Wisconsin/Würm glacial stage ice in the subtropical dunde ice cap, China
Tóm tắt
The insoluble microparticle concentrations and size distributions and oxygen isotope abundances (δ18 0) in two 1-meter ice cores from the margin of the Dunde ice cap (38° 06 'N; 96° 24 'E; 5325 masl) drilled in 1986 and three ice cores drilled to bedrock at the summit of the ice cap in 1987 suggest the presence of Wisconsin/Würm Glacial Stage (LWGS) ice in the subtropics. A Sino-American research group recovered three ice cores 136, 138 and 139 m in length from the summit of the Dunde ice cap in the Qilian Shan which are providing long, high temporal resolution climatic and environmental records for the NE section of the Tibetan Highlands. Particulate concentrations, conductivity and δ18 0 are the ice core constituents best established as indicators of the glacial/interglacial transition. The analyses of two shallow cores from the margin reveal a 14-fold increase in particulate concentration which is correlative with a 1% to 5% decrease (more negative) in δ18 0. The lower 10 to 13 m of three ice cores drilled to bedrock at the summit contain a ten-fold increase in dust (both soluble and insoluble) and a 1.2% decrease in oxygen isotopes. Additionally, the morphological properties of the particles in the LWGS ice are identical to those of the thick, extensive loess deposits of central china which accumulated during the cold, dry glacial stages of the Pleistocene. When the climatic and environmental records are fully extracted from the three deep cores they will provide a very detailed record of variations in particulates (soluble and insoluble), stable isotopes, net balance, pollen and perhaps atmospheric gases of CO2 and methane through the Holocene into the last glacial in the subtropics on the climatically important Tibetan Plateau.
Tài liệu tham khảo
Barkov, N. I.; Korotkevich, E. S.; Gordienko, F. G.; Kotlyakov, V. M.: The isotope analysis of ice cores from Vostok station (Antarctica), to the depth of 950 m. IAHS-AISH Pub. No. 118, 382–397 (1977)
Barnett, T. P.; Dümenil, L.; Schlese, U.; Roeckner, E.: The effect of Eurasian snow cover on global climate. Science 239, 504–507 (1988)
Birks, H. J. B.: Late Wisconsin vegetational and climatic history at Kylen Lake, Northeastern Minnesota. Quat. Res. 16, 322–355 (1981)
Birks, H. H.; Mathews, R.: Studies in the vegetational history of Scotland. New Phytol. 80, 455–484 (1978)
Dansgaard, W.; Clausen, H. B.; Gundestrup, N.; Hammer, C. U.; Johnsen, S. F.; Kristinsdotter, P. M.; Reeh, N.: A new Greenland deep ice core. Science 218 (4579), 1273–1277 (1982)
De Angelis, M. D.; Barkov, N. I.; Petrov, V. N.: Aerosol concentrations over the last climatic cycle (160 Kyr) from an Antarctic ice core. Nature 325, 318–321 (1987)
Derbyshire, E.: On the morphology, sediments, and origin of the Loess Plateau of central China. pp. 172–194 In: Gardner, R.; Scogin, I. (eds.) Mega-Geomorphology. Clarendon Press, Oxford 1983.
Eicher, U.: Pollen- und Sauerstofftisotopen-analysen an spätglazialen Profilen vom Gerzonsee, Faulenseemoos und vom Regenmoos ob Boltigen. Mitteilungen Naturforschende Gesellschaft, Bern. Neue Folge 37, 65–80 (1980)
Eicher, U.; Siegenthaler, U.: Klimatische Informationen aus Sauerstoffisotopenverhältnissen in Seesedimenten. Physische Geographie 1, 103–110 (1982)
Eicher, U.; Siegenthaler, U.; Wegmüller, S.: Pollen and oxygen isotope analysis on late-glacial and post-glacial sediments of the Tourbiere de Chirens (Dauphine, France). Quartenary Research 15, 160–170 (1981)
Flohn, H.: Larger scale aspects of the summer monsoon in south and east Asia. Journal of the Meteorological Society of Japan, 75th Anniversary Volume, 108–136 (1957)
Flohn, H.: Thermal effects of the Tibetan Plateau during the Asian monsoon season: Australian Meteorological Magazine 49, 55–58 (1965)
Flohn, H.: Contribution to a meteorology of the Tibetan highlands. Department of Atmospheric Science Report 30, University of Colorado, Fort Collins, CO. (1968)
Hammer, C. U.; Clausen, H. B.; Dansgaard, W.; Neftel, A. P.; Kristinsdotter, P.; Johnson, E. pp. 90–94 In: Greenland Ice Core: Geophysics, Geochemistry and the Environment. Geophysical Monograph Vol. 33, 1985.
Herron, M. M.; Langway, Jr., C. C.: Chloride, nitrate and sulfate in the Dye 3 and Camp Century, Greenland, ice cores. pp. 79–84 In: Greenland Ice Core: Geophysics, Geochemistry and the Environment. Geophysical Monograph Vol. 33, 1985.
Johnsen, S. J.; Dansgaard, W.; Clausen, H. B.; Langway, C. C.: Oxygen isotope profiles throught the Antarctic and Greenland ice sheets. Nature 235, 429–434 and correction 236, 249 (1972)
Koerner, R. M.: Distribution of microparticles in a 299-m core through the Devon Island ice cap, Northwest Territories, Canada. IAHS-AISH Pub. No. 118, 371–376 (1977)
Koteswaran, P.: The easterly jet stream in the tropics. Tellus 10, 1, 43–87 (1958)
Kuhle, M.: Subtropical Mountain and Highland Glaciation as Ice Age Triggers and the Waning of the Glacial Period in the Pleistocene. GeoJournal 14, 4, 393–421 (1987)
Lau, K. M.; Li, M. T.: The monsoon of East Asia and its global associations — a survey. Bulletin of the American Meteorological Society 65, 2, 114–125 (1984)
Liu, T.; Zhang, S.; Han, J.: Stratigraphy and paleoenvironmental changes in the loess of central China. pp. 489–495 In: Quaternary Glaciations in the Northern Hemisphere. Quaternary Science Review 6 (1987)
Lorius, C.; Merlivat, L.; Jouzel, J.; Pourchet, M.: A 30,000-year isotope climate record from Antarctic ice. Nature 280, 644–648 (1979)
Lorius, C.; Jouzel, J.; Ritz, C.; Merlivat, L.; Barkov, N. I.; Korotkevich, Y. S.; Kotlyakov, V. M.: A 150,000-year climatic record from Antarctic ice. Nature 316, 591–596 (1985)
Luo, H.; Yanai, M.: The large scale circulation and heat sources over the Tibetan Plateau and the surrounding area during the early summer of 1979, Part I. precipitation and kinematics. Monthly Weather Review 111, 922–944 (1983)
Murakami, T.: Geographic influence of the Tibetan Plateau on the asiatic winter monsoon circulation, Part I, large-scale aspects. Journal of the Meteorological Society of Japan 59, 66–84 (1981)
Paterson, W. S. B.; Koerner, R. M.; Fisher, D.; Johnsen, S. J.; Clausen, H. B.; Dansgaard, W.; Bucher, P.; Oeschger, H.: An oxygen isotope climatic record from the Devon Island ice cap, arctic Canada. Nature 266, 508–511 (1977)
Reiter, E. R.: Teleconnections with tropical precipitation surge. Journal of the Atmospheric Sciences 40, 7, 1631–1647 (1983)
Thompson, L. G.: Variations in magnitude and concentrations, size distribution and elemental composition found in Camp Century, Greenland, and Byrd Station, Antarctica, deep ice cores. IAHS-AISH Pub. No. 118, 351–364 (1977)
Thompson, L. G.; Mosley-Thompson, E.: Microparticle concentration variations linked with climatic change: evidence from polar ice cores. Science 212, 812–815 (1981)
Thompson, L. G.; Mosley-Thompson, E.; Petit, J. R.: Glaciological and climatological interpretation of microparticle concentrations from the French 905-meter Dome C, Antarctica, core. IAHS-AISH Pub. No. 118, 227–237 (1981)
Thompson, L. G.; Mosley-Thompson, E.: Bolzan, J. F.; Koci, B. R.: A 1500-year record of tropical precipitation recorded in ice cores from the Quelccaya ice cap, Peru. Science 229 (4717), 971–973 (1985)
Thompson, L. G.; Mosley-Thompson, E.; Dansgaard, W.; Grootes, P. M.: “The Little Ice Age” as recorded in the stratigraphy of the tropical Quelccaya ice cap. Science 234, 361–364 (1986)
Thompson, L. G.; Wu, X.; Mosley-Thompson, E.; Xie, Z.: Climate records from the Dunde Ice Cap, China. Ann. Glaciol. (1988)
Virgi, H.: Summer circulation over South America from Satellite data. Ph. D. thesis, University of Wisconsin, Madison, WJ 1979.
Wang, Y. Y.; Wu, Z. B.; Yue, L.: Constituent materials and structures of loess in Lanxhou and the dates of its formation. Northwest University Bulletin, Science Edition (in Chinese) 3, 1–27 (1978)
Woillard, G. M.; Mook, W. G.: Carbon-14 dates at Grande Pile: correlation of land and sea chronologies. Science 215, 159 (1982)
Yeh, T. C.: Some characteristics of the summer circulation over the Qinghai-Xizang (Tibet) Plateau and its neighborhood. Bulletin of the American Meteorological Society 62, 14–19 (1981)