An enormous Jurassic turtle bone bed from the Turpan Basin of Xinjiang, China
Tóm tắt
A spectacular new terrestrial Konzentratlagerstätte is introduced from the Turpan Basin of Xinjiang, China that probably belongs to the late Middle Jurassic Qigu Formation. It contains a mass accumulation of “xinjiangchelyid” turtles preliminarily identified as Annemys sp. In the zone with the highest turtle concentration, complete and articulated turtle skeletons are tightly packed at a density of up to 36 turtles per square meter. The fossiliferous layer is thickened here and shows an erosional base. This high concentration zone outcrops approximately 10 m in length and shows no decrease in turtle density after exposing 2 m of the layer into the hillside. Adjacent is a more expansive zone of at least 10 m by 30 m. In this region, the fossiliferous layer is evenly thick, and approximately five, fully disarticulated turtles are present per square meter. A conservatively estimated 1,800 turtles may, therefore, have been deposited at this site. It is likely that these aquatic turtles gathered in a retreating water hole in a riverine environment during a drought, much as some aquatic turtles will do today, but perished when the habitat dried up completely. A following catastrophic rainfall event caused a debris flow, possibly channelized in a dry river bed, which transported complete turtles, disarticulated turtles, and mudstone clasts and deposited them after a short distance. This taphonomic model is consistent with previous environmental reconstructions of the Turpan Basin during the late Middle Jurassic in predicting the episodic breakdown of regional monsoonal circulation resulting in a seasonally dry climate with severe episodic droughts.
Từ khóa
Tài liệu tham khảo
Batsch AJGC (1788) Versuch einer Anleitung, zur Kenntniß und Geschichte der Thiere und Mineralien. Akademische Buchhandlung, Jena
Brand LR, Goodwin HT, Ambrose PD, Buchheim HP (2000) Taphonomy of turtles in the Middle Eocene Bridger Formation, SW Wyoming. Palaeogeogr Palaeoclimatol Palaeoecol 162(1–2):171–189
Brinkman DB, Eberth D, Clark J, Xing X, Wu X-C (2012) Turtles from the Jurassic Shishugou Formation of the Junggar Basin, People’s Republic of China, and the Basicranial Region of Basal Eucryptodires. In: Brinkman DB, Holroyd PA, Gardner JD (eds) Morphology and Evolution of Turtles.
Collinson JD, Mountney N, Thompson DB (2006) Sedimentary structures. Terra, Harpenden
Dong Z-M (1992) Dinosaurian faunas of China. China Ocean, Beijing
Dong Z-M (1997) Vertebrates of the Turpan Basin, the Xinjiang Uygur Autonomous Region, China. In: Dong Z-M (ed) Sino-Japanese silk road dinosaur expedition. China Ocean, Beijing, pp 96–101
Eberth DA, Brinkman DB, Chen P, Yuan F, Wu S, Li G, Cheng X (2001) Sequence stratigraphy, paleoclimate patterns, and vertebrate fossil preservations in Jurassic-Cretaceous strata of the Junggar Basin, Xinjiang autonomous region, People's Republic of China. Can J Earth Sci 38(12):1627–1644
Eberth DA, Britt BB, Scheetz R, Stadtman KL, Brinkman DB (2006) Dalton wells: geology and significance of debris-flow-hosted dinosaur bonebeds in the Cedar Mountain Formation (Lower Cretaceous) of eastern Utah, USA. Palaeogeogr Palaeoclimatol Palaeoecol 236(3–4):217–245. doi:10.1016/j.palaeo.2005.11.020
Ernst CH, Barbour RW (1989) Turtles of the world. Smithsonian Institution, Washington D.C
Evans J, Kemp TS (1975) The cranial morphology of a new lower cretaceous turtle from southern England. Palaeontology 18(1):25–40
Fastovsky D, Clark J, Strater N, Montellano M, R Hernandez R, Hopson J (1995) Depositional environments of a Middle Jurassic terrestrial vertebrate assemblage, Huizachal Canyon, Mexico. J Vert Paleont 15(3):561–575
Hendrix MS, Graham SA, Carroll AR, Sobel ER, McKnight CL, Schulein BJ, Wang Z (1992) Sedimentary record and climatic implications of recurrent deformation in the Tian Shan; evidence from Mesozoic strata of the north Tarim, south Junggar, and Turpan basins, Northwest China. Geol Soc Am Bull 104(1):53–79
Joyce WG (2007) Phylogenetic relationships of Mesozoic turtles. Bull Peabody Mus Nat Hist 48(1):3–102
Joyce WG, Lyson TR (2011) New material of Gilmoremys lancensis nov. comb. (Testudines: Trionychidae) from the Hell Creek Formation and the diagnosis of plastomenid turtles. J Paleont 85(3):442–459. doi:10.1666/10-127.1
Kaznyshkin MN, Nalbandyan LA, Nessov LA (1990) Middle and Late Jurassic turtles of Fergana (Kirghiz SSR) [in Russian]. Yezhegodnik Vsesoyuz Paleontol Obshch 33:185–204
Khand Y, Badamgarav D, Ariunchimeg Y, Barsbold R (2000) Cretaceous system in Mongolia and its depositional environments. In: Hakuyu O, Nlall JM (eds) Cretaceous environments of Asia. Elsevier Science, Amsterdam, pp 49–79. doi:10.1016/S0920-5446(00)80024-2
Kidwell S, Fürsich F, Aigner T (1986) Conceptual framework for the analysis and classification of fossil concentrations. Palaios 1:228–238
Liu LY, Di SX (1997) Characteristics of Middle Jurassic sedimentation and reservoir pore evolution in Turpan Depression [In Chinese with English abstract]. Oil Gas Geol 3(18):247–260
Lyson TR, Joyce WG (2009a) A new species of Palatobaena (Testudines: Baenidae) and a maximum parsimony and Bayesian phylogenetic analysis of Baenidae. J Paleont 83(3):457–470. doi:10.1666/08-172.1
Lyson TR, Joyce WG (2009b) A revision of Plesiobaena (Testudines: Baenidae) and an assessment of baenid ecology across the K/T boundary. J Paleont 83(6):833–853. doi:10.1666/09-035.1
Major JJ (2003) Debris flow. In: Middleton GV (ed) Encyclopedia of sediments and sedimentary rocks. Kluwer Academic, Dordrecht, pp 186–188
Rogers RR (2005) Fine-grained debris flows and extraordinary vertebrate burials in the Late Cretaceous of Madagascar. Geology 33(4):297–300. doi:10.1130/g21036.1
Schwermann L (2010) Der Mittlere bis Obere Jura östlich von Shanshan im zentralen Turpan-Becken, Uigurisches Autonomes Gebiet Xinjiang (NW China). Unpublished Diplom Mapping Thesis, University of Bonn, Bonn
Seilacher A (1970) Begriff und Bedeutung der Fossil-Lagerstätten. Neues Jahrb Geol Paläont, Monatsh 1970:34–39
Shao L, Stattegger K, Li W, Haupt BJ (1999) Depositional style and subsidence history of the Turpan Basin (NW China). Sed Geol 128:155–169
Shipman PAT (1975) Implications of drought for vertebrate fossil assemblages. Nature 257(5528):667–668
Sukhanov VB (2000) Mesozoic turtles of Middle and Central Asia. In: Benton MJ, Shishkin MA, Unwin DM, Kurochkin EN (eds) The age of Dinosaurs in Russia and Mongolia. Cambridge University Press, Cambridge, pp 309–367
Sukhanov VB, Narmandakh P (2006) New taxa of Mesozoic turtles from Mongolia. Fossil Turtle Research 1 (Russ. J. Herpetol. 13 Suppl.):119–127
Wang SE, Gao LZ (2012) SHRIMP U-Pb dating of zircons from tuff of Jurassic Qigu Formation in Junggar Basin, Xinjiang. Geol Bull China 31(4):503–509
Wang SE, Pang QQ, Wang DN (2012) New advances in the study of Jurassic-Cretaceous biostratigraphy and isotopic ages of the Junggar Basin in Xinjiang and their significance. Geol Bull China 31(4):493–502
Weigelt J (1989) Recent vertebrate carcasses and their paleobiological implications. University of Chicago Press, Chicago
Wings O, Schellhorn R, Mallison H, Thuy B, Wu W, Sun G (2007) The first dinosaur tracksite from Xinjiang, NW China (Middle Jurassic Sanjianfang Formation, Turpan Basin)—a preliminary report. Global Geol 10(2):113–129
Zhao XJ (1980) Mesozoic vertebrate-bearing beds and stratigraphy of northern Xinjiang [in Chinese]. Mem Inst Vert Paleontol Paleoanthropol 16(1):1–120