Marine fauna in the North Pacific area during the latest Mesozoic

2015 Fiscal Year Final Research Report

• Project/Area Number: 25400502
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: National Museum of Nature and Science, Tokyo
• Principal Investigator: SHIGETA Yasunari 独立行政法人国立科学博物館, 地学研究部, 研究主幹 (30270408)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 化石 / 白亜紀 / 絶滅 / アンモナイト / 中生代最末期 / 化石層序

Outline of Final Research Achievements

The geological survey in Hokkaido and Alaska reveals that the gaudryceratid and pachydisciid ammonoids are very useful for establishment of high-resolution biochronology of the uppermost Cretaceous in the North Pacific area. The ammonoid species diversity was relatively high (14 species) during the early Maastrichtian, but it was abruptly reduced by nearly half (7 species) in the middle Maastrichtian. Disappearance of inoceramid bivalves occurred in the middle Maastrichtian. These evidences provide an important key for understanding the middle Maastrichtian event.

Free Research Field

数物系科学