Material composition of the Late Permian granite-rhyolitic formation of islands of Peter the Great bay (Sea of Japan)

Kramchanin K.Y., Anokhin V.V., Ogorodny A.A.

V.I. Il’ichev Pacific Oceanological Institute feb ran, Vladivostok, Russia

altair@poi.dvo.ru

The considered territory is located in a southwest part of Primorski Krai in which limits following large tectonic constructions: I. Laoelin-Grodekovsky terribly-folding system with the West seaside zone II. Activated southern suburb of preriphean of the Hankajsky massive with zones Barabashsko-Muravevskaya and Dunajsko-Anuchinskaya, III. Sihote-Alinskaja terribly-folding system. In water area of Peter the Great bay there is a set of islands the majority from which is concentrated in a strip traced in a southwest direction from peninsula Muravyova-Amurskogo on the distance about 60 km. Largest of them are islands Russian, Popova, Rejneke, Rikorda and the Big Pelis, concerning the Barabashsko-Muravevsky tectonic zone. Two large islands – Askold and Putjatin – are located to the south peninsula Danube (the Dunajsko-Anuchinsky tectonic zone).

Late Permian granite-rhyolitic formation of islands of Peter the Great bay (Sea of Japan). As a result of formation analysis of the late Permian magmatic formations of islands of Peter the Great bay among them allocate following vulkano-plutonic associations

A. Gabbro-basaltic: 1) cover facies: barabashskaja suite; 2) subvolcanic and intrusive facies: muravevsky complex.

B. granite-rhyolitic (sedankinsky a complex): 1) subvolcanic and extrusive facies: rhyolites; 2) subvolcanic facies of granites.

Sedankinsky complex. Massives of the sedankinsky complex were generated as a result of three intrusive phases accompanied dikes and lodes bodies. The first phase is presented hornblendic and biotite-hornblendic quartz diorites, the second – hornblende-biotitic granodiorites, often passing in biotitic granites, the third – granite-porphyries. Mutual relations between these phases are most accessible to supervision and are in details studied in the massifs bared on islands Russian, Popova, Moiseyev and others. For the first time they have been established in a massive located in pool of the river Pioneer (Sedanka) on peninsula Muraveva-Amurskogo, whence the complex has received the name. Granodiorites and leucocratic granites of the second and third phases are connected among themselves, along with phase mutual relations as well facial transitions, and with quartz diorites of the first phase have only active contacts. Leucocratic granites quite often border the central parts of the massifs combined by granitoids of the second phase, and represent, in this case formations of the regional facies. The petrotypes of a sedankinsky complex is considered a massive of an island Russian where formations of granitoids of all three intrusive phases are most full presented. It is necessary to notice also that granodiorites and granites of a considered massive quite often contain xenoliths in various degree granitized and hornfelsed rocks of a gabbro-diabase of a complex.

Subvolcanic and extrusive facies. Rhyolites, felsorhyolites white, violet, pink, glassy, it is frequent fluidal, albitized, chloritized and sericitized. They are combined stock bodies and dykes; the central parts powerful dykes by granite-porphyries. Porphyritic allocation (0–10%) in rhyolites are presented albite-oligoclase (№ 10–25), is more rare andesine and quartz. A great bulk – quartz-feldspathic, vitrophyric. Rhyolites find out all scale of transitions with granite-porphyries which form the whole group of small rods. These are pink porphyritic shape of rock to which phenocrist are presented by albite and, less often, quartz – in the form of roundish grains in the size to 2-3 mm against aplitic or granophyric basic mass. With rhyolites spatially also are genetically closely connected rhyodacite – gray and light gray aphyric glassy rocks which differ from rhyolites presence nodules of amphibole (1–3%).

Facies of subvolcanic granites. Biotitic granites pink, red, medium-grained, porphyric, consist of a microwedge (35–40 %), a plagioclase, albite and oligoclase (20–24 %), quartz (30–38 %) and a biotite (2–5 %). Biotitic granites are connected by gradual transitions (through granite-porphyries) with rhyolites: such mutual relations can be observed at the western coast of passage of Stark. Granosienites red, medium-grained, are combined by potassium feldspar (to 60 %), quartz (10–15 %), a plagioclase (5–10%), a horn blende (8–15 %) and a biotite (1–3 %).

Late Cambrian granite-rhyolitic formation of Primorski Krai. Late Cambrian granite-rhyolitic formation represents the vulkano-plutonic community which all members are connected by gradual transitions. It consists of: 1) suputinskaja stratum of rhyolites and them tuff, lying down with angular disagreement on bottom Cambrian and with stratigraphic disagreement blocked Devonian flora-bearing volcanites (cover facies); 2) extrusives of rhyolites (funnel facies) and 3) massifs of subvolcanic type of voznesenskie granites.

Suputinskaja stratum (cover facies). Tuffolava of felsorhyolites, felsorhyolites – pink, green, violet, white, spherolitic, fluidal and massive rocks. They consist of spherolites (10–30 %) the size 0,5–1,0 sm combined by felsite, and fluidal quartz-feldspathic groundmass felsitic structure. Felsorhyolites sometimes contain rare nodules of potassium feldspar and a plagioclase. Potassium field spars pertitized, forms prismatic crystals with the melted off edges, chloritized and sericitized. Plagioclases are marked also in the form of prismatic crystals; sometimes on them develop grains of leucocsenized sphen. The groundmass of rocks possesses micropoikilitic, spherolitic, occasionally micropegmatitic structure; sometimes quartz forms worm-shaped enclosures in potassium feldspar. Fluidal differences of felsorhyolites, having glassy and microfelsitic structure, consist of cryptocrystallic not individualized substance, in which there are non-uniformly distributed grains of quartz or streaks of secondary quartz.

Crystalolithovitroclastic tuffs consist of fragments (0,3–0,4 mm) of felsorhyolites (5–10 %), splinters of crystals potassium feldspar, quartz, plagioclase (in the sum – about 20 %), volcanic glass (65–70 %). Lithovitrocrystaloclastic tuffs on 75–80 % consist of large (from 0,1 mm to 2–5 mm) splinters of crystals potassium feldspar, quartz, plagioclase and rare fragments of glassy rhyolites. The cementing weight of tuffs is combined by acute-angled fragments of volcanic glass. Lithocrystalovitroclastic psammitic tuffs consist of fragments (40 %) of volcanic glass (80 %), felsorhyolites (10 %), potassium feldspars (5 %), quartz (5 %) and individual grains of a plagioclase and andesites. Lithocrystaloclastic tuffs psefo-psammitic are formed by fragments (60 %) of quartz (55 %), felsorhyolites (43 %) and potassium feldspar (2 %). The groundmass of rocks – similar to a felsite, sometimes crystallized epidotized. Crystalolithoclastic tuffs psefo-psammitic (gravelic) consists of splinters (50 %) of quartz (50 %), potassium feldspar (40 %), felsorhyolites (10 %) and individual fragments of granites. The groundmass of tuffs similar to a felsite, sericitized. Crystaloclastic tuffs psammitic are combined by splinters (35–40 %) of potassium feldspar (50 %), quartz (30 %) and a sour plagioclase (20 %). The groundmass at them ashes, similar to a felsite, sericitized and chloritized.

Extrusives of rhyolites (funnel facies). Extrusive massifs are combined by fluidal rhyolites, felsorhyolites and massive orthophyres which are usually developed among integumentary volcanites. When volcanites bodies break through low Cambrian adjournment, we, possibly, deal with roots of extrusive or with subvolcanoes when the magmatic center didn't incorporate to a surface. However, to distinguish facial an accessory of the given formations it is not obviously possible.

One of large (3×5 km) extrusive massifs ellipsoidal forms with fault restrictions acts in vicinities with village Ljalichi where forms Alunitovaja hill. It is remarkable that it has the root zone opened with erosion presented by the Chapaevsky massif of voznesensky granites which is located on its northwest continuation and is tracked in a river valley Oozy by boreholes. In a development area extrusive rhyolites with abruptly put fluidal fields are observed secondary quartzites, pyrophyllites, dyckites, alunites and sericitized rocks. Most intensively changed volcanites are dated for the central part of a file, and its regional zones are combined by gray and dark-violet rhyolites to which phenocrysts (30–40 %) are presented by quartz, an orthoclase and a biotite, and the groundmass has microfelsitic and spherolitic structure.

Massifs of the voznesensky granites subvolcanic type. Biotitic granites – gray, pink-gray, medium-grained, it is frequent porphyric, hypidiomorphic-granular. They consist of potassium feldspar – a microwedge (30–55 % – 46–50 %), quartz (25–40 % – 32–35 %), a sour plagioclase (11–18 % – 15–30 %) – oligoclase №17–20, more rare №11–13, № 25–27 and albite №5–8, biotite (1-20 %), tourmaline (to 4 %), muscovite (0,8 %), horn blende (0,5 %), ore minerals (0,2-0,7 %) and zircon (0,3–0,4 %). Alaskitic porphyric granites differ from them presence of rather insignificant quantity of a biotite, more sour composition of plagioclases (albite-oligoclase) and the big maintenance potassium field spars – a microwedge (36–60 %). Often meeting granites containing tourmaline hypidiomorphic-granular or micropegmatitic structures are combined by potassium feldspar – a microwedge (33–54 %), quartz (25–30 %), plagioclase (9–22 %) – oligoclase №17–20, №11–13, tourmaline (to 4–7 %; Sometimes to 15 %), a biotite (0,3–2 %), muscovite (0,6 %), ore mineral (0,3 %), zircon (0,2 %) and fluorite (0,7 %). In porphyric granites and granite-porphyries nodules belong to a microwedge (to 7 %), to quartz (5–10 %) and a plagioclase (1–5 %); the basic hypidiomorphic-granular weight the microwedge (44–56 %), a plagioclase (7–15 %) – oligoclase №11–13 form, a biotite (1–2 %).

Besides, on contacts of voznesensky granites with low Cambrian limestones meet trondemites, close to those of Southern Norway, Mountain and Ore Altai. They have hypidiomorphic-granular structure and are combined by oligoclase №18–25 (50–60 %), quartz (15–32 %) and a microwedge (4–13 %). And on contacts of granites with low Cambrian clay slates are established quartz sienites hypidiomorphic-granular structures consisting of a microwedge (40–65 %), oligoclase №25–27 (30–55 %) and quartz (5–10 %).

Above have been considered two similar on composition, but uneven-age vulkano-plutonic associations, first of which contains the sulphidic mineralization which is not representing interest in the industrial purposes, and the second containing industrial mineralization. In formation voznesensky biotitic and Li-F granites and connected with them deposits (fluorite, tantalum, tin, beryl etc.) fluorine played large role. In gaseous-liquid inclusions concentration of fluorine are met to 0.6m. Richest with fluorine voznesensky Li-F granites, containing Ta-Nb mineralization and deposits and in which exocontact blue cap carbonate rocks are transformed to fluorite deposits (Voznesensky, Boundary, etc.). Lower maintenance of fluorine is characteristic for biotitic granites of voznesensky complex and other granitoids.

References:

1. L. A. Izosov, V. T Sedin, T. A. Emeljanova, etc. (2008) The new data on magmatic complexes of island Popova and some problems of geology of Peter the Great bay: the Current state and tendencies of change of environment of Peter the Great bay of sea of Japan. M: GEOS. 355–378.

2. A.M. Aksjuk, A. A. Konyshev, L. A. Izosov. (2010) Experimental researches of fusion of granites and physical and chemical conditions of formation of deposits of Voznesensky ore knot, Primorski Krai: Theses of reports of XVI Russian meeting for experimental mineralogy. On September, 21-23st, 2010 IEM the Russian Academy of Sciences (Chernogolovka). 35–36.

2. L. A. Izosov, S. N. Kononets, M. G. Valitov. (2008) Voznesenskaya granite-rhyolitic formation of Primorski Krai: problems of geology and metallogeny: Regional problems №10. 55–63.