Stratigraphy and Age of the Permian-Triassic Boundary Siliceous Rocks of the Mino Terrane in the Mt. Funabuseyama Area, Central Japan

Abstract

Abstract. This paper presents the litho- and biostratigraphy of the Permian-Triassic boundary (PTB) siliceous rocks that accumulated on the lower flank of a seamount in a mid-oceanic realm of the Panthalassa Ocean. The study section correlates with the upper part of the Lower Permian to Lower Triassic Hashikadani Formation of the Mino terrane in the Mt. Funabuseyama area, central Japan. The lithologic succession comprises a lower unit (ca. 6.2 m thick) dominated by gray chert with small amounts of black chert and black claystone, middle unit (ca. 0.7 m) of black chert with subordinate black claystone and gray chert including pyrite nodules near the top, and upper unit (ca. 0.9 m) characterized by black claystone with thin black chert beds. The lithologic change from the middle unit to the upper unit is sharp and abrupt. The lower and middle units correlate to the upper Wuchiapingian to Changhsingian (Neoalbaillella ornithoformis to N. optima zones). The upper unit includes the lower Induan, as the black c...