Through the scientific results of IGCP Project 355, which studied Pacific gateways, the timing of onset or closure of each gateway has been defined. Some geological and paleontological events recognized in local areas took place as a result of gateway events. For instance, the appearance of siliceous biomarkers during the earliest Miocene in Sakhalin, northwestern Pacific, is coeval with the opening of Drake Passage during the earliest Miocene (23 Ma), and the invasion event of Hataiarca, an extinct Miocene bivalve, at 16.4 Ma in the Japanese Islands, is coeval with the closure of the Indonesian seaway. This closure indicates the first distinct appearance of the paleo-Kuroshio Current around the Philippine Islands. Japanese Paleogene faunas have been compiled recently from the biochronological aspect, and Miocene molluscan faunas are now divided into the subtropical Akeyo-Kunugidaira fauna (20-16.4 Ma), the tropical and/or subtropical Yatsuo-Kadonosawa fauna (16.4-15.3 Ma), the subtropical and/or warm temperate Moniwa fauna (15.3-15 Ma), the warm-temperate Older Shiobara-Yama fauna (15-11 Ma) and the mildtemperate and/or cool-temperate Younger Shiobara-Yama fauna (11-5.3 Ma). These faunas can be considered as responses to stepwise cooling stages from tropical to cool-temperate realms, respectively. Opening and closure of the Bering Strait during the Neogene was recently precisely redefined using diatom biochronology and fossil records of the bivalve Astarte. However, sea-water cooling is obvious after 6 Ma in high-latitude areas and tends to remain distinct until 2.5 Ma. The modern sub-arctic cold water-mass may have first appeared around 1 Ma as indicated by the first fossil record of the Chlamys islandica group in Hokkaido, Japan.It is important to consider that some kinds of geological events recognized in a local and/or regional area might have taken place in response to global events. In addition, the precise age determination of related geological events is very important for the consideration of the cause and effect of events.

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