SISSVoc Default

chalk

http://resource.geosciml.org/classifier/cgi/lithology/chalk

definition 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. more like this
source http://en.wikipedia.org/wiki/Chalk; C.S. Harris, 2009, unpublished web page, http://www.geologyshop.co.uk/chalk.htm more like this
type
Resource original
Concept original
broader
http://resource.geosciml.org/classifier/cgi/lithology/limestone original
narrower chalk original
in scheme simplelithology original
is primary topic of chalk