Responses of Japanese Cenozoic molluscs to Pacific gateway events
Fuente:
Redalyc
Salvato in:
| Autore principale: | |
|---|---|
| Natura: | Artículo científico |
| Lingua: | en |
| Pubblicazione: |
Universidad Nacional Autónoma de México
2002
|
| Soggetti: | |
| Accesso online: | |
| Tags: |
Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
|
| _version_ | 1876467125458042880 |
|---|---|
| author | Kenshiro Ogasawara |
| author_facet | Kenshiro Ogasawara |
| contents | Responses of Japanese Cenozoic molluscs to Pacific gateway events Kenshiro Ogasawara Ciencias de la Tierra event Pacific gateway cooling Cenozoic The Cenozoic history of Pacific Ocean gateways can be divided into seven stages, extendingfrom the Eocene onset of the Tasmanian seaway to the Pliocene closure of the Central Americanseaway. The first stage was the interval before 43 Ma, tentatively named the proto-Tasmanian stage.Development of the Tasmanian seaway (43-29 Ma) occupied the second stage. The third stage (29-23.5 Ma) was the oceanographically and paleoceanographically most open system, because thePacific was not isolated from other oceans. The 4th stage consists of the closing of the Bering Straitprior to closure of the Indonesian seaway (23.5-17 Ma). The 5th stage was the time during which theIndonesian and Bering Seaways were both closed (17-5 Ma). The 6th stage consisted of a closedIndonesian seaway, and an open Bering Strait and Central American seaway (5-2 Ma). The 7th andfinal stage is the modern situation, with a closed Central American seaway.The responses of Japanese Cenozoic molluscan faunas to these Pacific gateway events reflectPacific-wide patterns. The remarkable faunal changes from the late Eocene to the early Oligocenerecord the transition from warm-water environments to temperate or cool-water environments. TheOligocene Ashiya and Asagai molluscan faunas evidently developed as a response to oceanic cooling,which may have been related to the onset of both the Drake and Tasmanian Seaways (32-29 Mato 23.5 Ma). A drastic change in bio-siliceous sedimentation in the early Miocene, recently recognizedin Sakhalin may have been related to diatom floral turnover. As with the early MioceneKunugidaira-Akeyo molluscan fauna that lived from 20 to 16.4 Ma, the diatom turnover may havebeen related to the stepwise closure of the Indonesian seaway. The Kadonosawa fauna lived duringthe first Neogene climatic optimum, at about 16 Ma. Formation of the modern north-flowingKuroshio Current may have resulted from closure of the Indonesian seaway at that time. The widespreadoccurrence of the bivalve Chlamys cosibensis during the late Miocene and early Pliocene inthe North Pacific implies that surface waters were within the temperate realm. 2002 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57219307 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.3 Vol.19 |
| format | Artículo científico |
| id | redalyc_57219307 |
| institution | Redalyc |
| language | en |
| publishDate | 2002 |
| publisher | Universidad Nacional Autónoma de México |
| spellingShingle | Responses of Japanese Cenozoic molluscs to Pacific gateway events Kenshiro Ogasawara Ciencias de la Tierra event Pacific gateway cooling Cenozoic Responses of Japanese Cenozoic molluscs to Pacific gateway events Kenshiro Ogasawara Ciencias de la Tierra event Pacific gateway cooling Cenozoic The Cenozoic history of Pacific Ocean gateways can be divided into seven stages, extendingfrom the Eocene onset of the Tasmanian seaway to the Pliocene closure of the Central Americanseaway. The first stage was the interval before 43 Ma, tentatively named the proto-Tasmanian stage.Development of the Tasmanian seaway (43-29 Ma) occupied the second stage. The third stage (29-23.5 Ma) was the oceanographically and paleoceanographically most open system, because thePacific was not isolated from other oceans. The 4th stage consists of the closing of the Bering Straitprior to closure of the Indonesian seaway (23.5-17 Ma). The 5th stage was the time during which theIndonesian and Bering Seaways were both closed (17-5 Ma). The 6th stage consisted of a closedIndonesian seaway, and an open Bering Strait and Central American seaway (5-2 Ma). The 7th andfinal stage is the modern situation, with a closed Central American seaway.The responses of Japanese Cenozoic molluscan faunas to these Pacific gateway events reflectPacific-wide patterns. The remarkable faunal changes from the late Eocene to the early Oligocenerecord the transition from warm-water environments to temperate or cool-water environments. TheOligocene Ashiya and Asagai molluscan faunas evidently developed as a response to oceanic cooling,which may have been related to the onset of both the Drake and Tasmanian Seaways (32-29 Mato 23.5 Ma). A drastic change in bio-siliceous sedimentation in the early Miocene, recently recognizedin Sakhalin may have been related to diatom floral turnover. As with the early MioceneKunugidaira-Akeyo molluscan fauna that lived from 20 to 16.4 Ma, the diatom turnover may havebeen related to the stepwise closure of the Indonesian seaway. The Kadonosawa fauna lived duringthe first Neogene climatic optimum, at about 16 Ma. Formation of the modern north-flowingKuroshio Current may have resulted from closure of the Indonesian seaway at that time. The widespreadoccurrence of the bivalve Chlamys cosibensis during the late Miocene and early Pliocene inthe North Pacific implies that surface waters were within the temperate realm. 2002 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57219307 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.3 Vol.19 |
| title | Responses of Japanese Cenozoic molluscs to Pacific gateway events |
| topic | Ciencias de la Tierra event Pacific gateway cooling Cenozoic |
| url | https://www.redalyc.org/articulo.oa?id=57219307 |