USGS - science for a changing world

Pacific Coastal & Marine Science Center

Bedform Sedimentology Site: “Bedforms and Cross-Bedding in Animation”

Cross-Bedding, Bedforms, and Paleocurrents

Photographs

Photo of rock or sand showing pertinent structure or structures; see caption below.

FIG. 39.  Horizontal section through the deposit of a bedform with superimposed longitudinal spurs and scour pits; fluvial deposits, Colorado River, Grand Canyon National Park, Arizona.

RECOGNITION: The trend of the ripples that deposited these rib- and-furrow structures was roughly from left to right, and the ripples migrated toward the top of the photograph.  The two trough-shaped sets in the vicinity of the knife were filled relatively symmetrically and have axes that trend roughly normal to the strike of the somewhat straighter cross-beds at the top of the photograph, characteristics that are indicative of transverse bedforms (as simulated in FIG. 38).  In contrast, two sets of cross-beds (to the left) have been preferentially truncated on their right sides; when systematic, such preferential truncation is more typical of oblique bedforms (FIG. 46).  

 

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://walrus.wr.usgs.gov/seds/bedforms/photo_pages/pic3.html
Page Contact Information: PCMSC Web Team
Page Last Modified: 21 March 2012 (lzt)