Chikyukagaku

Ca–Al-rich inclusions (CAIs) in meteorites are the oldest objects formed in the Solar System. CAIs are considered to have had complex thermal histories in the solar protoplanetary disk; they formed by condensation and multiple melting and crystallization. Here, I summarize recent progresses of Al–Mg chronological study of CAIs and its problems.

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The biodiversity crisis across the Triassic–Jurassic boundary (TJB; ca. 201 Ma) is characterized by one of the largest mass extinctions in the Phanerozoic. Significant increases in the extinction rate of marine fauna, and major turnovers in terrestrial vegetation and vertebrate groups, have been well documented across the TJB. In addition to the extinction, several unique geological events around the TJB were recognized; i.e., the emplacement of the Central Atlantic Magmatic Provinces (CAMP) which is associated with the breakup of Pangea, meteorite impact, carbon cycle perturbations, widespread ocean anoxia, and ocean acidification. In the last decade, based on of the numerous data-set obtained from the peri-Pangean shelf sequences, major advances have been made in our understanding of the TJB biotic crisis, related environmental changes, and the CAMP volcanism. However, the casual relationships between the CAMP volcanism and extinction-related environmental changes of global context still remain unclear due to the lack of data from pelagic domains. Here, I introduce my recent studies about the mid-superocean Panthalassa, which occupied major portion of the global ocean during the Triassic-Jurassic transition, and discuss the future prospects at the end of the paper.

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