Ca2++2HCO3−⇌CaCO3↓+CO2↑+H2OCa raised to the 2 plus power plus 2 HCO sub 3 raised to the negative power is in equilibrium with CaCO sub 3 down arrow positive CO sub 2 up arrow positive H sub 2 O The saturation state ( Ωcap omega
Example: A rock composed of fossil fragments cemented by clear sparite is a . If embedded in lime mud, it is a Biomicrite . 6. Diagenesis: From Sediment to Rock
Carbonate sedimentary rocks are formed through a combination of biological and chemical processes. The main sources of carbonate minerals are: origin of carbonate sedimentary rocks pdf extra quality
Precipitated calcium carbonate that fills pore spaces. 2. Depositional Environments and Formation
. It is thermodynamically unstable at standard surface temperatures and pressures relative to calcite. Aragonite incorporates significant amounts of strontium ( Sr2+Sr raised to the 2 plus power Depositional Environments and Formation
Marine autotrophs (algae, cyanobacteria, seagrasses) consume dissolved inorganic carbon, raising the local pH and creating a highly alkaline microenvironment conducive to mineral precipitation. Mineralogical Polymorphs: Aragonite vs. Calcite
High photosynthetic activity removes CO2CO sub 2 , shifting the balance to promote CaCO3CaCO sub 3 precipitation. 3. Mechanisms of Formation: Sedimentary Components carbonates were rare
rather than products of mechanical weathering. They form in a wide range of environments, from freshwater lakes to deep marine systems , and serve as critical archives of Earth's climatic and evolutionary history Creation.com Primary Mechanisms of Formation
Deeply buried basinal brines are heated under high geothermal gradients, overcoming the kinetic barriers of the magnesium hydration shell and facilitating long-term recrystallization.
The precipitation and dissolution of calcium carbonate are governed by a reversible chemical equilibrium controlled by temperature, pressure, salinity, and atmospheric CO2CO sub 2
For most of Earth’s early history, carbonates were rare, muddy precipitates. Then came the (541 million years ago). Life suddenly discovered the advantage of hard parts.