THE END-GUADALUPIAN EVENT: WHEN ALL GEOLOGICALLY STRANGE PHENOMENA STARTED

The end-Guadalupian event is apparently more significant than the P-T boundary event in various geological and evolutionary aspects. Major unique phenomena occurred during the Capitanian (Late Guadalupian) were 1) the first major extinction with the end of gigantism, 2) the lowest sea-level of the Phanerozoic, 3) the lowest value of seawater Sr ratio (Paleozoic minimum), 4) onset of the volatile C-isotope fluctuation (Kamura event) across the Paleozoic-Mesozoic transition, 5) onset of ocean redox anomaly (superanoxia), 6) mantle superplume-related magmatism, 7) initial break-up of Pangea, and 8) change in geomagnetic polarity-flipping pattern (Illawarra Reversal). Among them, the major changes in the planet’s surface including the biodiversity decline were likely related to the temporary but global cooling during the Capitanian, even after the major Gondwana glaciation period. The end-Guadalupian event in the biosphere could be triggered by the surface temperature drop in response to the episodic activity of mantle plumes, relevant change in geomagnetic intensity, and the penetration of galactic cosmic radiation into the atmosphere (integrated “plume winter” scenario). The combination of "geomagnetic cooling" and "volcanic cooling" likely contributed effectively for the end-Guadalupian biosphere catastrophe. In contrast, the P-TB event might represent merely a second wave effect of the overall global processes that worked through the Paleozoic-Mesozoic transition interval.