ТЕРМИНАЛЬНЫЙ КОМПЛЕКС ПЕРМСКИХ БРАХИОПОД ВЕРХОЯНЬЯ, СЕВЕРО-ВОСТОК РОССИИ

Abstract

Brachiopods from the upper Khalpirkian Regional Stage of the Tiryakh-Kobyume section of the Kobyume structural-facies zone of Southern Verkhoyan were 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, which indicate that the host deposits belong to the Crassispirifer monumentalis beds. These beds were previously established by us only in the lower part of the Khalpirkian Regional Stage. A review of reliable finds of brachiopods of the terminal assemblage, confined to the Khalpirkian regional stage of the Upper Permian, is given. 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. identified from linoproductids. An important element of the terminal assemblage are the spiriferids Crassispirifer monumentalis. Athyridids of the Khalpirkian Regional Stage, known only in its lower part, are represented by Cleiothyridina nikolaevi Grunt, Cleiothyridina sp., and Bajtugania sp. In the studied regional stage are also finds 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 the rhynchonellids Piarorhynchia sp. appear at the base of the Regional Stage. At the beginning of the Khalpirkian time, the brachiopod community had an extended area in the shelf zone of the Verkhoyan Sea along the coastline of Angaraland. Subsequently, this area was reduced, initially dividing into two independent subareas confined to the East Kharaulakh and South Verkhoyan sectors. In the late Khalpirkian time, the brachiopod community concentrated only in the Kobyume zone, where it ended its existence during 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.