A generally soft, white, very fine-grained, extremely pure, porous limestone. It forms under marine conditions from the gradual accumulation of skeletal elements from minute planktonic green algae (cocoliths), associated with varying proportions of larger microscopic fragments of bivalves, foraminifera and ostracods. It is common to find flint and chert nodules embedded in chalk.
http://en.wikipedia.org/wiki/Chalk; C.S. Harris, 2009, unpublished web page, http://www.geologyshop.co.uk/chalk.htm
Parents: Limestone (156)
[Description taken from GeoSciML SimpleLithology201012.rdf]
Category: Analysed material
The different kinds of sample material collected in the field have been classified hierarchically. Examples: “till”, “soil”, “vegetation”. Taken from the “Sample_Types_SHARED” database table.
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