Cementation is the process of deposition of dissolved
mineralA mineral is a naturally occurring solid formed through geological processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties. A rock, by comparison, is an aggregate of minerals and/or mineraloids, and need not have a specific...
components in the interstices of
sedimentSediment is any particulate matter that can be transported by fluid flow, and which eventually is deposited.Sediments are most often transported by water transported by wind and glaciers...
s. It is the sticking together of sediment to form a new rock and is an important factor in the consolidation of coarse-grained clastic
sedimentary rockSedimentary rock is the type of rock that is formed by sedimentation of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
s such as
sandstoneSandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow,...
s,
conglomerateA conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...
s, or
brecciaBreccia is a rock composed of angular fragments of minerals or rocks in a matrix , that may be similar or different in composition to the fragments. The word is a loan from italian, and in that language indicates both loose gravel and stone made by cemented gravel...
s during
diagenesisIn geology and oceanography, diagenesis is any chemical, physical, or biological change undergone by a sediment after its initial deposition and during and after its lithification, exclusive of surface alteration and metamorphism. These changes happen at relatively low temperatures and pressures...
or
lithificationLithification is the process in which sediments compact under pressure, expel connate fluids, and gradually become solid rock. Essentially, lithification is a process of porosity destruction through compaction and cementation...
.
Cementing materialsThe term cement in geology means the fine-grained minerals which bind the coarser-grained matrix in sedimentary rocks. Such cements are typically composed of calcite, quartz or clay minerals....
may include carbonates,
quartzQuartz is the second most abundant mineral in the Earth's continental crust . It is made up of a continuous framework of SiO
4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO
2.There are many different varieties of...
,
iron oxideIron oxides are chemical compounds composed of iron and oxygen. Altogether, there are sixteen known iron oxides and oxyhydroxides.-Oxides:* FeO, iron oxide, * Fe3O4, iron oxide,...
s, or clay minerals.
Cementation is also continually going on in the
groundwaterGroundwater is water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in...
zone, so much so that the term "zone of cementation" is sometimes used interchangeably.
Cementation is the process of deposition of dissolved
mineralA mineral is a naturally occurring solid formed through geological processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties. A rock, by comparison, is an aggregate of minerals and/or mineraloids, and need not have a specific...
components in the interstices of
sedimentSediment is any particulate matter that can be transported by fluid flow, and which eventually is deposited.Sediments are most often transported by water transported by wind and glaciers...
s. It is the sticking together of sediment to form a new rock and is an important factor in the consolidation of coarse-grained clastic
sedimentary rockSedimentary rock is the type of rock that is formed by sedimentation of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
s such as
sandstoneSandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow,...
s,
conglomerateA conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...
s, or
brecciaBreccia is a rock composed of angular fragments of minerals or rocks in a matrix , that may be similar or different in composition to the fragments. The word is a loan from italian, and in that language indicates both loose gravel and stone made by cemented gravel...
s during
diagenesisIn geology and oceanography, diagenesis is any chemical, physical, or biological change undergone by a sediment after its initial deposition and during and after its lithification, exclusive of surface alteration and metamorphism. These changes happen at relatively low temperatures and pressures...
or
lithificationLithification is the process in which sediments compact under pressure, expel connate fluids, and gradually become solid rock. Essentially, lithification is a process of porosity destruction through compaction and cementation...
.
Cementing materialsThe term cement in geology means the fine-grained minerals which bind the coarser-grained matrix in sedimentary rocks. Such cements are typically composed of calcite, quartz or clay minerals....
may include carbonates,
quartzQuartz is the second most abundant mineral in the Earth's continental crust . It is made up of a continuous framework of SiO
4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO
2.There are many different varieties of...
,
iron oxideIron oxides are chemical compounds composed of iron and oxygen. Altogether, there are sixteen known iron oxides and oxyhydroxides.-Oxides:* FeO, iron oxide, * Fe3O4, iron oxide,...
s, or clay minerals.
Cementation is also continually going on in the
groundwaterGroundwater is water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in...
zone, so much so that the term "zone of cementation" is sometimes used interchangeably. Cementation occurs in fissures or other openings of existing rocks and is a dynamic process more or less in equilibrium with a dissolution or dissolving process.
Types of carbonate cement
BeachrockBeachrocks are created by the rapid cementation of beach sediments in the intertidal zone which leads to the formation of characteristic synsedimentary lithified structures.- Overview :...
is a type of carbonate beach sand that has been cemented together. Beachrock may contain meniscus cements or pendant cements. As the water between the narrow spaces of grains drains from the beachrock, a small portion of it is held back by
capillaryCapillary action, capillarity, capillary motion, or wicking refers to two phenomena:1 The movement of liquids in thin tubes.
2 The flow of liquids through porous media, such as the flow of water through soil....
forces, where meniscus cement will form. Pendant cements form on the bottom of grains where water droplets are held.
Hardgrounds are hard crusts of carbonate material that form on the bottom of the ocean floor, below the tide. Isopachous (which means equal thickness) cement forms in subaqueous conditions where the grains are completely surrounded by water (Boggs, 2006).