THE GUADALUPIAN (MIDDLE PERMIAN) KAMURA EVENT AND ITS AFTERMATH

The second half of the Guadalupian witnessed a global cooling event that terminated various tropical fauna and drove the lowest sea-level in the Phanerozoic. The extremely high carbon isotope ratios in shallow marine carbonates from the low-latitude mid-Panthalassa (Japan) and western Tethys (Croatia) essentially recorded the high primary productivity induced by the vigorous oceanic circulation coupled with high nutrient supply. This unusual episode (the Kamura event) started immediately before the Capitanian (Late Guadalupian), and lasted up to the Guadalupian-Lopingian boundary (G-LB; ca. 260 Ma). The biodiversity of the Guadalupian fauna declined gradually during the Kamura event that lasted for more than 5 million years (~265-260 Ma). The cause of this unusual episode is still controversial but the popularly discussed Emeishan LIP (ca. 260-257 Ma) can be eliminated, as it was too young to trigger the event. A major change in the geomagnetic histroy, the Illawarra Reversal, occurred within the Wordian (Middle Guadalupian), suggesting the intimate cause-effect link between the interior and the surface environment of the Earth. The Kamura event ended abruptly at the G-LB, and the rapid increase in C isotope ratios in shallow marine carbonates (Early Wuchiapingian carbon isotope excursion; EWCE) recorded the aftermath of the Guadalupian Kamura event with the oppositely-directed processes and consequences; i.e. global warming, sea-level rise, and biodiversity recovery.