Chalk is a soft, white, porous sedimentary carbonate rock, a form of limestone composed of the mineral calcite. It formed under the sea by the accumulation and lithification of the hard parts of organisms, mostly microscopic plankton such as foraminifera and coccolithophores, that had settled to the sea floor. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/
Facts
Formation ClassSedimentary, biochemical (a form of limestone built from the calcite remains of marine plankton such as foraminifera and coccolithophores) 1 Chemical Formula Classification
Classification UseBuilding and Construction 1 UseSoil Amendment or Fertilizer 1 Connections
Associated With
Host rock: chert occurring within chalk is conventionally distinguished by the name flint.
Source Chert (Wikipedia)
Host rock: flint occurs as nodules within chalk.
Source Flint (Wikipedia)
Source Møns Klint (Wikipedia)
Source Niobrara Formation (Wikipedia)
Source Old Harry Rocks (Wikipedia)
Source Wikipedia: Seven Sisters, East Sussex, Wikipedia
Source Wikipedia: White Cliffs of Dover - Wikipedia
Source Wikipedia: White Desert National Park
Caused By
Source Chalk (Wikipedia)
Classified As
In Discipline
Sources
1. Chalk (Wikipedia)
Wikimedia FoundationLead section
tiny fragments of the calcite shells or skeletons of plankton, such as foraminifera or coccolithophores.
Description
Chalk is typically almost pure calcite, CaCO3
Article body
Chalk is mined for use in industry, such as for quicklime, bricks and builder's putty, and in agriculture, for raising pH in soils with high acidity.
Article body, building-and-construction
Chalk is mined for use in industry, such as for quicklime, bricks and builder's putty, and in agriculture, for raising pH in soils with high acidity.
Article body, soil-amendment-or-fertilizer
Chalk is mined for use in industry, such as for quicklime, bricks and builder's putty, and in agriculture, for raising pH in soils with high acidity.
Lead section
Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed under the sea by the accumulation and lithification of hard parts of organisms, mostly microscopic plankton, which had settled to the sea floor.
Caused By: Sedimentation, Lead paragraph
Chalk is a soft, white, porous, sedimentary carbonate rock
View the Source 2. Geology.com: Chalk
Geology.comArticle text
Chalk is usually white or light gray in color.
Article text, colour-category
Chalk is a variety of limestone composed mainly of calcium carbonate derived from the shells of tiny marine animals known as foraminifera and from the calcareous remains of marine algae known as coccoliths. Chalk is usually white or light gray in color.
View the Source Wikidata: Chalk
Wikidata Q183670
Flint (Wikipedia)
Wikimedia FoundationAssociated With: Flint, Lead sectionQuote, Associated With: Flint, Lead section
categorized as the variety of chert that occurs in chalk or marly limestone.
Chert (Wikipedia)
Wikimedia FoundationAssociated With: Chert, Lead section, occurrence sentenceQuote, Associated With: Chert, Lead section, occurrence sentence
Where chert occurs in chalk or marl, it is usually called flint.
Møns Klint (Wikipedia)
Associated With: Mons Klint, Lead paragraphQuote, Associated With: Mons Klint, Lead paragraph
Møns Klint is a 6 km stretch of limestone and chalk cliffs along the eastern coast of the Danish island of Møn in the Baltic Sea, and as of July 2025 a World Heritage Site.
Wikipedia: Seven Sisters, East Sussex, Wikipedia
Associated With: Seven Sisters, England, Lead paragraphQuote, Associated With: Seven Sisters, England, Lead paragraph
The Seven Sisters are a series of chalk sea cliffs on the English Channel coast, and are a stretch of the sea-eroded section of the South Downs range of hills, in the county of East Sussex, in south-east England.
Niobrara Formation (Wikipedia)
Associated With: Niobrara Formation, Lead paragraph
It is composed of two structural units, the Smoky Hill Chalk Member overlying the Fort Hays Limestone Member.
Associated With: Niobrara Formation, Lead, rock Chalk
The Niobrara Formation , also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late Cretaceous.
View the SourceOld Harry Rocks (Wikipedia)
Associated With: Old Harry Rocks, Lead paragraphQuote, Associated With: Old Harry Rocks, Lead paragraph
Old Harry Rocks are three chalk formations, including a stack and a stump, located at Handfast Point, on the Isle of Purbeck in Dorset, southern England.
Cliff (Wikipedia)
Associated With: Cliff, Lead, rock ChalkQuote, Associated With: Cliff, Lead, rock Chalk
The sedimentary rocks that are most likely to form cliffs include sandstone, limestone, chalk, and dolomite.
Rügen (Wikipedia)
Associated With: Rügen, Article text, rock ChalkQuote, Associated With: Rügen, Article text, rock Chalk
The chalk cliffs of the Jasmund peninsula belong to the Rügen Chalk unit and were formed during the Maastrichtian stage of the Late Cretaceous, around 70 million years ago.
Wikipedia: White Cliffs of Dover - Wikipedia
Associated With: White Cliffs of Dover, Lead, rock ChalkQuote, Associated With: White Cliffs of Dover, Lead, rock Chalk
The cliff face, which reaches a height of 350 feet (110 m), owes its striking appearance to its composition of chalk accented by streaks of black flint, deposited during the Late Cretaceous.
Wikipedia: White Desert National Park
Associated With: White Desert, Egypt, Article text, rock ChalkQuote, Associated With: White Desert, Egypt, Article text, rock Chalk
The park is the site of large white chalk rock formations, created through erosion by wind and sand, "one of the most important karst massifs in the Western Desert.
Reader Challenges (0)
No disputes yet. Spotted an error or a better source? Open the first one.
Sign in to dispute this or suggest a correction.