Clay Pebbles in Providence Canyon, Georgia

September 04, 2019

Clay Pebbles collage_small (1)Photographer: Amy Stander 
Summary Author: Amy Stander 

The photos above showing colorful pebbles were taken at Providence Canyon (Little Grand Canyon) in Georgia. See the Earth Science Picture of the Day for August 8, 2019. These white, red, and yellow pebbles are chunks of clay weathered from the canyon walls. At the bottom of the canyons, a seasonal stream is often filled with eroded sand and clay sediments. Different layers of clay pebbles indicate higher water flow rates from large precipitation events and increased lateral (canyon wall) erosion.

The various colors represent different elements present in the sand and clay. For instance, purple is caused by manganese, and tan, buff/yellow, pink, salmon, and red are from varying levels of oxidation (or rusting) of iron as it bonds with oxygen in the groundwater. Note that the hand and foot belong to my 9-year-old niece. Photos taken on March 13, 2019.

Photo Details: Closeup of clay pebbles - Canon EOS Rebel T6 camera; f/5.6; 1/100 second exposure; ISO 100; 55mm; Landscape mode. Clay pebbles and vegetation - Canon EOS Rebel T6 camera; f/6.3; 1/50 second exposure; ISO 100; 28mm; Landscape mode. Close up of white clay pebble - GoPro HERO4 Silver camera; f/2.8; 1/282 second exposure.; ISO 100; 3 mm. GoPro worn on my niece’s head. Photo collage created using Adobe Photoshop.