Ideal marine carbonate production occurs at standard marine salinities (35–38 psu). Extreme hypersalinity or freshwater influx restricts biological diversity, shifting deposition to specialized microbialites or purely abiotic evaporitic carbonates.
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
| Environment | Characteristics | |---|---| | | Gently sloping continental margin (slope <1°); in direct communication with open ocean or bounded by reefs/shoals | | Rimmed Platform | A nearly horizontal shallow marine environment surrounded by marine waters, bounded by a reef or shoal barrier | | Lagoon | Restricted body of water between mainland and reef/shoal barrier; oxygen/salinity stress typical; low energy | | Peritidal | Tidally influenced areas including subtidal, intertidal, and supratidal zones | | Reef | In situ accumulation of wave-resistant organisms; forms on platform, ramp, or shelf margins | | Basin | Deep marine environment well below storm wave base; dominated by suspension deposition |
Origin of Carbonate Sedimentary Rocks: An In-Depth Geological Overview origin of carbonate sedimentary rocks pdf extra quality
Marked by rising temperatures and lithostatic pressure. Mechanical compaction crushes fragile shells, followed by chemical compaction (pressure solution) that forms jagged, clay-concentrated seams called stylolites . The Dolomitization Enigma Dolomite [ CaMg(CO3)2CaMg(CO sub 3 close paren sub 2
These resources provide a comprehensive overview of the origin, characteristics, and formation processes of carbonate sedimentary rocks.
End of article. For direct assistance in locating a specific "extra quality" PDF on the origin of carbonate sedimentary rocks, please provide the author or title of the work you are seeking. Ideal marine carbonate production occurs at standard marine
represent the concentrations of dissolved calcium and carbonate ions in seawater. Ksp′cap K sub s p end-sub prime
), extracting calcium ions and elevating the residual brine's Mg/CaMg/Ca ratio to drive downward dolomitization.
Once deposited, primary carbonate sediments are highly reactive. Diagenesis encompasses all chemical, physical, and biological changes that alter the sediment from the moment of deposition until the onset of low-grade metamorphism. If embedded in lime mud, it is a Biomicrite
Ca2++2HCO3−⇌CaCO3↓+H2O+CO2↑Ca 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 H sub 2 O plus CO sub 2 up arrow Any process that drives the removal of carbon dioxide ( CO2CO sub 2
Several factors control the formation of carbonate sedimentary rocks, including:
Dunham’s system focuses on depositional texture and the presence or absence of lime mud, which indicates the relative energy of the environment: Classification Textural Characteristics Mud-supported fabric; contains less than 10% grains. Wackestone Mud-supported fabric; contains more than 10% grains. Packstone Grain-supported fabric; contains intergranular lime mud. Grainstone Grain-supported fabric; lacks matrix lime mud entirely. Boundstone