Subsurface Ice

Subsurface Ice

 

ice in the earth’s crust of any origin or mode of occurrence. In terms of time of formation, a distinction is made between modern and fossil ice, and in terms of origin, primary (syngenetic), secondary (epigenetic), and buried ice are distinguished.

Primary subsurface ice is formed during the freezing of accumulating deposits that are loose before freezing. It constitutes a predominant part of subsurface ice and is found primarily in the form of contact, interstitial, and film basal ice cement and, more rarely, in the form of large lenses and bands, known as segregation or injection ice. The formation of the last two types of subsurface ice causes frost heaving on the earth’s surface.

Secondary subsurface ice is the product of the crystallization of water and water vapor in cracks (vein ice) and pores and cavities (honeycomb ice) of solidly frozen rock or already formed rock that is freezing. As a result of the annually recurring filling of frost cracks with ice, reveined ice is formed, occurring in the form of a tetragonal lattice of stratified vertical ice veins. If new sediments accumulate at the same time as ice veins form, the ice veins will gradually grow as the level rises. Such (syngenetic) ice veins grow during the accumulation of freezing sediments to a width of up to 8 m and a height of up to 40–80 m, constituting up to 70 percent of the area of the coastal plains of northern Siberia and Alaska.

Epigenetic recurring ice veins that penetrate frozen loose sediments do not extend to a depth of more than several meters.

Buried ice is formed initially on the earth surface (for example, snowfields, icing, and sea, lake, and river ice) and is later buried beneath sedimentary rock. The largest masses of buried ice are the “dead ice” of glaciers. All buried ice taken together constitutes the smallest portion of subsurface ice.

REFERENCES

Shumskii, P. A. Osnovy strukturnogo ledovedeniia. Moscow, 1955.
Osnovy geokriologii (merzlotovedeniia), part 1. Moscow, 1959.
Dostovalov, B. N., and V. A. Kudriavtsev. Obshchee merzlotovedenie. Moscow, 1967.
References in periodicals archive ?
The scarps directly expose bright glimpses into vast underground ice previously detected with spectrometers on NASA's Mars Odyssey (MRO) orbiter, with ground-penetrating radar instruments on MRO and on the European Space Agency's Mars Express orbiter, and with observations of fresh impact craters that uncover subsurface ice.
These pits may indicate locations where subsurface ice has melted or sublimated from below, causing the ground to collapse.
It might be from subsurface ice, though that shouldn't be buried at such shallow depths near the equator (which is generally where these streaks appear).
The identification of water ice peaks in the second experiment (Figure 3) helps detecting subsurface ice on Mars as in the polar or mid-latitude regions for example (Smith et al.
Shifting pockets of subsurface ice could put more spring into the overlying terrain, eroding the oldest craters.
Last month as Dawn neared Ceres, it relayed images of startlingly bright spots on the surface, which could be patches of subsurface ice exposed after an asteroid or comet impact.
Researchers at the American Geophysical Union meeting Tuesday in San Francisco discussed a range of current Martian activity, from fresh craters offering glimpses of subsurface ice to multi-year patterns in the occurrence of large, regional dust storms.
The craters are found primarily at higher latitudes, a location that correlates with thick, fine-grained sedimentary deposits rich with subsurface ice.
They say it is a thick layer of subsurface ice, amounting to several thousand tonnes of water.
When future astronauts need water on the Moon or Mars, they'll need to go only as far as an outpost where subsurface ice has been pumped out with microwave beams.
Mars is a cold, dry place, although the arctic region under study is believed to hold vast quantities of subsurface ice.
Their heat melted the subsurface ice and liberated huge amounts of water in a very short time.