Orthorhombic ferroselite and its
isometric polymorph dzharkenite are
iron
Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...
selenide A selenide is a chemical compound containing a selenium anion with oxidation number of −2 (Se2−), much as sulfur does in a sulfide. The chemistry of the selenides and sulfides is similar. Similar to sulfide, in aqueous solution, the selenide ion ...
s of general formula FeSe
2 precipitated under reducing conditions in anoxic environments. They are a source of selenium in the Rocky Mountains where selenium occurrence is associated with
Upper Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', th ...
shale deposits.
In the frame of safety assessment calculations made for deep disposal of high-level radioactive waste, ferroselite and dzharkenite are also considered in geochemical calculations as one of the mineral phases limiting the solubility of
Selenium-79
Selenium-79 is a radioisotope of selenium present in spent nuclear fuel and the wastes resulting from reprocessing this fuel. It is one of only 7 long-lived fission products. Its fission yield is low (about 0.04%), as it is near the lower end ...
.
Names
Dzharkenite's type locale is in the Suluchekinskoye Se-U deposit in the Dzharkenskaya Depression of the Middle Ili River,
Almaty Province
Almaty Region ( kk, Алматы облысы, Almaty oblysy; russian: Алматинская область, Almatinskaya oblast) is a region in Kazakhstan, located in the southeastern part of the country. Its capital, from 1997 to 2022 was the ...
, in southeastern
Kazakhstan
Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...
. It was discovered in 1995 and named after the depression.
Ferroselite was first reported in 1955 for an occurrence in the Ust’-Uyuk uranium deposit in
Tuva
Tuva (; russian: Тува́) or Tyva ( tyv, Тыва), officially the Republic of Tuva (russian: Респу́блика Тыва́, r=Respublika Tyva, p=rʲɪˈspublʲɪkə tɨˈva; tyv, Тыва Республика, translit=Tyva Respublika ...
,
Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive region, geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a ...
.
[ Its name comes from the ]Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''ferro'' (iron) and "sel" for selenium.
See also
* Coccolithophorid
Coccolithophores, or coccolithophorids, are single celled organisms which are part of the phytoplankton, the autotrophic (self-feeding) component of the plankton community. They form a group of about 200 species, and belong either to the kingd ...
, a group of marine planktonic unicellular algae fixing selenium in Upper Cretaceous chalk and shale formations
* Emiliania huxleyi, a major species of coccolithophorid active in selenium bioconcentration
External links
Dzharkenite (FeSe2)
on mindat.org
Dzharkenite (FeSe2)
on webmineral.com
References
{{Reflist
Iron minerals
Selenide minerals
Orthorhombic minerals
Minerals in space group 58