• Treffer 1 von 1
Zurück zur Trefferliste

Hydrological changes in western Central Asia (Kyrgyzstan) during the Holocene as inferred from a palaeolimnological study in lake Son Kul

  • The hydrology of western Central Asia is highly sensitive to climatic perturbations. In order to understand its long-term variability and to infer linkages between precipitation and atmospheric and oceanic systems, we conducted a thorough sedimentary and geochemical study on a composite core retrieved in lake Son Kul (central Kyrgyzstan). A multi-proxy approach was conducted on lake sediments based on grain size analyses, magnetic susceptibility, total organic carbon (TOC), total nitrogen (TN) and carbon and oxygen isotope analyses on bulk and biogenic materials (ostracoda and molluscs shells) at a resolution equivalent to ca 40 years, aiming to characterise the sequence of palaeolimnological changes in Son Kul. As indicated by delta O-18 record of bulk carbonates, mainly consisting of aragonite, the Holocene hydrological balance was negative during most of time, suggesting an excess of evaporation (E) over precipitation (P). Limnological conditions fluctuated rapidly before 5000 cal yr BP indicating significant changes in regionalThe hydrology of western Central Asia is highly sensitive to climatic perturbations. In order to understand its long-term variability and to infer linkages between precipitation and atmospheric and oceanic systems, we conducted a thorough sedimentary and geochemical study on a composite core retrieved in lake Son Kul (central Kyrgyzstan). A multi-proxy approach was conducted on lake sediments based on grain size analyses, magnetic susceptibility, total organic carbon (TOC), total nitrogen (TN) and carbon and oxygen isotope analyses on bulk and biogenic materials (ostracoda and molluscs shells) at a resolution equivalent to ca 40 years, aiming to characterise the sequence of palaeolimnological changes in Son Kul. As indicated by delta O-18 record of bulk carbonates, mainly consisting of aragonite, the Holocene hydrological balance was negative during most of time, suggesting an excess of evaporation (E) over precipitation (P). Limnological conditions fluctuated rapidly before 5000 cal yr BP indicating significant changes in regional hydrology and climate. In particular, the long-term negative hydrological balance was impeded by several short stages with marked increase of precipitation, lasting several decades to a few centuries (e.g., 8300-8200, 6900-6700, 6300-6100, 5500-5400, 5300-5200 and 3100 -3000 cal yr BP). Precipitation changes as inferred from 8180 data are also documented by increased minerogenic detritus and higher TOC. We propose that the seasonal pattern of precipitation varied transiently in western Central Asia during the Holocene, although evaporation changes may also account for the rapid changes observed in delta O-18 data. When the annual water balance was less critical (P <= E), the excess of water might be ascribed to increased precipitation during cold seasons mainly because winter precipitation has more negative delta O-18 than its summer equivalent. Conversely, when the annual water balance is negative (P E), the moisture was mainly delivered during the warm season, as between 5000 and 2000 cal yr BP. Our results thus imply that moisture sources could have changed as well during the Holocene. Moisture was delivered as today mainly during summer from the extended Caspian-Aral Basin and eastern Mediterranean, although Arctic and even North Atlantic seas might be important moisture sources when seasonal precipitation was dominated by winter precipitation. We hypothesise that warming Arctic and North Atlantic seas were important for the North Hemisphere circulation during the cold season. (C) 2014 Elsevier Ltd. All rights reserved.zeige mehrzeige weniger

Metadaten exportieren

Weitere Dienste

Suche bei Google Scholar Statistik - Anzahl der Zugriffe auf das Dokument
Metadaten
Verfasserangaben:Xiangtong Huang, Hedi Oberhaensli, Hans von Suchodoletz, Sushma PrasadORCiD, Philippe Sorrel, Birgit PlessenORCiDGND, Marie Mathis, Raskul Usubaliev
DOI:https://doi.org/10.1016/j.quascirev.2014.09.012
ISSN:0277-3791
Titel des übergeordneten Werks (Englisch):Quaternary science reviews : the international multidisciplinary research and review journal
Verlag:Elsevier
Verlagsort:Oxford
Publikationstyp:Wissenschaftlicher Artikel
Sprache:Englisch
Jahr der Erstveröffentlichung:2014
Erscheinungsjahr:2014
Datum der Freischaltung:27.03.2017
Freies Schlagwort / Tag:Holocene; Hydrological balance; Oxygen and carbon isotopes; Tien Shan (western Central Asia)
Band:103
Seitenanzahl:19
Erste Seite:134
Letzte Seite:152
Fördernde Institution:Helmholtz - CSC; Natural Science Foundation of China [40902046, 91128208]; Shanghai Committee of Science and Technology, China [13ZR1443500, 14XD1403600]
Organisationseinheiten:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Geowissenschaften
Peer Review:Referiert
Name der Einrichtung zum Zeitpunkt der Publikation:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Erd- und Umweltwissenschaften
Verstanden ✔
Diese Webseite verwendet technisch erforderliche Session-Cookies. Durch die weitere Nutzung der Webseite stimmen Sie diesem zu. Unsere Datenschutzerklärung finden Sie hier.