The path of an esker is governed by its water pressure in relation to the overlying ice.

As the snow and ice thicken it reaches a point where it begins to move due to a combination of gravity and pressure of the overlying snow and ice.

The consolidation of snow to ice necessary to trap the air takes place at depth ( the ' trapping depth ') once the pressure of overlying snow is great enough.

Since air can freely diffuse from the overlying atmosphere throughout the upper unconsolidated layer ( the ' firn '), trapped air is younger than the ice surrounding it.

A pocket of liquid water, which would normally evaporate instantly in the thin Martian atmosphere, is trapped around them by the overlying ice.

The overlying terrestrial sediments consist of an ice complex composed of ice-rich wind-blown silt in which ice wedges have developed.

The area had been protected by the overlying ice sheet from debris and sediment which was seen to be building up on the white microbial mats after the breakup of the ice sheet.

It requires a water supply to keep feeding the ice crystal growth ; and the growing ice is restrained by overlying soil, which applies a load that limits its vertical growth and promotes the formation of a lens-shaped area of ice within the soil.

Most people do not count it as the lowest point on land, since the overlying ice sheet makes it essentially subterranean.

During the eruption, the heat of the lava from the subglacial volcano melts the overlying ice.

The leaching of minerals from pumice gravel, soils, and overlying rock provides for deposition of secondary speleothems in lava tubes.

This part of the tongue is relatively dry and poorly cleansed, and the convoluted microbial structure of the tongue dorsum provides an ideal habitat for anaerobic bacteria, which flourish under a continually-forming tongue coating of food debris, dead epithelial cells, postnasal drip and overlying bacteria, living and dead.

* The connective tissue layer provides the blood vessels and nerves for the overlying secretory cells, and also serves as the binding layer which allows the whole serous membrane to adhere to organs and other structures.

The more the denture base ( pink material ) runs in smooth and continuous contact with the edentulous ridge ( the hill upon which the teeth used to reside, but now consists of only residual alveolar bone with overlying mucosa ), the better the stability.

In some locations, the Eemian lake deposits are thicker and laterally continuous enough to form a complete blanket overlying older sediments.

The fold fuses, forming a cylinder -- the neural tube -- and a continuous overlying layer of epidermal ectoderm.

Cuvier's claim that new fossil forms appear abruptly in the geological record and then continue without alteration in overlying strata was used by later thinkers to support creationism.

Marker horizons consist of a mineral such as feldspar that is buried at a known depth within wetland substrates to record the increase in overlying substrate over long time periods.

The temperature of the core is approximately 1, 000 degrees Celsius higher than that of the overlying mantle.

A total of 7, 000 feet ( 2, 100 m ) of overlying Mesozoic and Tertiary sediment has been removed by erosion in the area.

It is area of young rock ( less than 10. 000 years ), overlying the older pyroclasts of the Caldeira Formation, and includes two historical eruptions ( the 1672 Cabeço do Fogo and 1957 Capelinhos eruptions ).

Calcite deposits overlying the bone-bearing sediments have been dated as 121, 000 ± 4000 yr BP using uranium-thorium dating, confirming that the material dates from the Ipswichian interglacial.

In stars of more than approximately 0. 5 solar mass, electron degeneracy pressure may delay helium fusion for millions or tens of millions of years ; in more massive stars, the combined weight of the helium core and the overlying layers means that such pressure is not sufficient to delay the process significantly.

Over the last several million years, much of the overlying sediment has eroded away, bringing the sandstone layer with its seams of coal to the surface again in the Tongue River area.

After ten miles of overlying material was eroded over the last 70 million years, these intrusions became visible throughout the Sierra Nevada.

Image: EdwardsDisconformity. jpg | Disconformity with the Lower Cretaceous Edwards Formation overlying a Lower Permian limestone ; hiatus is about 165 million years ; Texas.

Eventually, over millions of years, the salt will pierce and break through the overlying sediment, first as a dome-shaped and then a mushroom-shaped-fully formed salt diapir.

Hot and semi-plastic rock deep below western North America responded to the lack of compression beginning 30 million years ago by slowly rising ; gradually pushing the overlying rock sideways both east and west.

Bore samples of sediments overlying the crater contain fossils dating from the Paleocene epoch, 65 to 54. 8 million years ago.

Post-crater erosion removed the ejecta, except for that overlying the graben, and lowered the regional ground surface less than 30 m. Within a few million years of the cratering event the entire structure was covered with shale deposits from the early Late Devonian Chattanooga Sea, creating one of the best-preserved ancient impact structures presently known.

The Paasselkä impact occurred about 229 million years ago ( Triassic ) and affected Paleoproterozoic crystalline rocks and some overlying sandstones of the Baltic Shield.

At least 55 or 60 million years elapsed between the crystallization of the last Mesozoic magma bodies and deposition of the youngest-preserved overlying strata.

Over the last several million years, much of the overlying sediment has eroded away, leaving the coal seams near the surface.

Over the next billion years, the now cooled granite was gradually exposed through erosion of overlying rocks.

Stochastic models of such repeating cycles following intermittent reincorporation into molecular clouds to rebuild the overlying shell mass for the grains demonstrate that the refractory grain cores have a much longer mean lifetime against destruction that does the grain mass ; viz for cores M /( dM / dt )= 3x10 < sup > 9 </ sup > years, about tenfold longer on average.

Disconformity with the Lower Cretaceous Edwards Formation overlying a Lower Permian limestone ; hiatus is about 165 million years ; Texas.

Paleomagnetic data indicates an age range of around 22 to 17 or 18 million years, with its base in the Oligocene, and its upper boundary, where it meets the overlying Vihowa Formation, of earliest Miocene.

Millions of years of erosion stripped away the overlying rock and left remnants of the arching folds in outcrops such as Seneca Rocks.

Exhumation of the granite body probably occurred mostly by erosion of overlying rocks over tens of millions of years, with glacial erosion processes dominating exhumation over the last 2. 5 million years.

Murchison thus took the Ludlow Bone Bed as the base of his Devonian Period, although over a century later this boundary was to be moved a little higher, the overlying rocks being ascribed to the Pridoli.

Seismic waves pass relatively slowly through the asthenosphere compared to the overlying lithospheric mantle, thus it has been called the low-velocity zone ( LVZ ), although the two are not exactly the same.

The rim of this crater is nearly circular with no overlying craters of note, although a small crater abuts against the northeastern side and another along the southern inner wall.