Asynchronous glaciation at Nanga Parbat, northwestern Himalaya Mountains, Pakistan

Abstract

We present a new glacial chronology demonstrating asynchroneity between advances of Himalayan glaciers and Northern Hemisphere icesheet volumes. Glaciers at Nanga Parbat expanded during the early to middle Holocene ca. 9.0-5.5 ka. No major advances at Nanga Parbat during the last global glacial stage of marine oxygen isotope stage 2 (MIS-2) between 24 and 11 ka were identified. Preliminary evidence also indicates advances between ca. 60 and 30 ka. These periods of high ice volume coincide with warm, wet regional climates dominated by a strong southwest Asian summer monsoon. The general lack of deposits dating from MIS-2 suggests that Nanga Parbat was too arid to support expanded ice during this period of low monsoon intensity. Advances during warm, wet periods are possible for the high-altitude summer accumulation glaciers typical of the Himalayas, and explain asynchronous behavior. However, the Holocene advances at Nanga Parbat appear to have been forced by an abrupt drop in temperature ca. 8.4-8.0 ka and an increase in winter precipitation ca. 7-5.5 ka. These results highlight the overall sensitivity of Himalayan glaciation to orbital forcing of monsoon intensity, and on millennial or shorter time scales, to changes in North Atlantic circulation.

Review of Holocene glacial chronologies based on radiocarbon dating in Tibet and its surrounding mountains

“…Their age was determined to be 9.0-10.7 ka (n ¼ 5) (Owen et al, 2002). The dates of moraines in Nanga Parbat show that two Holocene glacial advances occurred at 8.4-7.8 ka (n ¼ 4) and 6.2-4.1 ka (n ¼ 4) (Phillips et al, 2000). 3 He exposure dating also shows a significant retreat around 10 ka in glacial stadials at 8.5, 7.5 and 6-5 ka at the upper valley of the Mailun Khola, Ganesh Himal in central Nepal (Gayer et al, 2006).…”

New OSL dating of UK loess: indications of two phases of Late Glacial dust accretion in SE England and climate implications

“…Whilst SAR protocols use a test dose to correct for sensitivity changes during measurement cycles (Murray and Wintle, 2000) and work well with quartz grains (Duller, 2004), feldspars have proven problematic with this protocol (Wallinga et al, 2000a,b;Blair et al, 2005). Despite some concern that SAAD protocols (Duller, 1991) may be unable to correct for changes in trapping probability as a consequence of heating (Wallinga et al, 2000b(Wallinga et al, , 2001, this approach has shown some agreement with independent age control for polymineral fine grains (Phillips et al, 2000). The SAAD protocol employed here utilised measurement of IRSL for 0.5 s at 508C with a preheat of 2208C for 10 min.…”

Surface exposure dating of the Great Aletsch Glacier Egesen moraine system, western Swiss Alps, using the cosmogenic nuclide 10Be

“…Recent studies using cosmogenic nuclides have directly dated glacial deposits, in some cases with such precision as to allow the dating of short-lived glacial advances such as during the late-glacial Younger Dryas cold period (e.g. Phillips et al, 1990Phillips et al, , 1996Phillips et al, , 1997Gosse et al, 1995;Chadwick et al, 1997;Ivy-Ochs et al, 1999;Tschudi et al, 2000;Phillips et al, 2000;Shanahan and Zreda, 2000;Balco et al, 2002;Schaeffer et al, 2002;Kaplan et al, 2004).…”