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John Barron

Research Geologist

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Short Biography


1969    BS (Geology), University of California, Los Angeles
1974    PhD (Geology), University of California, Los Angeles

Professional Experience:   
•    1974-present Research Geologist/Micropaleontologist, US Geological Survey, Menlo Park, CA 94025
•    Assistant Team Chief for Climate Change, Volcano Science Center, 1998-present.
•    Project Chief on numerous projects dealing with California and North Pacific biostratigraphy and paleoecology; Project Chiefs of  PRISM -global reconstruction of the climate of the mid Pliocene 1995-97; Western Holocene Project, 1998-2000; Holocene Climate of the Pacific Coasts Project, 2001-12; Pacific Ocean Climate Variability: Effects on North American Precipitation Patterns, 2013-17.

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Barron, J.A., Bukry, D., and Field, D.B., 2013. Response of diatoms and silicoflagellates to climate change in the Santa Barbara Basin during the past 250 years and the rise of the toxic diatom Pseudo-nitzschia australis”, 2011 PACLIM Proceedings Volume, Quaternary International, [Link]

Barron, John A., Browning, James, Sugarman, Peter, and Miller, Kenneth G., 2013. Refinement of late-Early and Middle Miocene diatom biostratigraphy for the East Coast of the United States. Geosphere 9(5), 1286-1302. doi:10.130/GES00864. [Link]

Browning, James V., Miller, Kenneth G,, Sugarman, Peter J., Barron, John, McCarthy, Francine M.G., Kulhanek, Denise K., Katz, Miriam E., and Feigenson, Mark D., 2013. Chronology of Eocene-Miocene sequences on the New Jersey shallow shelf: Implications for regional, interregional, and global correlations. Geosphere 9(6), 1434-1456, December 2013. doi:10.130/GES00857 [Link]

Manchester, S.R., Herrera, F., Fourtanier, E., Barron, J., and Martinez, J.-N., 2012. Oligocene age of the classic Belen fruit and seed assemblage of north coastal Peru based on diatom biostratigraphy. Journal of Geology 120(4), 467-476. [Link]

Barron, J.A., Metcalfe, S. E., and Addison, J.A., 2012. Response of the North American Monsoon to regional changes in ocean surface temperature, 17 ms pages, 8 figs, 1 table. Paleoceanography v.27, PA3206, doi:10.1029/2011PA002235 [Link]

Davies, Andrew, Kemp, Alan. E.S., Weedon, Graham, P, and Barron, John A., 2012. El Niño-Southern Oscillation variability from the Late Cretaceous Marca Shale of California. Geology 40(1):15-18; doi:10.1130/G32329.1 [Link]

Lyle, Mitchell, Heusser, Linda, Ravelo, Christina, Yamamoto, Masanobu, Barron, John, Diffenbaugh, Noah, Herbert, Timothy, and Andreasen, Dyke, 2012. Out of the tropics: The Pacific, Great Basin lakes, and late Pleistocene water cycle in the western US. Science 337: 1629-1633; doi: 10.1126/science.1218390. [Link]

Barron, John A. and Anderson, Lesleigh, 2011.  Enhanced Late Holocene ENSO/PDO expression along the margins of the eastern North Pacific. Quaternary International 235:3-12.  doi:10.1016/j.quaint.2010.02.026

Barron, John A., Bukry, David, and Field, David, 2010. Santa Barbara Basin diatom and silicoflagellate records suggests coincidence of cooler SST with widespread occurrence of drought in the west during the past 2,200 years.  In 23rd Pacific Climate Workshop (PACLIM), Starratt, S.W. (ed.), Quaternary International 215:34-44. doi:10.1016/j.quaint.2008.08.007.

McGeehin, J.P., J.A. Barron, D.M. Anderson, and D.J. Verardo, 2008. Preface. In: Abrupt Climate Change. A report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. U.S. Geological Survey, Reston, VA, pp. 1–6.

Lyle, M., Barron, J., Bralower, T.J., Huber, M., Olivarez Lyle, A.,  Ravelo, A.C., Rea, D.K., and Wilson, P.A.,  2008. Pacific Ocean and Cenozoic evolution of climate, Rev. Geophys., 46, RG2002, doi:10.1029/2005RG000190.

Scherer, Reed, P., Gladenkov, A.Yu., and Barron, John A., 2007. Methods and applications of Cenozoic marine diatom biostratigraphy, in Starratt, Scott, W. ed., Pond Scum to Carbon Sink: Geological and Environmental Applications of the Diatoms, The Paleontological Society Papers 13:61-83

Barron, John A. and Bukry, D., 2007. Development of the California Current during the past 12,000 years based on diatoms and silicoflagellates.  Palaeogeography, Palaeoclimatology, Palaeoecology, 248:33-338.

Barron, John A. and Heusser, Linda, E., 2007.  High-resolution climate record of the past 2,400 years from the offshore of northernmost California and central Oregon, in Starratt, S.W., Cornelius, P., and Joelson, J.G., Jr., eds, Proceedings of the Twenty-first Annual Pacific Climate Workshop. Technical Report 77 of the Interagency Ecological Program for the San Francisco Estuary, pp. 17-30.

Barron, John A., and Bukry, David, 2007.  Solar forcing of the Gulf of California climate during the past two thousand years suggested by diatoms and silicoflagellates.  Marine Micropaleontology, 62:115-139.

Barron, John A., David Bukry, and Walter E. Dean, 2005.  Paleoceanographic history of the Guaymas Basin, Gulf of California, during the past 15,000 years based on diatoms, silicoflagellates, and biogenic sediments.  Marine Micropaleontology, 56:81-102.

Barron, John A., 2005. Diatom biochronology of the early Miocene of the equatorial Pacific.  Stratigraphy 2(4):281-309.

Barron, John A., 2005. Scanning electron microscope studies of some early Miocene diatoms from the equatorial Pacific Ocean with description of two new species, Actinocyclus jouseae Barron and Actinocyclus nigriniae Barron.  Proceedings of the California Academy of Sciences 56(34):639-655.

Barron, John A., David Bukry, and James L. Bischoff, 2004.  High resolution paleoceanography of the Guaymas Basin, Gulf of California, during the past 15,000 years. Marine Micropaleontology, 50:185-207.

Barron, John A., Fourtanier, Elisabeth, and Bohaty, Steven, 2004. Oligocene and Earliest Miocene Diatom Biostratigraphy of Site 1220, ODP Leg 199, Equatorial Pacific, in Lyle, M., Wilson, Paul W., Janecsek, Thomas R,, and Firth, J., Proceedings of the Ocean Drilling Program, Scientific Results, 199: College Station, TX, Ocean Drilling Program

Barron, John A., Heusser, Linda E. and Alexander, Clark, 2004.  High resolution climate of the past 3,500 years of coastal northernmost California, in Starratt, Scott W. and Blomquist, Nikki, L., eds., Proceedings of the Twentieth Annual Pacific Climate Workshop, Pacific Grove, CA, April 6-9, 2003.  Technical Report 72 of the Interagency Ecological Program for the San Francisco Estuary. (State of California, Dept. of Water Resources), p. 13-22.

Barron, J.A.,2003. Appearance and extinction of planktonic diatoms during the past 18 m.y. in the Pacific and Southern oceans. Diatom Research, 18(2):203-224.

Barron, John A.; Heusser, Linda; Herbert, Timothy; Lyle, Mitch. 2003.  High-resolution climatic evolution of coastal northern California during the past 16,000 years.  Paleoceanography Vol. 18 No. 1 10.1029/2002PA000768.

Barron, J.A., Lyle, Mitchel, and Koizumi, Itraru, 2002. Late Miocene and early Pliocene biosiliceous sedimentation along the California margin. Revista Mexican de Ciencias Geologicas. 19(3):161-169.

Lyle, Mitchell, Heusser, Linda, Herbert, Timothy, Mix, Alan, and Barron, John, 2001. Interglacial theme and variations: 500 k.y. of orbital forcing and associated responses from the terrestrial and marine biosphere, U.S. Pacific Northwest. Geology, 29(12):1115-1118.

Wilson, G.S,  Barron, J.A., A.C. Ashworth, R.A. Askin, J.A. Carter, M.G. Curren, D.H. Dalhuisen, E.I. Friedmann, D.G. Fyodorov-Davidov, D.A. Gilichinsky et al., 2002. The Mount Feather Diamicton of the Sirius Group: an accumulation of indicators of Neogene Antarctic glacial and climatic history, Palaeogeogr., Palaeoclim., Palaeoecol., 182:117-131.

Barron, J.A. and Isaacs, C.M., 2001.  Updated Chronostratigraphic framework for the California Miocene, in Isaacs, C. M., and Rullkötter, J., eds.: The Monterey Formation: From Rocks to Molecules: Columbia University Press: New York, pp. 393-395.

Nikolaev, Vladimir, D., Kociolek, John P., Fourtanier, Elisabeth, Barron, John A., and Harwood, David, M., 2001. Late Cretaceous Diatoms (Bacillariophyceae) from the Marca Shale member of the Moreno Formation, California.  Occasional Papers of the California Academy of Sciences, No. 152, 119 p.

Lyle, Mitchell, Heusser, Linda, Herbert, Timothy, Mix, Alan, and Barron, John, 2001. Interglacial theme and variations: 500 k.y. of orbital forcing and associated responses from the terrestrial and marine biosphere, U.S. Pacific Northwest. Geology, 29(12):1115-1118.

Poore, R.Z., Dowsett, H.J., Barron, J.A., Heusser, L., Ravelo, A.C., and Mix, A., 2000. Multiproxy Record of the Last Interglacial (MIS 5e) off  Central and Northern California, U.S.A., from Ocean Drilling Program Sites 1018 and 1020.  U.S. Geological Survey Professional Paper 1632, 19 pp.

Lyle, M., Koizumi, I., Delaney, M.L., and Barron, J.A., 2000.  Sedimentary  record of the California Current System, middle Miocene to Holocene: A synthesis of Leg 167 results, in Lyle, M., Koizumi, I., Richter, C. and Moore, T.C., Jr., Proceedings of the Ocean Drilling Program, Scientific Results, 167: College Station, TX, Ocean Drilling Program, 341-376.

Barron, J.A., 1998.  Late Neogene changes in diatom sedimentation in the North Pacific Journal of Asian Earth Sciences, 16(1):85-95.

Mahood, A.D. and Barron, J.A., 1997. Comparative ultrastructure of two closely related Thalassiosira species: Thalassiosira vulnifica (Gombos) Fenner and T. fasiculata Harwood et Maruyama. Diatom Research, v. 11(2):283-295.

Mahood, A. D. and Barron, J. A., 1996.  Late Pliocene diatoms in a diatomite from Prydz Bay, East Antarctica. Micropaleontology, 42(3): 285-302.

Barron, J.A., 1996. Diatom constraints on the position of the Antarctic Polar Front in the middle part of the Pliocene. Marine Micropaleontology, 27:195-213.

Dowsett, H., Barron, J., and Poore, R., 1996.  Middle Pliocene sea surface temperatures: a global reconstruction. Marine Micropaleontology, 27:13-26.

Barron, J.A., Basov, I.A., Beaufort, L., Dubuisson, G., Andrey Y. Gladenkov. A.Y., Morley, J.J., Okada, M., Olafsson, G., Pak, D.K., Roberts, A.P., Shilov, V.V., and Weeks, R.J., 1995. Biostratigraphic and magnetostratigraphic summary of ODP Leg 145, in Rea, D.K., Basov, I.A., Scholl, D.W., and Allan, J.F., eds., Proceedings of Ocean Drilling Program, Scientific Results, 145: 559-575. College Station, TX (Ocean Drilling Program).

Barron, J.A., 1995.  High resolution diatom paleoclimatology of the middle part of the Pliocene of the northwest Pacific, in Rea, D.K., Basov, I.A., Scholl, D.W., and Allan, J.F., eds., Proceedings of Ocean Drilling Program, Scientific Results, 145: 43-53. College Station, TX (Ocean Drilling Program).

Gladenkov, A.Y. and Barron, J.A., 1995.  Oligocene and early Miocene diatom biostratigraphy of Hole 884B, in Rea, D.K., Basov, I.A., Scholl, D.W., and Allan, J.F., eds., Proceedings of Ocean Drilling Program, Scientific Results, 145: 21-41. College Station, TX (Ocean Drilling Program).

Barron,J.A. and Gladenkov, A.Y, 1995.  Early Miocene to Pleistocene diatom stratigraphy of Leg 145, in Rea, D.K., Basov, I.A., Scholl, D.W., and Allan, J.F., eds., Proceedings of Ocean Drilling Program, Scientific Results, 145: 3-19. College Station, TX (Ocean Drilling Program).

Barron, J.A. and Baldauf, J. G., 1995. Cenozoic marine diatom biostratigraphy and applications to paleoclimatology and paleoceanography, in Blome, C.D., et al. eds., Siliceous Microfossils, Short Courses in Paleontology No. 8, p. 107-118. The Paleontological Society.

Mahood, A.D. and Barron, J.A., 1995. Thalassiosira tetraoestrupii var. reimeri var. nov., a distinctive diatom from the late Pliocene of the Southern Ocean, in Kociolek, J.P. & Sullivan, M.J., eds., A Century of Diatom Research in North America: A Tribute to the Distinguished Careers of Charles W. Reimer and Ruth Patrick. Koeltz Scientific Books USA, Champaign, Il., p. 1-8

Barron, J. A., and Mahood, A. D., 1993. Exceptionally well-preserved early Oligocene diatoms from glacial sediments of Prydz Bay, East Antarctica:  Micropaleontology, 39:29-45.

Mahood, A. D., Barron, J. A., and Sims, P. A., 1993. A study of some unusual, well preserved Oligocene diatoms from Antarctica:  Nova Hedwigia Beiheft, 106:243-267, 12 pls.

Barron, J.A., 1992. Paleoceanographic and tectonic controls on the Pliocene diatom record of California, in Tsuchi, R., and Ingle, J. C., Jr., eds., Pacific Neogene: Environment, Evolution, and Events:  University of Tokyo Press, Tokyo, p. 25-41.

Barron, J.A., 1992, Diatoms (Chapter 10), in Lipps, J. H., ed., Fossil Prokaryotes and Protists:  Boston, Blackwell Scientific Publications, p. 155-167.

Barron, J.A., 1992. Pliocene paleoclimatic interpretation of DSDP Site 580 (NW Pacific) using diatoms:  Marine Micropaleontology, 20:23-44.

Barron, J. A., 1992. Neogene diatom datum levels in the equatorial and North Pacific, in Ishizaki, K. and Saito, T., editors, The Centenary of Japanese Micropaleontology:  Terra Scientific Publishing Company, Tokyo, p. 413-426.

Baldauf, J. G., and Barron, J.A., 1991. Diatom biostratigraphy:  Kerguelen Plateau and Prydz Bay regions of the Southern Ocean, in Barron, J.A., Larsen, B., et al. eds., Proceedings of Ocean Drilling Program, Scientific Results, v. 119, p. 547-588, College Station, Texas.

Barron, J.A., Larsen, B., and Baldauf, J. G., 1991. Evidence for late Eocene-early Oligocene Antarctic glaciation and observations on late Neogene glacial history of Antarctica:  Results from ODP Leg 119, in Barron, J.A., Larsen, B., et al. eds., Proceedings of Ocean Drilling Program, Scientific Results, v. 119, p. 869-891, College Station, Texas.

Baldauf, J.G., and Barron, J.A., 1990. Evolution of biosiliceous sedimentation patterns for the Eocene through Quaternary:  Paleoceanographic response to polar cooling, in J. Thiede and U. Beil eds., Geologic History of the Polar Oceans:  Arctic versus Antarctic, NATO Workshop, October 10-14, 1988, Bremen, F.R. Germany:  Kluwer Academic Publication Group:  Dordrecht, Holland, p. 575-608.

Barron, J. A., and Baldauf, J. G., 1990. Development of biosiliceous sedimentation in the North Pacific during the Miocene and early Pliocene, in Tsuchi, R., editor, Pacific Neogene Events - Their Timing Nature and Interrelationship, p. 43-63, Tokyo:  University of Tokyo Press.

Barron, J.A., and Baldauf, J.G., 1989. Tertiary cooling steps and paleoproductivity as reflected by diatoms and biosiliceous sediments, in Berger, W. H., Smetacek, V. S., and Wefer, G. eds., Productivity of the Ocean:  Present and Past, Dahlem Konferenzen:  J. Wiley and Sons, Ltd., Chichester, UK, p. 341-354.

Barron, J. A., 1989, Chapter 15, The late Cenozoic stratigraphic record and hiatuses of the northeast Pacific:  Results from the Deep Sea Drilling Project in Winterer, E. L., Hussong, D. M., and Decker, R. W., eds., The Eastern Pacific Ocean and Hawaii, The Geology of North America, Volume N:  Geological Society of America, p. 311-322, Boulder, Colorado.

Keller, Gerta, and Barron, J.A., 1987. Paleodepth distribution of Neogene deep-sea hiatuses:  Paleoceanography, 2:697-713.

Barron, J.A., 1987. Diatomite:  environmental and geologic factors affecting its distribution, in Hein, J. R. ed., The Genesis of Ores and Petroleum Associated with Sedimentary Siliceous Deposits:  Van Nostrand-Reinhold (publ.), p. 164-178.

Baldauf, J. G., and Barron, J. A., 1987. Oligocene marine diatoms recovered in dredge samples from the Navarin Basin Province, Bering Sea:  U.S. Geological Survey Bulletin 1765, 17 p., 14 pls.

Barron, J.A., 1986. Paleoceanographic and tectonic controls on deposition of the Monterey Formation and related siliceous rocks in California. Palaeogeography, Palaeoclimatology, Palaeoecology, 27:27-45.

Kim, W. H., and Barron, J. A., 1986. Diatom biostratigraphy of the upper Oligocene to lowermost Miocene San Gregorio Formation, Baja California Sur, Mexico:  Diatom Research, 1:169-187.

Barron, J. A., and Baldauf, J. G., 1986. Diatom stratigraphy of the lower Pliocene Harris Grade section, California:  Micropaleontology, 32,:357-371.

Barron, J.A., 1985. Late Eocene to Holocene diatom biostratigraphy of the equatorial Pacific Ocean, Deep Sea Drilling Project Leg 85:  Initial Reports of the Deep Sea Drilling Project, vol. 85, p. 413-456.

Barron, J. A., Nigrini, K., Pujos, A., Saito, T., Theyer, F., Thomas, E., and Weinreich, N., 1985. Biostratigraphic summary and synthesis, Deep Sea Drilling Project Leg 85:  Initial Reports, Deep Sea Drilling Project, vol. 85, p. 905-945.

Barron, J. A., 1985. Diatom paleoceanography and paleoclimatology of the central and eastern equatorial Pacific between 18 and 6.2 Ma:  Initial Reports, Deep Sea Drilling Project, vol. 85, p. 935-945.

Barron, J.A., 1985. Neogene planktic diatom biostratigraphy, in Bolli, H. M., Saunders, J. B. and Perch-Nielsen, K. eds., Biostratigraphy by Marine Plankton: Cambridge University Press, p. 763-805.

Barron, J. A., 1985. Diatom biostratigraphy of the CESAR-6 core, Alpha Ridge, Arctic Ocean, in Jackson, H. R., et al., Initial geological data report on CESAR, The Canadian Expedition to Study the Alpha Ridge, Arctic Ocean:  Geological Survey of Canada Paper 84-22:137-148.

Barron, J. A., Bukry, David, and Poore, R. Z., 1984. Correlation of the middle Eocene Kellogg Shale of northern California:  Micropaleontology, 30:138-170.

Keller, Gerta, and Barron, J.A., 1983. Paleoceanographic implications of Miocene deep-sea hiatuses:  Geological Society of America Bulletin 94:590-613.

Barron, J. A., and Keller, Gerta, 1983. Paleotemperature oscillations in the middle and late Miocene of the northeastern Pacific:  Micropaleontology, 29:150-181.

Barron, J.A., and Keller, Gerta, 1982. Widespread Miocene deep-sea hiatuses: Coincidence with periods of global cooling:  Geology, 10:577-581.

Barron, J.A., 1983. Latest Oligocene through early middle Miocene diatom biostratigraphy of the eastern tropical Pacific:  Marine Micropaleontology, 7:487-515.

Baldauf, J. G., and Barron, J. A., 1982. Diatom biostratigraphy and paleoecology of the type section of the Luisian Stage, central California:  Micropaleontology, 28:59-84.

Barron, J.A., 1981. Late Cenozoic diatom biostratigraphy and paleoceanography of the middle latitude eastern North Pacific, DSDP Leg 63:  Initial Reports, Deep Sea Drilling Project, v. 63, p. 507-538.

Barron, J. A., 1981. Marine diatom biostratigraphy of the Montesano Formation near Aberdeen, Washington, in Armentrout, J. M., ed., Pacific Northwest Cenozoic Biostratigraphy:  Geological Society of America Special Paper 184, p. 113-126.

Barron, J.A., 1980. Lower Miocene to Quaternary diatom biostratigraphy of DSDP Leg 57, off northeastern Japan:  Initial Reports, Deep Sea Drilling Project, v. 56 and 57, p. 641-685.

Barron, J. A., 1980. Upper Pliocene and Quaternary diatom biostratigraphy of Deep Sea Drilling Project Leg 54, tropical eastern Pacific:  Initial Reports, Deep Sea Drilling Project, v. 54, p. 455-485.

Barron, J.A., 1976. Revised Miocene and Pliocene diatom biostratigraphy of Upper Newport Beach, California:  Marine Micropaleontology, 1:27-63.

Barron, J. A., 1976, Marine diatom and silicoflagellate biostratigraphy of the type Delmontian Stage and type Bolivina obliqua Zone, California: U.S. Geological Survey Journal of Research, 4:339-352..

Barron, J.A., 1975. Late Miocene-Early Pliocene marine diatoms from southern California:  Palaeontographica, 151(B):97-170.

Barron, J. A., 1975. Marine diatom biostratigraphy of the upper Miocene-lower Pliocene strata of southern California:  Journal of Paleontology, 4:619-632.

Barron, J.A., 1973. Late Miocene-Early Pliocene paleotemperatures for California from marine diatom evidence:  Palaeogeography, Palaeoclimatology, Palaeoecology, 14:277-291.


My Science Topics

Science Topic
Atmosphere and Climateclimate change
Earth Characteristicsearth history
Earth Characteristicsfossils
Earth Characteristicsstratigraphy
Oceans and Coastlinespaleoceanography

My USGS Science Strategy Areas

Climate Variability & Change

Marine Diatoms as Tools for Paleoclimatology & Earth History

Image of Current Focus for Marine Diatoms as Tools for Paleoclimatology & Earth History

Synopsis of Research: Diatoms are microscopic algae that form bivalved siliceous skeletons.  They are abundant, diverse, and ubiquitous in aqueous environments (oceans, estuaries, lakes, rivers, etc) that are illuminated by sunlight and are at the base of the food chain in productive regions of the ocean.  Individual species are sensitive to temperature, nutrient and tracer metal concentrations, salinity, sea ice, and other chemical and physical factors, making them excellent tracers of environmental change.  I helped refine diatoms as a biochronologic tool for dating Cenozoic and Late Cretaceous rocks and sediments from polar waters and coastal upwelling regions like California.  This biochronology was used to date tectonic events in California and the North Pacific, determine periods of widespread deep-sea hiatuses in the world's oceans, and detail the Cenozoic history of the Antarctic ice sheet.  Paleoclimatic and paleoenvironmental studies document climate variability and require an integrated knowledge of other chemical, physical, and biologic tracers.  My research has been concentrated in the North Pacific, equatorial Pacific, and the Southern Ocean surrounding Antarctica.

Pacific Ocean Climate Variability: Effects on North American Precipitation Patterns

This project will publish high-resolution records of marine SST and surface water productivity from the southeastern margins of Alaska and the margins of Oregon, California, and Mexico, developing decadal scale records of the past 2,000 years that can be compared with regional and global reconstructions of the Medieval Climate Anomaly (~AD 950-1250), Little Ice Age (~AD 1350-1850).  Data will also be compared with instrumental records of the past 100+ years in an effort to distinguish anthropogenic-forced warming from naturally occurring climate cycles.  Analyses will include state-of-the-art tools for high-resolution climate study (core scanning XRF) and develop new alkenone-based SST records in the poorly studied North Pacific. Whenever possible proxies of coastal precipitation (pollen, detrital geochemistry, isotopes) will be studied in the same cores in order to test whether El Niņo Southern Ocean Oscillation (ENSO) or Pacific Decadal Oscillation (PDO) operated on similar temporal and geographic scales in the past.

         The project’s marine studies will be complemented by high-resolution analysis of terrestrial environments (mostly lake sediments from California, Nevada, Alaska {Lesleigh Anderson project}, and possibly Utah and Arizona utilizing precipitation proxies (pollen, charcoal, sediment geochemistry, diatoms, isotopes). Development of decadal-scale records of the past 1,200 years will also be a major goal of this effort, and sites will be selected from environments and geographic regions known to be sensitive to changing ENSO/PDO conditions.  A major aim of this terrestrial effort will also be to develop regional records of precipitation (and drought) during the Holocene (past ~11,500 years) that can be compared with those being compiled by other CLU R&D projects in the United States and North America. Syntheses of these regional studies should help climate modelers determine how modern precipitation patterns in the United States have responded to changing atmospheric and oceanic conditions during the Holocene.  This effort will be aided by ongoing studies of paleoclimate records from Guatemala and the equatorial Pacific that are aimed at establishing the changing dynamics of tropical climate and its effect on human populations.  Finally, this project aims to clarify the timing and extent of abrupt climate events such as the onset of the Younger Dryas cold interval (~12,900 years ago) and termination of the Medieval Climate Anomaly in order to establish regional patterns and possible forcing mechanisms. 

Contact Information

John Barron
345 Middlefield Road
Menlo Park, CA 94025-3561
650-329-5203 - Fax
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