Alkaline Rocks and Carbonatites of the World

Setup during HiTech AlkCarb: an online database of alkaline rock and carbonatite occurrences

Chernigovskii (Novopoltavskii)

stripes

Occurrence number: 
171-00-011
Country: 
Ukraine
Location: 
Longitude: 36.25, Latitude: 47.23
Carbonatite: 
Yes

This massif was discovered over 20 years ago and has been described in a number of publications including a comprehensive report by Glevassky and Krivdik (1981b) and a more recent one by Shramenko et al. (1992). The occurrence of alkaline rocks and carbonatites is confined to the so-called Chernigovka (after the village of Chernigovka, Zaporozhye region) fault zone of highly metamorphosed (granulite facies) Archaean rocks, which include gneiss, charnockite, migmatite, granite, metabasite and two-pyroxene schists. The alkaline igneous rocks and carbonatites occur intermittently in the fault zone over a length of about 20 km. The Chernigovskii massif has an elongated shape and consists of two lenticular parts, a northern larger part, Chernigovka proper, the so-called New Poltava, and a southern, or Begim-Chokrak part. The most widely developed rocks of the massif are alkaline syenites, tveitasites, a nordmarkite series and carbonatites; nepheline syenites (canadites) and alkaline pyroxenites are subordinate. Other rocks, including ijolite-melteigite, phlogopite olivinite and peridotite, are found either as inclusions in carbonatites or in bodies of small size which occur sporadically (kimberlitic carbonatites, albite-barkevikite essexites). Enclosing granitoids and metabasites in the contact zone are variably fenitized. Carbonatites, alkaline pyroxenites and canadites occur as steeply dipping, up to vertical, dyke-like bodies which strike approximately north-south. The maximum thickness of rocks in the complex, including fenites, is 600-700 m. Four major types of carbonatites can be distiguished, namely sovites, alvikites, beforsites and kimberlitic carbonatites. Closely associated with the beforsites are phoscorites - rocks rich in apatite and/or magnetite. Carbonate-silicate rocks, which are of rare occurrence and transitional in composition from syenite-tveitasite to carbonatite, are classified as ringites. The sovites are calcite carbonatites containing apatite, aegirine-salite, biotite and amphibole. Accessory minerals include pyrochlore-hatchettolite, rare columbite, zircon, titanite, monazite, orthite, magnetite and sulphides. In spite of their widespread occurrence the sovites are of subordinate development accounting for only one quarter of the total mass of carbonatites. The alvikites are calcite carbonatites containing apatite, olivine, diopside or aegirine-diopside, phlogopite or tetraferriphlogopite and magnetite. Typical accessories include zircon, ilmenite (picro-ilmenite), sulphides and rarely anatase, columbite, pyrochlore, hatchettolite and monazite. The alvikites account for about 15% of the total mass of carbonatites in the complex: they are best developed in the southern part of the massif (Fig. 47). Beforsites are calcite-dolomite, dolomite-calcite and dolomite carbonatites containing apatite, olivine, phlogopite and magnetite. Accesories are represented by spinels, sulphides, columbite, cerian fergusonite, pyrochlore-hatchettolite, baddeleyite, zircon, monazite and ancylite. Beforsites are the most widely developed of the carbonatites of the Chernigovka massif, accounting for about 60% of the carbonatites. With increase in the content of apatite, magnetite and phlogopite in the beforsites they grade into predominantly apatite, apatite-magnetite, olivine-apatite and phlogopite-apatite rocks, that is phoscorites. Kimberlitic carbonatites are compositionally transitional between carbonatites and kimberlites. They are brecciated or massive phlogopite-olivine (serpentine)-calcite rocks containing a smaller amount of carbonate (25-50%) as compared with the carbonatites described above. Kimberlitic carbonatites occur only in the southern part of the massif in the form of thin, rarely more than 10 m thick, vertical dykes. Carbonatites of the Chernigovskii massif are also characterized by inclusions of the associated cumulative ultrabasic rocks, of which the silicate minerals (olivine, pyroxene, amphibole, biotite, phlogopite) are identical to those occurring in the carbonatites. Thus, olivine carbonatites, beforsites and alvikites generally contain inclusions of olivinite, olivine-bearing glimmerite and peridotite, while biotite-amphibole and pyroxene carbonatites, which are usually sovites, include biotite-amphibole and amphibole-pyroxene-biotite ultrabasic rocks. Whole rock carbonatite analyses and extensive modal and other data on the minerals of the carbonatites are given by Vil'kovich and Pozharitskaya (1986), and data on REE in carbonatites by Shramenko and Kostyuchenko (1985). Vozvnyak et al. (1981) have described melt and mineral inclusions from baddeleyite in carbonatite. Although the Chernigovskii massif as a whole has many features characteristic of carbonatite complexes, it also has a number of peculiar structural, petrological and mineralogical features. The elongated form of the massif is distinct from that of the central type, which comprise the majority of carbonatite complexes. Olivines in alkaline ultrabasic rocks and carbonatites of the massif are characterised by abnormally high iron content (up to Fa70); the olivine is frequently associated with graphite. Nepheline syenites are represented by biotite-albite canadites in which Ca-Na amphiboles are transitional between edenite-hastingsite and katophorite. Accessory cerian fergusonite (brocenite) is only the second occurrence in the world.

Economic: 
There is rare metal, apatite-magnetite and magnetite-ilmenite mineralization associated with the massif (Glevassky and Krivdik, 1981b; Zshukov et al., 1973).
Age: 
A minimum age of 1820 Ma was obtained by K-Ar on phlogopite from phlogopite olivinite, and a maximum age of 2190 Ma was determined by the lead method on zircon from carbonatite (Scherback et al., 1978).
References: 

GLEVASSKII, E.B. and KRIVDIK, S.G. 1981b. Peculiarities of metallogeny of the Chernigov carbonatite massif. In: Ore formation and metallogeny. 72-6. Naukova Dumka, Kiev.
SHERBACK, N.P. (ed), ZLOBENKO, V.G., ZSHUKOV, G.V. et al. 1978. Catalogue of isotope data of the rocks of the Ukrainian Shield. Naukova Dumka, Kiev. 233 pp.
*SHRAMENKO, I.F. and KOSTYUCHENKO, N.G. 1985. Rare-earth elements in Azov carbonatites. Geochemistry International, 22(8): 43-6.
SHRAMENKO, I.F., STADNIK, V.A. and OSADCHII, V.K. 1992. The geochemistry of carbonatites from the Ukrainian shield. Naukova Dumka, Kiev. 211 pp.
*SHRAMENKO, I.F., LEGKOVA, G.V., IVANITSKIY, V.P. and KOSTYUCHENKO, N.S. 1991. Mineralogical and geochemical studies of the petrogenesis of the Chernigov carbonatites. International Geology Review, 28(8): 102-9.
*VIL'KOVICH, R.V. and POZHARITSKAYA, L.K. 1986. Compositional evolution of carbonatites in the Chernigov zone, Azov region. Geochemistry International, 23(7): 92-100.
*VOZYNAK, D.K., KVASNITSA, V.N. and KROCHUK, V.M. 1981. Solidified melt inclusions in baddeleyite from carbonatite of the Azov region. Doklady Earth Science Sections. American Geological Institute, 259: 167-70.
ZSHUKOV, G.V., BARKHOTOV, V.A. and SAKHATSKY, I.I. 1973. About the discovery of phosphate mineralization in the western Azov region. Geologicheskii Zhurnal, 33: 144-6.

Map: 
Fig. 2_47. Chernigovskii (after Krivdik and Tkachuk, 1990, Fig. 4).
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith