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<article article-type="research-article" dtd-version="1.3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="ru"><front><journal-meta><journal-id journal-id-type="publisher-id">litosphere</journal-id><journal-title-group><journal-title xml:lang="ru">Литосфера</journal-title><trans-title-group xml:lang="en"><trans-title>LITHOSPHERE (Russia)</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">1681-9004</issn><issn pub-type="epub">2500-302X</issn><publisher><publisher-name>A.N. Zavaritsky Institute of Geology and Geochemistry</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.24930/2500-302X-2025-25-3-438-450</article-id><article-id custom-type="edn" pub-id-type="custom">DQTPYJ</article-id><article-id custom-type="elpub" pub-id-type="custom">litosphere-2305</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>Статьи</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="en"><subject>Articles</subject></subj-group></article-categories><title-group><article-title>Первые данные об изотопном составе углерода конодонтовых элементов из средней перми (казанский ярус) в разрезе Чимбулат (Вятские дислокации, Волго-Уральская антеклиза)</article-title><trans-title-group xml:lang="en"><trans-title>First data on the carbon isotope composition of conodont elements from the Middle Permian (Kazanian Stage) of the Tchimbulat section (Vyatka Dislocations, Volga-Ural Anteclise)</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Журавлев</surname><given-names>А. В.</given-names></name><name name-style="western" xml:lang="en"><surname>Zhuravlev</surname><given-names>A. V.</given-names></name></name-alternatives><bio xml:lang="ru"><p>167982, г. Сыктывкар, ул. Первомайская, 54</p></bio><bio xml:lang="en"><p>54 Pervomaiskaya st., Syktyvkar 167982</p></bio><email xlink:type="simple">micropalaeontology@gmail.com</email><xref ref-type="aff" rid="aff-1"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="ru"><institution>Институт геологии им. академика Н.П. Юшкина ФИЦ Коми НЦ УрО РАН</institution><country>Россия</country></aff><aff xml:lang="en"><institution>N.P. Yushkin Institute of Geology, FRC Komi SC UB RAS</institution><country>Russian Federation</country></aff></aff-alternatives><pub-date pub-type="collection"><year>2025</year></pub-date><pub-date pub-type="epub"><day>15</day><month>07</month><year>2025</year></pub-date><volume>25</volume><issue>3</issue><fpage>438</fpage><lpage>450</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Журавлев А.В., 2025</copyright-statement><copyright-year>2025</copyright-year><copyright-holder xml:lang="ru">Журавлев А.В.</copyright-holder><copyright-holder xml:lang="en">Zhuravlev A.V.</copyright-holder><license xml:lang="ru" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>Данная работа распространяется под лицензией Creative Commons Attribution 4.0.</license-p></license><license xml:lang="en" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>This work is licensed under a Creative Commons Attribution 4.0 License.</license-p></license></permissions><self-uri xlink:href="https://www.lithosphere.ru/jour/article/view/2305">https://www.lithosphere.ru/jour/article/view/2305</self-uri><abstract><sec><title>Объект исследования</title><p>Объект исследования. Изотопный состав углерода конодонтовых элементов среднепермского возраста из разреза немдинской свиты в карьере Чимбулат.</p></sec><sec><title>Цель</title><p>Цель. Палеоэкологическая интерпретация данных по изотопному составу углерода конодонтовых элементов из раннеказанских отложений Волго-Вятского района.</p></sec><sec><title>Материалы и методы</title><p>Материалы и методы. Изотопный состав углерода изучен в 11 конодонтовых элементах родов Stepanovites, Sweetina и Kamagnathus из 9 образцов. Образцы характеризуют региональную конодонтовую зону Kamagnathus khalimbadzhae.</p></sec><sec><title>Результаты</title><p>Результаты. Средний изотопный состав углерода конодонтовых элементов в изученных образцах составляет –27.3‰, что ниже среднего значения для девонско-каменноугольного интервала палеотропической области (–26.7‰) и сходно с изотопным составом конодонтов из биогермных и прибиогермных фаций среднего карбона Пай-Хоя. Судя по относительно легкому изотопному составу углерода по сравнению с другими конодонтами, среднепермская группа Stepanovites–Sweetina, вероятно, занимала трофическую позицию первичных консументов. По соотношению изотопного состава конодонтов и вмещающих карбонатов реконструируется низкая до умеренной первичная биопродуктивность пелагиали раннеказанского бассейна в Волго-Вятском районе. С учетом полученных данных отмечен отрицательный тренд в изменении изотопного состава углерода конодонтовых элементов в позднедевонско-среднепермском интервале. Этот тренд совпадает со снижением содержания углекислоты в атмосфере. δ13C конодонтов могло быть связано с содержанием углекислоты в атмосфере через интенсивность фракционирования изотопов углерода фитопланктоном.</p></sec><sec><title>Выводы</title><p>Выводы. Реконструирована относительно невысокая первичная биопродуктивность пелагиали раннеказанского морского бассейна в Волго-Вятском районе. Конодонты группы Stepanovites–Sweetina в трофической сети пелагиали казанского бассейна занимали позицию первичных консументов, питавшихся фитопланктоном с изотопно-легким углеродом. Легкий изотопный состав углерода может быть связан с относительно медленным ростом фитопланктона и, опосредованно, с низким содержанием углекислоты в атмосфере в раннеказанское время. Предполагаемая зависимость δ13C конодонтов отряда Prioniodinida от содержания углекислоты в атмосфере может использоваться для приближенной оценки вариаций содержания углекислого газа для отдельных стратиграфических интервалов.</p></sec></abstract><trans-abstract xml:lang="en"><sec><title>Research subject</title><p>Research subject. Carbon isotope composition of conodont elements of Middle Permian age from the section of the Nemda Formation in the Chimbulat quarry.</p></sec><sec><title>Aim</title><p>Aim. Paleoecological interpretation of data on the carbon isotope composition of conodont elements from Early Kazanian deposits of the Volga-Vyatska region.</p></sec><sec><title>Materials and Methods</title><p>Materials and Methods. Carbon isotope composition was studied in 11 conodont elements of the Stepanovites, Sweetina, and Kamagnathus genera from 9 samples. The samples characterize the Kamagnathus khalimbadzhae regional conodont zone.</p></sec><sec><title>Results</title><p>Results. The average carbon isotopic composition of conodont elements in the studied samples was –27.3‰, which is lower than the average value for the Devonian-Carboniferous interval of the palaeotropical realm (–26.7‰) and similar to the isotopic composition of conodonts from biohermal and near-biohermal facies of the Middle Carboniferous of Pai-Khoi. Judging by the relatively light carbon isotopic composition, the Middle Permian Stepanovites–Sweetina group probably occupied the trophic position of primary consumers. The relation of the isotopic composition of conodonts and host carbonates allow us to reconstruct the low to moderate pelagic primary bioproductivity of the Early Kazanian basin in the Volga-Vyatka region. According to the obtained data, a negative trend in the change of carbon isotope composition of conodont elements in the Late DevonianMiddle Permian interval was noted. This trend coincides with the decrease in carbon dioxide content in the atmosphere. The δ13C of conodonts could be related to the atmospheric carbon dioxide content through the intensity of carbon isotope fractionation by phytoplankton.</p></sec><sec><title>Conclusions</title><p>Conclusions. The relatively low pelagic primary bioproductivity of the Early Kazanian marine basin in the Volga-Vyatka region was reconstructed. Conodonts of the Stepanovites–Sweetina group in the pelagic trophic network of the Kazanian basin occupied the position of primary consumers feeding on phytoplankton with a light carbon isotope composition. This light carbon isotope composition may have been caused by a relatively low phytoplankton growth rate and, indirectly, with a low atmospheric carbon dioxide content in the Early Kazanian time. The assumed dependence of δ13C of Prioniodinida conodonts on the atmospheric carbon dioxide content can be used for approximate estimation of carbon dioxide content variations for some stratigraphic intervals.</p></sec></trans-abstract><kwd-group xml:lang="ru"><kwd>изотопный состав углерода</kwd><kwd>конодонты</kwd><kwd>средняя пермь</kwd><kwd>казанский ярус</kwd><kwd>Волго-Уральская антеклиза</kwd></kwd-group><kwd-group xml:lang="en"><kwd>carbon isotope composition</kwd><kwd>conodonts</kwd><kwd>Middle Permian</kwd><kwd>Kazanian Stage</kwd><kwd>Volga-Ural Anteclise</kwd></kwd-group><funding-group><funding-statement xml:lang="ru">Исследования проводились в рамках государственного задания по теме № 122040600008-5.</funding-statement><funding-statement xml:lang="en">The research was conducted within the framework of the state assignment on topic No. 122040600008-5.</funding-statement></funding-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Журавлев А.В. 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