Calcisiltite
Encyclopedia
Calcisiltite is a type of limestone
that is composed predominately, more than 50 percent, of detrital (transported) silt
-size carbonate
grains. These grains consist either of the silt-size particles of ooids, fragments of fossil shells, fragments of older limestone
s and dolomite
s, intraclasts
, pellets
, other carbonate grains, or some combination of these. Calcisiltite is the carbonate equivalent of a siltstone
. Calcisiltites can accumulate in a wide variety of coastal, lacustrine
, and marine environments. It is typically the product of abrasion and bioerosion
.
The term calcisiltite was not an original part of the calcilutite
, calcarenite
and calcirudite
classification system for limestones, which Grabau proposed in 1903. Instead, the term calcisiltite was created by Kay in 1951 for limestone consisting predominantly of detrital silt-size, 0.062 to 0.002 mm, grains. As a result, calcisiltite is equivalent to the coarser part of "calcilutite" as it was originally proposed by Grabau and as calcilutite is normally defined and used by geologists. Calcisiltite is the carbonate equivalent of siltstone
.
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
that is composed predominately, more than 50 percent, of detrital (transported) silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
-size carbonate
Carbonate rock
Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite and dolostone, which is composed of the mineral dolomite .Calcite can be either dissolved by groundwater or precipitated by...
grains. These grains consist either of the silt-size particles of ooids, fragments of fossil shells, fragments of older limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
s and dolomite
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
s, intraclasts
Intraclasts
Intraclasts are irregularly-shaped grains that form by syndepositional erosion of partially lithified sediment.Gravel grade material is generally composed of whole disarticulated or broken skeletal fragments together with sand grade material of whole, disaggregated and broken skeletal debris...
, pellets
Pellets (petrology)
Pellets are small spherical to ovoid or rod-shaped grains that are common component of many limestones. They are typically 0.03 to 0.3 mm long and composed of carbonate mud . Their most common size is 0.04 to 0.08 mm. Pellets typically lack any internal structure and are remarkably uniform in size...
, other carbonate grains, or some combination of these. Calcisiltite is the carbonate equivalent of a siltstone
Siltstone
Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystones.- Description :As its name implies, it is primarily composed of silt sized particles, defined as grains 1/16 - 1/256 mm or 4 to 8 on the Krumbein phi scale...
. Calcisiltites can accumulate in a wide variety of coastal, lacustrine
Lacustrine
Lacustrine means "of a lake" or "relating to a lake".Specifically, it may refer to:*Lacustrine plain*Lacustrine delta-Fish:*Lacustrine goby , a type of small fish found in Philippine waters belonging to the Gobiidae family, known in Tagalog as dulong-See also:*Fluvial - of or relating a...
, and marine environments. It is typically the product of abrasion and bioerosion
Bioerosion
Bioerosion describes the erosion of hard ocean substrates – and less often terrestrial substrates – by living organisms. Marine bioerosion can be caused by mollusks, polychaete worms, phoronids, sponges, crustaceans, echinoids, and fish; it can occur on coastlines, on coral reefs, and...
.
The term calcisiltite was not an original part of the calcilutite
Calcilutite
Calcilutite is a type of limestone that is composed of predominately, more than 50 percent, of either clay-size or both silt-size and clay-size detrital carbonate grains. These grains consist either of fossil fragments, ooids, intraclasts, pellets, other grains, or some combination of them...
, calcarenite
Calcarenite
thumb|250px|The [[Pietra di Bismantova]] in central [[Italy]] is an example of calcarenite formation.Calcarenite is a type of limestone that is composed predominately, more than 50 percent, of detrital sand-size , carbonate grains...
and calcirudite
Calcirudite
Calcirudite is a type of limestone that is composed predominately, more than 50 percent, of carbonate grains that are larger in size than sand . The grains can consist of either fragments of fossils, fragments of older limestones and dolomites, other carbonate grains, or some combination of these...
classification system for limestones, which Grabau proposed in 1903. Instead, the term calcisiltite was created by Kay in 1951 for limestone consisting predominantly of detrital silt-size, 0.062 to 0.002 mm, grains. As a result, calcisiltite is equivalent to the coarser part of "calcilutite" as it was originally proposed by Grabau and as calcilutite is normally defined and used by geologists. Calcisiltite is the carbonate equivalent of siltstone
Siltstone
Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystones.- Description :As its name implies, it is primarily composed of silt sized particles, defined as grains 1/16 - 1/256 mm or 4 to 8 on the Krumbein phi scale...
.