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Geomorphology and Flooding
Published in Saeid Eslamian, Faezeh Eslamian, Flood Handbook, 2022
Giovanni Barrocu, Saeid Eslamian
Meltwater, reaching the glacier terminus, also named toe or snout, and flowing out beyond it in meltwater rivers wears out considerable quantities of fluvioglacial material, named outwash. The steep-sided divides between valleys, abandoned by receding glaciers, are often unstable, and landslides and screes border their bottom. The conspicuous mixed sediment deposits, named moraines, visible on and around glaciers, are a source of abundant debris for rain, river, and wind erosion. Glaciers, armed with morainic and other debris, grind down the rocks over which they pass during their slow descent from ice fields and high mountain valleys. Drumlins are large, streamlined elliptical ridges with axes parallel to ice flow, made of soft sediments (tills), also with a bedrock core; their lengths may be over 10–100 m.
Sediments and Sedimentary Rocks
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
When glaciers melt during warm times of the year, streams flow from their tops, bottoms, and sides. These streams carry large sediment loads that include rock flour and lots of coarser material. Eventually this material is deposited as outwash composed of moderately sorted layers of stratified drift, in large outwash plains in front of the glaciers. Seasonal meltwater streams, often braided, are commonly present in outwash plains. The streams deposit coarser materials near their headwaters at the glacier terminus and clays and silts farther away. The largest outwash plains form after some glacial retreat has occurred, so they lie between the present-day glacier terminus and the former terminal moraine. Eventually, a glacier that deposits outwash may disappear, but the distinctive material in the outwash plain is evidence of a glacier’s former presence.
Distributions and light absorption property of water soluble organic carbon in a typical temperate glacier, southeastern Tibetan Plateau
Published in Tellus B: Chemical and Physical Meteorology, 2018
HEWEN NIU, SHICHANG KANG, XIXI LU, XIAOFEI SHI
Surface aged-snow and granular ice samples were collected from different elevations (ranged from 4340 to 4825 m asl) on Baishui glacier mostly in the melt season in 2014. Meltwater of surface snow on glacier was collected along the tributary from the glacier terminus to the upper ablation zone during the extensive melting period. Glacial stream water was collected from miniature streams on glacier surface during the extensive melting season. Two snow pits were excavated on 01 June and 10 June 2014, at the same site with an elevation of 4700 m asl on Baishui glacier. Maximum depth of the two snow pits were 1.6 m (excavated on 01 June) and 1.3 m (excavated on 10 June). Snow pit samples were immediately collected as soon as the pits were excavated, and samples were collected continuously at 10 cm depth intervals from the bottom to the top. Detailed information of sample collection is summarized in Table 1. Air temperature at the glacier surface was measured using a portable temperature transducer. The average temperature at the glacier surface was 0.3 °C on Mt. Yulong, when Baishui glacier has been experiencing extensive ablation.