Return to MSSS Home PageGIF-1: Sorted polygon in glacial debris covering floor of Bull Pass in Southern Victoria Land, Antarctica. Located at 77 deg 26.7 min S 161 deg 40.2 min E, at an altitude of 730 m (2460 ft). Both coarse and fine-grained materials can be found in polygonal depressions, and both raised and depressed centers can occur. These polygons have coarse, raised centers, coarse marginal trenches, and coarse-depleted, gently sloping shoulders. Sorted polygons are among a number of enigmatic landforms developed in periglacial environments. A leading explanation for these types of sorted polygons is that the upper regolith in periglacial environments convects, or experiences diapirism, driven either by temperature or density gradients. Photographed 1/15/94 by M. Malin.
GIF-2: Cavernously weathered boulder in the Olympus Range, Southern Victoria Land, Antarctica, at 77 deg 36.2 min S, 160 deg 57.9 min E, at 1578 m (5180 ft). Many granite and dolerite boulders in moderately to old glacial moraines show evidence of cavernous weathering. This form of weathering can develop by either or both of two mechanisms: case hardening and core softening. In the former, silica or other minerals are precipitated into microfractures, strengthening the outer portion of the rock against the attack of other physical and chemical processes. In the latter, water-assisted chemical and physical weathering dis-integrates individual crystal grains from one another, while the rock still maintains its three-dimensional integrity. Attack by wind action and frost or salt wedging eventually cracks the "shell" of these rocks, and the softer interior materials break down and are removed by wind and gravity. Photographed 1/10/94 by M. Malin.
GIF-3: Test rack of basalt chips in Victoria Valley, Southern Victoria Land, Antarctica, at 77 deg 23.9 min S, 161 deg 52.0 min E, at 378 m (1240 ft). This site is investigating the effects of wind-driven sand on natural materials exposed for long periods of time in the cold desert environment. The rocks on the right actually perturb the wind flow sufficiently to modify the amount and nature of abrasion on the lower portions of this rack, but two nearby racks are not similarly affected, which permits the effects on the lower samples to be determined. This site was activated during the 1983-1984 austral summer, and samples have been returned after 1, 5, and now 10 years. Other samples seen on the rack will be returned 15, 20, 30, 40, and 50 years after the initial deployment. The heights of the rock targets were selected to provide good sampling of the lower portion of the boundary layer, where most of the sand is transported. Photographed 1/12/94 by M. Malin.
GIF-4: View to southeast from the north slope of Victoria Valley, towards the eastern portion of the Olympus Range. This location, one of eleven sites at which chemical and physical weathering of rock materials is under study, is at 77 deg 22.0 min S, 161 deg 58.6 min E, at an altitude of 713 m (2340 ft). The light rock on the far mountains is granite; the dark rock cutting that material is dolerite that has intruded through the granite. The boulders in the foreground are dolerite--this site is in material corresponding to the dark unit on the north side of the valley. The light blue in the center left is a portion of Lake Vida, an ice covered, perennially frozen paternoster lake. Photographed 1/14/94 by M. Malin.
GIF-5: View east down the central Wright Valley, Southern Victoria Land, Antarctica. The alpine glaciers feeding into this ice-free valley (one of a very few in Antarctica) are, from left to right, the Goodspeed, Hart, Meserve, and Bartley Glaciers, named after field assistants (graduate students) of Robert Nichols during his pioneering studies of the glacial history of these valleys during the International Geophysical Year and subsequent field seasons. This image clearly shows the classic U-shaped cross section of a glacially-eroded valley. Close inspection also shows that the valley wall is in fact compoundly U shaped, reflecting multiple episodes of glaciation. From his studies during the IGY, Troy Pewe first proposed that these valleys had experienced several episodes of glaciation; this view has been substantiated by many subsequent investigators, and the details have been further amplified by, among others, George Denton, a Professor at the University of Maine who was another of Nichols' assistants. Photographed 1/8/94 by M. Malin.
GIF-6: Penguins are abundant in the McMurdo Sound region. There are major rookeries at Cape Royds, Cape Barne, and Cape Bird on the western shore of Ross Island. This is an Adelie penguins: it is about 40-45 cm tall (16-18 inches). When Adelies see humans, they almost always approach very rapidly, calling in a loud, inquisitive voice (i.e., the pitch of their call rising at the end) "Huh? Huh?" Once they realize that these are humans who don't seem to understand what they're saying, their call begins to sound frustrated, and ultimately, irritated (i.e., the pitch of the sound is flat or lowering): "Huh!!! Huh!!!" Photographed 1/20/94 by M. Malin.
MPEG-1: Malin and his field assistant, Mike Ravine, arrive at Williams Field on the Ross Ice Shelf. After several days of preparation at McMurdo Station on Ross Island, they helicopter west across the Ross Sea to the antarctic mainland, through Taylor Valley, to the test site on Bonney Riegel south of Lake Bonney.
MPEG-2:The Bonney Riegel test site (Site 9) consists of abrasion targets and sand collectors, and artificial rocks set at various locations around the site.
MPEG-3: This short video shows artifically shaped rocks that have been placed on the surface to observe their behavior and weathering over the course of the 50 year study. Each cube, made of native Antarctic granite, is about 8 cm on a side. Visible below each cube is a 2.5 cm diameter, 5 cm long cylinder made of native dolerite. The first cube and cylinder, left fully resting on the surface, have moved from their intial postition by a combination of wind gusts, and substrate erosion (undermining). The cube's shape has clearly influenced this process, but movement of the cylinder, despite its more aerodynamic shape, suggests that shape is not the sole factor governing this motion. The second pair of artifically shaped rocks were half-buried in the sandy substrate. As expected, these have not moved, but material has been moved around them differentially, such that they will likely be partially exhumed and ultimately also move by rotation. This part of the study suggests that, in the absence of other competing processes, and when substrate conditions permit, some rocks experience considerable motion (mostly tumbling) on geologically short timescales. Photographed 1/14/94 by M. Malin.
MPEG-4: This is an aerial view of one of eleven abrasion and weathering test sites in Southern Victoria Land, Antarctica. The site, located at 77 deg 36.2 min S, 160 deg 57.9 min E, at 1578 m (5180 ft) is in the Olympus Range between the Wright and Victoria ice-free valleys. In this sequence, light glints from three 1 m X 1 m X 1 m high aluminum racks can be seen, as well as the white plastic spacers of the 1.7 m tall sand collector assembly. Helicopters provide notoriously bumpy platforms for photography. Photographed 1/10/94 by M. Malin.
MPEG-5: Test racks of rock chips and part of sand collecting apparatus in Victoria Valley, Southern Victoria Land, Antarctica, at 77 deg 23.9 min S, 161 deg 52.0 min E, at 378 m (1240 ft). Part of the central Olympus Range (part of the Transantarctic Mountains) are seen in the background. This site is investigating the effects of wind-driven sand on natural materials exposed for long periods of time in the cold desert environment. The light rock on which the site has been established is the Vida Granite; the horizontal layers of dark rock are portions of the Ferrar Dolerite intruded into the granite. Photographed 1/12/94 by M. Malin.
MPEG-6: View across the central portion of the Victoria Valley, Southern Victoria Land, Antarctica. This scence shows Lake Vida, an ice covered, perennially frozen paternoster lake, centered at approximately 77 deg 23.5 min S, 161 deg 55 min E, at an altitude of 340 m (785 ft). Lake Vida is about 5.5 km long by just under 3 km at it widest. The sandy valley floor is seen east of the lake at the end of this sequence. Photographed 1/10/94 by M. Malin.
MPEG-7: Sorted polygon in glacial debris covering floor of Bull Pass in Southern Victoria Land, Antarctica. Located at 77 deg 26.7 min S 161 deg 40.2 min E, at an altitude of 730 m (2460 ft). Both coarse and fine-grained materials can be found in polygonal depressions, and both raised and depressed centers can occur. These polygons have coarse, raised centers, coarse marginal trenches, and coarse-depleted, gently sloping shoulders. Sorted polygons are among a number of enigmatic landforms developed in periglacial environments. A leading explanation for these types of sorted polygons is that the upper regolith in periglacial environments convects, or experiences diapirism, driven either by temperature or density gradients. Photographed 1/15/94 by M. Malin.
MPEG-8: View of Upper Wright Glacier and AirDevronSix Ice Falls, Wright Valley, Southern Victoria Land, Antarctica. The glacier is located at roughly 77.5 deg S, 160.6 deg E, at an altitude of about 1000 m (3280 ft). This view shows how the present upper glacier is "underfit" (that is, does not fill its valley), and is vestigial to the original glaciers that carved the Wright Valley. At the beginning of the sequence, a portion of the Labyrinth is visible. This set of hills and troughs are carved into a sill of the Ferrar dolerite. Several alternative explanations for these troughs have been offered, including formation by salt weathering and subsequent wind removal of sand-sized particles, proglacial drainage, and sub-glacial drainage. The absence of evidence for large scale crystal wedging in the dolerite, and the absence of a continuous path for water to flow, suggests that the sub-glacial explanation (probably involving water) is correct. Photographed 1/8/94 by M. Malin.
MPEG-9: This view shows the abrasion and weathering test site adjacent to the Allan Hills "blue ice field", near 76 deg 42 min S, 159 deg 24.5 min E, at an altitude of 2000 m (6560 ft). At this site, the experimental objective is to determine if wind-blown ice/snow grains, which are very hard at the low temperatures found on the polar plateau, is capable of abrading rock. Preliminary results suggest that they are: mass loss from abrasion is perhaps an order of magnitude less than in most areas within the ice-free valleys, where sand is abundant, but it is measurable. Photographed 1/20/94 by M. Malin.
MPEG-10: Killer whales are abundant in the southern ocean, and visit McMurdo Sound after the sea ice disrupts in mid-to-late summer. McMurdo Station is on Ross Island, a volcanic island off the coast of, but linked by the permanent ice field of the McMurdo Ice Shelf, to mainland Antarctica. On one of our flights between the station and the ice-free valleys, we stopped along the ice edge to watch the whales and penguins. The ice was only a foot or two thick, but was sufficient to support the helicopter and people walking to the edge of the ice. The whales appeared to be attracted to the location by the noise of the helicopter. A few minutes after we shut down the engines, they left. Photographed 1/20/94 by M. Malin.
MPEG-11: Penguins are even more abundant than Killer whales in the McMurdo Sound region. There are major rookeries at Cape Royds, Cape Barne, and Cape Bird on the western shore of Ross Island. These are Adelie penguins: they stood about 40-45 cm tall (16-18 inches). When Adelie's see humans, they almost always approach very rapidly, calling in a loud, inquisitive (i.e., the pitch of their call rising at the end) voice "Huh? Huh?" Once they realize that these are humans who don't seem to understand what they're saying, their call begins to sound frustrated, and ultimately, irritated (i.e., the pitch of the sound is flat or lowering): "Huh!!! Huh!!!" Photographed 1/20/94 by M. Malin.
MPEG-12: Large gravel ripples in the Allan Hills, Southern Victoria Land, Antarctica, near 76 deg 30 min S, 159 deg E. Viewed looking down from a height of several hundred feet, these large ripples have wavelengths in excess of 5 to 10 m and amplitudes of several tens of cm. They sometimes mimic bedrock undulations; other times they form on essentially flat topography. Particle sizes range up to cobbles, and down to silt, with the majority of the material in the coarse pebble (few cm) range. The best developed ripples will often show coarse bedding or laminations, with imbricated fragments. The matrix is mostly clast supported, and on the whole the material appears ungraded. Several alternative explanations for these ripples have been offered, although none seems to explain all of their attributes. Originally thought to be the result of sub-glacial fluvial processes, they have been variously described as eolian, fluvial, glacial, glaciofluvial, and periglacial. Arguments against eolian and fluvial origins center around the high velocities needed to move such coarse materials by wind (sustained speeds would have had to exceed 240 kph [150 mph]) and the relative angularity of the debris. Arguments against glacial and glaciofluvial processes center on the lack of similar features anywhere else on Earth; there is no known glacial or glaciofluvial process that creates such ripples. Photographed 1/20/94 by M. Malin.
MPEG-13: Sand blowing around glacial debris near the Victoria Valley sand dunes, Southern Victoria Land, Antarctica (77 deg 22.6 min S, 162 deg 10 min E, 380 m or 1250 ft). Sand moves in response to wind gusts in a very non-uniform way. Both in this sequence, and in the other blowing sand sequence, faint brightness fluctuations occur where streamers of sand wiggle across the surface in response to turbulence in the wind flow. To a stationary object, impingement of these "sand snakes" or "sand ghosts" represent intense periods of flux, and are essentially the only time such an object is abraded. However, at any location the amount of time a given cross-sectional area experiences the movement of a ghost is very small. The commonly held view that sand moves in a "saltating curtain" must be modified to include the movement of sand in organized but chaotic form (i.e., in ghosts). Photographed 1/19/94 by M. Malin.
MPEG-14: Sand blowing on ice-impregnated, frozen sand dunes in Victoria Valley, Southern Victoria Land, Antarctica (77 deg 22.6 min S, 162 deg 10 min E, 380 m or 1250 ft). Sand moves in response to wind gusts in a very non-uniform way. Both in this sequence, and in the other blowing sand sequence, faint brightness fluctuations occur where streamers of sand wiggle across the surface in response to turbulence in the wind flow. Here, dark, moist sand acts as a hard substrate across which trails of sand (sand "ghosts" or "snakes") can be seen streaking. Photographed 1/19/94 by M. Malin.
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