Metamorphic Minerals

• Actinolite
• Alurgite
• Andalusite
• Andalusite (chiastolite)
• Antigorite
• Anthophyllite-Gedrite
• Biotite
• Brucite
• Calcite
• Cassiterite
• Charoite
• Chlorite
• Chloritoid
• Chrysocolla
• Cordierite
• Corundum
• Corundum (ruby)
• Kyanite
• Kornerupine
• Kyanite (reticite)
• Deerite
• Dumortierite
• Epidotes
Allanite
Pistacite
Piemontite
Zoisite

• Fassaite
• Fluorite
• Glaucophane
• Garnet
• Hercynite
• Hedenbergite
• Hydrogrossular
• Howieite
• Humites
• Jadeite
• Lawsonite
• Lazulite
• Lazurite
• Malachite
• Minnesotaite
• Muscovite
• Olivine
• Omphacite
• Omphacite Cr
• Pargasite
• Piemontite (Praborna)
• Pyrite
• Prehnite
• Pumpellyite
• Quartz
• Rhodonite
• Rutile
• Sapphirine
• Scapolite
• Serpentine
• Sillimanite
• Sillimanite (fibrolite)
• Staurolite
• Stilpnomelane
• Sugilite
• Talc
• Taramellite
• Thulite
• Tinaksite
• Tinzenite
• Titanite
• Tremolite
• Tourmaline
• Vesuvianite
• Violan
• Wollastonite
• Yoderite
• Zussmanite

Texture and Microstructure

• Augen
• Book shelf sliding
• Boudinage
• Corona
• Decussate
• Deformation lamellae
• Deformation twins
• Crenulation cleavage
• Fringes
• Granoblastic
• Kelyphite
• Kink Bands
• Lepidoblastic
• Mesh
• Mica fish
• Mylonitic
• Nematoblastic
• Oblique foliations
• Polygonal
• Porphyroblastic
• Porphyroclastic
• Pseudomorph
• Ribbon
• S-C fabric
• Skeletal garnet
• Symplectite
• Veins

Metamorphic Rocks

• Albite greenshist
• Amphibolite (felsic)
• Amphibolite (mafic)
• Amphibolite (mylonitic)
• Amphibolite with epidote
• Andalusite schist
• Anyolite
• Augen gneiss
• Blueschist
• Blueschist (Ile de Groix)
• Blueschist (retrograde)
• Buchite
• Calc-schists
• Carbonated peridotite
• Cataclasite
• Charoitite
• Chlorite schist
• Chloritoid Schist (Ile de Groix)
• Cordierite slate
• Corundum-fuchsite rock
• Deformed oolite
• Dunite (mylonitic)
• Eclogite
• Eclogite Porto Ottiolu
• Epidosite
• Gabbro (mylonitic)
• Garnet micaschist
• Glaucophane granofels
• Granite (mylonitic)
• Granulite (felsic)
• Granulite (mafic)
• Granulite (retrograde)
• Granulite (sapphirine-bearing)
• Greenschist
• Hornfels
• Hornfels (albite-epidote)
• Hornfels (cordierite, plagioclase)
• Hornfels (corundum, plagioclase)
• Hornfels (hydrogarnet)
• Jadeite metagranite
• Jadeitite
• Kinzigite
• Lapis lazuli
• Marble
• Marble (calc-silicate)
• Marble (diopside)
• Marble (forsterite)
• Marble (mylonitic)
• Marble (tremolite)
• Mylonite
• Ocean jasper
• Ophicalcite
• Peridotite (mylonitic)
• Phyllite
• Prasinite
• Pseudotachylyte
• Pseudotachylyte (Ivrea-Verbano)
• Quartzite
• Quartzite (tourmaline)
• Rhyolite (mylonitic)
• Rodingite
• Schist
• Seafloor basalt
• Serpentinite
• Serpentinized lherzolite
• Skarn
• Skiddaw Metamorphic Aureole
Skiddaw
1) Spotted slate
2) Andalusite slate
3) Cordierite slate

• Slate
• Slate (ottrelite)
• Talc schist
• Tourmalinite
• Ultramylonite (granitic)
• Ultramylonite (mafic)

Tinaksite - K₂Na(Ca,Mn)₂TiOSi₇O₁₈(OH)

Tinaksite, first described in 1960, is a very rare mineral found in the Murun Massif (Fig.1), Aldan Shield, Yakutia, Russia and is a widespread mineral in the charoitites. Tinaksite can be grayish-white, yellowish, orange, or brown, it occurs as an accessory mineral in potassic feldspar metasomatites at the contact with limestones. It is closely associated with hisingerite, astrophyllite, aegirine, pyroxene, orthoclase, xonotlite, canasite, quartz, and potassic feldspar. Its name is derived from its composition: titanium (Ti), sodium (Na) potassium (K) and silicon (Si).

Optical Properties:
• Form: Fibrous - Crystals made up of fibers.
• Color: Colorless-light yellow.
• Relief: Moderate.
• Interference colors: Strong.

Murun Complex

Mesozoic K-alkaline intrusions are abundant at the Aldan shield and they are distributed in the northern part with a strike roughly parallel to the NE-SW trending Mongolia-Okhotsk orogenic belt (Fig.2). This orogenic belt is a reflection of subduction of the Mongolia-Okhotsk oceanic plate. The Mongolia-Okhotsk Ocean closed at the Carboniferous in the west and in the Late Cretaceous in the east.





By the time of magmatism at the Malyy Murun, the Mongolia-Okhotsk subduction ceased at the central part of the orogenic belt and thus Early Cretaceous magmatism at the Malyy Murun massif represents a post-subduction process, which was coeval to rifting at the central part of the Mongolia-Okhotsk orogenic belt. The Malyy Murun massif (ca.48 km²) is a part of a larger Murun ultrapotassic complex (150-180 Km²), which consists of the Bolshoy (Great) Murun, Malyy (Little) Murun, and Dagaldyn massifs (Fig 3). The Malyy Murun and Dagaldyn massifs are Early Cretaceous and Early Jurassic, respectively. The Bolshoy Murun massif is not yet dated. The northern part of the Malyy Murun syenite massif is bounded by skarns at the contact with the carbonate wall rocks. The southern part of the massif is bounded by quartz sandstones, where a broad contact aureole of fenites developed. All known outcrops of charoitite rocks were found within fenites.



The complex was discovered in the late 1930-s - early 1940-s by the VG Ditmar expedition. Since then, dozens of scientists have been involved in the geological exploration of Murun. As this exploration progressed, the complexity of the geological and tectonic situation at Murun became increasingly evident. The Murun complex is, perhaps, best known for a suite of Ca-rich fenitic rocks developed from the Proterozoic carbonaceous sandstones. Beginning in the 1960-s, a number of new minerals of unusual composition and structure have been discovered in the fenites. Many of these, including frankamenite and the gemstone charoite, are quite common in the Murun rocks, but have not been encountered anywhere else in the world.
There is no agreement between geologists as to what the composition of the parental magma was, or how the intrusions developed in time, or regarding genetic relationships between the individual petrographic series.

At present, there are two major views on the evolution of the Murun complex:

1) Orlova et al. (1987, 1988) suggest that the complex developed as a single layered lopolith by magmatic differentiation.
2) Ivanyuk & Evdokimov (1991), Mitchell & Vladykin (1996), Konev et al. (1996), (Vladykin, 2000) and others suggests that the individual intrusive phases were emplaced independently as a series of plutonic and hypabyssal bodies. They recognized four magmatic stages in the Malyi Murun Massif:

Early phase: makes up the northeastern part of the massif. It includes the following rocks: (1) Cumulate formations: olivine-spinel rock seggregations with zones of melilite-bearing olivinepyroxene-phlogopite-monticellite rocks, which occur as xenoliths in biotite pyroxenites. (2) Layered complex of ultrabasic ultrapotassic rocks composed of Biotite-pyroxenites, olivine, K-ijolites, leucitic fergusites, and shonkinites.

Major phase: occupies the central part of the massif. It is made up of a horizontally, layered units of various pseudoleucitic, kalsilitic, and biotite-pyroxene-bearing K-feldspathic syenites, whose crystallization terminated in the formation of quartz syenites and dykes and stocks of alkali granites. The pseudoleucitic syenites (synnyrites) in the northeast of the massif form a large body not less than 600 m in thickness.

Volcanic phase: comprises the central and northern parts of the massif. This is a layered flow of leucitic melaphonolites, leucitites, and leucitic lamproites (minette) with zones of tuff breccias. The dyke complex of this phase is formed by leucitic tinguaites, richterite-sanidine lamproites, trachyte-porphyries and syenite-porphyries.

Late phase: It occupies the southeastern part of the massif, covering 10 km2, and is made up of banded layered complex of potassic silicate-carbonate rocks which form 1 to 20-30 m wide bands. These bands are: (1) white microgranular K-feldspathic rocks consisting of K-feldspar with minor admixtures of pyroxene and tinaksite; (2) quartz-calcite-pyroxene-microcline rocks with calcite contents varying from 5 to 20%; (3) pyroxene-K-feldspathic rocks with widely varying contents of both components.
The rocks have diverse structures and textures: banded, spherolitic (for pyroxene), equigranular, fine- and coarse-grained, etc.; (4) essentially pyroxene rocks. This layered banded outcrop contains carbonatites and charoite rocks, which are represented by veins, dykes, and some sill-like formations having no sharp contacts with the silicate-carbonate rocks.

Tan colored long prismatic tinaksite crystals embedded in purple charoite, Chara River area, Murun Massif, northwest Aldan, Siberia, Russia. From RRUFF.

Tan colored long prismatic tinaksite crystals embedded in purple charoite, Chara River area, Murun Massif, northwest Aldan, Siberia, Russia. From RRUFF.

Bibliography

• Reguir, E. (2002). Aspects of the Mineralogy of the Muran Alkaline Complex, Yakutia, Russia. National Library of Canada. Bibliothèque nationale du Canada.
• Wang, Y., He, H., Ivanov, A. V., Zhu, R., & Lo, C. (2014). Age and origin of charoitite, Malyy Murun massif, Siberia, Russia. International Geology Review, 56(8), 1007-1019.

Photo

Fibrous tinaksite (colorless), fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 2x (Field of view = 7mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)
Fibrous tinaksite (high interference colors) and fibrous charoite (I order gray) in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)
Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 2x (Field of view = 7mm)	Fibrous tinaksite (colorless), fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
Fibrous tinaksite (colorless), fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (colorless), fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
Fibrous tinaksite (colorless), fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (colorless) and fibrous charoite (beige color) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
Fibrous tinaksite (colorless), fibrous charoite (beige color) and green aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (colorless) and fibrous charoite (beige color) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)
Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (high interference colors), fibrous charoite (I order gray) and aegirine crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
Fibrous tinaksite (high interference colors) and fibrous charoite (I order gray) in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (colorless) and fibrous charoite (beige color) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (high interference colors) and fibrous charoite (I order gray) in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)
Fibrous tinaksite (colorless) and fibrous charoite (beige color) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (high interference colors) and fibrous charoite (I order gray) in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 10x (Field of view = 2mm)	Fibrous tinaksite (colorless) crystals in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. PPL image, 20x (Field of view = 1mm)
Fibrous tinaksite (high interference colors) in a charoitite. Murun Massif, Aldan Shield, Yakutia, Russia. XPL image, 20x (Field of view = 1mm)