Gadley, Kyle L. and Marsaglia, Kathleen M. (2006): Petrography and correlation of Cenozoic ash layers recovered on Shatsky Rise, ODP Leg 198

ODP 198


Gadley, Kyle L.
California State University, Department of Geological Sciences, Northridge, CA, United States

Marsaglia, Kathleen M.
Universita di Milano, Italy

Petrography and correlation of Cenozoic ash layers recovered on Shatsky Rise, ODP Leg 198
In: Bralower, Timothy J., Premoli Silva, Isabella, Malone, Mitchell J., Arthur, Michael A., Averyt, Kristen B., Bown, Paul R., Brassell, Simon C., Channell, James E. T., Clarke, Leon J., Dutton, Andrea, Eleson, Jason W., Frank, Tracy D., Gylesjo, Susanne, Hancock, Haidi J. L., Kano, Harumasa, Leckie, R. Mark, Marsaglia, Kathleen M., McGuire, Jennifer, Moe, K. T., Petrizzo, Maria Rose, Robinson, Stuart A., Roehl, Ursula, Sager, William W., Takeda, Kotaro, Thomas, Deborah, Williams, Trevor, Zachos, James C., Proceedings of the Ocean Drilling Program; scientific results; extreme warmth in the Cretaceous and Paleogene; a depth transect on Shatsky Rise, Central Pacific; covering Leg 198 of the cruises of the drilling vessel JOIDES Resolution; Yokohama, Japan, to Honolulu, Hawaii; Sites 1207-1214; 27 August-23 October 2001
Texas A&M University, Ocean Drilling Program, College Station, TX, United States
In this study of volcanic ash retrieved from Shatsky Rise during Ocean Drilling Program Leg 198, the texture and composition of the volcanic components (glass and crystals) were used to fingerprint ash layers for detailed correlation. Correlations among ash layers in holes drilled at the same site as well as between sites, including sites on different parts (highs) of the rise, were tested. Although high-to-high correlations failed, intrahigh correlations were more successful. Our data suggest a significantly different source for some pyroclastic debris, especially at Site 1208, possibly associated with pumice rafts carried northward from the Izu-Bonin arc by the Kuroshio Current. Other ashes are consistent with rhyolitic to dacitic air fall ash from Asian arc volcanoes. We were not able to texturally distinguish between air fall ash and pumice-raft fallout but suspect that the latter is associated with higher percentages of vesiculated ash components, as we demonstrate occur in more proximal Izu-Bonin pyroclastic deposits.
Coverage:Geographic coordinates:
West:157.1500East: 162.4600

Igneous and metamorphic petrology; Stratigraphy; Cenozoic; correlation; igneous rocks; large igneous provinces; Leg 198; lithostratigraphy; marine sediments; North Pacific; Northwest Pacific; Ocean Drilling Program; Pacific Ocean; petrography; pumice; pyroclastics; sediments; Shatsky Rise; tephrostratigraphy; textures; volcanic ash; volcanic rocks; volcaniclastics; West Pacific;