Here's a breakdown:
* Clastic: Rocks formed from fragments (clasts) of other rocks, like sandstone, shale, and conglomerate.
* Nonclastic: Rocks formed by chemical precipitation or biological processes, like limestone, rock salt, coal, and chert.
Characteristics of Nonclastic Rocks:
* Crystalline structure: They have a crystalline structure, meaning their minerals are arranged in a specific, repeating pattern.
* Chemical composition: Their formation is primarily driven by chemical reactions or biological activity.
* Absence of clasts: They lack the characteristic fragments or grains found in clastic rocks.
Examples of Nonclastic Rocks:
* Limestone: Formed by the accumulation of marine organisms' shells and skeletons.
* Rock salt: Formed by the evaporation of saltwater.
* Coal: Formed from the accumulation of plant matter over millions of years.
* Chert: Formed by the precipitation of silica from water.
In contrast to clastic rocks, which are defined by their grain size and composition, nonclastic rocks are defined by their chemical and/or biological origins.