litosphereЛитосфераLITHOSPHERE (Russia)1681-90042500-302XA.N. Zavaritsky Institute of Geology and Geochemistry10.24930/1681-9004-2022-22-5-599-611litosphere-1727Research ArticleСтатьиArticlesПроявление позднеаэронского события в разрезе силура на западном склоне Приполярного УралаManifestation of the Late Aeronian event in the Silurian section on the western slope of the Subpolar UralsБезносоваТ. М.BeznosovaT. M.

167982, г. Сыктывкар, ул. Первомайская, 54

Tat’yana M. Beznosova

54 Pervomaiskaya st., 167982 Syktyvkar

beznosova@geo.komisc.ruМатвеевВ. А.MatveevV. A.

167982, г. Сыктывкар, ул. Первомайская, 54

Vladimir A. Matveev

54 Pervomaiskaya st., 167982 Syktyvkar

Институт геологии ФИЦ Коми НЦ УрО РАНРоссияN. P. Yushkin Institute of Geology, Federal Research Centre KSС, UB RASRussian Federation202204112022225599611Copyright © Безносова Т.М., Матвеев В.А., 20222022Безносова Т.М., Матвеев В.А.Beznosova T.M., Matveev V.A.Данная работа распространяется под лицензией Creative Commons Attribution 4.0.This work is licensed under a Creative Commons Attribution 4.0 License.https://www.lithosphere.ru/jour/article/view/1727Объект исследования

Объект исследования. В статье приводятся результаты изучения следов глобального позднеаэронского биотического и изотопного (δ13Cкарб) событий, сохранившихся в новом опорном разрезе нижнего силура на Приполярном Урале.

Материалы и методы

Материалы и методы. Образцы осадочных пород, пробы на микрофауну, изотопный анализ и коллекции с остатками бентосной фауны собраны авторами в разные годы во время полевых работ. Исследования подтверждены седиментологическими, биостратиграфическими и хемостратиграфическими авторскими данными.

Результаты

Результаты. Событийно-стратиграфический интервал, установленный в верхней части лолашорского горизонта (аэрония) силура, характеризуется усилением регрессивных тенденций, сокращением биоразнообразия, исчезновением конодонтов Pranognathus tenuis и брахиопод рода Pentamerus, а также δ13Cкарб-аномалиями, наблюдаемыми в верхней толще лолашорского горизонта.

Выводы

Выводы. Полученные данные свидетельствуют об эвстатическом падении уровня моря, крупной экосистемной перестройке и перерыве в осадконакоплении в конце лолашорского времени. Рубеж лолашорского и филиппъельского горизонтов (аэрония и теличия) фиксирует резкий отрицательный сдвиг δ13Cкарб, впервые установленный в разрезе нижнего силура на территории Европейского Северо-Востока России.

Research subject

Research subject. The article presents the results of studying traces of the global Late Aeronian biotic and isotopic (δ13Ccarb) events preserved in a new reference section of the Lower Silurian in the Subpolar Urals.

Materials and methods

Materials and methods. The samples of sedimentary rocks and microfauna, the results of isotope analysis, as well as the collections with remains of benthic fauna collected by the authors in different years during fieldwork were investigated. The studies were confirmed by sedimentological, biostratigraphic and chemostratigraphic data obtained by the authors.

Results

Results. The The event-stratigraphic interval, established in the upper part of the Lolashor stage (Aeronian) of the Silurian, is characterized by increasing regressive tendencies, decreasing biodiversity, disappearance of Pranognathus tenuis conodonts and brachiopods of the genus Pentamerus, as well as by δ13Ccarb anomalies in the upper strata of the Lolashor stage.

Conclusions

Conclusions. The obtained data indicate a eustatic drop in the sea level, a major ecosystem restructuring, and a sedimentation gap at the end of the Lolashor time. The boundary between the Lolashor and Philippel stages (Aeronian and Telychian) records a sharp negative isotopic shift of δ13Ccarb, which was first observed in the Lower Silurian section in the European Northeast of Russia.

силурлландовериаэронтеличСобытие Сэндвикизотопы углеродаSilurianLlandoveryAeronianTelychianSandvika Eventcarbon isotopesИсследования проведены в соответствии с темой № 1021062311460-9-1.5.3 государственного задания ИГ ФИЦ Коми НЦ УрО РАН. Мы благодарим П. Мянника за совместные полевые работы на Приполярном Урале, И.В. Смолеву – инженера ЦКП “Геонаука” Института геологии ФИЦ Коми НЦ УрО РАН за определение изотопного состава углерода в карбонатных породах. Особая благодарность двум анонимным рецензентам за конструктивные замечания и предложения, которые помогли улучшить эту статью.The work was conducted within the framework of the projects No. 1021062311460-9-1.5.3 of the Institute of Geology, Federal Research Centre Komi Scientific Centre uB, RAS. The authors are grateful to P. Männik for joint field work, I.V. 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The authors declare that there are no conflicts of interest present.