Evaporites are sedimentary rocks that form when water evaporates from an aqueous solution, leaving behind mineral deposits. There are two types: marine evaporites, which form from ocean water, and non-marine evaporites, which form from inland bodies of water. Minerals precipitate from solution in reverse order of solubility as the water evaporates. Common evaporite minerals include halite, gypsum, and anhydrite. Evaporites are economically important as sources of minerals and because some formations can trap oil and gas deposits.

1. Evaporite 1
Evaporite
Evaporite (pron.: /ɪˈvæpəraɪt/) is a name for a water-soluble mineral
sediment that result from concentration and crystallization by
evaporation from an aqueous solution.[1] There are two types of
evaporate deposits: marine, which can also be described as ocean
deposits, and non-marine, which are found in standing bodies of water
such as lakes. Evaporites are considered sedimentary rocks.
Formation of evaporite rocks
Although all water bodies on the surface and in aquifers contain
dissolved salts, the water must evaporate into the atmosphere for the Cobble encrusted with halite evaporated from the
minerals to precipitate. For this to happen, the water body must enter a Dead Sea, Israel.
restricted environment where water input into this environment
remains below the net rate of evaporation. This is usually an arid environment with a small basin fed by a limited
input of water. When evaporation occurs, the remaining water is enriched in salts, and they precipitate when the
water becomes oversaturated.
Evaporite depositional environments
Marine evaporites
Marine evaporites tend to have thicker deposits and are usually the
focus of more extensive research.[2] They also have a system of
evaporation. When scientists evaporate ocean water in a
laboratory, the minerals are deposited in a defined order that was
first demonstrated by Usiglio in 1884.[2] The first phase of the
experiment begins when about 50% of the original water depth
remains. At this point, minor carbonates begin to form.[2] The next
phase in the sequence comes when the experiment is left with
about 20% of its original level. At this point, the mineral gypsum
begins to form, which is then followed by halite at 10%,[2]
excluding carbonate minerals that tend not to be evaporates. The
most common minerals that are generally considered to be the
most representative of marine evaporates are calcite, gypsum and
anhydrite, halite, sylvite, carnallite, langbeinite, polyhalite, and Anhydrite
kanite. Kieserite (MgSO4) may also be included, which often will
make up less than four percent of the overall content.[2] However, there are approximately 80 different minerals that
have been reported found in evaporite deposits (Stewart,1963;Warren,1999), though only about a dozen are common
enough to be considered important rock formers.[2]

2. Evaporite 2
Non-marine evaporites
Non-marine evaporites are usually composed of minerals that are not common in marine environments, because in
general the water from which non-marine evaporite precipitates have proportions of chemical elements different
from those found in the marine environments.[2] Common minerals that are found in these deposits include blödite,
borax, epsomite, gaylussite, glauberite, mirabilite, thenardite and trona. Non-marine deposits may also contain halite,
gypsum, and anhydrite, and may in some cases even be dominated by these minerals, although they did not come
from ocean deposits. This, however, does not make non-marine deposits any less important; these deposits often help
to paint a picture into past Earth climates. Some particular deposits even show important tectonic and climatic
changes. These deposits also may contain important minerals that help in today's economy.[3] Thick non-marine
deposits that accumulate tend to form where evaporation rates will exceed the inflow rate, and where there is
sufficient soluble supplies. The inflow also has to occur in a closed basin, or one with restricted outflow, so that the
sediment has time to pool and form in a lake or other standing body of water.[3] Primary examples of this are called
"saline lake deposits".[3] Saline lakes includes things such as perennial lakes, which are lakes that are there
year-round, playa lakes, which are lakes that appear only during certain seasons, or any other terms that are used to
define places that hold standing bodies of water intermittently or year-round. Examples of modern non-marine
depositional environments include the Great Salt Lake in Utah and the Dead Sea, which lies between Jordan and
Israel.
Evaporite depositional environments that meet the above conditions include:
• Graben areas and half-grabens within continental rift environments fed by limited riverine drainage, usually in
subtropical or tropical environments
• Example environments at the present that match this is the Denakil Depression, Ethiopia; Death Valley,
California
• Graben environments in oceanic rift environments fed by limited oceanic input, leading to eventual isolation and
evaporation
• Examples include the Red Sea, and the Dead Sea in Jordan and Israel
• Internal drainage basins in arid to semi-arid temperate to tropical environments fed by ephemeral drainage
• Example environments at the present include the Simpson Desert, Western Australia, the Great Salt Lake in
Utah
• Non-basin areas fed exclusively by groundwater seepage from artesian waters
• Example environments include the seep-mounds of the Victoria Desert, fed by the Great Artesian Basin,
Australia
• Restricted coastal plains in regressive sea environments
• Examples include the sabkha deposits of Iran, Saudi Arabia, and the Red Sea; the Garabogazköl of the Caspian
Sea
• Drainage basins feeding into extremely arid environments
• Examples include the Chilean deserts, certain parts of the Sahara, and the Namib
The most significant known evaporite depositions happened during the Messinian salinity crisis in the basin of the
Mediterranean.

3. Evaporite 3
Evaporitic formations
Evaporite formations need not be composed entirely of halite salt. In
fact, most evaporite formations do not contain more than a few percent
of evaporite minerals, the remainder being composed of the more
typical detrital clastic rocks and carbonates. Examples of evaporate
formations include occurrences of evaporite sulfur in Eastern Europe
and West Asia.[4]
For a formation to be recognised as evaporitic it may simply require
recognition of halite pseudomorphs, sequences composed of some
proportion of evaporite minerals, and recognition of mud crack
textures or other textures.
Hopper crystal cast of halite in a Jurassic rock,
Carmel Formation, southwestern Utah.
Economic importance of evaporites
Evaporites are important economically because of their mineralogy, their physical properties in-situ, and their
behaviour within the subsurface.
Evaporite minerals, especially nitrate minerals, are economically important in Peru and Chile. Nitrate minerals are
often mined for use in the production on fertilizer and explosives.
Thick halite deposits are expected to become an important location for the disposal of nuclear waste because of their
geologic stability, predictable engineering and physical behaviour, and imperviousness to groundwater.
Halite formations are famous for their ability to form diapirs, which produce ideal locations for trapping petroleum
deposits.
Major groups of evaporite minerals
This is a chart that shows minerals that form the marine evaporite rocks, they
are usually the most common minerals that appear in this kind of deposit.
Calcite

4. Evaporite 4
Mineral class Mineral name Chemical Composition
Chlorides Halite Sylvite NaCl KCl
Carnallite KMgCl3 * 6H2O
Langbeinite K2Mg2(SO4)3
Polyhalite K2Ca2Mg(SO4)6 * H2O
Kainite KMg(SO4)Cl * 3H2O
Sulfates Anhydrite Gypsum CaSO4 CaSO4 * 2H2O
Kieserite MgSO4 * H2O
Carbonates Dolomite Calcite CaMg(CO3)2 CaCO3
Magnesite MgCO3
• Halides: halite, sylvite (KCl), and fluorite
• Sulfates: such as gypsum, barite, and anhydrite
• Nitrates: nitratine (soda niter) and niter
• Borates: typically found in arid-salt-lake deposits plentiful in the
southwestern US. A common borate is borax, which has been used
in soaps as a surfactant.
• Carbonates: such as trona, formed in inland brine lakes.
• Some evaporite minerals, such as Hanksite, are from multiple
Hanksite, Na22K(SO4)9(CO3)2Cl, one of the few
groups. minerals that is both a carbonate and a sulfate
Evaporite minerals start to precipitate when their concentration in
water reaches such a level that they can no longer exist as solutes.
The minerals precipitate out of solution in the reverse order of their solubilities, such that the order of precipitation
from sea water is
1. Calcite (CaCO3) and dolomite (CaMg(CO3)2)
2. Gypsum (CaSO4-2H2O) and anhydrite (CaSO4).
3. Halite (i.e. common salt, NaCl)
4. Potassium and magnesium salts
The abundance of rocks formed by seawater precipitation is in the same order as the precipitation given above. Thus,
limestone (calcite) and dolomite are more common than gypsum, which is more common than halite, which is more
common than potassium and magnesium salts.
Evaporites can also be easily recrystallized in laboratories in order to investigate the conditions and characteristics of
their formation.
References
[1] Jackson, Julia A., 1997, Glossary of Geology 4th edition, American Geologic Institute, Alexandria Virginia
[2] Boggs, S., 2006, Principles of Sedimentology and Stratigraphy (4th ed.), Pearson Prentice Hall, Upper Saddle River, NJ, 662 p.
[3] Melvin, J. L.(ed) 1991, Evaporites, petroleum and mineral resources; Elsevier, Amsterdam
[4] C.Michael Hogan. 2011. Sulfur. Encyclopedia of Earth, eds. A.Jorgensen and C.J.Cleveland, National Council for Science and the
environment, Washington DC (http:/ / www. eoearth. org/ article/ Sulfur?topic=49557)
• California State University evaporites page (http://seis.natsci.csulb.edu/bperry/Sedimentary Rocks Tour/
evaporites.htm)
• Gore, Rick. "The Mediterranean: Sea of Man's Fate." National Geographic. Dec. 1982: 694-737.
• Gueguen and Palciauskas (1984). Introduction to the Physics of Rocks.

5. Article Sources and Contributors 5
Article Sources and Contributors
Evaporite Source: http://en.wikipedia.org/w/index.php?oldid=539689085 Contributors: 06mkittle, Anon lynx, Askewchan, Aymatth2, Blanchardb, BlueAmethyst, Bob Palin, Boleslaw,
Cferrero, Christian75, DanielCD, David110994, Deflective, Drphilharmonic, Duncan.france, Dycedarg, Eztafette, Gaius Cornelius, Garranlp193, GeeJo, GeoGreg, Geolrock12, Gioto, Good
Olfactory, Greatjob, IW.HG, Iancarter, Igodard, Isaac Dupree, J.delanoy, Katoa, Kwamikagami, LAX, Looxix, MatthewDBA, Michael Hardy, Mikenorton, MountainB, Ohconfucius,
Pip2andahalf, Platonicmaria, Plazak, Poolkris, Qfl247, Redvers, Rjstott, Rolinator, SchfiftyThree, Seigeftw, Siim, Stan Shebs, Szilas, Teryx, Theo Pardilla, Transcendence, Turlo Lomon,
Twinsday, UnitedStatesian, Uranographer, Vidioman, Vsmith, Wilson44691, 50 anonymous edits
Image Sources, Licenses and Contributors
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