Kieselkalk is also known as the Helvetic Siliceous 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....

. It has sedimented during the Lower Cretaceous epoch. It can contain up to 40 % of very fine (1-10 μm), evenly distributed authigenic

Authigenic

An authigenic mineral or sedimentary rock deposit is one that was generated where it is found or observed. Authigenic sedimentary minerals form during sedimentation by precipitation or recrystallization instead of being transported from elsewhere by water or wind. Authigenic sediments are the main...

 quartz

Quartz

Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...

 crystals. Early diagenetic

Diagenesis

In 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...

 dissolution of opal

Opal

Opal is an amorphous form of silica related to quartz, a mineraloid form, not a mineral. 3% to 21% of the total weight is water, but the content is usually between 6% to 10%. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most...

 sponge spicule

Spicule

Spicules are tiny spike-like structures of diverse origin and function found in many organisms, such as the copulatory spicules of certain nematodes or the grains on the skin of some frogs.In sponges, spicules perform a structural function....

s led to silica enrichment of interstitial waters, which reprecipitated silica in the overlying horizons, forming tiny quartz crystals in pore spaces.

Because of its high silica content, the Kieselkalk is much less susceptible to karst

KARST

Kilometer-square Area Radio Synthesis Telescope is a Chinese telescope project to which FAST is a forerunner. KARST is a set of large spherical reflectors on karst landforms, which are bowlshaped limestone sinkholes named after the Kras region in Slovenia and Northern Italy. It will consist of...

ification than the overlying Schrattenkalk. In the Siebenhengste-Hohgant-Höhle

Siebenhengste-Hohgant-Höhle

Siebenhengste-Hohgant-Höhle is a cave located in Switzerland, in the canton of Bern at the north of the Lake of Thun, between the villages of Eriz and Habkern...

 cave system in Switzerland

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

, large galleries, easily developing in the Schrattenkalk, become impenetrable fissures networks when water disappears in the Kieselkalk.

Susceptibility to alkali silica reaction

Siliceous limestones can be very prone to the Alkali Silica Reaction

Alkali Silica Reaction

The alkali–silica reaction is a reaction which occurs over time in concrete between the highly alkaline cement paste and reactive non-crystalline silica, which is found in many common aggregates....

 (ASR) and their use as aggregate

Construction Aggregate

Construction aggregate, or simply "aggregate", is a broad category of coarse particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates. Aggregates are the most mined material in the world...

 is often the cause of premature concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

 degradation and problems in civil engineering (concrete spalling, bridges failure, ...).

See also

• Alkali Silica Reaction
  Alkali Silica Reaction
  The alkali–silica reaction is a reaction which occurs over time in concrete between the highly alkaline cement paste and reactive non-crystalline silica, which is found in many common aggregates....
  
  
• Alkali-aggregate reaction
  Alkali-aggregate reaction
  Alkali–aggregate reaction is a term mainly referring to a reaction which occurs over time in concrete between the highly alkaline cement paste and non-crystalline silicon dioxide, which is found in many common aggregates...
  
  
• 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....
  
  
• Silica
• Siebenhengste-Hohgant-Höhle
  Siebenhengste-Hohgant-Höhle
  Siebenhengste-Hohgant-Höhle is a cave located in Switzerland, in the canton of Bern at the north of the Lake of Thun, between the villages of Eriz and Habkern...