Contrary to gravels and sands, clays show high natural radioactivity values: 100 200 API (American Petroleum Institute units).
The sedimentary region is mainly sandstones, silts, gravelly sands, clays, and shale which are porous enough to be producible aquifers.
The Recent formations comprising mainly sands, clays and gravels are confined to major drainage courses in the district.
The section, a mixture of sands, clays, and silts that were deposited in a shallow offshore sea, is thought to span the PETM carbon injection period.
The valleys and coastal plains are covered with deposits of sand, clay, and fertile alluvium.
The metal is found combined in practically all rocks, sand, clay, and other soils.
Other resources extracted in the area include limestone, sand, clay, and gravel.
Centuries ago, the Indians of the Southwest used a mix of sand, clay, straw and water to make adobe homes.
Australian suburban backyards of every demographic stripe had one, or had one within reach: grass, sand, clay, sometimes concrete.
Made of sand, clay, dirt and, in some cases, unknown materials, some levees guard towns, others protect farm fields.
