THE GUADALUPIAN (PERMIAN) KAMURA EVENT IN EUROPEAN TETHYS

A global-scale environmental change relevant to mass extinction occurred in the late Guadalupian (Middle Permian) as recorded in unique litho-, bio-, and chemostratigraphic signatures. In order to document paleoenvironmental conditions of the equatorial western Tethys during the late Middle Permian prior to the end-Guadalupian mass extinction, chemostratigraphic analysis using stable carbon isotopes was conducted for the Guadalupian rocks at Brusane in the Velebit Mtn., central Croatia. By analyzing limestone samples of the Capitanian (Upper Guadalupian) Velebit Formation, we found an interval with unusually high stable carbon isotope ratios (+4 to +6 ‰) in the ca. 150 m-thick Yabeina (fusulines) Zone. The present find clarifies that the surface seawater became enriched in ¹³C, indicating that the primary productivity was considerably high during the Capitanian in westernmost Tethys. This chemostratigraphic signal is correlated with the “Kamura event” detected in a mid-Panthalassan paleo-atoll limestone in Japan. The present results identify the Capitanian “Kamura event” for the first time in European Tethys, and suggest that the event was global in context because mid-Panthalassa and westernmost Tethys were almost on the opposite side of the globe during the Permian. In this regard, the similar signature from the Delaware basin in Texas was not of local origin as previously understood but of global average. In order to enhance bioproductivity on a global scale, active oceanic circulation, in particular, upwelling of deep-sea water enriched in nutrients was likely vital at least for the low-latitude domains of both Panthalassa and Tethys.