Life at Interfaces: Biocomplexity in Extreme Environments

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Research Location: Alvord Basin (southeast Oregon)

Structural Setting:

photo of the Alvord Basin
Looking east across the Alvord Desert. --photo by T. Jones

The setting for these investigations is the remote and scenic Alvord Basin, located in southeastern Oregon. This sinuous basin stretches roughly 70 miles in a north-south direction and is up to 8 miles wide. Lying in the rainshadow of Steens Mountain, which rises dramatically a vertical mile above the basin floor, the Alvord Basin receives only about 7 inches of rainfall each year.
shaded relief map of the Alvord Basin

Colorized shaded relief map (oblique view) of the Alvord Basin showing locations of major geothermal areas: Borax, Alvord, and Mickey hot springs.
The Alvord Basin is a complex graben (down-dropped fault block) derived from tectonic extension within the northern Great Basin physiographic province of the Western U.S. The basin is bound on the west by Steens Mountain and the Pueblo Mountains, and on the east by the Trout Creek Mountains. Faults within and along the margin of the Alvord Basin are generally steeply dipping (~60°) normal faults that strike north to northeast and cut sequences of Miocene-age volcanic rocks (basalts, rhyolites, and tuffs), as well as Quaternary basin-fill sediments. It is believed that faulting controls the location of major hot spring activity within the Alvord Basin (e.g., Borax Lake, Alvord, and Mickey hot springs).
fault map for the Alvord Basin
Shaded relief map of the Alvord Basin showing fault locations in red.
[Map area is from 118° to 119° W longitude, and from 42° to 43° N latitude.]
Fault data from Walker and McLeod, 1991 (1:500,000 scale).
last update: June 2006 | webmaster: jhinds@uidaho.edu