Murun and other Aldan localities

Thanks to the authors of the article mentioned below and to László Horváth for his help with the list, as to Peter G.Seroka for the Kogarko/Woolley book.

Murun is an alkaline massive of 180 km² (plus 2 small massifs of 6 and 8 km²) in eastern Siberia/Yakutia (between Irkutsk and Chitinsk on the continental divide between the rivers Chara and Tokko on the Olekminsk plateau), which belongs to the upper mesozoic complex of the Aldansk plate. About 200 mio years ago the first alkaline magmas rose, a period which lasted for a about 100 mio years. The massif consists of rocks like potassium basaltoides to alkaline granites and carbonatites. The geology is rather complicated, as 7 different phases can be distinguished, some of them even to be split up further:

1: alkaline shonkinites, dark augitic syenites
2a: alkaline syenites of the main phase
2b: nepheline syenites of the main phase
3a: synnyrite, melanosynnyrite, fergusite - ring intrusion
3b: kalsilite-syenites, jakutites
4a: agpaitic alkaline syenites
4b: agpaitic nepheline syenite and pegmatites
4c: veins and breccia of ijolites and urtites
5a: lavas, tuffs, leucite porphyres, trachytes, phonolites
5b: potassium basaltoides

5c: inclusion complex with leucite porphyres, potassium-alkaline minettes

6: alkaline granosyenites, granites, selvsbergites, grorudites

7: torgolites, carbonatites and charoitites


The stocks of phase-1-rocks are crisscrossed by the type-4-rocks, often accompanied by magnesium-skarns and marbles. Phase-3a-rocks form a ring zone together with phase 3b. Jakutites are a new rock type of kalsilite and aegirine without any feldspar. Phase 4c is also to be found in the ring zone, whereas phase 5a is restricted to the NW of the massive as remnants of an ancient volcano. Phase-6-rocks are restricted to the rim of the massiv, mainly the Kedrovy massive 6 km SE. They contain a different mineralisation, Phase-7-rocks occur in an area of 1x5 km in the southern part of the intrusion. It should be mentioned, that Murun is the world´s only occurrence of barium-strontium-carbonatites. Altogether there are more than 200 minerals described from here (which means that my list very incomplete and urgently needs upgrading!)

Mineral list (bold=type locality, italics=variety):

Aegirine
Aegirine-augite
Agrellite
Agrellite-Sr
Albite
Anatase
Ancylite-(Ce)
Banalsite
Barite
Barytocalcite
Barytolamprophyllite
Batisite-K
Benstonite
Brookite
Brucite
Calcite
Canasite
Chalcopyrite
Chalcosite
Charoite
Clinohumite
Copper
Covellite
Dalyite
Davanite
Denisovite
Digenite
Diopside (var. Fassaite)
Djerfisherite
Ekanite (probably wrong - steacyite)
Elpidite
Epididymite
Eudialyte
Fedorite
„Feldspar-group“
Ferroclinoholmquistite
Fluorite
Frankamenite
Froodite
Galena
Geikielite
Gold
Idaite
Ilmenite
Kalsilite
Labuntsovite
Labuntsovite-K
Lamprophyllite
Leucite
Leucosphenite
Loparite-(Ce)
Lorenzenite
Magnesioarfvedsonite
Microcline
Miserite
Monticellite
Mosandrite
Murunskite
Muscovite
Narsarsukite
Nepheline
Odintsovite
Olekminskite
Paralsonite
Pectolite
Periclase
Perlialite
Phlogopite
Quartz
Richterite-Mg-Sr-K
Rosenbuschite
Rutile
Serandite
Silver
Sobolevskite
Sperrylite
Sphalerite
Spinel
Steacyite
Strontianite
Taeniolite
Tausonite
Thalcusite
Thorosteenstrupine
Tinaksite
Titanite
Tokkoite
Vishnevite
Wadeite
Witherite-Sr
Wollastonite

Xonotlit

Yuksporite

Zircon



&Suggested reading:

Kogarko,L.N., V.A.Kononova, M.P.Orlova, A.R.Woolley: Alkaline Rocks and Carbonatites of the World. Part 2: Former USSR. Chapman and Hall, London, 1995.

Konev,A.A., E.I.Vorobjov, A.Bulach: Charoite - der Schmuckstein aus Sibirien und seine seltenen Begleitminerale. LAPIS 4(93), pp.13-20 (in German)

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In the area of Aldan there are many other alkaline localities - some you will still find on the Aldan page, meaning that I don´t know enough about them. But here is:

Inagli

Ingalia is an alkaline complex 30 km NW of the town of Aldan in Siberia/Yakutia - for siberian distances close to Murun (200 W of Aldan). It is a ring complex of 30km² and consists of 5 structures: a central zone of dunites with layers of wehrlites, a surrounding zone of phlogopitized dunites and wehrlites (metamorphosed), an inner ring zone of pyroxenite/missourite/shonkinite, an outer ring zone of shonkinite/pulaskite/syenite, and ring zones of metasomatic rocks and pegmatites. The age of the complex is ahbout 110-130 Ma.

Sorry, but the mineral list seems to be incomplete.



Mineral list (bold=type locality):
Aegirine
Albite
Arfvedsonite
Batisite
Cr-Diopside (mining for jewellry)
Erlichmanite
Eudialyte
Fluorapatite
Inaglyite
Innelite
Isoferriplatinum
Lamprophyllite
Leucosphenite
Lorenzenite
Magnesioarfvedsonite
Nepheline
Olivine
Orthoclase
Phlogopite
Strontiumapatite
Uranothorite
Vermiculite
Vinogradovite


&Suggested reading:
Kogarko,L.N., V.A.Kononova, M.P.Orlova, A.R.Woolley: Alkaline Rocks and Carbonatites of the World. Part 2: Former USSR. Chapman and Hall, London, 1995.

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