The Quaternary glacial history of the Zanskar Range, north-west Indian Himalaya

Three glacial Stages and a minor advance are recognised from the Zanskar ra nge of the north-western Indian Himalaya. A glaciated palaeosurface > 280 m above river level (a.r.l.) with associated erratics represents the oldest and most extensive glaciation, the Chandra Stage. This ice covered a landsc ape of broad, gentle valleys probably as an ice-cap with an erratic distrib ution indicating that the ice-shed lay to the south over the High Himalaya. A change in valley form from broad glacial troughs to narrow V-shaped gorg es along with large subdued moraine ridges delimits a separate later extens ive valley glaciation, the Batal Stage, with its maximum at similar to 78.0 +/- 12.3 ka BP. Distinct sets of moraine ridges represent a less extensive younger glaciation, the Kulti Stage, which dates close to the global Last Glacial Maximum. A minor advance, the Sonapani, is represented by sharp cre sted moraine ridges within 2 km of current ice bodies, possibly belonging t o the Little Ice Age. Glacier Elevation Indexes (GEIs) calculated for this and adjacent areas, show a rise in elevation from the south-west to the nor th-east, but dip again to the Indus valley for both the Batal and Kulti Sta ges, reflecting attenuation of the south-westerly monsoon and possible chan nelling of westerly depressions along the broad upper Indus valley. GEI dep ression are similar to 500 and similar to 300 m for the Batal and Kulti Sta ges, respectively. The change in extent and style from the Chandra Stage to the later glaciations may be related to uplift of more southerly ranges bl ocking monsoon precipitation and incision of the landscape such that ice re ached lower altitudes over shorter horizontal distances. Why ice extent was greater during Oxygen Isotope Stage (OIS) 4 than 2 is not clear, although recent high-resolution plaeomonsoon records show complex peaks in monsoon i ntensity, and it is possible that there was a more favourable combination o f precipitation and temperature earlier rather than later during the list g laciation. (C) 2000 Elsevier Science Ltd and INQUA. All rights reserved.