Maruyama, Toshiaki (2000): Middle Miocene to Pleistocene diatom stratigraphy of Leg 167

Leg/Site/Hole:
ODP 167
Identifier:
2000-080019
georefid

10.2973/odp.proc.sr.167.226.2000
doi

Creator:
Maruyama, Toshiaki
Yamagata University, Department of Earth and Environmental Sciences, Yamagata, Japan
author

Identification:
Middle Miocene to Pleistocene diatom stratigraphy of Leg 167
2000
In: Lyle, Mitchell, Koizumi, Itaru, Richter, Carl, Behl, Richard J., Boden, Per, Caulet, Jean-Pierre, Delaney, Margaret L., deMenocal, Peter, Desmet, Marc, Fornaciari, Eliana, Hayashida, Akira, Heider, Franz, Hood, Julie A., Hovan, Steven A., Janecek, Thomas R., Janik, Aleksandra G., Kennett, James P., Lund, David, Machain Castillo, Maria L., Maruyama, Toshiaki, Merrill, Russell B., Mossman, David J., Pike, Jennifer, Ravelo, A. Christina, Rozo Vera, Gloria A., Stax, Rainer, Tada, Ryuji, Thurow, Juergen W., Yamamoto, Masanobu, Nessler, Susan (editor), Miller, Christine M. (editor), Peters, Lorri L. (editor), Proceedings of the Ocean Drilling Program, scientific results, California margin; covering Leg 167 of the cruises of the drilling vessel JOIDES Resolution, Acapulco, Mexico, to San Francisco, California, sites 1010-1022, 20 April-16 June 1996
Texas A & M University, Ocean Drilling Program, College Station, TX, United States
167
63-110
Ocean Drilling Program Leg 167 represents the first time since 1978 that the North American Pacific margin was drilled to study ocean history. More than 7500 m of Quaternary to middle Miocene (14 Ma) sediments were recovered from 13 sites, representing the most complete stratigraphic sequence on the California margin. Diatoms are found in most samples in variable abundance and in a moderately well-preserved state throughout the sequence, and they are often dominated by robust, dissolution-resistant species. The Neogene North Pacific diatom zonation of Yanagisawa and Akiba (1998) best divides the Miocene to Quaternary sequences, and updated ages of diatom biohorizons estimated based on the geomagnetic polarity time scale of Cande and Kent (1995) are slightly revised to adjust the differences between the other zonations. Most of the early middle Miocene through Pleistocene diatom datum levels that have been proven to be of stratigraphic utility in the North Pacific appear to be nearly isochronous within the level of resolution constrained by sample spacing. The assemblages are characterized by species typical of middle-to-high latitudes and regions of high surface-water productivity, predominantly by Coscinodiscus marginatus, Stephanopyxis species, Proboscia barboi, and Thalassiothrix longissma. Latest Miocene through Pliocene assemblages in the region of the California Current, however, are intermediate between those of subarctic and subtropical areas. As a result, neither the existing tropical nor the subarctic (high latitude) zonal schemes were applicable for this region. An interval of pronounced diatom dissolution detected throughout the Pliocene sequence apparently correspond to a relatively warmer paleoceanographic condition resulting in a slackening of the southward flow of the California Current.
Coverage:Geographic coordinates:
North:42.0000
West:-128.0000East: -114.1500
South:28.0000

Stratigraphy; algae; biostratigraphy; biozones; California; California Current; Cenozoic; continental margin; diatoms; East Pacific; floral list; Leg 167; microfossils; middle Miocene; Miocene; Neogene; North Pacific; Northeast Pacific; Ocean Drilling Program; Pacific Ocean; paleo-oceanography; paleoclimatology; Plantae; Pleistocene; Quaternary; species diversity; temperature; Tertiary; United States;

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