Central Arizona Phoenix Long Term Ecological Research project: Quaternary geology and geomorphology research component

Supervised by Prof. Ramón Arrowsmith with Sarah Robinson and Steve Holloway and in coordination will Will Graf and his students from the ASU Geography Department

As the population in southwestern cities such as Phoenix, Las Vegas and Tucson grows, housing is creeping out of the flat basin floors that attracted humans hundreds of years ago and moving onto the piedmonts of the surrounding mountain ranges. Intact piedmonts that are both unaltered and easily accessible are becoming increasingly rare and should be studied while they remain intact. There are still many unanswered geologic questions about these environments that will be easier to answer before developments cover this landscape. Research in a landscape targeted for develop allows for the interaction between scientific curiosity and practical societal needs.

Much of our research is conducted in the White Tank Mountains, west of Phoenix, that have served as a natural laboratory to investigate the geologic history, material, and surficial processes in a piedmont analogous to many rapidly developing areas in the desert Southwest. Research has focused on testing the hypothesis that satellite imagery in conjunction with field mapping can aid in identifying flood hazards and using cosmogenic dating to develop an absolute chronology for the area.

While piedmont environments lend themselves well to relative dating, a long-standing challenge for geomorphologists has been to determine numerical ages and refine geologic chronologies. A promising technique to address this need is the measurement of in-situ cosmogenic isotopes. Cosmogenic isotopes will improve the resolution of the geologic history of this area and aid in our understanding of the surface and subsurface processes acting in this environment.

LTER and Globe photo showing the urban fringe

Download 6Mb tiff file (used in Science News and Views)

Images below were prepared by Steve Wood
Landsat 753 image of the Phoenix Basin

Different band combinations of Landsat imagery of the Phoenix Basin

Landsat 432 draped on a 100 m USGS DEM. View from south Tempe toward Phoenix Mtns. McDowell Mtns are in the upper right.

Landsat 752 drape on 100m USGS DEM. View is from south Tempe/Chandler toward the South Mountains and Estrella Mtns with the White Tanks in the far distance on the right. Note differen land types. ASU Research Park is in the lower left (double figure 8 pattern).

Cosmogenic dating project in collaboration with Darryl Grainger of Purdue University and Fred Phillips of New Mexico Tech. PhD. project of Sarah Robinson. 1998 GSA Annual Meeting abstract.
wt maps

Research with Prof. Laura Mussachio from the School of Planning and Landscape Architecture:
To what extent have geological patterns shaped the location and boundaries of the public open space system of Phoenix?

January 17, 2003 field photos and notes
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Prof. Ramón Arrowsmith