Explore Geology
geology fieldnotes title

Bering Land Bridge

National Preserve


cover of park brochure

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Tors at Bering Land Bridge
Bering Land Bridge, Alaska

The park contains extensive lava flows and ash and steam explosion craters now turned to lakes called maars. It also offers dynamic coast and beach environments of barrier islands and low sand dunes. Granite tors stand as craggy testimony to past volcanism at Serpentine Hot Springs. Today's hot springs reveal the continuing presence of substantial geothermal energy in this area.

Continental Glaciation
Grasping the magnitude of Ice Age glaciation is possible today only on Earth's two extant polar glacial map ice sheets in Greenland and Antarctica. During the final Ice Age push - the Wisconsinan glacial period (illustrated at left) - vast ice sheets up to nearly two miles thick burdened much of North America. Because the amount of water in the Earth's hydrosphere is constant, the great ice sheets' hoarding of global waters caused sea levels to fall significantly. As a result, land masses grew dramatically where continental shelves slope gradually, as they do here in the Bering Strait.

Continental shelves are the shallow submarine plains that border many continents and typically end in steep slopes to an oceanic abyss. Where a wide continental shelf slopes gradually, a small drop in sea level can increase shoreline areas greatly. At Beringia, a sea level drop of approximately 300 feet during the Wisconinan glacial period revealed a relatively flat, low-lying stretch of continental plain linking North America to Asia. Today's 55-mile stretch of sea waters that separates Alaska and Siberia was once dry land. Although popularly known as a "land bridge", this land mass linking Asia and North America was in fact up to 1,000 miles wide, as shown in the map at left.

Sea level now rises an average of one foot per century because global warming is melting the great polar ice masses of the Arctic and Antarctica. The greenhouse effect and loss of stratospheric ozone may have increased the rate of global warming recently. Many clues to this intriguing puzzle about how and when humans first peopled the Americas undoubtedly lie under water now.

20,000 years ago20,000 years ago.
In the four Wisconsinan stages of the Pleistocene Age, Beringia joined Asia and North America. Most of the Aleutian island chain became a peninsula and with its islands also nearly linked the continents. As glaciers fluctuated, much of Beringia - even inland of today’s Alaska coast - often stood free of ice and would have been habitable by humans.

Some 150 U.S. citizens live just three miles from Russia. They are the mostly Inupiat Eskimo residents of Little Diomede Island in the Bering Strait. From Alaska's Seward Peninsula it is just 25 miles to Little Diomede and from there only three miles to Big Diomede Island, Russia, and then 28 miles on to Siberia. The US / Russia fishing boundary is also the International Date Line.

park maps subheading

The General park map handed out at the visitor center is available on the park's map webpage.

For information about topographic maps, geologic maps, and geologic data sets, please see the geologic maps page.

photo album subheading

A geology photo album has not been prepared for this park.

For information on other photo collections featuring National Park geology, please see the Image Sources page.

books, videos, cds subheading

Currently, we do not have a listing for a park-specific geoscience book. The park's geology may be described in regional or state geology texts.

Please visit the Geology Books and Media webpage for additional sources such as text books, theme books, CD ROMs, and technical reports.

Parks and Plates: The Geology of Our National Parks, Monuments & Seashores.
Lillie, Robert J., 2005.
W.W. Norton and Company.
ISBN 0-393-92407-6
9" x 10.75", paperback, 550 pages, full color throughout

The spectacular geology in our national parks provides the answers to many questions about the Earth. The answers can be appreciated through plate tectonics, an exciting way to understand the ongoing natural processes that sculpt our landscape. Parks and Plates is a visual and scientific voyage of discovery!

Ordering from your National Park Cooperative Associations' bookstores helps to support programs in the parks. Please visit the bookstore locator for park books and much more.

geologic research subheading


For information about permits that are required for conducting geologic research activities in National Parks, see the Permits Information page.

The NPS maintains a searchable data base of research needs that have been identified by parks.

A bibliography of geologic references is being prepared for each park through the Geologic Resources Evaluation Program (GRE). Please see the GRE website for more information and contacts.

selected links subheading

NPS Geology and Soils Partners

NRCS logoAssociation of American State Geologists
NRCS logoGeological Society of America
NRCS logoNatural Resource Conservation Service - Soils
USGS logo U.S. Geological Survey

teacher feature subheading

Currently, we do not have a listing for any park-specific geology education programs or activities.

For resources and information on teaching geology using National Park examples, see the Students & Teachers pages.
updated on 01/04/2005  I   http://www.nature.nps.gov/geology/parks/bela/index.cfm   I  Email: Webmaster
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