Where: Russian Federation (55.8° N, 48.9° E: paleocoordinates 28.3° N, 42.8° E)
• coordinate stated in text
• outcrop-level geographic resolution
When: Seryi Kamen Member (Pechishchi Formation), Wordian (268.8 - 265.1 Ma)
• Upper Kazanian beds, numbered K6/16 - K6/21 from bottom to top; K6/16 is the top of Member C (Podboi Member), K6/17- K6/20 are from Member D (Seryi Kamen Member), and K6/21 is the bottom of the overlying Member E (Shikhany Member) (Nurgaliev et al. 2015)
Environment/lithology: marine; dolomite
•Bed no. 16, Nizhniy Mylnik ('Lower Soapstone') of Noinsky (1899, 1924)
•Here the upper 0.35m of unit 16 is described as hard, pale, yellowish grey, fine-grained dolostone (17.65-17.75m) grading upwards into grey thin-bedded fine-grained dolostones with molds of bivalve shells (17.75-18.00m) In polished slabs, retains fine-grained laminated ooid grainstone texture.
•Unit K6/17 Interval 18.00-20.05m Thickness 2.05m
•Bed no. 17, Nizhniy Peschanyi Kamen ('Lower Sandy Stone') of Noinsky (1899, 1924)
•Dolostone: grey to yellowish, buff, very fine grained and finely crystalline (0.2mm) idiotopic, seemingly impregnated with organic matter, microporous, relatively soft; locally retains ooidal and bioclastic-ooidal texture and inclined to horizontal lamination sets; the ooids are sometimes internally leached. Brecciation and small (up to 8mm) pebbles of carbonate rocks in the middle (1.0-1.25m from base). The upper part above the pebble horizon shows numerous bivalves and vugs. Numerous macrofossils, preserved as biomoulds. The erosional base (ravinement) locally hosts conglomerate with small dolostone and dolomarl pebbles. At the top buff dolostone, moderately argillaceous.
•Unit K/18 Interval 20.05-20.95m Thickness 0.90m, off-station locally increases to 2.0m
•Bed no. 18, Verkhniy Mylnik ('Uppe Soapstone') of Noinsky (1899, 1924)
•Dolostone: argillaceous and buff-coloured, microporous, thick-bedded and grading at the top into thin-bedded, showing characteristic rhombohedrical jointing and lenticular pattern. In polished slabs, vague horizontally trending features may be an expression of primary lamination or lithostatic compaction. Diverse macrofauna, encountered only in the uppermost part. The unit seems to laterally grade into fine-grained ('sandstone-like') dolostones similar to packages above and below.
•Unit K6/19 Interval 20.95-23.05m Thickness 2.10m
•Bed no. 19, Verkhniy Peschanyi Kamen ('Upper Sandy Stone') of Noinsky (1899, 1924)
•Dolostone: grey, very fine-grained ('sandstone-like'), locally mottled, medium to thick bedded. Nodules and secondary open-space large crystals of gypsum. From base to top: grey and yellow-mottled, weakly fissile dolostone with faintly laminated mudstone texture (0.00-0.25m); brownish grey thick-bedded dolostone with fissile top, partly cross-laminated, showing fine-grained bioclastic-oolitic grainstone texture (0.25-2.10m). Two bivalve horizons are locally abundant, some of them filled with gypsum and chert. Local presence of 1-2m thick partly dolomitised buildups with bryozoan framework and massive ooidal-bioclastic matrix.
•Unit K6/20 Interval 23.05-24.75m Thickness 1.70m
•Dolostone: grey, fine-grained, tight to locally vuggy, partly chertified and dedolomitised into a crystalline limestone. The base yields rare bivalves, brachiopods and branching bryozoans. The upper part (0.85-1.30m) bears numerous chert nodules (0.3x0.4m) and quartz druses; the 40cm at the top is notably vuggy, with gypsum nodules.
•Unit K6/21 Interval 24.75-26.45m Thickness 1.70m
•Bed no. 21, Shikhany of Noinsky (1899, 1924)
•Dolostone: white to pale grey, unevenly crystalline, porous, relatively hard, with thin buckled lamination, rich in granules, nodules and flakes of gypsum (originally anhydrite). The atter locally dominates the rock in the upper part of the unit. Some rock slabs show, typical for sabkha, chickenwire fabric with gypsum nodules displacing and contorting dolomite partings. The rock is vuggy and soft where the gypsum is weathered out. Gypsum nodules contain celestine crystals. Common elliptical chert nodules. The bed top is textured by desiccation polygons." (Nurgaliev et al. 2015)
Size class: macrofossils
Primary reference: D. K. Nurgaliev, V. V. Silantiev, and S. V. Nikolaeva. 2015. Type and reference sections of the Middle and Upper Permian of the Volga and Kama River Regions: A Field Guidebook of XVIII International Congress on Carboniferous and Permian. 1-208 [A. Dunhill/B. Allen/P. Wagner]more details
Purpose of describing collection: taxonomic analysis
PaleoDB collection 197540: authorized by Alex Dunhill, entered by Bethany Allen on 15.11.2018
Creative Commons license: CC BY (attribution)