HOLOCENE GLACIER FLUCTUATIONS 525 a possible few small stagnant ice masses or semiperma- Tirich Mir (7,690 m) and Noshaq (7,492 m) massifs tower nent snowfields remaining after years of drought and high enough to intercept sufficient monsoonal moisture to melting. produce a very few glaciers up to 24 km in length. Middle or Central Hindu Kush Summary This region occurs to the northeast and east of the Kabul The Hindu Kush ranges of Afghanistan and the Pakistan Basin, and includes all of the mountains of Nuristan south border region can be subdivided into a Western, Central, and east of the Panjshir Valley and over the Anjuman Pass and Eastern Hindu Kush, as well as a Northern or Khwaja to the Dorah Pass into Pakistan near Chitral, down to the Mohammed Range. Collectively the Hindu Kush ranges Kunar River Valley, all of which are in the Kabul River have many small glaciers that are dominantly only a few drainage basin. The Mir Samir glacierized area near the km in length. Meltwater from these glaciers constitutes Panshir Valley (Gilbert et al., 1969) is important to any a vital late season supply of critical irrigation that is threat- study because it received some of the first glaciological ened with climate change in this chronically drought-torn work ever done in Afghanistan (Shroder and Bishop, region. 2009). Bibliography Eastern Hindu Kush Braslau, D., 1974. The glaciers of Keshnikhan. In Gratzal, K. (ed.), This mountainous region extends east from its Kokcha Hindukusch; Ősterreichische Forschungsexpedition in den River border with the Khawaja Mohammed Range, and Wakhan 1970. Graz: Akademische Druck-u. Verlagsanstalt, east to the Ab-i-Panj river border of the Wakhan Corridor, pp. 112–116. as well as from the Anjuman to Dora Pass valley route to Burrard, S. G., and Hayden, H. H., 1907. A sketch of the Geography – and Geology of the Himalaya Mountains and Tibet. Survey of Chitral, as far as Baroghil Pass along the Afghanistan India, 359 pp. Pakistan border in the Wakhan where it terminates. The Gilbert, O., Jamieson, D., Lister, H., and Pendlington, A., 1969. Eastern Hindu Kush therefore includes all the high peaks Regime of an Afghan glacier. Journal of Glaciology, 8(52), along the Afghanistan–Pakistan border, including Noshak 51–65. (7,492 m), the highest peak in Afghanistan, as well as Grötzbach, E., 1990. Afghanistan: Eine geographische Tirich Mir (7,706 m) above Chitral in Pakistan. In the Landeskunde (Wissenschaftliche Landerkunden). Darmstadt: Wissenschaftliche Buchgesellschaft, 449 pp. west, close to the Kokcha River border with the Khwaja Shroder, J. F., Jr., and Bishop, M. P., 2010. Glaciers of Afghanistan. Mohammed Range, occurs the Koh-i-Bandaka area of gla- In Williams, R. S., Jr., and Ferrigno, J. G. (eds.), Satellite Image ciers that have been mapped and studied recently (Shroder Atlas of Glaciers of the World. U.S. Geological Survey Profes- and Bishop, 2010). The Keshnikhan Glacier in sional Paper 1386-F-3, F-167-F199. Afghanistan a few km NNE of the Noshaq and Tirich Mir peaks was first mapped and studied by an Austrian Expedi- tion of 1970 (Braslau, 1974), and is again the focus of HOLOCENE GLACIER FLUCTUATIONS recent attention (Shroder and Bishop, 2009). Khwaja Mohammed Range Johannes Koch Department of Earth Sciences, Simon Fraser University, This northernmost of the main Hindu Kush ranges extends Burnaby, BC, Canada northward from the southern boundary along the line of the Andarab–Khwak Pass–Anjuman Pass, between the Kokcha River on the east and the Surkhab–Kunduz River Definition on the west. Holocene is the most recent geological Epoch spanning – North of the Hindu Kush and still inside Afghanistan the past 10,000 12,000 years. are the Pamir ranges of Badakshan and the Wakhan Corri- Glacier fluctuations are advance and retreat phases of dor. Outside of Afghanistan to the north in Tajikistan and individual glaciers due to changes in their mass balance. neighboring states occur many more ranges of the Pamir, as well as the Pamir Knot. Introduction Collectively the diverse sets of Hindu Kush ranges are Glacier extent during the Holocene was limited compared characterized by 3,000 small glaciers in Afghanistan to the Pleistocene, but recent studies point to significant, that are almost nowhere more than a few kilometers in rapid fluctuations of climate throughout the Holocene length. The glaciers of the Hindu Kush are dominantly (e.g., Mayewski et al., 2004). One proxy of Holocene cli- nourished by winter westerly precipitation, although those mate variability that has long been used is alpine glacier in the southeast of Afghanistan can receive some summer fluctuations (e.g., Denton and Karlén, 1973). Most alpine snows from monsoonal augmentation from moisture glaciers react rapidly to changes in their mass balance and sources in the Indian Ocean. In fact, the largest glaciers thus to changes in temperature and precipitation, and stud- of the Hindu Kush actually occur on the south side of ies of past glacier fluctuations allow reconstruction of cli- the Eastern Hindu Kush of northwest Pakistan where the mate variability on centennial and decadal timescales. 526 HOLOCENE GLACIER FLUCTUATIONS Reconstruction of Holocene glacier fluctuations is Early Holocene advances compromised by the fact that glacier advances in the Evidence for glacier advances prior to the 8.2 ka event is Northern Hemisphere during the last millennium were sparse. A few glaciers in western Canada advanced generally the most extensive of the Holocene and obliter- slightly between 9.5 and 8.5 ka (Koch et al., 2007). Alpine ated or obscured most of the evidence of previous glaciers in western Greenland advanced between 9 and advances. Older moraines have been identified at few of 10 ka (Kelly and Lowell, 2009), and glaciers in Norway the sites that have been investigated (e.g., Ryder and advanced around 9.7 and 9.2 ka, but this evidence has Thomson, 1986; Bakke et al., 2005), but dating control been questioned by more recent interdisciplinary studies of these moraines is often poor. More complete Holocene (Nesje, 2009). Nicolussi and Patzelt (2000) report histories have been inferred from sediments in lakes a short-lived advance in the Austrian Alps about 10.1 ka, downvalley of glaciers (e.g., Karlén, 1988; Bakke et al., while data from the central Swiss Alps indicate smaller 2005), but these records can be complicated by non- than present glaciers about 9.7 ka (Hormes et al., 2001). climatic factors. The most direct evidence for glacier In Tibet glaciers advanced 9.4–8.8 ka, and continental gla- advances that predate the last millennium is found in areas ciers in northwestern China around 9.3 ka (Owen, 2009). deglacierized in the twentieth century. Remnants of forests Glaciers in the Southern Hemisphere appear to have been in these forefields include in situ tree stumps and detrital as extensive or more extensive in the early Holocene than logs and branches. In addition, organic soils and detrital during the past millennium with two advances recorded wood are exposed in composite lateral moraines. High- in the Patagonian Precordillera and New Zealand quality data on Holocene glacier fluctuations have been (Röthlisberger, 1986; Gellatly et al., 1988; Wenzens, retrieved from many of these forefields and moraines 1999). (e.g., Luckman, 2000; Nicolussi and Patzelt 2000; Glasser et al., 2004; Holzhauser et al., 2005; Koch et al., 2007; The 8.2 ka event Barclay et al., 2009). This entry summarizes Holocene glacier fluctuations in Evidence for this event is also sparse. Detrital wood mountainous areas around the world in chronological along with an increase in clastic sediment in proglacial order. The summary benefits from recent regional reviews lakes in the Coast Mountains indicate a minor advance (Barclay et al., 2009; Briner et al., 2009; Geirsdóttir et al., coeval with this event (Menounos et al., 2009). Alpine 2009; Hall, 2009; Ivy-Ochs et al., 2009; Kelly and Lowell, glaciers on Baffin Island advanced (Briner et al., 2009), 2009; Menounos et al., 2009; Nesje, 2009; Owen, 2009; and glacier expansion in Scandinavia was widespread Rodbell et al., 2009). Data presented here cover western (Nesje, 2009), with some glaciers likely more extensive North America, the North Atlantic region (Baffin Island, at this time than during the past millennium. Brief Greenland, Iceland), Europe (Scandinavia, Alps), Asia advances of limited extent occurred in Austria (Nicolussi (Tibet, Himalaya, Tian Shan, Pamir-Alai, Altai, Caucasus, and Patzelt, 2000), but Hormes et al. (2001), argue for Polar Urals, Yakutia, and Kamtchatka), Africa, South less extensive glaciers in the central Swiss Alps. Glaciers America, New Zealand, and Antarctica. Chronological advanced in the Himalaya and Karakoram (Owen, 2009), control for most of these studies was provided by dendro- as well as in Kamtchatka (Yamagata et al., 2002). chronology, lichenometry, radiocarbon dating of fossil Moraines well beyond the past millennium extent were wood in moraines, cosmogenic surface exposure dating, deposited in the Patagonian Precordillera (Wenzens, proglacial lake sediments, tephras, and radiocarbon dating 1999) and near the Northern Patagonian Icefield of basal organics in pits, bogs, and lakes that provide min- (Rodbell et al., 2009). imum limiting ages. 7.3–5.9 ka events Evidence for these events is widespread in both hemi- Global Holocene glacier fluctuations spheres. Glaciers in the Coast and Rocky Mountains in There is evidence for broadly synchronous periods of gla- western Canada advanced during this time (Menounos cier advance around the world at 8.6–8.1, 7.3–5.9, et al., 2009), and the data indicates that glaciers advanced 5.1–4.2, 4.2–1.9, 1.9–0.9 ka (ka is used here instead of two or three times and reached positions within 1 km of cal.