last update 2022.07.27
REE partitioning between Fe-Mn oxyhydroxide deposits and seawater
Presentation
Ohta A. "Experimental and theoretical studies of REE partitioning between Fe-Mn oxyhydroxides and seawater" The 52th annual meeting of Geochemical Society of Japan, Ryukyu University, September 26–28, 2005 (The Geochemical Society of Japan Award for Young Researchers).
Ohta A. and Kawabe I. "The elucidation of Ce(III) oxidative uptake reaction by Mn dioxide and the changes of tetrad effect with pH in REE partitioning Mn dioxide/solution systems" The 47th annual meeting of Geochemical Society of Japan, Yamagata University, September 25–27, 2000.
Ohta A. and Kawabe I "Experimental study of distribution coefficients of rare earth elements between Fe-Mn deposit and seawater in view of REE(III)-carbonate complexation constants." Ninth Annual V. M. Goldschmidt Conference, Harvard University, August 22–27, 1999.
Ohta A. and Kawabe I. "Experimental study of REE(III) partitioning in Fe oxyhydroxide/solution and Mn oxide/solution systems: Distinct difference in Ce anomaly" The 46th annual meeting of Geochemical Society of Japan, Geological Survey of Japan, September 29-Octorber 1, 1999.
Ohta A. and Kawabe I. "Apparent Kd(REE) between deep-sea Mn-Fe nodule and sea water in view of REE(III)-carbonate complexation constants" The 45th annual meeting of Geochemical Society of Japan, Kyusyu University, October 9–11, 1998.
Ohta A. and Kawabe I. "Stability constants of REE(III)-CO32− complexes determined by using REE partitioning coefficients between Fe oxyhydroxides and aqueous solution" the 44th annual meeting of Geochemical Society of Japan, Tokyo Metropolitan University, September 17–19, 1997.
Ohta A. and Kawabe I. "Experimental study on distribution coefficients of REE between Fe-Mn oxyhydroxides and aqueous solutions (II) : Ln3+-CO32− complexes" the 43rd annual meeting of Geochemical Society of Japan, Hokkaido University, August 27–31, 1996.
A. Ohta, S. Ishii, M. Sakakibara, A. Mizuno, and I. Kawabe "The relationship between Ce anomaly and Co/(Ni+Cu+Zn) ratio in the North Pacific ferromanganese nodules" the 42nd annual meeting of Geochemical Society of Japan, Thokai University, November 10–12, 1995.
A. Ohta, K. Naitoh and I Kawabe "The Geochemical survey of the Antarctic ferromanganese nodules" the 42nd annual meeting of Geochemical Society of Japan, Thokai University, November 10–12, 1995.
Geochemical mapping
Presentation
Ohta, A. "Relationship between the chemical compositions of stream sediments and the dominant lithologies distributed in the watershed area based on hydrological analysis of geochemical maps" The 69h annual meeting of Geochemical Society of Japan, Kochi Unversity, September 7, 2022. (keynote lecture).
Ohta, A., Imai, N., Okai, T., Manaka, M., Kubota, R., Nakamura, A., and Tachibana, Y. "New geochemical data set of 53 elements in stream sediments classified by the dominant lithology in a drainage basin –GSJ Medal Lecture– " The 22th Goldschmidt Conference 2022, Hawaiʻi Convention Center, Honolulu, Hawaii, USA, July 13, 2022. (award lecture).
Ohta, A. "Geochemical datasets of stream sediments classified by the dominant lithology in their watersheds" JpGU (Japan Geoscience Union) Meeting 2022, Makuhari Messe International Conference Hall, May 22, 2022. (Invited lecture).
Ohta, A. "Application of geochemical maps for provenance and transfer process of marine sediments around Kyushu Island" The 66th annual meeting of Geochemical Society of Japan, in the University of Tokyo, September 17–19, 2019.
Ohta, A. "Quantitative elucidation of controlling factors in geochemical mapping – Effectiveness of “effect size”– " The 65th annual meeting of Geochemical Society of Japan, in Ryukyu University, September 11–13, 2018.
Ohta, A. "Evaluation of particle transfer process from the land to the sea using nationwide geochemical maps in Japan" The 122th annual meeting of Geological Society of Japan, in Shinshu University, Nagano, September 11–13, 2015.
Ohta, A. and Imai, N. "The spatial distribution of chalcophile elements in terrestrial and marine areas of Japan" Goldschmidt Conference 2013, in Florence, Italia, August 25–30, 2013.
Ohta, A., Imai, N. and Tachibana, Y. "A nationwide marine geochemical mapping project in Japan" The 34th Session of the International Geological Congress (IGC), in Brisbane, Australia, August 6–10, 2012.
Ohta, A., Imai, N. "Elucidation of mass transfer processes in the coastal sea areas of Japan using terrestrial and marine geochemical maps" The 58th annual meeting of Geochemical Society of Japan, Hokkaido University, September 14–16, 2011.
Ohta, A. Imai, N. and Minami, M. "A combined terrestrial and marine geochemical mapping in Japan" The Japan Society for Analytical Chemistry (JSAC) Meeting 2010, Tohoku University, September 15–17, 2010.
Ohta, A. and Imai, N. "A combined terrestrial and marine geochemical mapping in Central Japan" JpGU (Japan Geoscience Union) Meeting 2009, Makuhari Messe International Conference Hall, May 23–19, 2009.
Ohta, A., Imai, N., Terashima, S., Tachibana, Y., Okai, T., Ujiie-Mikoshiba, M. and Kubota, R. "A combined terrestrial and marine geochemical mapping project in Japan" The 17th Goldschmidt Conference 2007, Cologne University, Cologne, Germany. (abstract: Geochim. Cosmochim. Acta 70, A454, 2007).
Ohta, A. and Imai, N. "Speciation of the elements of stream sediments by a sequential extraction method" The 52th annual meeting of Geochemical Society of Japan, Ryukyu University, September 26–28, 2005.
Ohta, A. and Imai, N. "Application of a multiple comparison procedure to investigate elemental behaviors in the stream sediment" The 51th annual meeting of Geochemical Society of Japan, Shizuoka University, September 20–22, 2004.
Ohta, A. and Imai, N. "Statistical analysis of geochemical mapping based on GIS (Geographic Information Systems)" The 48th annual meeting of Geochemical Society of Japan, Gakushu-in University, October 18–20, 2001.
Seminar, Meeting, Event
Ohta, A and Minami, M. "Sr isotopic mapping of Japan for provenance study of archaeological samples and agricultural products" The Japan Society for Analytical Chemistry, the 21th lecture meeting, Tokyo Denki University, August 8, 2019. (Invited lecture).
Ohta, A "Application of Japanese geochemical maps for provenance analysis" The Japan Society for Analytical Chemistry, the 106th lecture meeting of Discussion Group for Plasma Spectrochemistry, Tokyo Sales Office of HORIBA, Ltd., May 31, 2019. (Invited lecture).
CGS–CCOP Seminar on CCOP Geochemical Mapping, International Conference Hotel of Nanjing, Nanjing, China, 28–29 March 2012.
CCOP meeting "Seminar on Regional Geochemical Exploration" CCOP (The Coordinating Committee for Coastal and Offshore Geoscience Programs in East and South Asia), Training Center of the China Geological Survey, Beijing, China, May 20–26, 2001.
Ohta, A. "Terrestrial and marine geochemical mapping project in Japan" The International Workshop on KamLAND Geoscience, Tokyo Prince Hotel, Tokyo, Japan, January 15–16, 2015.
XAFS spectroscopy
Presentation
Ohta, A., Kagi, H. Nomura, M. and Tsuno, H. "Speciation analysis of lanthanide compounds using full width at half maximum (FWHM) of the LIII-edge x-ray absorption near edge structure (XANES) spectra", The 64th Geochemical Society of Japan, Tokyo Institute of Technology, September 13–15, 2017.
Ohta, A. "Systematic variation of FWHM of white line of L3-edge XANES spectra of lanthanide ions in FeOOH and aqua ions", The 20th XAFS Symposium, the Jibasan building, August 4–6, 2017.
Ohta, A. "Influence of structural changes in REE in solid and liquid phases on distribution coefficients between ferromanganese deposit a sea water", ASLO 2017 Aquatic Sciences Meeting, Hawaii Convention Center, Honolulu, Hawaii, US, February 27–March 3, 2017.
Ohta, A., Kagi, H. Nomura, M. and Tsuno, H. "EXAFS application to reductive reaction of hexavalent chromium in soil", The 56th annual meeting of Geochemical Society of Japan, Hiroshima University, September 15–17, 2009.
Ohta, A., Kagi, H. Nomura, M., Tsuno, H. and Kawabe, I. "Correspondence of systematic variations of local structures of REEs sorbed on Fe hydroxide and Mn oxide to the variations of partitioning coefficients between solid and liquid phases". The 55th annual meeting of Geochemical Society of Japan, University of Tokyo, September 17–19, 2008.
Ohta, A., Tsuno, H., Kagi, H. and Nomura, M. "Coordination study of lanthanide and yttrium in aqueous nitrate solutions" The 16th V. M. Goldschmidt Conference, Melbourne Exhibition and Convention Centre, Melbourne, Australia, August 27–September 1, 2006.abstract: Geochim. Cosmochim. Acta 70, A---, 2006).
Ohta, A., Tsuno, H., Kagi, H. and Nomura, M. "XAFS characterization of REE adsorbed on ferrihydrite and manganese dioxides" The 19th IMA General Meeting, an International Convention Center Kobe, Japan, July 23–28, 200.
Ohta, A., Tsuno, H., Kagi, H. and Nomura, M. "Structural change of REE coprecipitated with Fe-Mn oxyhydroxides" The 13th V. M. Goldschmidt Conference, Kurashiki-Saputo University, Japan, September 7–12, 2003.
Ohta, A., Kagi, H., Tsuno, H., Takahashi, Y., Hand, T., Nomura, M. and Kawabe, I. "XAFS characterization of REE coprecipitated with Fe-Mn oxyhydroxides" The 49th annual meeting of Geochemical Society of Japan, Kagoshima University, September 26–28, 2002.
Ohta, A., Tsuno, H., Kagi, H. and Nomura, M. "XAFS characterization of La and Nd coprecipitated with Mn dioxide and Fe oxyhydroxide" The 12th V. M. Goldschmidt Conference, Harvard University, August 18–23, 2002.
Aeolian Dust
presentation
Ohta, A., Kanai, Y., Terashima, S., Kamioka, H., Imai, N., Matsuhisa, Y., Shimizu, H., Takahashi, Y., Kai, K., Hayashi, M., Zhang, R., Tsuno, H., Kagi, H. and Nomura, M. "Elucidation of elemental behavior of aeolian dust transported from China to Japan" The 4th ADEC (Aeolian Dust Experiment on Climate Impact ) Workshop, ANA HOTEL NAGASAKI GLOVERHILL, January 26–28, 2005. URL
Ohta, A., Kanai, Y., Terashima, S., Tsuno, H., Kagi, H., Kamioka, H., Imai, N., Matsuhisa, Y., Hayashi, M., Zhang, R. and Nomura, M. "Elucidation of heavy metals' behavior on aeolian dust during its long-haul transportation" The 51the annual meeting of Geochemical Society of Japan, Shizuoka University, September 20–22, 2004.
Research for metal speciation in soils and sediments
Presentation
Ohta, A. and Tanaka, K. "Lanthanoid coordination and speciation in rare earth minerals using the L3-edge XANES ". Goldschmidt Conference 2019, Barcelona, Spain, August 19–July 23, 2019.
Ohta, A. and Kubota, R. "Influence of different drying conditions on Cu and Zn speciation in sediment and soil substances". Goldschmidt Conference 2016, Yokohama, Japan, June 27–July 1, 2016.
Ohta, A. "Determination of Cr speciation in geochemical reference materials by XAFS spectroscopy after a sequential extraction procedure". The 61th annual meeting of Geochemical Society of Japan, Toyama University, September 16–18, 2014.
Ohta, A. and Kubota, R. "Speciation study of Zn in geochemical reference materials by XAFS spectroscopy after a sequential extraction procedure". The 60th annual meeting of Geochemical Society of Japan, Tsukuba University, September 11–13, 2013.
Ohta, A. and Kagi, H. "Speciation study of copper in stream sediments and soils". The 22th V. M. Goldschmidt Conference, Montréal, Canada, June 24–29, 2012.
Ohta, A. "Speciation study of heavy metals in stream sediments and soils using XAFS". The 57th meetings of the Society of the Science of Soil and Manure, International Congress Center Epocal Tsukuba, August 8–10, 2011 (Invited lecture).
Ohta, A., Kubota, R., Kagi, H. and Ishibashi, H. "Determination of Cu speciation in geochemical reference materials by XAFS spectroscopy after a sequential extraction procedure", The 57th annual meeting of Geochemical Society of Japan, Rissho University, September 7–9, 2010.
Ohta, A., Tsuno, H., Kagi, H., Fukura, S., Nomura, M. and Imai, N. "Application of speciation analysis to investigate trace memory of past hexavalent chromium pollution" The 53th annual meeting of Geochemical Society of Japan, Nihon University, September 13–15, 2006.
Ohta, A., Terashima, S., Imai, N., Okai, T., Mikoshiba, M. and Taniguchi, M. "Geochemistry of toxic trace elements in the soils from the Kanto Distinct" The 109th annual meeting of Geological Society of Japan, Niigata University, September 14–16, 2002.