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Formula: Na(AlSi3O8)
Tectosilicate (framework silicate), feldspar group, orthorhombic
paramorph of triclinic albite and
of lingunite
Crystal System: Orthorhombic
Environments
Metamorphic environments
Meteorites
Kumdykolite is an orthorhombic high-pressure paramorph of
albite. It may be a metastable phase formed at high temperatures followed by
rapid cooling in the absence of water
(Mindat).
Localities
At the Dabie Orogen, Eurasian Plate, Central China, kumdykolite formed during internal mineral carbonation within
amphibole-hosted fluid inclusions in post-collisional
hornblendite. Amphibole
in the hornblendite trapped CO2-rich fluid inclusions at
the magmatic stage, and mineral carbonation, referring to the reaction of minerals rich in divalent cations and
CO2 into carbonate, occurred in situ within the fluid inclusions due to the interaction between trapped
CO2-rich fluids and host amphibole during cooling of the
hornblendite. Kumdykolite was produced along with
calcite, dolomite,
chlorite, talc, an SiO2 phase
(quartz or cristobalite), a
TiO2 phase (rutile or
anatase), and mica during internal
mineral carbonation within the fluid inclusions. It is estimated that kumdykolite in the fluid inclusions
crystallised under near-surface conditions, which are significantly different from the conditions of crystallisation
proposed in previous studies. It is further inferred that kumdykolite may crystallize metastably across the
stability field of albite, and the presence of kumdykolite is not
indicative of extreme thermobaric and fluid-absent conditions
(AM 109.11.1995–2005).
At the České středohoří Mountains, Ústí nad Labem Region, Czech Republic, kumdykolite was discovered in an
ultrahigh-pressure, diamond-bearing
felsic garnet -
kyanite - feldspar -
quartz granulite from the
northern Bohemian Massif. It is associated with phlogopite and
quartz in a multiphase solid inclusion within
garnet, considered to represent a trapped fluid or melt phase. Analysis revealed
the presence of a sub-equant, elongated grain of kumdykolite reaching 20 μm in length.
The kumdykolite-bearing multiphase inclusion must have been trapped at a pressure greater than 4 GPa. The inclusion
minerals, however, crystallised upon decompression and cooling during the exhumation
(AM 99.1798–1801).
At the type locality, the Lake Kumdikol diamond deposit, Lake Kumdikol, Prirechnoye, Zerendy, Akmola Region, Kazakhstan,
kumdykolite occurs in association with diopside,
quartz-cristobalite,
phengite-phlogopite, an unidentified
aluminosilicate, calcic amphibole,
dolomite, calcite or
talc, as micrometer-scale mineral inclusions in
omphacite of eclogite from the
Kokchetav ultrahigh-pressure massif.
Kumdykolite is presumed to be a metastable phase formed at high temperatures followed by rapid cooling in the
absence of water. It is further postulated that it may have resulted from the interaction between infiltrated melt and
omphacite when the massif was exhumed from mantle depths to the base of the
crust
(EJM 21.1325-1334).
Kumdykolite from Lake Kumdikol - Image
At the Sahara 97072 meteorite, Sahara Desert, North Africa, kumdykolite occurs in the core of a concentrically
zoned metal-sulphide nodule. It is proposed that kumdykolite formed above 1,027o and cooled rapidly
enough to preserve its unique structure
(AM 98.1070–1073).
Associated minerals include oldhamite,
niningerite, zinc-rich
daubréelite and sulphur-rich porous
silica
(HOM).
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