Head of the Department "Structure of the Lithosphere" of the Institute of Geology and Geophysics named after Kh.M.Abdullaev of the State Committee on Geology of the Republic of Uzbekistan
This paper present results of comprehensive analysis of the geologo-geophysical data in Uzbekista... more This paper present results of comprehensive analysis of the geologo-geophysical data in Uzbekistan using GIS&RS, which show in the spatial interrelations between the peculiarities of the tectonic structures of the region and geodynamic processes occurring there. Long-term observations of deep structures of Central Asia's lithosphere elucidated the maintenance of large faults as Central Kyzylkum, North Nurata and South Ferghana, Atbashin
IOP Conference Series: Earth and Environmental Science, 2021
This paper presents an integrated geophysical study of the Western Central Asia (WCA) in the Uzbe... more This paper presents an integrated geophysical study of the Western Central Asia (WCA) in the Uzbekistan area. It presents new interpretations of deep seismic sounding (DSS) data and new analyses of potential fields data. An integrated model of the physical properties and lithosphere structures displays distinct features that are related to tectonic history of the study WCA-Darius area. Task-oriented complex geological and geophysical research revealed in the lithosphere of western Uzbekistan series of crust blocks with abnormal petrophysical characteristics and established some correlation dependences between the distribution and placement of these objects (in plan) with deposits of minerals.
This study was made with complex geophysical observations by the DSS transects, which cross WCA A... more This study was made with complex geophysical observations by the DSS transects, which cross WCA Asia domain in the part Uzbekistan. New regional features have been revealed on the base of re-evaluation of the tectonic setting and history of WCA mainly from seismic, gravity and magnetic data. They include peculiarities of the Earth's crust deep geological structure and spatial distribution of deposits: they are disposing in contrast areas of the earth's crust geoblocks with anomalously high and low seismic and density parameters. The complexity of the region involved in the tectonic assemblage between the Central Asian Orogenic Belt and the tectonic blocks which were subsequently amalgamated from the south, probably involved multi-phase subduction/accretion of various micro-continents, ancient island arcs and fragments of oceanic islands. Linear positive magnetic anomalies and sharp gravity gradients reflect the position of associated faults, which define the location of palaeosubduction zones distinguished by DSS transects interpretation. Mantle-rooted structures represent pathways favorable for the transfer of heat, magma and ore-forming fluids, as well as seismic energy towards the Earth's surface. The intersections of the mantle-rooted pathways with structures of other trends may become preferential places for the release of seismic energy by earthquakes, or, in connection with lithology and geochemical parameters, become favorable loci for concentration of oil-gas or metals.Using obtained regularities it is carried out integrated interpretation and distinguishing of new potential oil-gas occurrences in Gissar and Nurata regions.
This study, granted by the Darius Programme, aims at proposing a model of tectono-stratigraphic e... more This study, granted by the Darius Programme, aims at proposing a model of tectono-stratigraphic evolution of the Amu Darya basin since the Late Palaeozoic and to understand the relationship with the nearby basins. The Amu Darya basin, as its close eastern neighbour, the Afghan-Tajik basin, lies on the Turan platform, after the closure of the Turkestan Ocean during the Late Paleozoic. These two basins, spread on mainly lowlands of Turkmenistan, southwest Uzbekistan, Tajikistan, and northern Afghanistan, are separated from one another by the SouthWestern Gissar meganticline, where series of the northern Amu Darya margin are outcropping.
Geological Society, London, Special Publications, 2017
The Amu Darya Basin (ADB) has been studied primarily for its important hydrocarbon reserves and t... more The Amu Darya Basin (ADB) has been studied primarily for its important hydrocarbon reserves and to a lesser extent for its geodynamic evolution. The ADB is located on the SE portion of the Turan Platform, between the sutures of the Turkestan and Palaeo-Tethys oceans, which closed during the Late Palaeozoic and Early Mesozoic, respectively. Blocks and island arcs accreted to Eurasia during the Palaeozoic form a poorly defined, heterogeneous basement underlying the ADB. They played an important role in shaping its composite structure into variously orientated sub-basins and highs. In this paper, depth–structure and isopach maps, and regional cross-sections, are analysed to unravel the location and origin of the main structural elements and to characterize the subsidence evolution of the ADB. The main tectonic events leading to the formation and evolution of the ADB took place: (1) in the Late Palaeozoic–Early Triassic (back-arc, rollback and extension/strike-slip); (2) from the Middle...
Geological Society, London, Special Publications, 2017
Abstract The Bukhara-Khiva region forms the northern margin of the Mesozoic Amu-Darya Basin. We r... more Abstract The Bukhara-Khiva region forms the northern margin of the Mesozoic Amu-Darya Basin. We reconstructed several cross-sections across this margin from subsurface data. The objectives included examining the structure of the Bukhara and Chardzhou steps and determining the tectonic–sedimentary evolution of the basin during the Jurassic. Subsequent to the Cimmerian collision in the Middle Triassic, an extensional event controlled the deposition of the Early–Middle Jurassic siliciclastic succession in the Bukhara-Khiva region. The main Late Palaeozoic inherited structures were reactivated as normal faults during this period. Continental coarse-grained siliciclastic sediments are mainly confined to the basal Lower Jurassic section, probably Pliensbachian–Toarcian in age, whereas marine siliciclastic sediments occur in the early Late Bajocian. In the Early–Middle Jurassic the Bukhara and Chardzhou steps were predominantly sourced by areas of relief, the remains of Late Palaeozoic orogens located to the north. The rate of extension significantly declined during the Middle Callovian–Kimmeridgian period. Deposition of the overlying Lower Cretaceous continental red-coloured clastic sediments was related to the interaction of basin subsidence, a fall in eustatic sea-level and sediment supply. Subsequent marine transgression in the Late Barremian, partially related to broad thermal subsidence in the Amu-Darya Basin, resulted in the deposition of an extensive Late Cretaceous clay–marl succession.
London 2013, 75th eage conference en exhibition incorporating SPE Europec, 2013
ABSTRACT We propose a model of tectono-stratigraphic evolution of Western Central Asia since the ... more ABSTRACT We propose a model of tectono-stratigraphic evolution of Western Central Asia since the Late Palaeozoic. The evolution during this 300My-long period is mainly controlled by successive accretions of continental blocks and collisions that succeeded in Late Carboniferous-Early Permian, Late Triassic-Early Jurassic, Early Cretaceous and Cenozoic times. These orogenies controlled the deposition of thick clastics sequences in the surrounding platforms and basins. The eastern part of Tien-Shan, emerged since the Late Paleozoic, was the main source of sediments during the Mesozoic. Between the main orogenic periods the sea periodically invaded part of the domain. It is only in Cenozoic, with the beginning of the India/Eurasia collision, that the whole western Central Asia domain was emerged.
Sedimentological investigations have been carried out in the southwestern part of the Gissar Rang... more Sedimentological investigations have been carried out in the southwestern part of the Gissar Range (Uzbekistan) in order to document the stratigraphic evolution of a vast Middle-Upper Jurassic carbonate platform developed on the northern margin of the Amu Darya Basin. Two major sequences are distinguished, based on their contrasting facies pattern, platform configuration and carbon isotope signature: (1) a Callovian Sequence and (2) an Upper Jurassic Sequence, potentially Oxfordian to early Tithonian in age. A carbonate ramp with a double proximal-distal polarity developed during the Callovian Sequence. Oo-bioclastic grainstones were produced in two permanently agitated shallow water areas developing to the north and to the south. Patch and pinnacle reefs mainly built up close to the storm-wave base, passing distally to pellet-and foraminiferal-oncoid-rich mid-to outer-ramp deposits. The top of the Callovian Sequence is a regional discontinuity that could have formed by subaerial exposure of the platform. This probable hiatus could record a major climatic change associated to the Middle-Late Jurassic transition. The Upper Jurassic Sequence consists of metre-thick alternations of pellet/algal-pack-to grainstones, microbial oncoid floatstones, ooid grainstones, and mudstones, which have likely accumulated in a vast lagoon protected by a large-scale barrier reef observed south of the study area. Gypsum and anhydrite content gradually increased towards the top of the Upper Jurassic Sequence, ending up with a thick
This paper present results of comprehensive analysis of the geologo-geophysical data in Uzbekista... more This paper present results of comprehensive analysis of the geologo-geophysical data in Uzbekistan using GIS&RS, which show in the spatial interrelations between the peculiarities of the tectonic structures of the region and geodynamic processes occurring there. Long-term observations of deep structures of Central Asia's lithosphere elucidated the maintenance of large faults as Central Kyzylkum, North Nurata and South Ferghana, Atbashin
IOP Conference Series: Earth and Environmental Science, 2021
This paper presents an integrated geophysical study of the Western Central Asia (WCA) in the Uzbe... more This paper presents an integrated geophysical study of the Western Central Asia (WCA) in the Uzbekistan area. It presents new interpretations of deep seismic sounding (DSS) data and new analyses of potential fields data. An integrated model of the physical properties and lithosphere structures displays distinct features that are related to tectonic history of the study WCA-Darius area. Task-oriented complex geological and geophysical research revealed in the lithosphere of western Uzbekistan series of crust blocks with abnormal petrophysical characteristics and established some correlation dependences between the distribution and placement of these objects (in plan) with deposits of minerals.
This study was made with complex geophysical observations by the DSS transects, which cross WCA A... more This study was made with complex geophysical observations by the DSS transects, which cross WCA Asia domain in the part Uzbekistan. New regional features have been revealed on the base of re-evaluation of the tectonic setting and history of WCA mainly from seismic, gravity and magnetic data. They include peculiarities of the Earth's crust deep geological structure and spatial distribution of deposits: they are disposing in contrast areas of the earth's crust geoblocks with anomalously high and low seismic and density parameters. The complexity of the region involved in the tectonic assemblage between the Central Asian Orogenic Belt and the tectonic blocks which were subsequently amalgamated from the south, probably involved multi-phase subduction/accretion of various micro-continents, ancient island arcs and fragments of oceanic islands. Linear positive magnetic anomalies and sharp gravity gradients reflect the position of associated faults, which define the location of palaeosubduction zones distinguished by DSS transects interpretation. Mantle-rooted structures represent pathways favorable for the transfer of heat, magma and ore-forming fluids, as well as seismic energy towards the Earth's surface. The intersections of the mantle-rooted pathways with structures of other trends may become preferential places for the release of seismic energy by earthquakes, or, in connection with lithology and geochemical parameters, become favorable loci for concentration of oil-gas or metals.Using obtained regularities it is carried out integrated interpretation and distinguishing of new potential oil-gas occurrences in Gissar and Nurata regions.
This study, granted by the Darius Programme, aims at proposing a model of tectono-stratigraphic e... more This study, granted by the Darius Programme, aims at proposing a model of tectono-stratigraphic evolution of the Amu Darya basin since the Late Palaeozoic and to understand the relationship with the nearby basins. The Amu Darya basin, as its close eastern neighbour, the Afghan-Tajik basin, lies on the Turan platform, after the closure of the Turkestan Ocean during the Late Paleozoic. These two basins, spread on mainly lowlands of Turkmenistan, southwest Uzbekistan, Tajikistan, and northern Afghanistan, are separated from one another by the SouthWestern Gissar meganticline, where series of the northern Amu Darya margin are outcropping.
Geological Society, London, Special Publications, 2017
The Amu Darya Basin (ADB) has been studied primarily for its important hydrocarbon reserves and t... more The Amu Darya Basin (ADB) has been studied primarily for its important hydrocarbon reserves and to a lesser extent for its geodynamic evolution. The ADB is located on the SE portion of the Turan Platform, between the sutures of the Turkestan and Palaeo-Tethys oceans, which closed during the Late Palaeozoic and Early Mesozoic, respectively. Blocks and island arcs accreted to Eurasia during the Palaeozoic form a poorly defined, heterogeneous basement underlying the ADB. They played an important role in shaping its composite structure into variously orientated sub-basins and highs. In this paper, depth–structure and isopach maps, and regional cross-sections, are analysed to unravel the location and origin of the main structural elements and to characterize the subsidence evolution of the ADB. The main tectonic events leading to the formation and evolution of the ADB took place: (1) in the Late Palaeozoic–Early Triassic (back-arc, rollback and extension/strike-slip); (2) from the Middle...
Geological Society, London, Special Publications, 2017
Abstract The Bukhara-Khiva region forms the northern margin of the Mesozoic Amu-Darya Basin. We r... more Abstract The Bukhara-Khiva region forms the northern margin of the Mesozoic Amu-Darya Basin. We reconstructed several cross-sections across this margin from subsurface data. The objectives included examining the structure of the Bukhara and Chardzhou steps and determining the tectonic–sedimentary evolution of the basin during the Jurassic. Subsequent to the Cimmerian collision in the Middle Triassic, an extensional event controlled the deposition of the Early–Middle Jurassic siliciclastic succession in the Bukhara-Khiva region. The main Late Palaeozoic inherited structures were reactivated as normal faults during this period. Continental coarse-grained siliciclastic sediments are mainly confined to the basal Lower Jurassic section, probably Pliensbachian–Toarcian in age, whereas marine siliciclastic sediments occur in the early Late Bajocian. In the Early–Middle Jurassic the Bukhara and Chardzhou steps were predominantly sourced by areas of relief, the remains of Late Palaeozoic orogens located to the north. The rate of extension significantly declined during the Middle Callovian–Kimmeridgian period. Deposition of the overlying Lower Cretaceous continental red-coloured clastic sediments was related to the interaction of basin subsidence, a fall in eustatic sea-level and sediment supply. Subsequent marine transgression in the Late Barremian, partially related to broad thermal subsidence in the Amu-Darya Basin, resulted in the deposition of an extensive Late Cretaceous clay–marl succession.
London 2013, 75th eage conference en exhibition incorporating SPE Europec, 2013
ABSTRACT We propose a model of tectono-stratigraphic evolution of Western Central Asia since the ... more ABSTRACT We propose a model of tectono-stratigraphic evolution of Western Central Asia since the Late Palaeozoic. The evolution during this 300My-long period is mainly controlled by successive accretions of continental blocks and collisions that succeeded in Late Carboniferous-Early Permian, Late Triassic-Early Jurassic, Early Cretaceous and Cenozoic times. These orogenies controlled the deposition of thick clastics sequences in the surrounding platforms and basins. The eastern part of Tien-Shan, emerged since the Late Paleozoic, was the main source of sediments during the Mesozoic. Between the main orogenic periods the sea periodically invaded part of the domain. It is only in Cenozoic, with the beginning of the India/Eurasia collision, that the whole western Central Asia domain was emerged.
Sedimentological investigations have been carried out in the southwestern part of the Gissar Rang... more Sedimentological investigations have been carried out in the southwestern part of the Gissar Range (Uzbekistan) in order to document the stratigraphic evolution of a vast Middle-Upper Jurassic carbonate platform developed on the northern margin of the Amu Darya Basin. Two major sequences are distinguished, based on their contrasting facies pattern, platform configuration and carbon isotope signature: (1) a Callovian Sequence and (2) an Upper Jurassic Sequence, potentially Oxfordian to early Tithonian in age. A carbonate ramp with a double proximal-distal polarity developed during the Callovian Sequence. Oo-bioclastic grainstones were produced in two permanently agitated shallow water areas developing to the north and to the south. Patch and pinnacle reefs mainly built up close to the storm-wave base, passing distally to pellet-and foraminiferal-oncoid-rich mid-to outer-ramp deposits. The top of the Callovian Sequence is a regional discontinuity that could have formed by subaerial exposure of the platform. This probable hiatus could record a major climatic change associated to the Middle-Late Jurassic transition. The Upper Jurassic Sequence consists of metre-thick alternations of pellet/algal-pack-to grainstones, microbial oncoid floatstones, ooid grainstones, and mudstones, which have likely accumulated in a vast lagoon protected by a large-scale barrier reef observed south of the study area. Gypsum and anhydrite content gradually increased towards the top of the Upper Jurassic Sequence, ending up with a thick
Uploads
Papers by Irina Sidorova