENTIAL OF THE MIOCENE-PLIOCENE AND MESOZOIC DEPOSITS OF THE ABSHERON ARCHIPELAGO

The article is devoted to the prospects of oil and gas potential of the Miocene-Pliocene and Mesozoic deposits of the Absheron archipelago. The geological information about the Absheron archipelago dates back to the middle of the 19th century, the century of the industrial revolution. The offshore area of the Absheron archipelago, located to the east of the Absheron peninsula, is abundant with islands, surface and underwater hidden rocks, ridges, ledges and sand banks. The largest islands of the archipelago Pirallahi and Chilov are located here. They are confined to the anticlinal folds of the same name and their formation is associated with large thrusts of the SW limbs of these structures. The North Absheron oil and gas zone, located in the northern part of the Absheron archipelago, covers a vast territory stretching from the northwest to the southeast and is the southern end of the Scythian-Turanian Epi-Hercynian platform. An interesting feature from the point of view of the geology of the North Absheron tectonic zone is a peculiar tectonic structure, lithofacies features and oil and gas potential. Local uplifts differ from other uplifts located in the fold zone by their indeterminate location (Fig. 1). Despite the geological and geophysical work and the drilling of numerous prospecting wells, the Miocene-Pliocene deposits of the study area have not been sufficiently studied in terms of their oil and gas potential. Drilling of numerous wells in the Miocene-Pliocene deposits did not completely open the section of these deposits. The drilling of oil and gas bearing formations with full penetration and development is mainly associated with the optimal conduct of drilling operations. The anticlinal zone begins with structure bank Absheron. In connection with the washout on the structure bank Absheron, the upper section of the Productive series (PS) comes out on the day surface, and the lower section of the PS, with the exception of Gala suite, participates in all stratigraphic units. The Gala suite was found on the southwestern limb of the structure. Recently, hydrocarbon accumulations have been identified by prospecting and exploration work on the structures of Novkhany, Ashrafi, Garabagh. From this point of view, the correct assessment of hydrocarbon accumulations in the Miocene-Pliocene deposits in the North Absheron tectonic zone is considered the main one and complements the understanding of the oil and gas potential of the study area. Keywords: Absheron archipelago, Mesozoic complex, Pliocene deposits, Caspian Sea, prospecting and exploration, tectonic zone.

The validity of limestone rocks of Fat’ha Formation in the Hamrin Anticline/Salahaddin Governorate for riprap

To evaluate the probability of usage as a riprap, the study aims to identify some of the mechanical and physical characteristics of limestone rocks in the Fat’ha Formations in the northwest plunging area of the Hamrin Anticline fold within the Sallahaddin Governorate. These rocks have specific gravities between (2.161-2.521), dry density between (1.92-2.148) gm /cm3, water absorption rates between (4.104%-9.774%), mechanical abrasion between (29%-45.5%) and chemical abrasion ratios between (3.2%-5.8%), According to the specifications of the Florida Department of Transport and the Iraqi Standard Specifications No. (1385) for the year (1989), as well as the American standard (ASTM), it was found that most limestone rocks are not suitable for use as riprap stones in most stations because the percentage of absorption and dry density fall outside the limits of the specification, and it was found that limestone can be used as riprap stones only in the station (3) as a riprap stone for channels and trenches according to the specification of the Florida Department of Transport, as well as the station (4) suitable as a riprap stone according to the Iraqi standard No. (1385) for the year (1989).

GIS-Analysis for Active Tectonics Assessment of Wadi Al-Arish, Egypt

In this paper, we apply an effective method to evaluate relative tectonic activity by applying several morph-tectonic indices that are useful in evaluating topography and tectonics. These indices include stream length-gradient, asymmetric factor, hypsometric index, hypsometric curves, valley floor width to valley height ratio, drainage basin shape, and mountain front sinuosity. The study region of Wadi Al-Arish in northern Sinai Peninsula in northern Egypt is a natural laboratory to examine relative tectonic activity levels for calculating morpho-tectonic indices of several catchments and sub-catchments rather than an individual catchment. Northern Sinai, comprising the Waid Al-Arish area, is characterized by several large inversion anticline folds. The cumulative results extracted from morpho-tectonic indices ae presented as a new index, namely relative tectonic activity level (RTAL), which we classified into four levels: low, moderate, high, and very high relative tectonic activity. Therefore, the study region provides different levels of relative tectonic activity resulting from fault patterns affecting the northern Sinai inversion forms. The paper examines the concept that regions with various levels of tectonic activity are associated with specific values of RTAL.

Геохимическая зональность рудной залежи Ново-Учалинского колчеданного месторождения (Южный Урал, Россия)

Novo-Uchaly essentially zinc (CZn>>CCu) VMS deposit is one of the largest in the Urals. Currently, it is under additional exploration by fans of underground drilling wells and mine workings. The paper describes a novel geochemical zonation of the sulphide deposit (the example of Cu, Zn, Au and In), discusses conditions of formation and factors that caused its complication. We carried geostatistical calculations in addition to the analysis of the zonation of the deposit. The ore deposit is represented by a large subvertical ribbon of a whimsical structure, inclined southward, which is confined to the wing of an inverted large anticlinal fold, cut by mafic dikes and characterized by a complex, combined geochemical zonality. The distribution of Cu and Zn is generally asymmetric. Copper-rich ores tend to the northern wedge of the deposit, and to the south, along its declination, the concentration of Zn increases, while Cu decreases, and the middle part of the deposit is represented by zinc-rich ores. In the section, copper maxima are more often noted in the footwall side of the deposit, and zinc — in the hanging side. The intrusion of a thick gabbro-diorite dyke and subsequent dynamometamorphism, including hydrothermal solutions, caused the redeposition of more mobile Cu in the near-contact zones of the dyke and areas of swell of the ore body thickness. Within the swell of the thickness of the deposit, in the hinge of the fold of the 2nd order, rich copper-zinc ores occur, which are enriched by Zn, Pb, Au, Ag, In, Ba and some other rare elements. The similarity of their behavior in ores is confirmed by their high positive pair correlation. In the ore body, the distribution patterns of gold and indium are rather symmetrical. High concentrations of gold and indium are confined to a sharp bend in the ore body, and small indium maxima occur in the footwall of the ore lode. As a result of dynamometamorphism, the deposit acquired a whimsical structure with the formation of thick swells; ores were significantly recrystallized, and locally enriched by non-ferrous and precious metals.