Geology
Did people and dinosaurs live at the same time?
Can you identify my rock or mineral?
How can I tell if I have found an impact crater?
The USGS provides accurate geologic maps and geologic information that forms the critical framework for understanding everything from environmental change to natural hazards.
How old is glacier ice?
The age of the oldest glacier ice in Antarctica may approach 1,000,000 years old The age of the oldest glacier ice in Greenland is more than 100,000 years old The age of the oldest Alaskan glacier ice ever recovered (from a basin between Mt. Bona and Mt. Churchill) is about 30,000 years old. Glacier flow moves newly formed ice through the entire length of a typical Alaskan valley glacier in 100...
Was all of Alaska covered by glaciers during the Pleistocene Ice Age?
No--most of interior Alaska, south of the Brooks Range and north of the Alaska Range, was a non-glaciated grassland refuge habitat for a number of plant and animal species during the maximum Pleistocene glaciation. This ice-free corridor also provided one route for humans to move into North America. Learn more: USGS Water Science School - Glaciers: Things to Know
Do ice worms exist?
Yes, ice worms do, in fact, exist! They are small worms that live in glacial ice in Alaska, Washington, Oregon, and British Columbia; they have not been found in glaciers elsewhere. Contrary to stories and songs, they do not give glacier ice its blue color and they don't grow to lengths of 50 feet. These myths were made popular by poet Robert Service and the annual Cordova Iceworm Festival in...
Is glacier ice a type of rock?
Glacier ice, like limestone (for example), is a type of rock. Glacier ice is actually a mono-mineralic rock (a rock made of only one mineral, like limestone which is composed of the mineral calcite). The mineral ice is the crystalline form of water (H 2 O). Most glacier ice forms through the metamorphism of tens of thousands of individual snowflakes into crystals of glacier ice. Each snow flake is...
Where are glaciers found in continental North America?
Glaciers exist in both the United States and Canada. Most U.S. glaciers are in Alaska; others can be found in Washington, Oregon, California, Montana, Wyoming, Colorado, and Nevada (Wheeler Peak Glacier in Great Basin National Park). Utah’s Timpanogos Glacier is now a rock glacier (in which the ice is hidden by rocks), and Idaho’s Otto Glacier has melted away. Canada has glaciers in Alberta...
Why is glacier ice blue?
Glacier ice is blue because the red (long wavelengths) part of white light is absorbed by ice and the blue (short wavelengths) light is transmitted and scattered. The longer the path light travels in ice, the more blue it appears. Learn more: USGS Water Science School - Glaciers: Things to Know
How much of the Earth's water is stored in glaciers?
About 2.1% of all of Earth's water is frozen in glaciers. 97.2% is in the oceans and inland seas 2.1% is in glaciers 0.6% is in groundwater and soil moisture less than 1% is in the atmosphere less than 1% is in lakes and rivers less than 1% is in all living plants and animals. About three-quarters of Earth's freshwater is stored in glaciers. Therefore, glacier ice is the second largest reservoir...
Where are Earth’s glaciers located?
Glaciers exist on every continent except Australia. Approximate distribution is: 91% in Antarctica 8% in Greenland Less than 0.5% in North America (about 0.1% in Alaska) 0.2% in Asia Less than 0.1% are in South America, Europe, Africa, New Zealand, and Indonesia.
Where on Earth are temperate glaciers located?
A temperate glacier (as opposed to a polar glacier) is a glacier that’s essentially at the melting point, so liquid water coexists with glacier ice. A small change in temperature can have a major impact on temperate glacier melting, area, and volume. Temperate glaciers exist on the continents of North America, South America, Europe, Africa, and Asia; on both islands of New Zealand; and on the...
Is there a size criterion for a glacier?
While there is no global standard for what size a body of ice must be to be considered a glacier, USGS scientists in Glacier National Park use the commonly accepted guideline of 0.1 square kilometers (about 25 acres) as the minimum size of a glacier. Below this size, ice is generally stagnant and does not have enough mass to move. Learn more: Status of Glaciers in Glacier National Park
What is a glacier?
A glacier is a large, perennial accumulation of crystalline ice, snow, rock, sediment, and often liquid water that originates on land and moves down slope under the influence of its own weight and gravity. Typically, glaciers exist and may even form in areas where: mean annual temperatures are close to the freezing point winter precipitation produces significant accumulations of snow temperatures...
Were dinosaurs warm-blooded or cold-blooded?
Scientists have conflicting opinions on this subject. Some paleontologists think that all dinosaurs were 'warm-blooded' in the same sense that modern birds and mammals are: that is, they had rapid metabolic rates. Other scientists think it unlikely that any dinosaur could have had a rapid metabolic rate. Some scientists think that very big dinosaurs could have had warm bodies because of their...