Doklady Earth Sciences最新文献

{"title":"Cathodoluminescence Petrography and Stable Isotope Geochemistry of Carbonate Rocks to Evaluate Diagenetic Evolution of the Middle Jurassic Samana Suk Formation (SSF), Kahi Section, Nizampur Basin, NW Himalayas, Pakistan","authors":"H. U. Rahim, M. M. Shah, A. Kamal, T. Zafar, D. Navarro-Ciurana, M. S. Ahmed, M. Sami","doi":"10.1134/s1028334x24601779","DOIUrl":"https://doi.org/10.1134/s1028334x24601779","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Diagenetically modified carbonate rocks are more common in the rock record. These modifications, have altered the carbonate rocks significantly. The Middle Jurassic carbonates of the SSF are extensively altered by the diagenetic evolution and several dolomitization process in the Kahi Section, Nizampur Basin. The primary objective of this study is to investigate the diagenetic evolution and multiphase dolomitization through cathodoluminescence petrography and stable isotopic studies. Field investigations show both host limestone (oolitic, fossiliferous and massive) and dolomites. Different types of dolomites were recognized on the basis of color contrast as dark grey color replacive dolomite, light grey dolomite, brownish dolomite and yellowish dolomite. Beside replacive phase voids and fracture filling cementing saddle dolomite, and cementing calcites are also recognized in the field. Petrographic studies show the complex diagenetic history of Samana Suk Formation from near surface diagenesis including micritization, neomorphism and several varities of dolomites. These verities are: RD1 is very fine to fine grained dolomite, RD2 is medium to coarse grained and anhedral to subhedral dolomite, RD3 is coarse to very coarse grained and planner euhedral zoned dolomite, and RD4 is coarse grained euhedral to subhedral ferroan dolomite. In addition, cementing saddle dolomite SD have large crystal, curved faces with sweeping extinction. cementing calcite phases are CC1 is granular mosaic, CC2 is twin, CC3 is fracture filling, and CC4 is ferroan calcite. The stable isotope values of limestone (δ¹⁸O: –7.13 to –0.73‰ V-PDB and δ¹³C: –0.05 to 1.32‰ V-PDB) showing depletion in from the Jurassic marine signature. The multiphase dolomites RD1–RD4, SD values (δ¹⁸O: –8.65 to –3.16‰ and δ¹³C: –3.56 to +2.09‰) indicate multiphase dolomitization. The C1–C3 values (δ¹⁸O: –11.07 to –8.97‰ and δ¹³C: –2.14 to +0.76‰) indicate highly depleted values of δ¹⁸O showing its source from the hydrothermal origin. From field, petrography and stable isotopic geochemistry data it is deduced that possible source of the Mg for hydrothermal dolomites is through activation of faults and fractures during active tectonic regime in the area and can be related to activation and reactivation of Kahi Thrust system.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"50 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969825","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}

{"title":"New Finds of Vendian Macrofossils in the Upper Precambrian of Chetlasskii Kamen Hill of the Timan Ridge (Arkhangelsk Oblast)","authors":"A. V. Kolesnikov, V. N. Pan’kov, V. A. Pan’kova, I. V. Latysheva, A. V. Shatsillo, N. B. Kuznetsov","doi":"10.1134/s1028334x24602530","DOIUrl":"https://doi.org/10.1134/s1028334x24602530","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Macrofossils of the Vendian soft-bodied organisms were found for the first time in the Vizinga and Ust’-Palega formations of the Upper Precambrian in Chetlasskii Kamen Hill (Middle Timan, Arkhangelsk oblast). Representatives of palaeopascichnids, aspidellamorphs, and possible frondomorphs, trace fossils, and microbially induced arumberiamorph structures were identified among molds and three-dimensional casts of fossils. Previously we revealed Vendian macrofossils in the Upper Precambrian in Dzhezhim-Parma Hill (South Timan, Komi Republic). The discovery of one more locality of various Ediacaran fossils in the middle part of the Timan Ridge significantly expands their paleogeography and also clarifies the time frame of deposition of the Vizinga and Ust’-Palega formations, the position of which in the Upper Precambrian section of Central Timan was debatable.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"16 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141948949","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}

{"title":"The Nature of Deformations of the Western Slope of Shiveluch Volcano after the Eruption on April 11, 2023, Identified by SAR Interferometry","authors":"M. S. Volkova, V. O. Mikhailov, N. V. Gorbach","doi":"10.1134/s1028334x24602694","DOIUrl":"https://doi.org/10.1134/s1028334x24602694","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Using the images of the Sentinel-1A satellite, taken from May 1 to September 22, 2023, and the differential interferometry method (DInSAR) we calculated successive displacement fields in time, which clearly show a dome-shaped uplift on the western slope of Shiveluch volcano, 8‒8.5 km west of its active crater. The uplift grew especially intensely at the satellite acquisition intervals of May 1‒13, 2023; May 13‒25, 2023; and May 25‒June 6, 2023. To confirm the hypothesis on the formation of the displacement region due to magma intrusion beneath the western slope of the volcano, numerical modeling was carried out and the parameters of the sill-like magma body, which forms the displacements on the surface that best match the displacement observed from satellite radar interferometry data, were determined. It is assumed that, after the eruption on April 11, 2023, magma rose from a depth of 20‒25 km through a fissure formed under the western slope of the volcano and intruded horizontally beneath the slope at a depth of 1‒2 km in the north-northwesterly direction. Within the precision of data on slope displacements, the size of the magma body varies from 6.0 × 3.0 km at 1 km depth to 5.25 × 1.4 km at 2 km depth, while its height ranges from 0.5 to 1.75 m and its volume, from 0.009 to 0.0129 km³. Thus, based on radar interferometry data together with the data on the distribution of seismic activity accompanying the movement of magma, the model of the magma body that intruded beneath the western slope of Shiveluch volcano in the postparoxysmal phase of the eruption on April 11, 2023, was constructed. The formation of a new extrusive dome on the western slope of Shiveluch volcano at the end of April 2024 confirms the hypothesis about the intrusion of magmatic material beneath the western slope of the volcano and allows estimating the rate of magma rise to the surface.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"16 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969829","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}

{"title":"Sr Chemostratigraphy of the Lower Permian of the Omolon Massif (Northeast Asia): First Data and Importance for Correlation with the International Stratigraphic Scale","authors":"A. S. Biakov, A. B. Kuznetsov, V. G. Ganelin, I. V. Brynko, V. A. Chebotareva, I. L. Vedernikov","doi":"10.1134/s1028334x24602517","DOIUrl":"https://doi.org/10.1134/s1028334x24602517","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The Sr chemostratigraphic characteristics of marine sediments of the Lower Permian in the Omolon massif of Northeast Asia have been obtained for the first time based on a study of well-preserved brachiopod shells. The ⁸⁷Sr/⁸⁶Sr ratio in brachiopods from the Lower Permian regional horizons (regional stages) is within the following ranges: 0.70786–0.70794, Orochian; 0.70744–0.70786, Ogonerian; 0.70745–0.70748, Koargychanian; and 0.70742–0.70735, Khalalian. The obtained Sr-isotope data demonstrate good agreement with the standard variation curve of the ⁸⁷Sr/⁸⁶Sr ratio in the Permian Ocean. New Sr-isotope data can be used to correlate the units of the Regional Stratigraphic Scale of Northeast Russia directly with the stages of the International Permian Stratigraphic Scale. Based on recent data, the Asselian age of the Orochian regional stage of the lower part of the Permian section in the Omolon massif has been proved, and the regional correlation of the Upper Sakmarian interval established previously from biostratigraphic data has been refined.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"20 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141862765","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}

{"title":"New Data on Ages of the Basement of the Central Kamchatka Depression and the Base of the Klyuchevskaya Group of Volcanoes","authors":"E. A. Zelenin, N. V. Gorbach, S. A. Sokolov, V. A. Lebedev","doi":"10.1134/s1028334x24602669","DOIUrl":"https://doi.org/10.1134/s1028334x24602669","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>A unique feature of the Kamchatka Peninsula is an extensional structure running for more than 400 km along the peninsula—the Central Kamchatka Depression (CKD). Some geodynamic models associate the formation of the CKD with the movements of East Kamchatka toward the Pacific Ocean due to retreat of the northern edge of the subduction zone. However, isotope–geochronological data on the time of the CKD formation have been lacking up to the present time. Therefore, we could not directly associate the CKD emergence with the stages of the Kamchatka tectonic evolution and the intensity of its recent deformations. This work presents the chemical compositions and K–Ar ages of effusive rocks from the KL-1 borehole drilled in the northern part of the CKD. Samples from the depth interval of 50–475 m, represented by medium-K basalts and high-K basaltic trachyandesites date back to 0.7 to 1.5 Ma. By their composition, these rocks are close to effusive rocks forming the base of the Klyuchevskaya group of volcanoes. Before this study, the age of the effusives had been estimated as much younger, up to 0.3 Ma. Below, in the interval of 475–505 m, a pack of sands and boulder conglomerates was described. They unconformably overlap the aphyric and olivine–pyroxene porphyritic andesibasalts with interlayers of volcanic ash and volcanic sands of the same composition. At the depth of 905–1513 m, the borehole recovers highly altered tuffs, mafic and intermediate in composition, interbedded with andesites and andesibasalts. The K–Ar estimation of 3.5 ± 0.4 Ma was obtained for the least altered sample of medium-K andesibasalt from the depth of 1255 m. We suggest that the altered effusives at 905 m and below are associated with the completion of accretion of the Kronotskii Island Arc and with the formation of the modern structure of the Kamchatka Peninsula. The CKD setting occurred after this event in the interval of 1.5–3.5 Ma.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"95 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141862768","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}

{"title":"New View of the CO2 Content in Surface Waters of the Black Sea Based on Direct Measurements","authors":"S. K. Konovalov, N. A. Orekhova","doi":"10.1134/s1028334x24602943","DOIUrl":"https://doi.org/10.1134/s1028334x24602943","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The results of high-precision direct determination of CO₂ in the surface waters of the Black Sea are presented. These measurements made possible to obtain high precision characteristics of the content and intra-annual variations in <i>p</i>CO₂ for the first time. The average annual value of <i>p</i>CO₂ is 436 µatm, which is higher than the average annual value in the near-sea surface layer of the atmosphere (420 µatm). The seasonal variability has revealed decrease of <i>p</i>CO₂ in seawater from late spring to fall. The minimum values of <i>p</i>CO₂ are detected in January–February; the maximum ones, in July. The seasonal variations in the CO₂ content in the near-sea atmosphere reveal an inverse relationship, with maximum values in February and minimum values in July. This indicates different mechanisms of the evolution of CO₂ in the air and seawater. The content of CO₂ in the atmosphere is determined by external sources and depends on the burning intensity of organic carbon. Variations in <i>p</i>CO₂ in water is significantly affected by abiotic factors, such as the influence of temperature change on CO₂ solubility and the state of the carbon system. In the summer–fall season, <i>p</i>CO₂ is determined by a combination of abiotic and biotic factors, including variations in temperature and intensity of biological processes of organic matter transformation. Both the intensity and effect of these factors vary throughout the year, but the abiotic factor remains primay during the entire year.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"262 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141862767","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}

{"title":"Robust Deep Learning for Accurate Landslide Identification and Prediction","authors":"T. Bhuvaneswari, R. Chandra Guru Sekar, M. Chengathir Selvi, J. Jemima Rubavathi, V. Kaviyaa","doi":"10.1134/s1028334x23602961","DOIUrl":"https://doi.org/10.1134/s1028334x23602961","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Landslide is the most common natural risk in mountainous regions on all five continents and they can pose a serious threat in these areas. Strong earthquakes, unusual weather events such as storms and eruptions of volcanoes, and human-caused events such as creating roadways that crossed the slopes are the main causes of landslides and they cause significant dangers to residential properties and society as a whole. The Landslide4sense dataset is used for identifying landslides, which contains 3799 training samples and 245 testing samples. These image patches are taken from the Sentinel-2 sensor, while the slope and Digital Elevation Model (DEM) are from the ALOS PALSAR sensor. Data was gathered from four distinct geographical areas namely Kodagu, Iburi, Taiwan, and Gorkha. We use Deep Learning (DL) models such as ResNet18, U-Net, and VGG16 to predict the landslide. By comparing the above models with the evaluation metrics like loss, precision, recall, F1 score and accuracy, ResNet18 model is selected as the best model for landslide identification.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"20 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141862764","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}

{"title":"Vesuvianite, a New U–Pb Geochronometer Mineral for Dating Ore Deposits","authors":"M. V. Stifeeva, T. L. Panikorovskii, A. M. Larin, E. B. Salnikova, A. B. Kotov, V. V. Bortnikov","doi":"10.1134/s1028334x2460292x","DOIUrl":"https://doi.org/10.1134/s1028334x2460292x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract—</h3><p>The results of U–Pb (ID-TIMS) geochronological studies of vesuvianite from ore-bearing metasomatites of Khopunvaara ore occurrence (Pitkyaranta ore district, Northern Ladoga region) are presented. The resulting age estimate (1550 ± 6 Ma) coincides within the error with the age of formation of ore-bearing skarns that are genetically related to the rapakivi granites of the Salmi batholith. This indicates the possibility of using vesuvianite as a U–Pb mineral-geochronometer, including for ore-bearing contact-reaction rocks.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"357 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141862766","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}

{"title":"The First Data on Carbon Isotope Stratigraphy of the Asselian and Sakmarian Stages of the Lower Permian in Northern Verkhoyanie","authors":"V. I. Makoshin, R. V. Kutygin, A. S. Biakov, B. I. Gareev, A. N. Kilyasov","doi":"10.1134/s1028334x24602827","DOIUrl":"https://doi.org/10.1134/s1028334x24602827","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Changes in the values of δ¹³С_оrg in the lower part of the Permian deposits, obtained in the Kuba-lakh Section of the lower reaches of the Lena River and integrated with biostratigraphic data are detected in northeastern Russia for the first time. A comparison with isotope-carbon trends identified in the Asselian and Sakmarian stages of the Southern Urals is proposed. Based on the established sequence of negative shifts of the carbon isotope composition of organic matter, a conclusion is made that the Carboniferous–Permian boundary in the Kubalakh Section is located at the 80 m thick gap in section. The first data independent of the biostratigraphic and paleontological records are obtained on the Late Asselian age of the Tuora-Sis Formation beds containing the <i>Bulunites</i> ammonoid association, the stage assignment of which has been debated for many decades. The chronostratigraphic indefinite interval between the Asselian and Samarian stages is significantly reduced to the upper parts of the <i>Jakutoproductus lenensis</i> Beds. The data obtained indicate that the continuation of the work on the chemostratigraphy of stable carbon isotopes has good prospects for substantiating the division into stages and the interregional correlation of the Lower Permian deposits in Verkhoyanie.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"464 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744760","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}

{"title":"Age of Alkaline Ultramafic Explosion Pipes of the Chapinskii Complex (Yenisei Ridge)","authors":"Yu. V. Danilova, I. S. Sharygin, E. A. Gladkochub, E. I. Nikolenko, N. V. Bryansky, S. Yu. Skuzovatov, A. S. Gladkov, A. V. Ivanov, D. A. Koshkarev, F. A. Letnikov","doi":"10.1134/s1028334x2460289x","DOIUrl":"https://doi.org/10.1134/s1028334x2460289x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract—</h3><p>The age of formation of the explosion pipes of the Chapinskii complex in the Chingasan magmatic belt in the northern part of the Yenisei Ridge is determined. U–Pb dating of zircon megacrysts from alkaline ultramafic rocks has established the values of 657.7 ± 13.4 and 647.6 ± 9.7 Ma for the Natalyinskaya pipe and Pipe no. 3, respectively. The intrusion of alkaline ultramafic explosion pipes of the Chapinskii complex corresponds to the time of manifestation of alkaline ultramafic magmatism along the southern and southwestern margin of the Siberian Craton.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"79 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744821","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}