The long geological history of the formation Ilmeny (2300-160 000 000 years) It has led to a unique complex minerals and rocks, to a variety of minerals.
Ilmen Mountains and their foothills stacked array Ilmenogorsky miaskitic, bodies of syenite, Crushed, ultramafic and enclosing metamorphic rocks - granite-gneisses, amphibolites, schists, quartzites, - that integrates into Ilmenogorsky complex of igneous and metamorphic rocks (Steinberg, Levin, 1971).
Ilmen Mountains famous pegmatite with semi-precious and rare metals, rare-earth mineralization, which arose as a result of the formation of the pegmatite system lived about 290-240 million years ago. BUT. n. Zavarickim (1931, 1939) among pegmatites allocated miaskitic, syenite and granite. Traditionally, granite pegmatites are all, primary quartz containing rock-forming, to miaskitic - nepheline syenite pegmatite, to syenite - alkali feldspar pegmatite without quartz and nepheline. In recent years, marked another carbonatite and alkaline-ultramafic pegmatite (priest's, 2004).
The three virtual tours of the reserve kopyam we will try to introduce three types of pegmatites:

Vein field south of Ilmeny.
1 - Disdain granitov; 2-6 - pegmatites: 2 - domiaskitovye granite, 3 - feldspar, 4 - miaskitic, 5 - poslemiaskitovye granite, 6 - amazonite; 7 - metamorphic rocks (gneiss, amphibolites, quartzites); 8-11 - areas of uneven pegmatites, 12 - swamp. Numbers - numbers mines. Compilers: AT. BUT. priest's, AT. AND. Popova, AT. ABOUT. Poles, 1980 g.

granite pegmatites developed mainly in Western exocontact array miaskitic, near Kosyh mountains. Among them are several types of isolated. Earlier granitic pegmatites (domiaskitovye) - quartz-feldspar (ceramic). Suitable for the manufacture of glass. Poslemiaskitovye pegmatite rare earth, rare metal mineralization. The most recent and the most interesting - amazonite pegmatites with green feldspar. The first of this type are described mines - Prutovskaya lance № 74.

Kop number 74 (Prutovskaya mine)

AT 200 m east of the scientific and industrial base of the reserve "is the first time the development of topaz, Cossack lance Coated, open in the XVIII century " [1832, Lysenko]. This is one of the oldest nature reserve workings, blade which is visible from the road, leading to the lake. Argayaş.
Mine laid on the conductor amazonite pegmatite sublatitudinal. Lived was a source of topaz jewelry bluish, it is now almost fully developed.
Pegmatite occurs in the granite-gneisses and amphibolites Ilmenogorsky column. Contact sharp, tectonic, in roadways observed sliding mirror.
The general nature of the deposit is as follows: it is, apparently, two parallel pegmatite veins with topaz; parallel to them also go feldshpatolita veins, consisting of yellowish feldspar, white and partly black mica. Besides, It found a number of irregularities in the structure of, - namely, branching veins and give tap on her hips.
The structure of the main veins: at the selvages - yellow feldspar quartz xenomorphic, in the form of elongated discharge. Sometimes (rarely) - Quartz splice with yellow feldspar granite in the form of written, in the middle of the living enriched amazonite, albite, gray quartz, and black mica (sometimes rhombic restrictions), large crystals of amazonite small. The mine lived granitic pegmatite veins with whips feldspar and muscovite aeschynite.

M. P. Melnikov [1882] points: "Apparently, in the mines were only small topaz, but there were many. Topaz met in nests, substance containing white kaolinistoe (in the local - "fat"). Subsequently mine developed, but did not meet topaz, and in an era of stagnation, when no other topaz mines were discovered, These blades are washed clean, and there are small topaz. At the bottom of it was green feldspar (Amazon stone), but empty. Apparently, in its sailings Menge [1826] found crystal aeschynite with green beryl (apatite), in the rock, rich Garnet ".

Topaz

Minerals copy number 74

feldspars (microcline, amazonite, albite)
Quartz
Biotite
muscovite
Magnetite
Apatite
Garnet
Topaz
Tourmaline
fluorite
cassiterite
anatase
İlmenorutil

Blyumovskaya mine
"This is one of the richest mines lovely large topaz
(to pound), best transparent aquamarine, almost the only, where he met a rare mineral samarskite "
M. P. Melnikov, 1882


Famous Blyumovskaya mine is located in the southern part of the reserve, at 3 km east of the central database on the highway-Miass Chebarkul. It reveals the core amazonite pegmatite, which extends in a latitudinal direction with falling north angled 70-75 °. Numerous excavations lived traced along strike to 150 m, It has a capacity of, on average 5 m.

Blyumovskaya mine. 1914 g.

The structure of the pegmatite mines Blyumovskoy (by Academic course).
1 - gneiss, 2 - amphibolites, 3 - Early granite pegmatite, 4 - krupnografichesky quartz-microcline pegmatite, 5 - also, melkografichesky, with pink and green microcline, 6 - a block amazonite pegmatite with topaz and beryl, 7 - quartz-albite blastomilonit with samarskite. VA. priest's, V.I. Popov, "Mineralogy pegmatite Ilmeny", 2006. WITH. 59. (by V.O. Polyakov).

mineralogists group field (from left to right): E.P. Makagonov, VA. priest's, V.I. Popova, E.I. Belogub, SN. Nikandrov. photo n. Bragin.

AT 1835 year in order to find topaz and aquamarine mine was originally laid P. BUT. Versilov, subsequently developed a mining engineer Fedor Fedorovich to Blum, presumably, 1843 of the year.
Pegmatite vein of the mine was rich in various minerals. In addition to the typical amazonite amazonite pegmatites, topaz, aquamarine, columbium, grenade, biotite numerous samarskite crystals have been found here, malakona (metamict zircon). Here is one of the largest of the Ilmen topaz was found, by weight exceeding 600 city.
In 1911-1917 years spent working in the ilmenite Radium expedition of Academy of Sciences under the guidance of. AND. Vernadsky. The copy for studying the structure of pegmatite and to mine radioactive samarskite, It was passed ditch length 30 m, width 1.5 m across the strike strands, which was named Academic course.

May be because, that this mine the most studied and well-opened, it is considered the best and most famous of all mines in the reserve.
Several kilograms samarskite, obtained Radium expedition, They were sent to the laboratory of Maria Sklodowska-Curie for radioactivity experiments on study. Russia's first absolute age measurements were also carried out using Ilmensky samarskite.

geological feature
Lived amazonite pegmatite, which laid mine, unconformably overlies among Ilmenogorsky rock strata - plagiogneiss with interbedded amphibolite.
In the western end of the vein divides into two parts, one of which is composed of amazonite pegmatite with topaz and beryl, and the other - with granite pegmatite samarskite.
The structure of the veins, Academic observed in the course of, symmetrychno-zonalnoe.
the marginal zone krupnograficheskim stacked parallel columnar quartz aggregate, microcline and oligoclase perthite № 12-15 and is the actual geometric selection zone. Ubiquitous biotite and dark red opaque garnet to 1.5 cm, occasionally observed magnetite and zircon.zircon
The next zone melkograficheskaya two-feldspar It has a capacity of 1 to 2 m. Biotite occurs in the form of thin laths, which forms stellate intergrowths. Occasionally found magnetite and reddish-brown opaque garnet. In this zone there are areas monomineral microcline- perthite, miarolitovye which contains voids with the quartz crystals, feldspar and silvery white mica, and met zanoryshi with beryl and topaz.
bloc (pegmatoid, central) part strands represented by gigantic crystals microcline (up to tens of cm) with saber-like biotite. Power zone increases east, wherein lenses are arranged smokestone. In this zone, garnet crystals found, samarskite, columbium, zircon, fergusonita. Amazonit It is located in the sites of the block area. In the western part of the vein amazonitic green coloration brighter and abundant. The yellow microcline, Amazon and albite are found amazonite quartz-veins capacity of a few centimeters. The streaks are cavity with amazonite crystals, quartz and topaz. AT amazonite observed prismatic silver-gray mica spherical shape - "Barbot Eye", and crystals Topaz, small needles of tourmaline, large crystals of garnet, Dr. ilmenorutil.

mine 232

Amazonite granite pegmatites (quartz-feldspar rare metal) compose a series of vein bodies of serpentinized ultramafic among. mine 232 located on the southern shore of Lake. B. Tatkul. By the structure of veins and type of accessory mineralization similar to amazonite pegmatites.
Mine workings number 232 (rooted in 1978 g. by finding in the piled YP. Zapevalova tourmaline and beryl) four lenticular graphic autopsy granite pegmatite in actinolite, anthophyllite and chlorite schists, gneisses and amphibolites interbedded with quartzites, as well as olivine-enstatite pegmatoids (Popova, Levanov, 1980).Structure pegmatite mines in the southern wall of the number 232.
1 - amphibolites and gneiss; 2-9 - pegmatite zone: 2 - graphics quartz-microcline, 3 - bloc microcline, 4 - a graphical two-feldspar, 5 - quartz-albite with muscovite and beryl, 6 - large pack of muscovite, 7 - clusters of pomegranate, 8 - tourmaline, 9 - quartz core; 10 - drusy cavity; 11 - topsoil; 12 - violations. in V.I. Popova.

Clearing amazonitic copy number 70, 1975.
We knob A.Ustinov (left)
and S.Nikandrov (case),
the copy V.A. priest's.
Photos VI. Popova

Boris V. Chesnokov (1928-2005.),
Doctor of Geological and Mineralogical Sciences,
honorary member of the Russian Mineralogical Society,
Demidov Prize Laureate
The largest vein, traced along strike to 27 m at power up to 8 m, asymmetric-zonal: selvages are composed of graphic two-feldspar pegmatite, block microcline alternating to the vein center and then quartz-albite pegmatite with feathery muscovite, spessartine, beryllium, columbite-tantalite, tapiolite, ganit, cirtolite, monacitom-(is), fluormicrolite. The core of the core is made of quartz, in which a triplite nest with secondary phosphates developing along it was encountered. It is here in 1979 year B. AT. Chesnokov found new minerals: kaluginitis, matveevit (benyakarit) and ear, which, along with other phosphates, included in the triplet modification products. Beryl crystals before 60 cm in length and up to 12 cm in diameter.












“Is the history of the study of the Ilmen mountains completed?? Of course not. Our common work on geology, petrography and mineralogy of the Ilmen mountains showed us, how much remains unfinished, unexplored, unknown. The exploration of the Ilmen mountains must and will continue.”

AT. AND. Kryzhanovsky, 1949 g.

System of nepheline-feldspar veins mine No. 7.
1–2 - miaskites: 1 - biotite, 2 - biotite-gastingsitovye; 3 - pegmatites; 4 - blastomylonitis area; 5 - elements of bedding of bodies (according to E. P. Makagonov)

Vein bodies miaskite pegmatites most fully opened by mines in the southern end of the Ilmen mountains, the largest number of them are localized in miaskites and fenites. Many veins have undergone boudinage, reversal, stretching and dissociation of body fragments and even individual parts of crystals. Separate large crystals of feldspar and nepheline are transformed into chains of "pseudoporphyroblasts" upon deformation of slot-like voids.

Distribution of minerals, their relative value, deformation phenomena, dissolution, metasomatosis recrystallization and produce a plurality of patterns and textures miaskitic pegmatite. Pegmatite structures proper are determined by the sequence of crystallization of minerals in cavities.

Geometric sampling of nepheline-feldspar aggregate in the selvage of miaskite pegmatite. Kop number 7. Ore fragment 10 cm.
Photo B. BUT. priest's

Fragment of the structure of a nepheline-feldspar aggregate with manifestation of geometric selection of minerals.
1 - microcline-perthite, 2 - albite, 3 - nepheline, 4 - annit, 5 - ilmenite, 6 - pyrochlor. According to T. P. Nishanbaev (1982)

Nepheline-feldspar pegmatites in miaskites are often subconcordant with deformation banding of miaskites or form bodies of complex shape with pyrochlore-ilmenite-zircon specialization; in terms of number, this type is absolutely predominant among miaskite pegmatites. They have been opened by many mines, as well as in quarries, where miaskites were mined. During the construction of the buildings of the laboratory building and the museum of the Ilmensky Reserve in 1978-1979, a system of veins was exposed on the cleared area, intersecting gneissed miaskites and their amphibole varieties (mine number 7) laid back at the beginning of the 19th century. P. n. Barbota de Marne).

Vein is severely deformed, but in the surviving ("Shadow") areas and apophyses show a structure of geometric selection with large ingrowths of nepheline, annite and ilmenite along the growth zones of potassium feldspar crystals, reflecting the formation of pegmatite in cavities. Crystallization took place in unstable conditions, which manifested itself in the formation of small microcline ingrowths on the faces of its large crystals in the cavity, as well as in the zonal structure of nepheline crystals, zircon, pyrochlore, in partial replacement of nepheline with cancrinite, sodalite and zeolites in fractured areas. Large faceted crystals of nepheline were found in one of the cavities in pegmatite. In the northern part of the Ilmen mountains and beyond, in the mountains of Dogs and Potanins, there is "solar" nepheline.

Vein of nepheline-feldspar pegmatite, opened by mines No. 113-107-121 in the fenite halo of the massif, in the marginal zone is composed of an almost non-pheline-free feldspar aggregate and, except pyrochlore and zircon, contains eshinite(is), typical for miaskite pegmatites in metamorphic rocks of the southern part of the Ilmen mountains (minerals…, 1949; etc.). The first two mines were laid at the beginning of the 19th century. P.N. Barbot de Marney on "Pleonast" (pirohlor) and zircon, a No. 121 - South Ural Mining Trust in 1925 g. on feldspar; later explored for pyrochlore (Sidorov, Talantsev, 1956f).

Plan and section of miaskite pegmatite vein from mines No. 121-107-113.
1 - miaskites, 2 - amphiboles, 3 - granite pegmatite, 4 - pyroxene syenites and fenites, 5 - feldspar veins (and zones lived), 6 - miaskite pegmatite. According to E. F. Sidorov and A. WITH. Talantsev (1956f), with changes.
Except ilmenite, zircon, pyrochlore and echinite, calcite is developed in nepheline-feldspar pegmatites of different veins, ftorapatit, titanate, magnetite, fluorite and a number of other minerals. In the copy № 210 columnar corundum is found with nepheline in paragenesis with elongated tabular ferrocolumbite and long prismatic zircon.
Nepheline-cancrinite-feldspar pegmatites were found in mines No. 9, 114, 115. They are mostly similar to nepheline-feldspar, but are distinguished by a large amount of primary large-giant-grained colorless and bright yellow cancrinite. Nepheline in these veins is partly replaced by fine-grained cancrinite, cherry, sodalite and zeolites. In the copy № 9 solid solution decomposition is manifested in transparent cancrinite, like "solar nepheline" and feldspars. In the spears № 114 and 115 there are pyrochlores with very contrasting color zoning. Probably, this type may include miaskite pegmatite with primary sodalite and cancrinite, found in the core of the S-2000 well.
Cancrinite yellow
Solnechny-kankrinite

Vyshnevyt

Nepheline-calcite-feldspar pegmatites occur in the southeastern endo- and exocontact of the Ilmenogorsk miaskite massif. These are the famous ilmenite and apatite mines.: № 6 ("Apatite mine in limestone"), 16, 190, 154 and 155 (Savelyev's log and g. Firsova), where the central parts of some sections of veins are composed of a calcite aggregate. maybe, carbonate body, secant and partially located in the nepheline-feldspar pegmatite vein of mine no. 6 among miaskites, is the first find of carbonatites, although the term "carbonatite" appeared only after 100 years old (at 1921 city); really, together with calcite, annite was formed here, ftorapatit, zircon, pirohlor, ilmenite - typical minerals of carbonatites.

Vein bodies of the ilmenite mines of Mount Firsova.
1 - gneisses biotite-plagioclase, 2 - syenite aegirine-augite and feldspatolites, 3 - syenites biotite with interlayers of miaskites, 4 - myositis biotite, 6 amphibole miaskites, 7 - pegmatite veins. According to A. AND. Simonov.

Vein bodies of the ilmenite mines of Mount Firsova.
1 - gneisses biotite-plagioclase, 2 - aegirine-augite syenites and feldspatolites, 3 - syenites biotite with interlayers of miaskites, 4 - myositis biotite, 5 - amphibolite syenites, 6 - amphibolite miaskites,7 - pegmatite veins. According to A. AND. Simonov.

The veins of the Firsova and Lokhmataya mountains were described in most detail by A.. Simonov (1954). The length of the veins reaches 300 m, power - up to 10 m. The structure of pegmatite bodies is usually asymmetric.. The cavities are often filled with a calcite aggregate of different grains with annite, fluorapatite. ilmenite, zircon and rare pyrochlore. Interesting, that the structure of small veins is almost the same, like large, and the central part of them, according to the observations of B. BUT. Berezina, also made with calcite. According to our data, calcite began to crystallize already in the early growth zones of feldspars (2–3 %, small rare ingrowths), then it became more in the zone with annite and nepheline, and, finally, calcite absolutely predominates in volume at the end of the formation of the pegmatite vein, forming a medium-grained, and coarse-grained aggregate with other minerals - fluorapatite, annitom, ilmenite, zircons, pyrochlore, pyrrhotite, etc.. Sometimes in the nepheline-feldspar aggregate, the amount of calcite increases gradually, but relatively abrupt transitions are more common, suggesting "carbonatite-pegmatite" completion of crystallization of some miaskite pegmatites in the first case and the superposition of the carbonatite process in the second.
















“Is the history of the study of the Ilmen mountains completed?? Of course not. Our common work on geology, petrography and mineralogy of the Ilmen mountains showed us, how much remains unfinished, unexplored, unknown. The exploration of the Ilmen mountains must and will continue.”

AT. AND. Kryzhanovsky, 1949 g.

«Sienitovыe pegmatitы. The breeds are united under this name, devoid of quartz, and nepheline, characterized by a pegmatoid structure and occurring in the form of dikes or concordant lenticular bodies. Syenite-pegmatites of the Ilmen Mountains form a less defined, so to speak, group of rocks, than miaskite or granite pegmatites. There are several subgroups among them., interconnected transitions, but presenting some peculiarities and petrographic, and according to the conditions of occurrence. With the naked eye, in the composition of syenite pegmatites, feldspar and a colored mineral are distinguished as the main minerals., most often biotite, then - aegirine-augite or aegirine. Muscovite replaces biotite in some dykes. Corundum is also a mineral, playing the role of a colored component of some pegmatites rich in this mineral ".

Acad. BUT. n. Zavaritskii

Classification of syenite pegmatites:

- Pyroxene-feldspar
- Feldspatolites
- Biotite-two-feldspar
- Anorthoclase biotite
- Muscovite-feldspar
- Calcite-biotite-pyroxene-feldspar

corundum

ZAVARITSKY Alexander Nikolaevich
geologist-petrographer, academician, explorer Ilmen.
Pyroxene-feldspar pegmatites, or, by A. n. Zavaritsky, aegirine-augite syenite-pegmatites occur in fenites and syenites of the exocontact of the miaskite massif and in syenites of the Central alkaline belt. The most complete pyroxene-feldspar pegmatites are exposed by mines No. 15, 65 and 178. In numerous mine workings No. 15, pledged P. n. Barbot de Marni at the beginning of the 19th century. and later explored as the Ilmenogorsk molybdenite deposit (Lobova, 1944f), echelon-shaped lenticular bodies exposed, forming three zones of pyroxene-feldspar pegmatites. Length of zones 100-200 m, extension of the NE 20–35 °, SE dip 35–40 °

In pegmatite bodies, zones or areas with a predominance of feldspars are recorded, piroksyenov (egirin-augita, diopside), amphibole (magnesiohorn blendite, ferroactinolite, fluororichterite) or phlogopite; the central parts of a row of veins are composed of an aggregate of calcite with phlogopite (carbonatite), less often with dolomite and fluororichterite. Aggregate structures are uneven (from average- to giant-grained). Accessory minerals - titanite, molybdenite, gipogennyj povellit, pirohlor, zircon, chevkinite, eshinit-(is), allanit-(is), ftorapatit, magnetite, pyrrhotine, pyrite, chalcopyrite, blende. Occasionally there are voids with clinochlore., quartz or heulandite.

The structure of molybdenite-bearing syenite pegmatite mine No. 15
1 - pyroxene and amphibole-pyroxene syenite-gneisses (fenits), 2 - leukocratic syenitis-pegmatitis, 3 - melanocratic aegirine-augite syenite pegmatite, 4 - phlogopite-bearing carbonatite, 5 - quartz vein, 6 - accumulations of molybdenite. Sketch of the roadway wall from the pit No. 2, depth 12.5 m. According to L.. AND. Frontal, simplified.

Feldspatolites, or substantially plagioclase medium-grained and non-grained vein rocks, usually constituents of feldspar vein systems and represent a combination of metasomatites and veins filling cavities. They are common in areas of localization of bodies of two-feldspar pegmatites., biotite-anorthoclase pegmatites, muscovite-plagioclase veins, nepheline-feldspar and granite pegmatites, including amazonite. In feldspatolites, the medium-grained albite-oligoclase aggregate often contains larger potassium feldspar grains.. Minor minerals are biotite or pyroxenes of the diopside-hedenbergite series, accessory - magnetite, zircon, pirohlor, titanate, ftorapatit, allanit-(is), eshinit-(is).


The shape and position of the bodies of feldspatolites and pegmatites intersecting them.
1 - amphibolites, 2 - biotite granite-gneisses, 3 - biotite syenite, 4 - feldspatolites, 5 - biotite-feldspar pegmatite with zircon, 6 - anorthoclase-annite pegmatite, 7 - pyroxene-quartz-anorthoclase pegmatite, 8 - geological boundaries, 9 - occurrence of rock contacts, 10 - mine workings mine No. 23. According to V. Popova

Biotite – two-feldspar pegmatites make up most of the known veins of syenite pegmatites, opened in zircon, pyrochlore and orthite (allanite) I was digging. Extensive steeply dipping bodies of submeridional and diagonal striking pegmatites are developed in a narrow strip ~ 15 km along the eastern slope of the Ilmen Mountains in the fenite halo of the miaskite massif. Veins usually occupy a cross-cutting position relative to the contacts and gneissiness of the host rocks.. Vein bodies of plate-like or complex shape, developed along the systems of joining cracks. Zircon development P is historically famous. n. Barbota de Marni and F. F. Bloom on the river. Cheremshanke, where in 1837 g. the largest intergrowth of zircon crystals in the Ilmen mountains was mined (3 kg 580 g). This type includes mine No. 12, which exposed a vein of biotite-feldspar pegmatite up to 3 m. zircon
Vein bodies of mines No. 28-29.
1 - pyroxene plagiognes, 2 - amphibolites, 3 - granite-gneiss amphibole-pyroxene, 4 - biotite syenite-gneisses, 5 - feldsparit, 6 - feldspar pegmatite, 7 - granite pegmatite. According to R. B. ruble, with additions B. Popova

Among biotite-feldspar pegmatites, the richest in zircon was mine number 28 on the western slope of Kosaya Mountain near the. Nyashevki, but it is known as "uralorite mine" And. AND. Redikortseva, who laid it, probably, in the middle of the 19th century. AT 1937-38 gg. during exploration for zircon, the mine was expanded, and passed new workings. AT 1975 g. when examining the mine, some workings were cleared and further south, the copy № 29, contacts were opened. Biotite-feldspar pegmatite is composed of predominant oligoclase with a small amount of anorthoclase (antipertitis) and microcline-perthite. Allanit-(is) met in clusters before 50 cm in vein-like segregations with biotite. Zircon with magnetite is rather large (to 3 cm). Preserved information, what in 1929 g. mined from this mine 22 kg zircon, and 1937 g. - more 200 kg (Ustinova, 1940).

The amount of biotite in such veins is not more than 10 %. Accessory minerals - magnetite, zircon, pirohlor, allanit-(is), aeschynite, ftorapatit, titanite - form grains in feldspar and biotite, sometimes with clearly visible surfaces of simultaneous growth. There are also independent crosscutting veins of allanite, zircon, magnetite. ilmenite
Anorthoclase-biotite housing, crosscutting feldspar pegmatite.
1 - amphibolites, 2 - biotite syenite-gneisses, 3 - biotite-two-feldspar pegmatite, 4 - brushes of crystals of anorthoclase, 5 - biotite plates, 6 - fall asleep. SE wall copy № 23-I. According to V. Popova
Anorthoclase-biotite pegmatites are most contrasting in copy no. 23-1, where the biotite-feldspar pegmatite vein is cut with an offset. Large crystals of anorthoclase are in the selvages of the vein, and biotite tables up to 20 cm fill the central largest part of the vein. Geometric selection between crystals is directed towards the center of the core. Zircon is noted from accessory minerals, magnetite, betafit, eshinit-(is), allanit-(is). maybe, in biotite-feldspar pegmatites of a number of mines (№ 28, 146 etc.) similar aggregates with allanite form vein-like segregations.

Muscovite-feldspar pegmatites opened in the XVIII century. a large number of mines for the extraction of white mica in the strip of gneisses and amphibolites of the southeastern extremity of the Ilmen mountains. Feldspar veins with muscovite crystals up to 10 cm, form sublatitudinal, diagonal and, less often, submeridional steeply dipping bodies,. In many veins in selvages, a zone of geometric selection of muscovite and albite-oligoclase individuals inside the vein is manifested, filling cavities. There are surfaces of simultaneous growth between individuals of muscovite and feldspar. Except muscovite, many of these veins are famous for the large crystals of monazite and eshinite (in the mines of Razderishin No. 42–48 and others.); there are also zircon, magnetite, ftorapatit, biotite.

The intersection of feldspatolite residential muscovite-feldspar pegmatite.
1 - gneisses and amphibolites, 2 - feldsparit, 3 - muscovite-feldspar pegmatite, 4 - copy contour № 56. According to V. Popova

Vein structure No. 1 on the horizon 32 m adit No. 1.
1 - amphibolites, 2 - biotite and biotite-amphibole syenites; 3–5 - zones of pegmatite: 3 - biotite-feldspar, 4 - feldspar, 5 - amphibole-pyroxene melanocratic; 6 - accumulations of fluorapatite, 7 - ilmenite-ilmenorutilovye accumulations; 8 - contours of workings. According to V. M. Shemelin and M. AT. Bragin (1941f)

Calcite-biotite-pyroxene-feldspar pegmatites are most vividly represented in mines No. 158, 370, 375.
In the quarries and adits of the Selyankinsky deposit ilmenorutila (numbered as mine # 158) opened 7 ore veins of submeridional strike. Length of veins 20-180 m, thickness 1.3–5 m, in inflated to 14 m; explored to a depth of 50-80 m, stocks over 1000 t, mined from the bowels ~ 300 tons of ore concentrate.
The veins are heterogeneous in structure and composition. In the workings of the adit at a depth 32 m in the vein № 1 marginal zones are composed of biotite-vermiculite giant-grained aggregate, melanocratic feldspar-richterite-pyroxene and then biotite-feldspar alternating to the center of the vein. Biotite-vermiculite aggregate with large precipitates of ilmenorutil and ilmenite, sometimes with zircon and pyrochlore, found in the central zones of pegmatite, forming secant later lenses.

The mouth of the adit No. 1 Selyankinskoye field (1941g).
According to V. M. Shemelin and M. AT. Bragin, 1941f
Zhelvaki ilmenorutila (deformed aggregates) found up to 7-15 kg, ilmenite - up to 40-50 kg. Coarse-giant-grained aegirine-augite aggregate, anorthoclase and barium-containing micropertite potassium feldspar also contains ingrowths of ilmenite, ilmenorutila, calcite, fluoroapatite, titanite. Ilmenite prevails in the veins of the southern part of the deposit.














“Is the history of the study of the Ilmen mountains completed?? Of course not. Our common work on geology, petrography and mineralogy of the Ilmen mountains showed us, how much remains unfinished, unexplored, unknown. The exploration of the Ilmen mountains must and will continue.”

AT. AND. Kryzhanovsky, 1949 g.

Close Menu