Geology and Geomorphology of the San Pedro River, Southeastern Arizona

Pearthree, P.A.; Cook, J.P.

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Pearthree, P.A. and Cook, J.P., Geology and Geomorphology of the San Pedro River, Southeastern Arizona. Arizona Geological Survey Special Paper 10, 24 p.

Description

The San Pedro River flows through the rugged landscape of San Pedro Valley from the U.S. – Mexico border to its confluence with the Gila River at Winkelman (Figure 1). The river has incised (downcut) moderately to deeply into the valley floors that were accumulating sediment until the past few million years or less. River incision has in turn driven incision of all of its tributaries and erosion of the surrounding landscape. The inception of river incision resulted in a dramatic narrowing of the extent of river deposits, and this trend has continued to the present. As the river has incised, it has carved an erosional trough in older basin-fill deposits and bedrock, and has left behind remnants of older river deposits (river terraces) that record previous levels of the river. During the Holocene (the past ~10,000 yrs) the river has operated within a relatively narrow corridor bounded by eroded basin deposits, older river terrace deposits, tributary deposits, and bedrock, so all Holocene river deposits are restricted to this corridor. The primary purpose of this paper is to summarize the geologic setting and the geomorphic development and evolution of San Pedro River during the middle and late Quaternary. The latter point is particularly important for understanding the physical setting of Holocene San Pedro River deposits. This work was undertaken to assist Arizona Department of Water Resources staff in their efforts to delineate areas associated with river subflow in the San Pedro River Watershed.

URI

http://hdl.handle.net/10150/629378

Additional Links

https://library.azgs.arizona.edu/

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Series/Report no.

AZGS Special Paper #10

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Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact azgs-info@email.arizona.edu.

North Bounding Coordinate

31.9881

South Bounding Coordinate

31.3429

West Bounding Coordinate

-110.336

East Bounding Coordinate

-109.962

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AZGS Document Repository