[B-CG05] Frontier in diversity and ecology of protists and microfossils

[BCG05-P09] The Caribbean-Colombian Oceanic Plateau (CLIP) volcanism and its paleoclimatic impact during OAE3 events (Coniacian-Santonian)

*Peter Oliver Baumgartner¹、Claudia Baumgartner-Mora¹、Goran Andjic¹、Rie Hori, S.² (1.Institut des Sciences de la Terre, Université de Lausanne、2.Department of Earth Sciences, Ehime University)

The Caribbean-Colombian Plateau (or CLIP), among other large igneous provinces (LIPs), has classically been regarded as the principal cause of the late Cenomanian/Turonian Boundary climatic Event (CTBE ~94 Ma), or Oceanic Anoxic event 2 (OAE2). However, the main CLIP phase (92–87 Ma) is younger and did not contribute significantly to the climate crisis of the CTBE. Radiolarian biochronological work of the last decades allows us to correlate radiolarian-bearing sediments associated with basalts and intrusive rocks of the CLIP with well-calibrated pelagic sections of the Coniacian–Santonian (C-S, OAE3, 89.8 – 83.6 Ma) in the Mediterranean region. Black, organic-rich radiolarites dated as C-S are interbedded with and/or directly overlying basalts of the CLIP phase (Ar/Ar ages of 92-83 Ma) of the Nicoya Complex (Costa Rica) and in the Azuero Plateau (Panama). Radiolarian-dated C-S volcano-pelagic, organic-rich strata directly overly CLIP-related basalts in the Manzanillo Terrane (S-Nicoya Peninsula) and in the Tireo Group (Dominican Republic). While the presence of organic matter is restricted to areas of high paleo-fertility, the C-S is a period of hot paleoclimate resulting in globally enhanced terrestrial chemical weathering and punctuated silica sequestration in sediments, because of the volcanism of the CLIP and other LIPs.