{"title":"The Terminal Assemblage of Permian Brachiopods in the Verkhoyanie, Northeast Russia","authors":"R. V. Kutygin, V. I. Makoshin, A. S. Biakov","doi":"10.1134/s1819714024010068","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Brachiopods from the upper part of the Khalpirkian Regional Stage of the Tiryakh–Kobyume section of the Kobyume structural–facies zone in Southern Verkhoyanie have been studied. The collection is dominated by <i>Strophalosia</i>? <i>vollossovitschi</i> (Fredericks) and <i>Cancrinella</i>? sp. Single spiriferids are assigned to <i>Crassispirifer monumentalis</i> Abramov et Grigorjeva and <i>Cr.</i> aff. <i>monumentalis</i> Abramov et Grigorjeva, and, thus, host deposits are referred to the <i>Crassispirifer monumentalis</i> Beds. We found these beds earlier only in the lower part of the Khalpirkian Regional Stage. Reliable findings of the terminal brachiopod assemblage confined to the Khalpirkian of the Upper Permian have been reviewed. The assemblage is dominated by strophalosiids represented by <i>Wyndhamia gijigensis</i> (Zavodowsky), <i>Marginalosia</i>? <i>magna</i> Abramov et Grigorjeva, <i>Subtaeniothaerus lungersgauzeni</i> Solomina, and <i>Strophalosia</i>? aff. <i>vollossovitschi</i> (Fredericks). “<i>Magadania</i>” sp. and <i>Cancrinella</i>? sp. have been identified from linoproductids. <i>Crassispirifer monumentalis</i> spiriferids are an important element of the terminal assemblage. Athyridids of the Khalpirkian Regional Stage, known only in its lower part, are represented by <i>Cleiothyridina nikolaevi</i> Grunt, <i>Cleiothyridina</i> sp., and <i>Bajtugania</i> sp. The studied regional stage also contains findings of terebratulids attributed to <i>Marinurnula</i>? aff. <i>mantuanensis</i> (Campbell) and <i>M.</i>? aff. <i>chivatschense</i> (Zavodowsky). No brachiopods are known at the top of the Khalpirkian Regional Stage, while rhynchonellids <i>Piarorhynchia</i> sp. appear at the base of the Nekuchan Regional Stage. At the beginning of the Khalpirkian, the brachiopod community had an extended natural habitat in the shelf zone of the Verkhoyan Sea along the Angaraland coastline. Subsequently, this area was reduced and initially divided into two independent subareas confined to the East Kharaulakh and South Verkhoyan sectors. In the Late Khalpirkian, the brachiopod community was concentrated only in the Kobyume zone, where it ended up under the end-Permian mass extinction. Some taxa of the identified brachiopod assemblage have been traced in the Okhotsk region, the Ayan—Yuryakh anticlinorium, and the Omolon massif.</p>","PeriodicalId":49583,"journal":{"name":"Russian Journal of Pacific Geology","volume":"6 1","pages":""},"PeriodicalIF":0.9000,"publicationDate":"2024-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Russian Journal of Pacific Geology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1134/s1819714024010068","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Brachiopods from the upper part of the Khalpirkian Regional Stage of the Tiryakh–Kobyume section of the Kobyume structural–facies zone in Southern Verkhoyanie have been studied. The collection is dominated by Strophalosia? vollossovitschi (Fredericks) and Cancrinella? sp. Single spiriferids are assigned to Crassispirifer monumentalis Abramov et Grigorjeva and Cr. aff. monumentalis Abramov et Grigorjeva, and, thus, host deposits are referred to the Crassispirifer monumentalis Beds. We found these beds earlier only in the lower part of the Khalpirkian Regional Stage. Reliable findings of the terminal brachiopod assemblage confined to the Khalpirkian of the Upper Permian have been reviewed. The assemblage is dominated by strophalosiids represented by Wyndhamia gijigensis (Zavodowsky), Marginalosia? magna Abramov et Grigorjeva, Subtaeniothaerus lungersgauzeni Solomina, and Strophalosia? aff. vollossovitschi (Fredericks). “Magadania” sp. and Cancrinella? sp. have been identified from linoproductids. Crassispirifer monumentalis spiriferids are an important element of the terminal assemblage. Athyridids of the Khalpirkian Regional Stage, known only in its lower part, are represented by Cleiothyridina nikolaevi Grunt, Cleiothyridina sp., and Bajtugania sp. The studied regional stage also contains findings of terebratulids attributed to Marinurnula? aff. mantuanensis (Campbell) and M.? aff. chivatschense (Zavodowsky). No brachiopods are known at the top of the Khalpirkian Regional Stage, while rhynchonellids Piarorhynchia sp. appear at the base of the Nekuchan Regional Stage. At the beginning of the Khalpirkian, the brachiopod community had an extended natural habitat in the shelf zone of the Verkhoyan Sea along the Angaraland coastline. Subsequently, this area was reduced and initially divided into two independent subareas confined to the East Kharaulakh and South Verkhoyan sectors. In the Late Khalpirkian, the brachiopod community was concentrated only in the Kobyume zone, where it ended up under the end-Permian mass extinction. Some taxa of the identified brachiopod assemblage have been traced in the Okhotsk region, the Ayan—Yuryakh anticlinorium, and the Omolon massif.
期刊介绍：
Russian Journal of Pacific Geology publishes the results of research on the Earth crust and mantle composition and provides articles on the geological structure and patterns of distribution of mineral deposits in the Pacific Ocean, marginal seas and continental margins. It discusses the topics of stratigraphy, sedimentology, magmatic activity, and seismicity. The journal deals with the problems of lithosphere plates tectonics, and offers the results of neotectonic, geomorphological, geodesic, environmental and mining studies in the Pacific region. The journal accepts theoretical, methodical and philosophical articles covering general issues of geology, geophysics, geochemistry, geoecology and mining. The journal also publishes critical notes and comments, and reviews.
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