Hydrological variations on the Central Tibetan Plateau since the Last Glacial Maximum and their teleconnection to inter‐regional and hemispheric climate variations

Abstract

Decadal to sub‐decadal variability of inflow, evaporation and biological productivity derived from Lake Nam Co was used to reconstruct hydrological changes for the past ca. 24 k cal a BP. The timing of these variations corresponds to known climatic shifts on the Northern Hemisphere. After a dry and cold Last Glacial Maximum the lake level of Nam Co initially rose at ca. 20 k cal a BP. Moist but further cold conditions between ca. 16.2 and 14 k cal a BP correspond to Heinrich Event 1. A warm and moist phase between ca. 14 and 13 k cal a BP is expressed as a massive enhancement in inflow and biological productivity and might be associated with a first intensification of the Indian Ocean Summer Monsoon coinciding with the Bølling–Allerød complex. A two‐step decrease in inflow and a contemporaneous decline in biological productivity until ca. 11.8 k cal a BP points to cool and dry conditions during the Younger Dryas. Lake levels peak at ca. 9.4 k cal a BP, although hydrological conditions remain relatively stable during the Holocene with only low‐amplitude variations observed.

Morphodynamics and lake level variations at Paiku Co, southern Tibetan Plateau, China

“…19 cal ky BP old lacustrine deposits in section PC-4 are strong evidence for a still higher lake level, although the water balance of Paiku Co was slightly negative during this time interval. This finding contradicts the general opinion of cold and dry climate conditions during the LGM (e.g., Herzschuh, 2006) being the major trigger for very low lake levels on the Tibetan Plateau (e.g., Nam Co: Daut et al, 2010;Kasper et al, 2015;Qinghai Lake: Coleman et al, 2007;Lake Ximencuo: Zhang and Mischke, 2009;Hala Lake: Yan and Wünnemann, 2014). Some lakes, however (such as Zhabuye Lake, Zhacang Caka and Zigetang Co) experienced high to medium-high lake status records too, according to Yu et al (2001).…”

Investigating the long-term palaeoclimatic controls on the δD and δ18O of precipitation during the Holocene in the Indian and East Asian monsoonal regions

“…The temporal resolution of the data from Paru Co (Bird et al, 2014) and Koucha Lake (Aichner et al, 2010a) are relatively lower than those from the other sites. The sediment chronologies for Gonghai Lake Rao et al, 2016a), Nam Co (Mügler et al, 2010;Kasper et al, 2015) and Qinghai Lake Thomas et al, 2016) are highly reliable (Table 2); however, the chronology for Koucha Lake is relatively weak, based on only 4 AMS 14 C ages obtained from pollen extracts (Aichner et al, 2010a).…”

Biogeochemical evidence for freshwater periods during the Last Glacial Maximum recorded in lake sediments from Nam Co, south-central Tibetan Plateau

“…The chronology of the complete NC 08/01 sediment core is based on 24 AMS 14 C ages (Beta Analytic, Miami, USA) obtained from bulk sediment samples (Doberschütz et al 2014;Kasper et al 2015 (Kasper et al 2015). A reservoir effect of 1420 14 C years was inferred from the age of the core sediment-water interface and was subtracted from all radiocarbon ages prior to calibration (Doberschütz et al 2014 (Werner and Brand 2001).…”

“…Fig. 2 Chronology of Nam Co sediment core NC 08/01 for the investigated interval, as established from the calibrated median ages of five radiocarbon dates on bulk sediment samples (Kasper et al 2015). Error bars represent the 2r uncertainty range Identification and quantification of n-alkanes from the sediment core samples were accomplished using a GC-FID system (TRACE GC 2000, CE Instruments, Thermo Quest, Rodano, Italy) with a DB-1MS column (30 m length, 0.25 mm ID, 0.25 lm film thickness; Agilent Technologies, Santa Clara, USA) by comparing peak areas and retention times with an external nalkane standard mixture (n-C 10 to n-C 34 ).…”

“…The first period of the investigated sequence is characterized by large fluctuations in the amount of odd-numbered n-alkanes, probably caused by high sensitivity of the small and shallow lake to changes in nutrient supply (Kasper et al 2015). According to the dominant terrestrial cluster III, lake sediment was almost exclusively influenced by fresh material from macrophytes (emergent, submerged) as well as soil/dung (mainly n-C 31 ).…”