Cosmogenic radionuclide dating of glacial landforms in the Lahul Himalaya, northern India: defining the timing of Late Quaternary glaciation

Abstract

2001. Cosmogenic radionuclide dating of glacial landforms in the Lahul Himalaya, northern India: defining the timing of Late Quaternary glaciation.ABSTRACT: The timing of glaciation in the Lahul Himalaya of northern India was ascertained using the concentrations of cosmogenic 10 Be and 26 Al from boulders on moraines and drumlins, and from glacially polished bedrock surfaces. Five glacial stages were identified: Sonapani I and II, Kulti, Batal and Chandra. Of these, cosmogenic exposure ages were obtained on samples representative of the Batal and Kulti glacial cycles. Stratigraphical relationships indicate that the Sonapani I and II are younger. No age was obtained for the Chandra glacial advance. Batal Glacial Stage deposits are found throughout the valley, indicating the presence of an extensive valley glacial system. During the Kulti Stage, glaciers advanced ca. 10 km beyond their current positions. Moraines produced during the Batal Stage, ca. 12-15.5 ka, are coeval with the Northern Hemisphere Late-glacial Interstadial (Bølling/Allerød). Deglaciation of the Batal Glacial Stage was completed by ca. 12 ka and was followed by the Kulti Glacial Stage during the early Holocene, at ca. 10-11.4 ka. On millennial time-scales, glacier oscillations in the Lahul Himalaya apparently reflect periods of positive massbalance coincident with times of increased insolation. During these periods the South Asian summer monsoon strengthened and/or extended its influence further north and west, thereby enhancing high-altitude summer snowfall.

Quaternary glaciation of the Himalayan–Tibetan orogen

“…Defining the ages of landforms and sediments throughout much of the HimalayanTibetan orogen has been particularly difficult because of the Shiraiwa, 1993;Sharma and Owen, 1996;Phillips et al, 2000;Richards et al, 2000a,b;Owen et al, 2001Owen et al, , 2002aOwen et al, ,b, 2003aOwen et al, ,b,c, 2005Owen et al, , 2006aSchäfer et al, 2002;Tsukamoto et al, 2002;Yi et al, 2002;Finkel et al, 2003;Zech et al, 2003Zech et al, , 2005Barnard et al, 2004aBarnard et al, ,b, 2006aMeriaux et al, 2004;Spencer and Owen, 2004;Chevalier et al, 2005;Abramowski et al, 2006;Colgan et al, 2006;Seong et al, 2007Seong et al, , 2008a. The red dots in part (A) highlight regions where TCN surface exposure dating has been undertaken.…”

“…The possibility of numerous glacier advances also complicates correlations between regions based on TCN dating, especially because the TCN dating method is relatively imprecise ($8% systematic error; Balco et al, 2008). A detailed interpretation of the interregional variability therefore requires more comprehensive Owen et al, 2001Owen et al, , 2002aOwen et al, ,c, 2003aOwen et al, ,b,c, 2005Owen et al, , 2006aSchäfer et al, 2002;Finkel et al, 2003;Zech et al, 2003Zech et al, , 2005Barnard et al, 2004aBarnard et al, ,b, 2006aMeriaux et al, 2004;Chevalier et al, 2005;Abramowski et al, 2006;Colgan et al, 2006;Seong et al, 2007Seong et al, , 2008a. The number of samples used to produce each probability plot is indicated by 'n' All data 20 30 40 50 60 70 80 90 100 110 120 20 30 40 50 60 70 80 90 100 110 120 20 30 40 50 60 70 80 90 100 110 120 20 30 40 50 60 70 80 90 100 110 Figure 9 Probability density functions of TCN 10 Be ages for all published data from the Himalayan-Tibetan orogen plotted for each major climatic region.…”

“…The number of samples used to produce each probability plot is indicated by 'n' All data 20 30 40 50 60 70 80 90 100 110 120 20 30 40 50 60 70 80 90 100 110 120 20 30 40 50 60 70 80 90 100 110 120 20 30 40 50 60 70 80 90 100 110 Figure 9 Probability density functions of TCN 10 Be ages for all published data from the Himalayan-Tibetan orogen plotted for each major climatic region. (A) All published data; (B) MIS 1 and MIS 2; and (C) MIS 3 to MIS 5e (data from Phillips et al, 2000;Owen et al, 2001Owen et al, , 2002aOwen et al, ,b, 2003aOwen et al, ,b,c, 2005Owen et al, , 2006aSchäfer et al, 2002;Finkel et al, 2003;Zech et al, 2003Zech et al, , 2005Barnard et al, 2004aBarnard et al, ,b, 2006aMeriaux et al, 2004;Chevalier et al, 2005;Abramowski et al, 2006;Colgan et al, 2006;Seong et al, 2007Seong et al, , 2008a. The number of samples used to produce each probability plot is indicated by 'n' in the order of the regions shown in the legend of part (A).…”

Geomorphological applications of cosmogenic isotope analysis

“…Ice-marginal moraines: glacial history; climatic change. Brown et al (1991), Brook et al ( , 1995a, , Gosse et al (1995a, b), Phillips et al (1990Phillips et al ( , 1996Phillips et al ( , 1997, Zreda and Phillips (1995), Ivy-Ochs et al (1996), Fabel et al (1997, Jackson et al (1997Jackson et al ( , 1999, Chadwick et al (1997), Steig et al (1998), Davis et al (1999), Fabel andHarbor (1999), Gualtieri et al (2000), Shanahan and Zreda (2000), Tschudi et al (2000), Marsella et al (2000), Phillips et al (2000) Barrows et al (2001Barrows et al ( , 2002, Briner et al (2001;, Licciardi et al (2001), Owen et al (2001Owen et al ( , 2002a, Kaplan et al …”

“…Locations for such studies are worldwide, ranging from the British Isles (Bowen et al, 2002) to eastern Russia (Gualtieri et al, 2000), the western USA (Zreda and Phillips, 1995;Gosse et al, 1995a, b;Phillips et al, 1996Phillips et al, , 1997Phillips et al, , 1990Chadwick et al, 1997;Licciardi et al, 2001;James et al, 2002), western Canada (Jackson et al,1997(Jackson et al, , 1999, eastern Canada (Steig et al, 1998;Davis et al, 1999;Marsella et al, 2000;Kaplan et al, 2001;Miller et al, 2002), East Africa (Shanahan and Zreda, 2000), southeast Australia and Tasmania (Barrows et al, 2001(Barrows et al, , 2002, the Himalayas and Tibetan Plateau (Phillips et al, 2000;Owen et al, 2001Owen et al, , 2002aTaylor and Mitchell, 2002;Schäfer et al, 2002a), and Antarctica (Brown et al, 1991;Brook et al, , 1995aFabel et al,1997). A focal issue for a number of these and other studies of glacial deposits has been the chronology of glacial fluctuations marking the Late Glacial Maximum and the global synchrony, or otherwise, of the Younger Dryas (Ivy-Ochs et al, 1996Tschudi et al, 2000;Briner et al, 2001Briner et al, , 2002Phillips and Bowen, 2002;Bourlès et al, 2002;Schäfer et al, 2002b).…”