Limestone

Limestone (CaCO3) is a sedimentary rock composed of the mineral calcite (calcium carbonate). The primary source of this calcite is most commonly marine organisms. These organisms secrete shells that settle out of the water column and are deposited on ocean floors as pelagic ooze (see lysocline for information on calcite dissolution). Secondary calcite may also be deposited by supersaturated meteoric waters (groundwater that precipitates the material in caves). This produces speleothems such as stalagmites and stalactites. A further form is composed of oolites (Oolitic Limestone) and can be recognised by its granular appearance. Limestone makes up about 10 percent of the total volume of all sedimentary rocks.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Pure limestones are white or almost white. Because of impurities, such as clay, sand, organic remains, iron oxide and other materials, many limestones exhibit different colors, especially on weathered surfaces. Limestone may be crystalline, clastic, granular, or dense, depending on the method of formation. Crystals of calcite, quartz, dolomite or barite may line small cavities in the rock. Chert or Flint nodules are common in limestone layers.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Travertine is a banded, compact variety of limestone formed along streams, particularly where there are waterfalls and around hot or cold springs. Calcium carbonate is deposited where evaporation of the water leaves a solution that is supersaturated with chemical constituents of calcite. Tufa, a porous or cellular variety of travertine, is found near waterfalls.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Limestone is a parent material of Mollisols.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Sedimentary rock: Sedimentary rock is one of the three main rock groups (along with igneous and metamorphic rocks) and is formed in three main ways—by the deposition of the weathered remains of other rocks (known as clastic sedimentary rocks); by the deposition of the results of biogenic activity; and by precip...

Mineral: This article is about minerals in the geologic sense; for nutrient minerals see dietary mineral; for the band see Mineral (band)....

Calcite: The carbonate mineral calcite is a calcium carbonate corresponding to the formula CaCO3 and is one of the most widely distributed minerals on the Earth's surface. It is a common constituent of sedimentary rocks, limestone in particular. It is also the primary mineral in metamorphic marble. It also o...

Limestone related Images and Photos (experimental)

Karst Limestone Tower in Halong Bay Vietnam	Limestone Karst Formations Along the Li River at Yangshu	Limestone Cliffs New Mexico United States of America North America	Halong Bay Karst Limestone Rocks House Boats Vietnam
The Limestone Venus of Willendorf is Commonly Assumed to be a Fertility Symbol	Diving off Limestone Platform into Blue Hole at Bat Cave Gene's Bay Bahamas	Planting Rice with Limestone Karst Mountains in the Background Near Guilin	Punting Boats on Delta River Limestone Mountain Scenery Van Long South of Hanoi
Punting Boats on Delta River Limestone Mountain Scenery Van Long South of Hanoi	Three Pyramids on the Limestone Plateau at Giza 4th Dynasty Old Kingdom	Mayan Laborers Fit and Mortar a Temple's Limestone Blocks