# Minerals/Ices

A "polar vortex plunged much of the Midwest into dangerously frigid temperatures. More recently, a furious wind storm has been pummelling eastern Canada and United States, causing flight delays, school cancellations and thousands of power outages. Along the shores of Lake Erie, the gusts were so strong that blocks of ice surged over the shoreline and formed walls as high as 30 feet—a striking phenomenon known as an "ice tsunami"."
"In the lakeside community of Hoover Beach in New York State, the waves of ice crashed into several residential properties, prompting authorities to issue a voluntary evacuation notice."
"Ice tsunamis—also known as “ice shoves” and “ivu,” among other names—are rare, but well-documented events."
Ice "tsunamis were being studied as far back as 1822, when an American naturalist commented on “rocks, on level ground, taking up a gradual line of march [along a lakebed] and overcoming every obstacle in ... escaping the dominion of Neptune.”"
Ice "tsunamis tend to occur when three conditions are in place. The event is most common in springtime, when ice that covers large bodies of water starts to thaw, but has not yet melted. If strong winds then blow through the area, they can push the ice towards the water’s edge—and winds in the Lake Erie region were indeed quite powerful, reaching hurricane-like speeds of up to 74 miles per hour. The third condition is a gently sloping shoreline; the gentler the slope, the less resistance the ice meets as it piles up and pushes inland."
"The first slabs or sheets move on shore, creating a traffic jam, with ice piling on top and behind. With the buildup of ice, and the power behind it, it has the potential to damage anything in its path."

## Theoretical ices

Def. any frozen "volatile chemical, such as water, ammonia, or carbon dioxide" is called an ice.

## Water ices

Blue ice occurs when snow falls on a glacier, is compressed, and becomes part of a glacier. Blue ice was observed in Tasman Glacier, New Zealand in January 2011. Ice is blue for the same reason water is blue: it is a result of an overtone of an oxygen-hydrogen (O-H) bond stretch in water which absorbs light at the red end of the visible spectrum.

## Whites

White is the color of fresh milk and snow. It is the color the human eye sees when it looks at light which contains all the wavelengths of the visible spectrum, at full brightness and without absorption. It does not have any hue.

## Ice streams

On the right is a radarsat image of ice streams flowing into the Filchner-Ronne ice shelf. Annotations outline the Rutford ice stream.

## Ice wedging

A form of mechanical weathering, that is of/related to ice, is frost action (Alternate freezing and thawing of soil and rock). A famous type of frost action is the process of ice wedging.
Ice wedging starts when water seeps into the cracks [in the rocks] and, when the temperature drops to freezing temperatures, freezes. When it freezes, it also expands. The expanding ice pushes against the sides of the crack. This causes the crack to widen, and eventually (when repeated several and several times) breaks the rock apart.

## Earth's First Ice age

During the Paleo-proterozoic Era, the Earth experienced global glaciation. Evidence of this eustatic glaciation lies North of Lake Huron in the form of alternating layers of varved mudstones and tillites that were deposited between 2.6 billion years ago and 2.1 billion years ago and show that glaciers were once present. A varve is a thin sedimentary layer or pair of layers that represent the depositional record of a single year and usually form in glacial meltwater lakes. Tillites are unsorted glacial drift that has been converted into solid rock. The Paleo-proterozic glaciation was most likely the Earth's first ice age.

## Ice sheets

Def. "a dome-shaped mass of glacier ice that covers surrounding terrain and is greater than 50,000 square kilometers (12 million acres)" is called an ice sheet.

## Glaciers

Hypothesis:
* Glaciers occur in every 10° of longitude around the globe and in every 5° of latitude from pole to pole.

## Astroglaciology

Astroglaciology is the observation and interpretation of glacial structures on rocky objects such as Ganymede from above.