Carbon, oxygen and strontium isotopic composition of low-latitude Permian carbonates (Venezuelan Andes): climate proxies of tropical Pangea JUAN CARLOS LAYA 1,2 *, MAURICE E. TUCKER 1,3 , DARREN R. GRO ¨ CKE 1 & ALBERTO PEREZ-HUERTA 4 1 Department of Earth Sciences, Durham University, Durham DH1 3LE, UK 2 Grupo de investigaciones de ciencias de la tierra – TERRA, Universidad de Los Andes, Me ´rida, Venezuela 3 School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK 4 Department of Geological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA *Corresponding author (e-mail: layajc@ula.ve) Abstract: The Late Palaeozoic period was an important time in Earth history, primarily as a result of the formation of Pangea and the Gondwana glaciations that had direct influences in high latitudes and indirect, but no less important, effects in low latitudes. This study documents and interprets the isotopic record for the Early–Middle Permian in northern Gondwana from detailed fieldwork in the Venezuelan Andes. Sr-isotope dating of well-preserved brachiopod shells suggests a Kungurian age from samples located within the middle part of the Palmarito Formation. d 13 C data show a long-term trend through the section towards more positive values, but with some very negative d 13 C values suggesting carbonates affected by pedogenic processes. In the middle part of the succession, major excursions in d 13 C and d 18 O show a strong connection with glacial–deglacial events during the Early–Middle Permian. Overall results presented here fill an important gap in the regional palaeogeography and, therefore, have significant implications for the palaeoclimate and palaeoceanography of this Late Palaeozoic time. The assembly of Pangea during the Permian trig- gered important geological, oceanographical and climatic events, which had a direct influence on the geological record. Many isotope studies of Permian rocks from the equatorial region of Pangea have been undertaken during the last two decades, primar- ily focusing on understanding palaeoceanography and palaeoclimate (e.g. Tabor & Montan ˜ez 2002; Isbell et al. 2003; Brand 2004; Korte et al. 2006; Montan ˜ez et al. 2007; Tabor & Poulsen 2008; Field- ing et al. 2008; Peyser & Poulsen 2008). As a result, palaeoclimate models have been developed show- ing reconstructions of palaeoprecipitation, palaeo- temperature and the variation in position of the Intertropical Convergence Zone (ITCZ) during the Permian. However, there is still insufficient infor- mation about regions around northern Gondwana, particularly for Central and South America. In northern South America, Upper Palaeozoic strata were deposited extensively over pericratonic areas but in many places they are rarely exposed and so are poorly documented. This is largely the result of extensive weathering and dense vegetation in the tropical Andes, as well as the remoteness of the outcrop areas. However, these strata do have signi- ficant information for the palaeogeographical and palaeoclimatic reconstructions, and for the evol- ution of northern Gondwana, at this critical time in Earth history. The existence of a seaway connecting the Palaeotethys and Panthalassa oceans, which lasted until the late Early Permian, has been sug- gested by just a few authors (Davydov & Leven 2003; Izart et al. 2003; Vai 2003). This deduc- tion has been based on palaeontological evidence, including Tethyan brachiopod and fusulinid dis- tributions. An east – west seaway across northern Gondwana accounts for the shallow-marine sedi- mentary succession across western Venezuela dur- ing the Permian. These earlier publications have not described the depositional setting of this Vene- zuelan basin or how it was connected and related to the neighbouring oceans. Figure 1, modified from the map for 280 Ma of Blakey (2007), shows the palaeogeography following the reinterpretations of Laya & Tucker (2012). Permian rocks in Venezuela have previously been described in several studies (Arnold 1966; Garcı ´a 1972; Odreman & Wagner 1979; Bellizia 1992; Viscarret & Laya 2007). The From:Ga˛siewicz, A. & Slowakiewicz, M. (eds) Palaeozoic Climate Cycles: Their Evolutionary and Sedimentological Impact. Geological Society, London, Special Publications, 376, http://dx.doi.org/10.1144/SP376.10 # The Geological Society of London 2013. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics 10.1144/SP376.10 Geological Society, London, Special Publications published online February 28, 2013 as doi: