New Findings of Latest Early Olenekian (Early Triassic) Fossils in South Primorye, Russian Far East, and Their Stratigraphical Significance

• 作者: Yuri D.Zakharov Liana G.Bondarenko Alexander M.Popov Olga P.Smyshlyaeva
• 来源期刊: 地球科学学刊（英文版）
• 年，卷（期）: 2021,（3）
• 页码范围: 554-572
• 页数: 19页
• 语种: 英文

摘要

Information on latest early Olenekian (latest Smithian) ammonoids is available apparently from only seven regions of the world, including South Primorye. Latest Smithian evidences on this topic are recorded from the West SMID (abbreviation from the Russian name of the quarry: "Building Materials and Details"), East SMID and Golyj Cape areas in South Primorye. This provides additional information on systematic composition of latest Smithian ammonoid, as well as conodont and brachiopod assemblages from the recently identified Shimanskyites shimanskyi Zone, located between lower Olenekian Anasibirites nevolini Zone and upper Olenekian Tirolites subcassianus Zone. There are many common ammonoid spe-cies in the Shimanskyites shimanskyi Zone and the underlying Anasibirites nevolini Zone, e.g., Prosphingi-toides sp., Arctoceras septentrionale (Diener), Churkites syskoi Zakharov et Shigeta, Submeekoceras? subhhydaspis (Kiparisova), Prionites markevichi Zakharov et Smyshlyaeva, 'Anasibirites' simanenkoi Zak-harov et Smyshlyaeva, Xenoceltites? subvariocostatus Zakharov et Smyshlyaeva, and Mianwaliites zimini Zakharov et Smyshlyaeva. The base of the Shimanskyites shimanskyi Zone, marked by a negative δ13Corg excursion in the Kamenushka-2 Section by our previous study, coincides with the FO (first occurrence) of ammonoids Shimanskyites shimanskyi Zakharov et Smyshlyaeva and Glyptophiceras cf. sinuatum (Waagen) and conodont Hindeodella budurovi Buryi. This zone is characterized additionally by some fossils common for the overlying upper Olenekian Tirolites subcassianus Zone: ammonoids of the genus Kamenushkaites, brachiopods Bittnerihyris margaritovi (Bittner) and Lepismatina sp. and conodont 'Neogondolella' (=?Borinella) jubata Sweet. The latest Smithian ammonoids recorded from the Shimanskyites shimanskyi Zone totally consist of 30 taxa belonging to 11 families (Sageceratidae, Ussuiriidae, Aspenitidae, Paranan-nitidae, Arctoceratidae, Proptychitidae, ?Galfetitidae, Prionitidae, ?Kashmiritidae, Xenoceltitidae and Pa-laeophyllitidae). The problems of global correlation of uppermost Smithian strata are also discussed.