What is dolomitization in geology?
Dolomitization is a geological process by which the carbonate mineral dolomite is formed when magnesium ions replace calcium ions in another carbonate mineral, calcite. It is common for this mineral alteration into dolomite to take place due to evaporation of water in the sabkha area.
What causes dolomitization?
dolomitization, process by which limestone is altered into dolomite; when limestone comes into contact with magnesium-rich water, the mineral dolomite, calcium and magnesium carbonate, CaMg(CO3)2, replaces the calcite (calcium carbonate, CaCO3) in the rock, volume for volume.
What is dolomitization porosity?
The dolomitization is a process that dolomite precipitates accompanied by calcite or aragonite dissolution. Therefore, the porosity evolution is ultimately controlled by the difference in rates between dissolution and precipitation (Landes, 1946).
How does dolomitization influence the porosity of a formation?
If a lime mud is dolomitized, the mud will be compacted as the dolomite crystals grow, resulting in a decrease in porosity. Once the dolomite crystals form a space-supporting framework, the rate of compaction will decrease considerably.
Where does dolomitization occur?
Dolomitization occurs in nature or even in untied limestone deposit or in already solid limestone rocks. Dolomites that occur in the untied deposit are called early diagenetic or sin-sedimentary. It also forms by dolomitization of limestone as late-diagenetic or postsedimentary events.
How do I identify a dolostone?
Dolostone is quite similar to limestone, but is composed mostly of the mineral dolomite (CaMg(CO3)2). Both are sedimentary rocks that occur as thin to massive beds of fine- to coarse-grained rock. Their color is typically some shade of gray, but may be white, tan, yellow, pink, purple, reddish brown, brown, or black.
What kind of rock is dolomite?
sedimentary carbonate rock
Dolomite is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally CaMg(CO3)2. The term is also used for a sedimentary carbonate rock composed mostly of the mineral dolomite. An alternative name sometimes used for the dolomitic rock type is dolostone. Dolomite is an unusual carbonate mineral.
Does dolomitization increase porosity?
If a lime mud is dolomitized, the mud will be compacted as the dolomite crystals grow, resulting in a decrease in porosity. Replacement of the remaining mud will then lead to a marked increase in permeability and may also result in a porosity increase.
Where does dolomitization take place?
limestone
Dolomitization occurs in nature or even in untied limestone deposit or in already solid limestone rocks. Dolomites that occur in the untied deposit are called early diagenetic or sin-sedimentary. It also forms by dolomitization of limestone as late-diagenetic or postsedimentary events.
What type of rock is mudstone?
mudstone, sedimentary rock composed primarily of clay- or silt-sized particles (less than 0.063 mm [0.0025 inch] in diameter); it is not laminated or easily split into thin layers.
How old is dolomite?
about 250 millions years old
The Dolomites are about 250 millions years old and are composed mainly of sedimentary rocks and limestone. Today, we can hardly imagine that once the mighty mountains were an enormous coral reef, formed in the primordial ocean called Tethys.
What is the difference between limestone and dolostone?
What is the difference between Limestone and Dolomite? Limestone is a calcium carbonate mineral whereas dolomite is made of calcium magnesium carbonate. Sand, clay and silt are commonly found in limestone as impurities but not quite common in dolomite.
