The Lower Triassic sedimentary and carbon isotope records from Tulong (South Tibet) and their significance for Tethyan palaeoceanography Thomas Brühwiler a, ⁎, Nicolas Goudemand a , Thomas Galfetti b , Hugo Bucher a,c , Aymon Baud d , David Ware a , Elke Hermann a , Peter A. Hochuli a,c , Rossanna Martini e a Paläontologisches Institut und Museum der Universität Zürich, Karl Schmid-Strasse 4, 8006 Zürich, Switzerland b Holcim Group Support Ltd, Materials Technology, 5113 Holderbank, Switzerland c Department of Earth Sciences, ETH, Universitätsstrasse 16, 8092 Zürich, Switzerland d BGC, Parc de la Rouvraie 28, 1018 Lausanne, Switzerland e Department of Geology and Paleontology, University of Geneva, Rue des Maraîchers 13, 1205 Geneva, Switzerland abstract article info Article history: Received 18 June 2009 Received in revised form 23 September 2009 Accepted 11 October 2009 Keywords: Early Triassic South Tibet Microfacies Palaeoenvironments Carbon isotopes The Lower Triassic sedimentary and carbonate/organic carbon isotope records from the Tulong area (South Tibet) are documented in their integrality for the first time. New age control is provided by ammonoid and conodont biostratigraphy. The basal Triassic series consists of Griesbachian dolomitic limestones, similar to the Kathwai Member in the Salt Range (Pakistan) and to the Otoceras Beds in Spiti (India). The overlying thin-bedded limestones of Dienerian age strongly resemble the Lower Ceratite Limestone of the Salt Range. They are followed by a thick series of dark green, silty shales of Dienerian–early Smithian age without fauna that strikingly resemble the Ceratite Marls of the Salt Range. This interval is overlain by thin-bedded, light grey fossil-rich limestones of middle to late Smithian age, resembling the Upper Ceratite Limestone of the Salt Range. These are followed by a shale interval of early Spathian age that has no direct counterpart in other Tethyan sections. Carbonate production resumes during the late early and middle Spathian with the deposition of red, bioclastic nodular limestone (“Ammonitico Rosso” type facies). Apart from its colour this facies is similar to the one of the Niti Limestone in Spiti and of the Spathian nodular limestone in Guangxi (South China). As in other Tethyan localities such as Spiti, the early–middle Anisian part of the Tulong section is strongly condensed and is characterized by grey, thin-bedded limestones with phosphatized ammonoids. As for many other Tethyan localities the carbon isotope record from Tulong is characterized by a late Griesbachian–Dienerian positive δ 13 C carb excursion (2‰), and a very prominent positive excursion (5‰) at the Smithian–Spathian boundary, thus confirming the well-documented perturbations of the global carbon cycle following the Permian–Triassic mass extinction event. © 2009 Elsevier B.V. All rights reserved. 1. Introduction The end-Permian mass extinction is the biggest known crisis in life history and wiped out more than 90% of all marine species (e.g. Raup and Sepkoski, 1982). The subsequent Early Triassic recovery of marine and terrestrial ecosystems is considered to have been delayed when compared with other mass extinctions and to have lasted until the end of the Early Triassic (e.g. Erwin, 1998). Many marine clades such as corals (Stanley, 2003), foraminifers (Tong and Shi, 2000) or radiolarians (Racki, 1999) did not completely recover until the Spathian or the Anisian, and poorly diversified and small-sized ben- thonic shelly faunas predominated during the Early Triassic (e.g. Fraiser and Bottjer, 2004; Fraiser et al., 2005). Metazoan reef com- munities were completely absent in the Early Triassic (Pruss and Bottjer, 2005). On the other hand, ammonoids and conodonts recovered very fast in comparison with other marine clades (Brayard et al., 2006, 2009; Orchard, 2007). Moreover, recent analysis of outer platform paleoenvironments from South China reveals that increasing rates of diversity and abundance of skeletal material occurred already during well-oxygenated carbonate episodes of early Smithian and Spathian age, respectively (Galfetti et al., 2008). Stable carbon isotope studies have shown that the global carbon cycle was profoundly perturbed at the Permian–Triassic boundary and that several large and short-lived fluctuations occur in the Early Triassic, before the carbon cycle stabilizes in the Middle Triassic (Baud et al., 1996; Atudorei and Baud, 1997; Atudorei, 1999; Payne et al., 2004; Richoz, 2004; Corsetti et al., 2005; Galfetti et al., 2007a,b,c; Horacek et al., 2007a,b). The coincidence of carbon isotope cycle instabilities with the Early Triassic delayed recovery suggests a relationship between carbon cycling and biological rediversification in the aftermath of the extinction (Payne et al., 2004). Indeed, for instance, the major positive δ 13 C excursion at the Smithian–Spathian Sedimentary Geology 222 (2009) 314–332 ⁎ Corresponding author. Tel.: +41 44 634 26 98; fax: +41 44 634 49 23. E-mail address: bruehwiler@pim.uzh.ch (T. Brühwiler). 0037-0738/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.sedgeo.2009.10.003 Contents lists available at ScienceDirect Sedimentary Geology journal homepage: www.elsevier.com/locate/sedgeo