[SCG64-07] Was the Jurassic–Cretaceous boundary a critical event for marine life in the pelagic Panthalassa?
Keywords:Jurassic-Cretaceous boundary, GSSP, Panthalassa, radiolaria
Radiolarians are good candidates for defining the JKB because they are widespread and can be found in both shallow and deep sedimentary facies worldwide. Pelagic sequences across the JKB have been reported in ODP/International Ocean Drilling Program (IODP) sites in the western Pacific and land sections in Japan, the Philippines, southern Tibet, Oman and other locations. The evolutionary first appearance datums (FADs) within firmly recognized lineages are extremely valuable for difining radiolarian zones.
Although the JKB is a boundary between geological periods, no significant turnover of pelagic biota has been reported from the Panthalassa. This is principally because the age of the JKB has not been constrained in the pelagic Panthalassa. Therefore, some key questions have not been tested, such as: 1) Was the JKB a critical event for marine biota in the pelagic Panthalassa? 2) Was the JKB significant in the evolution of marine life through the Phanerozoic? It is highly possible that the radiolarian JKB could be obtained by drilling the tuffaceous rocks near the Jurassic–Cretaceous volcanoes at a site around the outer slope of the Mariana Trench. The new cores at this site will provide critical information for constraining the U–Pb ages of the JKB from zircon grains in the tuff, and provide new insights into the biological evolution among pelagic biota in the Panthalassa across the JKB.