Pub Date : 2024-04-01DOI: 10.1134/s0869593824020047
Abstract
The results of the study obtained for spores and pollen from the subfossil spectra of samples from the Bykovsky Peninsula (northern Yakutia) are presented in order to compare them with the current vegetation composition, to consider the major cryogenic disturbances of palynological remains, and to analyze their cryogenic destruction processes. The abundant alien pollen of Betula sect. Nanae and Alnus in the spectra is due to open landscapes, relatively low pollen productivity, and the transition of herbs and shrubs prevailing in the local phytocenoses to a vegetative propagation in severe climatic conditions. The selective role of cryogenesis in the spore–pollen spectra formation is related to repeated sediment thawing and freezing cycles, resulting in physical damage (ruptures and cracks) in palynological remains. The results of research contribute to the study of the methodological aspects of palynotaphonomy in cryolithic zone sediments. They can be used to reconstruct the Neopleistocene landscapes and vegetation and to study cryopreservation of fossil living organisms and their diversity in the permafrost areas.
{"title":"Subfossil Spore–Pollen Spectra of Northern Yakutia as a Key to the Interpretation of Paleoecological Studies","authors":"","doi":"10.1134/s0869593824020047","DOIUrl":"https://doi.org/10.1134/s0869593824020047","url":null,"abstract":"<span> <h3>Abstract</h3> <p>The results of the study obtained for spores and pollen from the subfossil spectra of samples from the Bykovsky Peninsula (northern Yakutia) are presented in order to compare them with the current vegetation composition, to consider the major cryogenic disturbances of palynological remains, and to analyze their cryogenic destruction processes. The abundant alien pollen of <em>Betula</em> sect. Nanae and <em>Alnus</em> in the spectra is due to open landscapes, relatively low pollen productivity, and the transition of herbs and shrubs prevailing in the local phytocenoses to a vegetative propagation in severe climatic conditions. The selective role of cryogenesis in the spore–pollen spectra formation is related to repeated sediment thawing and freezing cycles, resulting in physical damage (ruptures and cracks) in palynological remains. The results of research contribute to the study of the methodological aspects of palynotaphonomy in cryolithic zone sediments. They can be used to reconstruct the Neopleistocene landscapes and vegetation and to study cryopreservation of fossil living organisms and their diversity in the permafrost areas.</p> </span>","PeriodicalId":51168,"journal":{"name":"Stratigraphy and Geological Correlation","volume":"50 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140165209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.1134/s0869593824020072
Abstract
For more than half a century, the question remained unresolved why the closely located sequences of fluvial sands overlying Middle Pleistocene diamicton in the lower reaches of the Ob River near the village of Khashgort contain micromammal faunas of different evolutionary levels: Late Quaternary (430 km from the Ob River mouth) and Middle Quaternary (442 (440) km from the Ob River mouth). This was in contradiction with generally accepted ideas, according to which the absence of Middle Quaternary alluvium was assumed in this area and called into question either geological or paleontological interpretations of the Pleistocene history of north of Western Siberia. This paper presents the results of correlating two geological sections based on both geological and paleontological methods and suggests an updated biostratigraphic interpretation of the materials relevant to the Karginian and Tazovian horizons of Western Siberia collected in the 1980s and 2016–2022. It was established that the Late Quaternary assemblage of micromammals from the sections at kilometer 430 of the Ob River is confined to alluvium of the second terrace above the river floodplain, while the Middle Quaternary assemblage at kilometer 442 (the Khashgort locality, kilometer 440 of the Bolshaya Ob River) is associated with fluvioglacial sands showing signs of close redeposition of small mammal remains in the megaclasts contained in Middle Quaternary Khashgort boulder-bearing sandy aleuropelites. Thus, the study makes it possible to harmonize the geological and paleontological data that were in conflict for more than half a century.
{"title":"Justification of the Age of Sands with Middle and Late Quaternary Theriofaunal Complexes in the Lower Ob River near the Village of Khashgort (Northwestern Siberia)","authors":"","doi":"10.1134/s0869593824020072","DOIUrl":"https://doi.org/10.1134/s0869593824020072","url":null,"abstract":"<span> <h3>Abstract</h3> <p>For more than half a century, the question remained unresolved why the closely located sequences of fluvial sands overlying Middle Pleistocene diamicton in the lower reaches of the Ob River near the village of Khashgort contain micromammal faunas of different evolutionary levels: Late Quaternary (430 km from the Ob River mouth) and Middle Quaternary (442 (440) km from the Ob River mouth). This was in contradiction with generally accepted ideas, according to which the absence of Middle Quaternary alluvium was assumed in this area and called into question either geological or paleontological interpretations of the Pleistocene history of north of Western Siberia. This paper presents the results of correlating two geological sections based on both geological and paleontological methods and suggests an updated biostratigraphic interpretation of the materials relevant to the Karginian and Tazovian horizons of Western Siberia collected in the 1980s and 2016–2022. It was established that the Late Quaternary assemblage of micromammals from the sections at kilometer 430 of the Ob River is confined to alluvium of the second terrace above the river floodplain, while the Middle Quaternary assemblage at kilometer 442 (the Khashgort locality, kilometer 440 of the Bolshaya Ob River) is associated with fluvioglacial sands showing signs of close redeposition of small mammal remains in the megaclasts contained in Middle Quaternary Khashgort boulder-bearing sandy aleuropelites. Thus, the study makes it possible to harmonize the geological and paleontological data that were in conflict for more than half a century.</p> </span>","PeriodicalId":51168,"journal":{"name":"Stratigraphy and Geological Correlation","volume":"22 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140166011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-20DOI: 10.1134/s0869593824010027
Shreerup Goswami, Geetika Tripathy, Kamal Jeet Singh
Abstract
The Himgir sub-basin is the southwestern part of the Ib River Basin, Odisha, India. A Lower Gondwana fossil horizon was explored along the road section near Himgir Village, Sundargarh District, Odisha and plant megafossils (1002 specimens) comprising both pteridophytes and gymnosperms, four plant groups, ten genera and fifty-five species were reported. Pteridophytes (Equisetales, Sphenophyllales and Filicales) are represented by Schizoneura gondwanensis Feistmantel, 1876, equisetaceous stems, Trizygia speciosa Royle, 1839 and Neomariopteris talchirensis Maithy, 1974. Gymnosperms are represented by one plant group namely Glossopteridales (46 species Glossopteris) along with stem casts, fructifications and scale leaves. The occurrence of Late Permian floras, the lack of distinctive Dicroidium flora of the Triassic period in this assemblage, and the red bed facies (ferruginous red sandstone and ferruginous red shale) of the investigated locality reveal that the exposure belongs to Lower Kamthi Formation of Wuchiapingian to Changhsingian age. The macrofloral assemblage demonstrates a warm-humid climate with flashing rainfall and moderate light intensity. Vegetation of the studied sub-basin has also been studied to portray the palaeobiodiversity of the area.
{"title":"Biodiversity of Himgir Sub-Basin, India during Late Permian: A Comprehensive Study","authors":"Shreerup Goswami, Geetika Tripathy, Kamal Jeet Singh","doi":"10.1134/s0869593824010027","DOIUrl":"https://doi.org/10.1134/s0869593824010027","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The Himgir sub-basin is the southwestern part of the Ib River Basin, Odisha, India. A Lower Gondwana fossil horizon was explored along the road section near Himgir Village, Sundargarh District, Odisha and plant megafossils (1002 specimens) comprising both pteridophytes and gymnosperms, four plant groups, ten genera and fifty-five species were reported. Pteridophytes (Equisetales, Sphenophyllales and Filicales) are represented by <i>Schizoneura gondwanensis</i> Feistmantel, 1876, equisetaceous stems, <i>Trizygia speciosa</i> Royle, 1839 and <i>Neomariopteris talchirensis</i> Maithy, 1974. Gymnosperms are represented by one plant group namely Glossopteridales (46 species <i>Glossopteris</i>) along with stem casts, fructifications and scale leaves. The occurrence of Late Permian floras, the lack of distinctive <i>Dicroidium</i> flora of the Triassic period in this assemblage, and the red bed facies (ferruginous red sandstone and ferruginous red shale) of the investigated locality reveal that the exposure belongs to Lower Kamthi Formation of Wuchiapingian to Changhsingian age. The macrofloral assemblage demonstrates a warm-humid climate with flashing rainfall and moderate light intensity. Vegetation of the studied sub-basin has also been studied to portray the palaeobiodiversity of the area.</p>","PeriodicalId":51168,"journal":{"name":"Stratigraphy and Geological Correlation","volume":"30 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140169619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-20DOI: 10.1134/s0869593824020023
E. Yu. Baraboshkin, A. Yu. Guzhikov, G. N. Aleksandrova, V. V. Akinin, I. P. Ryabov, M. A. Ustinova, N. A. Rtischev, V. S. Vishnevskaya
Abstract—
Stratigraphy of Campanian deposits in the stratotype of the Kudrinskaya Formation in the Southwestern Crimea is revised. For the first time, integrated sedimentological, biostratigraphic (ichnofossils, cephalopods, inoceramids, foraminifers, dinocysts, nannoplankton, gilianelles), isotope-geochemical, paleo- and petromagnetic characteristics of the section were obtained. The boundary of the lower and upper Campanian is substantiated and confirmed by U–Pb dating of zircons from the well-known bentonite (kil) clay bed in the interval of 77–80 Ma. It is proposed to accept the Campanian Substage boundary of the General Stratigraphic Chart (for bipartite stage subdivision) at the top of the Chron C33r, located near the δ13C isotopic excursion “MCaE” – Mid-Campanian Event, near the first occurrence of the benthic foraminifer Brotzenella monterelensis and a number of other traditional biomarkers.
{"title":"Reference Section of the Campanian Stage of the Southwestern Crimea: Problems of Substage Subdivision and Global Correlation","authors":"E. Yu. Baraboshkin, A. Yu. Guzhikov, G. N. Aleksandrova, V. V. Akinin, I. P. Ryabov, M. A. Ustinova, N. A. Rtischev, V. S. Vishnevskaya","doi":"10.1134/s0869593824020023","DOIUrl":"https://doi.org/10.1134/s0869593824020023","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">\u0000<b>Abstract</b>—</h3><p>Stratigraphy of Campanian deposits in the stratotype of the Kudrinskaya Formation in the Southwestern Crimea is revised. For the first time, integrated sedimentological, biostratigraphic (ichnofossils, cephalopods, inoceramids, foraminifers, dinocysts, nannoplankton, gilianelles), isotope-geochemical, paleo- and petromagnetic characteristics of the section were obtained. The boundary of the lower and upper Campanian is substantiated and confirmed by U–Pb dating of zircons from the well-known bentonite (kil) clay bed in the interval of 77–80 Ma. It is proposed to accept the Campanian Substage boundary of the General Stratigraphic Chart (for bipartite stage subdivision) at the top of the Chron C33r, located near the δ<sup>13</sup>C isotopic excursion “MCaE” – Mid-Campanian Event, near the first occurrence of the benthic foraminifer <i>Brotzenella monterelensis</i> and a number of other traditional biomarkers.</p>","PeriodicalId":51168,"journal":{"name":"Stratigraphy and Geological Correlation","volume":"18 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140165215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-20DOI: 10.1134/s0869593824020035
Hayati Koç, Özge Sağaltıcı
Abstract
This study covers a detailed stratigraphy, microfacies analysis and depositional history of the Middle–Upper Jurassic succession in the central part of the Taurides Carbonate Platform (TCP), southern Turkey (Kıraç Mountain, west of Central Taurides). The succession is subdivided into four units (Unit-1–Unit-4) and nine microfacies (MF1–MF9) are distinguished. Based on microfacies three depositional facies belts are determined and the depositional history of the platform part is explained. The Aalenian is represented by occasionally sandy, oolitic limestones (Unit-1), which indicate predominantly high-energy platform edge environmental conditions (shoal facies belt). The Bajocian–Kimmeridgian?/Tithonian? is represented by limestones with occasionally interlayered dolomite–dolomitic limestones (Unit-2–Unit-3), which are dominated by inner platform conditions (lagoon facies belt). During the Late Jurassic (Кimmeridgian?/Tithonian?)–Early Cretaceous (Berriasian) a significant environmental change occurred, recording a rapidly occurring platform drowning event. This period is represented by dolomite–dolomitic limestone–limestone (Unit-4) containing interlayers of ammonite, radiolarite, laminated limestone, mudstone, and limestone blocks that indicate an open shelf environment (open-marine facies belt). The Middle–Upper Jurassic carbonate succession in Kıraç Mountain has characteristics similar to other parts of the Taurides Carbonate Platform. However, it differs in that it contains Unit-4 characterizing the open shelf environment in the latest Jurassic–earliest Cretaceous.
{"title":"Stratigraphy and Depositional History of the Middle–Upper Jurassic Platform Carbonate Succession in Kıraç Mountain (Western Central Taurides, S Turkey)","authors":"Hayati Koç, Özge Sağaltıcı","doi":"10.1134/s0869593824020035","DOIUrl":"https://doi.org/10.1134/s0869593824020035","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>This study covers a detailed stratigraphy, microfacies analysis and depositional history of the Middle–Upper Jurassic succession in the central part of the Taurides Carbonate Platform (TCP), southern Turkey (Kıraç Mountain, west of Central Taurides). The succession is subdivided into four units (Unit-1–Unit-4) and nine microfacies (MF1–MF9) are distinguished. Based on microfacies three depositional facies belts are determined and the depositional history of the platform part is explained. The Aalenian is represented by occasionally sandy, oolitic limestones (Unit-1), which indicate predominantly high-energy platform edge environmental conditions (shoal facies belt). The Bajocian–Kimmeridgian?/Tithonian? is represented by limestones with occasionally interlayered dolomite–dolomitic limestones (Unit-2–Unit-3), which are dominated by inner platform conditions (lagoon facies belt). During the Late Jurassic (Кimmeridgian?/Tithonian?)–Early Cretaceous (Berriasian) a significant environmental change occurred, recording a rapidly occurring platform drowning event. This period is represented by dolomite–dolomitic limestone–limestone (Unit-4) containing interlayers of ammonite, radiolarite, laminated limestone, mudstone, and limestone blocks that indicate an open shelf environment (open-marine facies belt). The Middle–Upper Jurassic carbonate succession in Kıraç Mountain has characteristics similar to other parts of the Taurides Carbonate Platform. However, it differs in that it contains Unit-4 characterizing the open shelf environment in the latest Jurassic–earliest Cretaceous.</p>","PeriodicalId":51168,"journal":{"name":"Stratigraphy and Geological Correlation","volume":"27 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140169613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-20DOI: 10.1134/s0869593824020060
V. V. Mitta, L. A. Glinskikh, Yu. N. Savelieva, O. V. Shurekova
Abstract
Microfossils of the Strenoceras niortense Zone of the Upper Bajocian of the Karachay-Cherkessian Republic are studied. The zone is represented mainly by dark gray silty-sandy clays, with scattered nodules often arranged in interbeds, and belongs to the lower part of the upper subformation of the Djangura Formation. The taxonomic composition and distribution of foraminifera, ostracods, dinoflagellate cysts, and miospores in the section has been identified. The ranges of biostratigraphic units based on foraminifera, ostracods, and dinocysts are emended and these units are correlated with the ammonite scale. The distribution of benthic foraminifers indicates that these are Beds with Ophthalmidium caucasicum, comparable with the entire Niortense Zone and most of the Garantiana Zone. The Beds with Globuligerina dagestanica established using planktonic foraminifera are correlated with the entire studied interval from the Niortense Zone to the Lower Bathonian, inclusive. In the middle-upper part of the Niortense Zone (Rostovtsevi and Baculatum Subzones), the Beds with ostracods Palaeocytheridea (Malzevia) subtilis were recognized for the first time. The beds with dinocysts Carpathodinium predae, Rhynchodiniopsis? regalis, Meiourogonyaulax valensii are correlated with the range of the Niortense and Garantiana Zones and the lower part of the Parkinsoni Zone, inclusive. Characteristic taxa of microfauna and dinocysts are illustrated.
{"title":"Microfauna, Palynomorphs, and Biostratigraphy of the Upper Bajocian Strenoceras niortense Zone (Middle Jurassic) of the Kuban River Basin, Northern Caucasus","authors":"V. V. Mitta, L. A. Glinskikh, Yu. N. Savelieva, O. V. Shurekova","doi":"10.1134/s0869593824020060","DOIUrl":"https://doi.org/10.1134/s0869593824020060","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">\u0000<b>Abstract</b>\u0000</h3><p>Microfossils of the Strenoceras niortense Zone of the Upper Bajocian of the Karachay-Cherkessian Republic are studied. The zone is represented mainly by dark gray silty-sandy clays, with scattered nodules often arranged in interbeds, and belongs to the lower part of the upper subformation of the Djangura Formation. The taxonomic composition and distribution of foraminifera, ostracods, dinoflagellate cysts, and miospores in the section has been identified. The ranges of biostratigraphic units based on foraminifera, ostracods, and dinocysts are emended and these units are correlated with the ammonite scale. The distribution of benthic foraminifers indicates that these are Beds with <i>Ophthalmidium caucasicum</i>, comparable with the entire Niortense Zone and most of the Garantiana Zone. The Beds with <i>Globuligerina dagestanica</i> established using planktonic foraminifera are correlated with the entire studied interval from the Niortense Zone to the Lower Bathonian, inclusive. In the middle-upper part of the Niortense Zone (Rostovtsevi and Baculatum Subzones), the Beds with ostracods <i>Palaeocytheridea (Malzevia) subtilis</i> were recognized for the first time. The beds with dinocysts <i>Carpathodinium predae, Rhynchodiniopsis? regalis, Meiourogonyaulax valensii</i> are correlated with the range of the Niortense and Garantiana Zones and the lower part of the Parkinsoni Zone, inclusive. Characteristic taxa of microfauna and dinocysts are illustrated.</p>","PeriodicalId":51168,"journal":{"name":"Stratigraphy and Geological Correlation","volume":"49 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140165838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-14DOI: 10.1134/s0869593824010052
E. M. Pervushov, I. P. Ryabov, A. Yu. Guzhikov, V. B. Seltser, E. A. Kalyakin, V. A. Fomin
Abstract
The lithological, paleontological and biostratigraphic characteristics of the Turonian–Coniacian deposits of the Lower Bannovka section, the stratotype of the Bannovka Formation (Volga region, Turonian) are presented. Magnetostratigraphic characteristics of thе sediments have been supplemented and elaborated. Petromagnetic data contribute to more refined stratigraphy of the section and facilitate the revealing of depositional rhythmicity. Paleomagnetic data combined with benthic foraminifera data enable the most detailed correlation of the Turonian–Coniacian deposits in the Volga region. Results of a comprehensive study of this stratigraphic unit within the southeastern arch of the Ulyanovsk-Saratov trough revealed patterns in the distribution of the Gubkino Horizon, determined by regional tectonics and processes preceding deposition in the Coniacian and Santonian.
{"title":"Bio-Magnetostratigraphy of the Turonian–Coniacian Deposits of the Lower Bannovka Section, South-East of the Russian Plate","authors":"E. M. Pervushov, I. P. Ryabov, A. Yu. Guzhikov, V. B. Seltser, E. A. Kalyakin, V. A. Fomin","doi":"10.1134/s0869593824010052","DOIUrl":"https://doi.org/10.1134/s0869593824010052","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The lithological, paleontological and biostratigraphic characteristics of the Turonian–Coniacian deposits of the Lower Bannovka section, the stratotype of the Bannovka Formation (Volga region, Turonian) are presented. Magnetostratigraphic characteristics of thе sediments have been supplemented and elaborated. Petromagnetic data contribute to more refined stratigraphy of the section and facilitate the revealing of depositional rhythmicity. Paleomagnetic data combined with benthic foraminifera data enable the most detailed correlation of the Turonian–Coniacian deposits in the Volga region. Results of a comprehensive study of this stratigraphic unit within the southeastern arch of the Ulyanovsk-Saratov trough revealed patterns in the distribution of the Gubkino Horizon, determined by regional tectonics and processes preceding deposition in the Coniacian and Santonian.</p>","PeriodicalId":51168,"journal":{"name":"Stratigraphy and Geological Correlation","volume":"141 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140149572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-14DOI: 10.1134/s0869593824010076
V. V. Yarmolyuk, A. M. Kozlovsky, E. A. Kudryashova, Ts. Oyunchimeg
Abstract
Geochronological studies of volcanic rocks ascribed to the Late Mesozoic Eastern Mongolian Volcanic Belt (EMVB) allowed the recognition of several groups, which differ in age and composition of igneous associations, as well as their occurrence. The youngest group (~215 Ma) includes the rocks of bimodal association abundant in the western part of the EMVB. The next group (170–150 Ma) mostly consists of felsic lavas of the shoshonite–latite association composing the large volcanic fields in the eastern part of the EMVB. The rocks with the age of 140–105 Ma form a cover of the EMVB and mostly include basaltic trachyandesite, the fields of which are accompanied by small volcanoes of trachydacite and trachyrhyolite. Separated extrusions of alkaline basaltoids formed in age range of 105–80 Ma. The rock associations of various ages have different geological links with ambient igneous complexes. By age and composition, the Late Triassic bimodal complex is compared with similar associations that occur in Central Mongolia and West Transbaikalia along the frame of the Khentei–Dauria batholith. Their origination is related to the formation of the Early Mesozoic Khentei–Dauria zoned igneous area. The Middle to Late Jurassic igneous complexes are mostly localized in the eastern part of the EMVB. Their fields occur within the area of Late Jurassic volcanic fields of the Great Xing’an Volcanic Belt (GXVB), which are similar both in the age of the formation and in the composition of volcanic associations. The Cretaceous magmatism was responsible for the main evolution of the EMVB, which was accompanied by rifting and formation of numerous troughs and grabens, as well as regular evolution of its mantle sources directed toward the increasing amount of an intraplate component. The sizes, boundaries, and characteristics of the EMVB magmatism are refined. Its western boundary is shifted to the east and is determined by a frontal NW-trending fault system, which controls a chain of Early Cretaceous granitic plutons, as well as rocks of the Late Mesozoic extrusive complex. The eastern boundary of the area is shifted to the west, where it coincides with a field of the Early Cretaceous extrusive complex. Taking into account data on the alien setting of the Late Triassic and Middle to Late Jurassic complexes in the EMVB structure, it is established that the EMVB igneous products mainly include mafic volcanic rocks. This is in agreement with similarity of the EMVB and other Late Mesozoic volcanic areas of the intracontinental part of East Asia, with a subordinate role of felsic igneous rocks.
摘要 对归属于晚中生代东蒙古火山带（EMVB）的火山岩进行的地质年代研究，确认了在年龄和火成岩组合组成及其出现方面存在差异的几个组别。最年轻的一组（约 215 Ma）包括东蒙古火山带西部丰富的双峰组合岩石。其次的一组（170-150 Ma）主要由闪长岩-腊岩联合的长熔岩组成，构成了东部EMVB的大型火山区。年龄在 140-105 Ma 之间的岩石构成了 EMVB 的覆盖层，主要包括玄武闪长岩，其岩场伴有闪长岩和闪长玢岩的小型火山。碱性玄武岩的分离挤压形成于 105-80 Ma 之间。不同时代的岩石群与周围的火成岩群有着不同的地质联系。根据年龄和成分，晚三叠世双峰复合体与出现在蒙古中部和外贝加尔西部沿肯泰-道里亚岩床框架的类似复合体进行了比较。它们的起源与早中生代肯特-道利亚带状火成岩区的形成有关。中侏罗世至晚侏罗世火成岩群主要分布在 EMVB 东部。它们位于大兴安火山带（GXVB）晚侏罗世火山岩区内，在形成年代和火山岩组合成分上都很相似。白垩纪岩浆活动是大兴安岭火山带演化的主要原因，伴随着断裂和众多海槽和地堑的形成，其地幔源也发生了规律性演化，板内成分不断增加。EMVB岩浆活动的规模、边界和特征得到了完善。该地区的西部边界向东偏移，由一个正面西北走向的断层系统所决定，该断层系统控制着一连串早白垩世的花岗质岩块以及中生代晚期的挤压复合岩。该地区的东部边界向西偏移，与早白垩世挤压岩群的一个区域重合。考虑到 EMVB 构造中晚三叠世和中晚侏罗世复合体的外来环境数据，可以确定 EMVB 的火成岩产物主要包括黑云母火山岩。这与EMVB和东亚大陆内部其他中生代晚期火山区的相似性一致，长粒火成岩的作用次之。
{"title":"Structure, Age, and Evolution of the Late Mesozoic Eastern Mongolian Volcanic Belt","authors":"V. V. Yarmolyuk, A. M. Kozlovsky, E. A. Kudryashova, Ts. Oyunchimeg","doi":"10.1134/s0869593824010076","DOIUrl":"https://doi.org/10.1134/s0869593824010076","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Geochronological studies of volcanic rocks ascribed to the Late Mesozoic Eastern Mongolian Volcanic Belt (EMVB) allowed the recognition of several groups, which differ in age and composition of igneous associations, as well as their occurrence. The youngest group (~215 Ma) includes the rocks of bimodal association abundant in the western part of the EMVB. The next group (170–150 Ma) mostly consists of felsic lavas of the shoshonite–latite association composing the large volcanic fields in the eastern part of the EMVB. The rocks with the age of 140–105 Ma form a cover of the EMVB and mostly include basaltic trachyandesite, the fields of which are accompanied by small volcanoes of trachydacite and trachyrhyolite. Separated extrusions of alkaline basaltoids formed in age range of 105–80 Ma. The rock associations of various ages have different geological links with ambient igneous complexes. By age and composition, the Late Triassic bimodal complex is compared with similar associations that occur in Central Mongolia and West Transbaikalia along the frame of the Khentei–Dauria batholith. Their origination is related to the formation of the Early Mesozoic Khentei–Dauria zoned igneous area. The Middle to Late Jurassic igneous complexes are mostly localized in the eastern part of the EMVB. Their fields occur within the area of Late Jurassic volcanic fields of the Great Xing’an Volcanic Belt (GXVB), which are similar both in the age of the formation and in the composition of volcanic associations. The Cretaceous magmatism was responsible for the main evolution of the EMVB, which was accompanied by rifting and formation of numerous troughs and grabens, as well as regular evolution of its mantle sources directed toward the increasing amount of an intraplate component. The sizes, boundaries, and characteristics of the EMVB magmatism are refined. Its western boundary is shifted to the east and is determined by a frontal NW-trending fault system, which controls a chain of Early Cretaceous granitic plutons, as well as rocks of the Late Mesozoic extrusive complex. The eastern boundary of the area is shifted to the west, where it coincides with a field of the Early Cretaceous extrusive complex. Taking into account data on the alien setting of the Late Triassic and Middle to Late Jurassic complexes in the EMVB structure, it is established that the EMVB igneous products mainly include mafic volcanic rocks. This is in agreement with similarity of the EMVB and other Late Mesozoic volcanic areas of the intracontinental part of East Asia, with a subordinate role of felsic igneous rocks.</p>","PeriodicalId":51168,"journal":{"name":"Stratigraphy and Geological Correlation","volume":"15 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140149570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-14DOI: 10.1134/s0869593824010039
V. G. Knyazev, A. S. Alifirov
Abstract
The grounds for identifying the Eboraciceras subordinarium Zone in the Upper Callovian of Siberia are critically discussed. The key sections of this zone and the ammonite assemblage that characterizes it are examined in detail. It is concluded that it is impossible to recognize the Eboraciceras subordinarium Zone and its further use in stratigraphic schemes is not suggested. North Siberian taxa, previously identified as Late Callovian Eboraciceras, are mostly assigned to Rondiceras and indicate a Middle Callovian age of the host rocks. Beds with Cadoquenstedtoceras begichevi have been proposed as an approximate equivalent of the European Q. lamberti Zone in the Upper Callovian of Siberia.
{"title":"The Middle-Upper Jurassic Boundary in the North of Siberia: Problems of the Evidence","authors":"V. G. Knyazev, A. S. Alifirov","doi":"10.1134/s0869593824010039","DOIUrl":"https://doi.org/10.1134/s0869593824010039","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The grounds for identifying the Eboraciceras subordinarium Zone in the Upper Callovian of Siberia are critically discussed. The key sections of this zone and the ammonite assemblage that characterizes it are examined in detail. It is concluded that it is impossible to recognize the Eboraciceras subordinarium Zone and its further use in stratigraphic schemes is not suggested. North Siberian taxa, previously identified as Late Callovian <i>Eboraciceras</i>, are mostly assigned to <i>Rondiceras</i> and indicate a Middle Callovian age of the host rocks. Beds with Cadoquenstedtoceras begichevi have been proposed as an approximate equivalent of the European Q. lamberti Zone in the Upper Callovian of Siberia.</p>","PeriodicalId":51168,"journal":{"name":"Stratigraphy and Geological Correlation","volume":"47 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140149645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-14DOI: 10.1134/s0869593824010064
A. I. Iakovleva
Abstract
This paper discusses the current state of knowledge of Paleogene stratigraphy of Kaliningrad Oblast, the age of local stratigraphic units and the duration of possible gaps in deposition and proposes trends for future regional Paleogene stratigraphy. The Paleocene Chistoozerskaya and Lubava formations in total probably correspond to the Danian–Selandian on the basis of foraminiferal zonation, but their relationship is not entirely clear. The Zaostrovskaya Formation probably corresponds to the upper Thanetian, but its fossil record is very poor. The Sambian Formation corresponds to the Ypresian according to foraminifera, but its precise stratigraphical interval remains insufficiently substantiated. The Alka Formation is presumably late Lutetian–early Bartonian. The age of the Prussian Formation is emended based on dinocysts as early–late Priabonian, while the Palvé Formation is now dated as the latest Priabonian. The Kurshskaya Formation corresponds to the uppermost Eocene–Oligocene–?lower Miocene. The problem of the recognition and duration of hiatuses between formations remains relevant.
{"title":"Regional Paleogene Stratigraphic Scheme of Kaliningrad Oblast: State of Art, Problems and Prospects for Improvement","authors":"A. I. Iakovleva","doi":"10.1134/s0869593824010064","DOIUrl":"https://doi.org/10.1134/s0869593824010064","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>This paper discusses the current state of knowledge of Paleogene stratigraphy of Kaliningrad Oblast, the age of local stratigraphic units and the duration of possible gaps in deposition and proposes trends for future regional Paleogene stratigraphy. The Paleocene Chistoozerskaya and Lubava formations in total probably correspond to the Danian–Selandian on the basis of foraminiferal zonation, but their relationship is not entirely clear. The Zaostrovskaya Formation probably corresponds to the upper Thanetian, but its fossil record is very poor. The Sambian Formation corresponds to the Ypresian according to foraminifera, but its precise stratigraphical interval remains insufficiently substantiated. The Alka Formation is presumably late Lutetian–early Bartonian. The age of the Prussian Formation is emended based on dinocysts as early–late Priabonian, while the Palvé Formation is now dated as the latest Priabonian. The Kurshskaya Formation corresponds to the uppermost Eocene–Oligocene–?lower Miocene. The problem of the recognition and duration of hiatuses between formations remains relevant.</p>","PeriodicalId":51168,"journal":{"name":"Stratigraphy and Geological Correlation","volume":"69 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140149644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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