Kimberlite, Udachnaya-East, Sakha-Yakutia (Russia)

The 350 Ma Udachnaya, the best known example of twin diatremes is located in the Daldyn-Alakit region of the Siberian diamondiferous kimberlite province (Fig.1). A remarkable characteristic of this region is that it contains more pipes with fresh, unaltered olivine than any other kimberlite region within the Siberian province. About 10% of the intrusions exhibit either two adjacent channelways or repeated intrusion of magma through the same chimney.

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Fig.1: Map of the Siberian Platform showing the major kimberlite fields. After Pearson et al. (1995).



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Fig.2: A geological cross-section of the Udachnaya kimberlite. 1 = SFUE kimberlite, 2 = Phase 1 hypabyssal kimberlites; 3 = Phase 2 volcaniclastic kimberlite breccia; 4 = Phase 3 massive volcaniclastic kimberlite breccia; 5 = Phase 4 of hypabyssal dyke kimberlites; 6 = large block of country rocks in kimberlite; 7 = upper and lower aquifers with Ca\Cl waters, 8 = lower aquifer (Na\Cl waters). Country rocks: 1-2UD = the Udachnaya suite, 500–600 m thick, limestones, carbonate sandstones, gravelites. 3CK = the Chukuck suite, 260–340 m thick, coarse clastic dolomites and limestones cemented by cryptocrystalline calcite and gypsum. The middle part of the suite comprises karst dolomite with leached cavities infilled with gypsum, halite, bitumen and oil. mrh = the Markha suite, 370 mthick, limestones and dolomites with occasional beds of carbonate siltstone and argillite. mrk = the Morkoka suite, 220 m thick, interstratified dolomitized limestones, dolomites, carbonate siltstones, argillites, carbonate conglomerates and sandstones. Modified by Kopylova (2013).






Udachnaya kimberlite comprises two separate pipes (Fig.2), the older West and the younger East pipe, that merge at 250 m below the present surface. Each of the Udachnaya pipes formed through 3 to 5 eruptive phases. The Udachnaya East kimberlite includes early hypabyssal diopside-phlogopite kimberlite found as clasts in the younger breccia, several phases of volcaniclastic kimberlite breccia and dykes of hypabyssal monticellite kimberlite. The Udachnaya West kimberlite contains serpentinized olivine throughout the entire explored depth (1200 m), whereas the profile of olivine serpentinization of the Udachnaya East kimberlite is complex. In the upper 400 m of the kimberlite, olivine is 80–95% serpentinized, at 400–500 m it is fresh. Below, the degree of serpentinization gradually increases to 100% at 700–1200 m. The kimberlite includes country rock xenoliths of limestones, dolomites, evaporites, argillites, carbonate siltstone and sandstones. Many carbonate-rich xenoliths, even with sizes of several tens of meters are fully recrystallized into ultracoarse(>20 cm) grains of calcite with quartz.

The block of kimberlite with fresh, unserpentinized olivine and serpentine-free groundmass (called Serpentine Free Udachnaya East, or SFUE) exists in the pipe at 400-500 m depthand encompasses all 3 magmatic phases. The upper contact of the SFUE kimberlite roughly matches the roof of the lower aquifer and is 20 m higher than the contact of the underlying Chukuck suite with the Markha suite above. The contact between SFUE kimberlite and more common kimberlite with serpentinized olivine is very sharp, even on the scale of a single thin section. The SFUE kimberlite is predominantly fragmental, containing 1-30% xenoliths of country rocks and clasts of early hypabyssal phlogopite kimberlite with massive texture.

Based on stratigraphic relationships both intrusions of Udachnaya pipe, formed at the Devonian-Carboniferous boundary (350 Ma), and the age estimates vary from 389 to 335 Ma. The eastern and western bodies of the Udachnaya kimberlite pipe are different from each other in terms of mineralogy, petrography, composition, and degree of alteration. As the alteration of the western pipe can be considered typical of this rock type, the rocks of the Udachnaya-East are unique in having lesser alteration, and in some places they are completely unaltered.
At depths greater than 350 m a particularly fresh porphyritic kimberlite has been found. These rocks are described as dark-grey massive kimberlite, characterized by unaltered euhedral-subhedral olivine phenocrysts set in a dominantly carbonate matrix.
At deeper levels (> 400 m) of the kimberlite body the amount of serpentine in the groundmass gradually decreases and the amount of carbonate in the groundmass increases. Intensive mining of the Udachnaya pipe revealed widespread chloride minerals (mostly halite) as dispersed masses in the groundmass and massive multi-mineral segregations of halite, serpentine, anhydrite, carbonates and hydrous iron oxides.

The Udachnaya-East kimberlites are olivine-rich rocks, a feature shared by the majority of known kimberlites, excluding rare aphanitic kimberlites, such as those from Kimberley, South Africa. Aphanitic varieties among the Udachnaya-East kimberlites are also present on a small scale, either showing sharp linear contacts with, or grading into the more common porphyritic rocks.

The Udachnaya-East kimberlites are dark massive rocks with porphyroclastic fragmental textures. They are exceptionally olivine-rich. The large abundance of olivine (45-60 vol%) is reflected in the high MgO content of the bulk rock compositions (28-36 wt%). Olivine is set in a fine-grained matrix of carbonates (calcite, shortite [Na2Ca2(CO3)3] and zemkorite [(Na,K)2Ca(CO3)2], chlorides (halite and sylvite), and minor phlogopite and opaque minerals (spinel group minerals and perovskite).



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Udachnaya mine, one of the bigger hole on Earth



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Udachnaya mine, one of the bigger hole on Earth



Sample kindly given to me by Anton Chakhmouradian (Manitoba Univesity)

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Panoramic view of the udachnaya kimberlite thin section. Image by Andy Tindle (Virtual Microscope). PPL image, field of view = 2.5cm.




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Panoramic view of the udachnaya kimberlite thin section. Image by Andy Tindle (Virtual Microscope). XPL image, field of view = 2.5cm.




Bibliography



• Kamenetsky, V. S., Kamenetsky, M. B., Sobolev, A. V., Golovin, A. V., Demouchy, S., Faure, K., & Kuzmin, D. V. (2008). Olivine in the Udachnaya-East kimberlite (Yakutia, Russia): types, compositions and origins. Journal of Petrology, 49(4), 823-839.
• Kamenetsky, V. S., Kamenetsky, M. B., & Maas, R. (2011). New identity of the kimberlite melt: Constraints from unaltered diamondiferous Udachnaya-East pipe kimberlite, Russia (pp. 181-214). InTech Open Access Publisher.
• Kopylova, M. G., Kostrovitsky, S. I., & Egorov, K. N. (2013). Salts in southern Yakutian kimberlites and the problem of primary alkali kimberlite melts. Earth-Science Reviews, 119, 1-16.



Photo
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Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 1x (Field of view = 9mm)
yakutia(2).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(3).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 1x (Field of view = 9mm)
yakutia(4).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(5).jpg

Olivine crystals (rounded and fragmented) and garnet with kelifitic rims (consisting of fibrous pyroxene) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 1x (Field of view = 9mm)
yakutia(6).jpg

Olivine crystals (rounded and fragmented) and garnet (isotropic) with kelifitic rims (consisting of fibrous pyroxene) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(7).jpg

Olivine crystals (rounded and fragmented) and phlogopite crystals (brown) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 1x (Field of view = 9mm)
yakutia(8).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(9).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(10).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(11).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(12).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 1x (Field of view = 9mm)
yakutia(13).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(14).jpg

Olivine crystals (rounded and fragmented) and garnet with kelifitic rims (consisting of fibrous pyroxene) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(15).jpg

Olivine crystals (rounded and fragmented) and garnet (isotropic) with kelifitic rims (consisting of fibrous pyroxene) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 2x (Field of view = 7mm)
yakutia(24).jpg

Olivine crystals (rounded and fragmented) and garnet with reaction rim set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(25).jpg

Olivine crystals (rounded and fragmented) and garnet (isotropic) with reaction rim set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 2x (Field of view = 7mm)
yakutia(26).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 1x (Field of view = 9mm)
yakutia(27).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(28).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 1x (Field of view = 9mm)
yakutia(29).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(30).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 1x (Field of view = 9mm)
yakutia(31).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(53).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 1x (Field of view = 9mm)
yakutia(54).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(55).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 1x (Field of view = 9mm)
yakutia(58).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 1x (Field of view = 9mm)
yakutia(56).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(57).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Note the big olivine crystal with intracrystalline deformation. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 2x (Field of view = 7mm)
yakutia(16).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(17).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 2x (Field of view = 7mm)
yakutia(18).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(19).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 2x (Field of view = 7mm)
yakutia(22).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(23).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 2x (Field of view = 7mm)
yakutia(37).jpg

Olivine crystals (rounded and fragmented) and phlogopite (brown) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(38).jpg

Olivine crystals (rounded and fragmented) and phlogopite set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 2x (Field of view = 7mm)
yakutia(39).jpg

Olivine crystals (rounded and fragmented) and phlogopite (brown) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(41).jpg

Olivine crystals (rounded and fragmented) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 2x (Field of view = 7mm)
yakutia(20).jpg

Olivine crystals (rounded and fragmented) and garnet with kelifitic rims (consisting of fibrous pyroxene) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(21).jpg

Olivine crystals (rounded and fragmented) and garnet (isotropic) with kelifitic rims (consisting of fibrous pyroxene) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 2x (Field of view = 7mm)
yakutia(32).jpg

Olivine crystals (rounded and fragmented) and garnet with kelifitic rims (consisting of fibrous pyroxene) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(34).jpg

Olivine crystals (rounded and fragmented) and garnet with kelifitic rims (consisting of fibrous pyroxene) set in a dark groundmass composed by carbonates. Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(36).jpg

Garnet with kelifitic rims (consisting of fibrous pyroxene). Hypabyssal kimberlite. Udachnaya- East, Sakha-Yakutia (Russia). PPL image, 10x (Field of view = 2mm)
yakutia(60).jpg

Garnet with kelifitic rims (consisting of fibrous pyroxene). Hypabyssal kimberlite. Udachnaya- East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(59).jpg

Garnet (isotropic) with kelifitic rims (consisting of fibrous pyroxene). Hypabyssal kimberlite. Udachnaya-East, Sakha-Yakutia (Russia). XPL image, 2x (Field of view = 7mm)
yakutia(44).jpg

Garnet with kelifitic rims (consisting of fibrous pyroxene). Hypabyssal kimberlite. Udachnaya- East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(45).jpg

Garnet (isotropic) with kelifitic rims (consisting of fibrous pyroxene). Hypabyssal kimberlite. Udachnaya- East, Sakha-Yakutia (Russia). XPL image, 2x (Field of view = 7mm)
yakutia(42).jpg

Garnet with kelifitic rims (consisting of fibrous pyroxene). Hypabyssal kimberlite. Udachnaya- East, Sakha-Yakutia (Russia). PPL image, 2x (Field of view = 7mm)
yakutia(43).jpg

Garnet (isotropic) with kelifitic rims (consisting of fibrous pyroxene). Hypabyssal kimberlite. Udachnaya- East, Sakha-Yakutia (Russia). XPL image, 2x (Field of view = 7mm)
yakutia(50).jpg

Garnet with kelifitic rims (consisting of fibrous pyroxene). Hypabyssal kimberlite. Udachnaya- East, Sakha-Yakutia (Russia). PPL image, 10x (Field of view = 2mm)
yakutia(46).jpg

Garnet with kelifitic rims (consisting of fibrous pyroxene). Hypabyssal kimberlite. Udachnaya- East, Sakha-Yakutia (Russia). PPL image, 20x (Field of view = 1mm)
yakutia(47).jpg

Garnet (isotropic) with kelifitic rims (consisting of fibrous pyroxene). Hypabyssal kimberlite. Udachnaya- East, Sakha-Yakutia (Russia). XPL image, 20x (Field of view = 1mm)
yakutia(48).jpg

Garnet with kelifitic rims (consisting of fibrous pyroxene). Hypabyssal kimberlite. Udachnaya- East, Sakha-Yakutia (Russia). PPL image, 20x (Field of view = 1mm)
yakutia(49).jpg

Garnet (isotropic) with kelifitic rims (consisting of fibrous pyroxene). Hypabyssal kimberlite. Udachnaya- East, Sakha-Yakutia (Russia). XPL image, 20x (Field of view = 1mm)