Browse: Weathering and sediment

Yosemite National Park, California
This granite boulder has fractured due to freeze-thaw weathering in this alpine environment (elevation 8500 feet in the Sierra Nevada).
Shippensburg, Pennsylvania
This boulder is undergoing physical weathering as the growing tree roots enlarge the fracture. Photo taken in 1999.
Shippensburg, Pennsylvania
Notice the fracture has grown substantially by the time of this photo in 2102.
Yosemite National Park, California
Half Dome, a massive exposure of granite towering above Yosemite Valley, has been weathered by exfoliation.
Sequoia National Park, California
This granite exposure has fractured into a set of joints that parallel the surface and is separating into layers due to pressure relief caused by "unloading".
Yosemite National Park, California
Tree roots accelerate the weathering process once the rock has fractured.
coastal California
Tree root growth aids the decomposition of rock. Here, both physical and chemical weathering are breaking down the rock.
  Shippensburg, Pennsylvania
This limestone has been chemical weathered as acidic groundwater has dissolved the calcium-carbonate minerals over long periods of time. The rock was excavated during residential construction and placed in a garden. Note that sinkholes may develop when this type of weathering becomes advanced.
Shippensburg, Pennsylvania
A sinkhole formed in this parking lot a short distance away from the previous photo. The sinkhole was filled with 3 dumptrucks of gravel, which later began to sink into the voids below the surface. Since this photo was taken in 2008 the parking lot was repaved and a new sinkhole opened in the same spot in 2009.
Death Valley, California
Salt - a chemical sediment - is produced by the evaporation of mineral-rich water in this desert basin. This is the lowest elevation (-282 feet) and one of the hottest and driest places in the U.S.
Death Valley, California
Close-up of salt crystals formed by evaporation.
Death Valley, California
Overview of the valley, showing the extent of "evaporite" salt deposits.
Bonaire, Netherlands Antilles
Salt is produced from evaportaing sea water, relying on the natural process that produces "evaporite" minerals. Salt has been produced on this Caribbean island for more than 400 years.
Nebraska Sand Hills
Wind-transported sediments are very well sorted. These sand dunes are nearly 100% sand, with smaller silts and clays blown further downwind.
Boulder, Colorado
Boulder Creek carries large caliber sediment that is fairly well sorted. The clear water indicates very little suspended matter. Larger rocks on the stream bed are stationary in this photo, but move episodically during larger discharge events.
Baja California, Mexico
This dry wash shows the type of sediment that is transported on the river bed. Notice the floodplain deposits on the left are composed largely of cobbles and boulders.
Baja California, Mexico
Downstream from the previous photo, the stream here enters the Pacific Ocean. Gravel sediment deposits accumulate here.
Colorado River, northern Arizona
The Colorado River here carries a sediment load largely consisting of silt and sand.
Buckskin Gulch, southern Utah
These layers of silt were deposited in a low-energy environment by a small tributary to the Colorado River. The color of individual layers of sediment relates to the geology of the original source area of the sediment.
Missouri River floodplain, eastern Missouri
This farm on the Missouri River floodplain was completely buried by sand deposits. Note the earth moving equipment in the lower right of the photo, clearing sand off the fields.
South-central Alaska
Deposits of glacial sediments are usually poorly sorted. Note the mixture of sand, silt, and clay with larger gravel and boulders.