Glaciers moraine

The sample was found in a glacier moraine in Bockfjorden, at an altitude of 30 metres above sea level, and shows an epilithic community on the crust which gives a greyish tonality to the white stone substrate, and a chasmolith inside a crack where several coloured strata, namely pinkish, black, green and brown areas, are visible. 

Stable sea level is characterized by neutral, depositional shorelines that prograde (extend) seaward, often at extremely rapid rates. The sediments are brought by rivers (deltas and estuaries), streams from nearby mountains (alluvial fans), glaciers (morainic outwash), and volcanoes (tephra beds and lava flows). In certain... 

Burt, R. Alexander, E.B. (1996) Soil development on moraines of Mendenhall Glacier, southeast Alaska. 2. Chemical transformations and soil micromorphology. Geoderma 72 19-36... 

Chemical weathering can occur in a number of glacial environments. These include the margins of glaciers (in lateral moraine and in debris covering the sidewall slopes), on top of the glacier, in... 

Most glaciers fluctuate in length as a result of climatic forcing on a variety of timescales. One consequence is that the area in front of the glacier terminus is usually a complex mosaic of moraine and sediment reworked by runoff (Wadham et ai, 2001). This loosely defined proglacial zone may... 

The Elephant Moraine (informal name) in Fig. 17.4 is located at 76°17.58 S and 157°20.082 E about 70 km west of the Allan Hills in southern Victoria Land. This area of the ice sheet is within the drainage basin of the David Glacier which crosses the Transantarctic Mountains north of the latitude of the Elephant Moraine. Accordingly, the ice sheet that underlies the Elephant Moraine is flowing in a northeasterly direction toward the Prince Albert Mountains. 

Fig. 17.4 The supraglacial moraine, known informally as the Elephant Moraine, is located about 70 km northwest of the Allan Hills in a large blue-ice basin of the East Antarctic ice sheet The ice sheet is flowing northeast at this locality into the ice-drainage basin of the David Glacier. The moraine consists of clasts and fine-grained sediment that are released by the ablation of sediment-...

Although these concepts have not been quantified, they support the conjecture that the Elephant Moraine began to form after the ice sheet had thinned sufficiently to cause basal ice to be exposed at the surface. Moreover, the limited length of the moraine (i.e., 5.6 km) indicates that the moraine is not old enough to have reached the David Glacier toward which the ice is moving. Accordingly, the age of Elephant Moraine can be approximated by the relation ... 

The blue-ice areas surrounding the Elephant Moraine are part of the broad ablation belt of the East Antarctic ice sheet located west of the Transantarctic Mountains. In this area the eastward flow of the ice sheet is blocked except for the ice that squeezes through the narrow valleys of the outlet glaciers. Therefore, ablation dominates the glaciological processes that are occurring in this areas and the rate of ablation is an important factor in the mass balance of the ice sheet. 

Fig. 17.39 A highly structured ice-marginal moraine has formed along the Law Glacier at the foot of Mt. Achemar (Section 13.3.1 Figure 13.22). The moraine ridges are ice-cored and the sediment that covers these ice ridges originated by sub-hmation of the underlying ice. Therefore, the moraine ridges...

Development of lateral moraines along the walls of glacial valleys at several different levels above the surface of present glaciers in these valleys Deposits of till in the form of terminal moraines and ground moraines... 

The present low-stand of the East Antarctic ice sheet is indicated by the exposure of aU of the geological features hsted above. For example, cirques that were once the sources of tributary glaciers are now anpty hanging valleys several tens or even hundreds of meters above the bottom of the valley that was once occupied by a valley glacier. Similarly, recessional moraines record the presence of glaciers that have since vanished. These observations have two possible explanations ... 

The Dominion Range in Fig. 19.6, located at the confluence of the Beardmore and Mill glaciers at 85°20 S and 166°30 E, was first visited by members of Robert Scott s and Ernest Shackleton s expeditions on their way to the South Geographyic Pole (Section 1.4). David and Priestley (1914) mentioned that members of Shackleton s party found several small limestone erratics on the summit of Mt. Hope on the western side of the mouth of the Beardmore Glacier and about 8(X) m above the present level of the ice. This observation was later confirmed by Oliver (1963) who reported that a lateral moraine on the northeast slope of Mt. Kyffin at the mouth of the Beardmore Glacier extends to an elevation of about 1,060 m above the present level of the Beardmore Glacier. 

The Mt. Mills Formation which overlies the Meyer Desert Formation may be of early Pleistocene age although it is unfossiliferous and is composed of diamictite, breccia, conglomerate, and sandstone. The sediment of the Mills Formation was eroded by glaciers that subsequently occupied the Beardmore and Mill valleys. These glaciers deposited lateral moraines along the valley walls which constitute the Beardmore drift composed of unconsolidated gravel and till... 

Mercer 1972). These moraines record the former levels of the glaciers in the area, where Beardmore I is the oldest and highest. The different levels of Beardmore drift are distinguished by the extent of weathering of... 

Mayewski (1975) used the elevations of the lateral moraines to project the level of ice in the outlet glaciers to the East Antarctic ice sheet. The resulting ice-sheet reconstruction indicated that during the Queen Maud Glaciation the Transantarctic Mountains were almost completely covered by ice and that the ice sheet along the central divide in East Antarctica was about 350 m thicker than it is at the present time. In addition, the grounding line of the Ross Ice Shelf moved forward to a position 225 km north of the present edge of the ice shelf. 

The Plio/Pleistocene deposits listed in Table 19.6 are lateral moraines associated either with the Taylor Glacier (i.e., Taylor II, III, IV) or with alpine glaciers (i.e., Alpine A, B, C, D). Both types of moraines are composed of boulders and cobbles in a matrix of sand and gravel. The boulders are composed of dolerite (-68%),... 

After the deposition of volcanic ash, the alpine glaciers formed sets of lateral moraines that were originally labeled by CaUdn and Bull (1972) by means of Roman numerals such that IV is the oldest and I is the youngest. 

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