John Cletheroe's
USA and Canada Holiday Hints
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Geology in the USA and Canada
Introduction
While a complete study of the geology of the USA and Canada is an immense subject, a little understanding can provide some useful background knowledge during a visit, especially to many of the National Parks, National Monuments and other similar areas.
The geological processes which created the landscape are frequently mentioned and explained in exhibits and displays at the parks. Many of the parks are of course excellent examples of such processes.
A few very basic definitions may be useful. The information on this page is only intended to cover the tip of the tip of the tip of the subject. A book on the subject or the relevant entries in a quality encyclopedia (either traditional or on CD-ROM) will provide much more information for those who are interested.
Erosion
Erosion is the effect of wind, water, frost, ice, temperature changes, plants, etc on rocks.
Examples of erosion over enormous periods of time include the creation of canyons by the rivers flowing through them (such as the Grand Canyon), the creation of caves by water dripping through them, and the creation of mountain landscapes by the advance and retreat of glaciers (such as in Canadian Rockies and Glacier National Park in Montana.
Another example of erosion, common in the western USA, is the wearing down over geological time of a mesa to form a butte, then a spire, which eventually disappears completely.
Geothermal Areas
Those areas of the world where the earth's crust is very thin and boiling mud pools, geysers, fumaroles, hot springs and steam vents occur. Examples include parts of Yellowstone National Park in Wyoming, and areas of Iceland and New Zealand. There are also some other less well known geothermal areas in parts of the western USA.
Igneous Rocks
Igneous rocks are formed when molten rock, called magma, cools and turns solid. The magma may be ejected as lava from a volcano but there are other processes which can bring it to the surface.
Examples of igneous rocks include granite and basalt.
Metamorphic Rocks
Metamorphic rocks are those which have been changed by heat and pressure within the earth's crust.
Examples of metamorphic rocks include slate and marble.
Plate Tectonics
Plate Tectonics, or Continental Drift, is the concept of large areas of the earth's surface moving very slowly over geological time. Earthquakes tend to occur where two of these plates meet - the best known example being the San Andreas Fault in California.
Sedimentary Rocks
Sedimentary rocks are formed from the sediment at the bottom of bodies of water.
Examples of sedimentary rock include sandstone (formed from sand) and limestone (which includes the remains of microscopic organisms which lived in the water).
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As with all the other pages on this personal web site, all the information on this page is solely the opinion of the author, who has no connection whatsoever with any of the companies and organisations mentioned other than as an actual or potential customer.
About this personal web site JohnCletheroe
EMail me While I have an interest in the subject of geology, I am not an expert. Therefore I regrettably cannot offer any information on the subject other than that which appears on these pages.
Most recently modified 12-Mar-04