Images

The lower Colorado River supports a verdant delta at the upper end of Lake Havasu, a reservoir on the Arizona-California border. Lake Havasu filled in 1938 following the completion of Parker Dam.

Acidic waters from Cement Creek are discharged in the circum-neutral Animas River near Keystone, Colorado. Mixing of the waters produces colloidal-size iron and aluminum hydroxide precipitates.

Linear tracts and small patches of well rounded and varnished pebbles and cobbles mark the traces of ancient channels, bars, and floodplain terraces of the lower Colorado River.

Deformed sediment of the Bouse Formation in Chemehuevi Valley, California. Complex deformation is a likely consequence of subaqueous mass wasting of part of a growing delta of the Colorado River.

Outcrop of the Bouse Formation in Chemehuevi Valley, Whipple Mountains, Calfornia in background. The Bouse Formation includes sedimentary deposits that chronicle the first arrival of Colorado River water into desert basins downstream from Grand Canyon. The deposits in Chemehuevi Valley are particularly well-exposed.

USGS geologic mappers walkinbg out an intermediate age (likely middle Pleistocene) alluvial fan surface near Broadwell Mesa, in the northern Bristol Mountains, Kelso Dunes Wilderness Area, Mojave Desert, California.

A view west of the western Columbia River Gorge National Scenic Area from near Cascade Locks, Oregon. The toe of the Bonneville landslide is on the right, which blocked the Columbia River about 500 years ago.

Summer flash-floods can introduce large amounts, of fine reddish-orange sediment to the Colorado River with spectacular results

Freshwater tidal marsh of the Columbia River estuary, Cathlamet Bay in foreground, uplifted coastal ranges of the Cascadia forearc of Washington in background.

Union for International Cancer Control (UICC) asbestos chrysotile 'B' standard.

Union for International Cancer Control (UICC) Asbestos Anthophyllite Standard.

Union for International Cancer Control (UICC) asbestos chrysotile 'A' standard.

Union for International Cancer Control (UICC) asbestos crocidolite standard.

Physiographic image of the Pacific Northwest, modified from USGS I-2689 by Haugerud (2004) Physiographic-Cascadia

Cascadia encompasses the volcanoes of the Cascade Range and the subduction zone that feeds them. The region is home to nearly 10 million people. Where and how these people live, work, and play are influenced by the shape, or physiography, of Cascadia. This map is a tool for visualizing and interpreting the physiography of Cascadia.

Oblique orbital view of California looking NNW from above NW Sonora, Mexico, and northern Gulf of California

The south area of the La Honda oil field, California, was discovered during the late 1950s and produced an estimated 595,000 barrels of oil from about 12 wells, including the well in this photo.

Photograph from summit of San Jacinto Peak looking north across San Gorgonio Pass toward San Gorgonio Mountain. San Gorgonio River and Interstate Highway 10 traverse the Pass lowland; the Whitewater River drains the San Bernardino Mountains and flows eastward into the Salton Trough.