Rocks

There are 9 entries matching this topic. They are listed below in alphabetical order.

Coal: The first European settlers in Ohio recognized the presence of coal in natural outcrops in stream and river banks in the eastern part of the state. As the industrial revolution began, Ohio’s coal resources became increasingly important. . . .
Concretions: Concretions are solid, rounded masses of mineral matter that occur in sedimentary rock. Concretions have a different composition from the rock in which they are found. . . .
Dolostone: Dolostone, sometimes called dolomite, is similar to limestone in many ways. The most important difference between the two rocks is that the main constituent of dolostone is the mineral dolomite rather than calcite as in limestone. . . .
Ironstone Rocks: Ironstone is a heavy, compact rock containing iron minerals. Typically ironstone is fine-grained and consists of clay and various iron minerals. Also it may contain other minerals such as calcite and quartz. In Ohio, most ironstone occurs in the eastern part of the state. . . .
Major Groups of Rocks: Geologists have named three major groups of rocks on the planet Earth. Within each group a particular source provides parent material for the formation of rocks. And a natural process forms rocks from that parent material. . . .
Ohio's Geologic Periods: The oldest record of Ohio’s geologic history is preserved in igneous and metamorphic rocks of this period. These rocks lie deep beneath the surface of Ohio. . . .
Rocks and Ores: Rock can be defined as a solid body of one or more kinds of minerals. In a few cases, however, rocks may contain material that is not mineral. An example of this is coal, which sometimes contains bits of organic matter. . . .
Sand and Gravel: Sand and gravel deposits are abundant in Ohio and are primarily a result of deposition by running water during the Pleistocene Ice Age. The terms sand and gravel refer to size of the grains of the materials rather than their composition. . . .
Sandstone and Conglomerate: Sandstone and conglomerate are fine-to-medium or coarse-grained rocks, respectively, that represent sand and gravel deposits in which the individual grains are held together by mineral cement. . . .