Nikolaev Formation

Nikolaev Fm

Period:

Jurassic

Age Interval:

late Oxfordian - early Kimmeridgian, U3

Province:
Ustyurt-Sultanuzdag

Type Locality and Naming

Along the Nikolaevskaya Pl. sq. 1 Assakeaudan, E. Ustyurt. V.N. Polyakov et al., 1977 (383, table 4, p. 2).

Synonym: Nikolaevskaya Suite, Николаевская св.

Lithology and Thickness

Alternation of gray clayey limestones, marls with layers of anhydrites. Thickness up to 138 m.

Lithology Pattern:

Clayey limestone

Relationships and Distribution

Lower contact

Nikolaev Fm is transgressively overlies the Aginish Fm

Upper contact

It is overlain with erosion by the Shakhpakhtin Fm.

Regional extent

Eastern Ustyurt. Stratotype Along sq. 1 Assakeaudan. N. suite is part of the Gaurdak Horizon (252).

GeoJSON

null

Fossils

In sq. 1 Nikolaevskaya in the interval 2437-2441 m, marine bivalve mollusks Buchia cf. palasi Reys., B. cf. mosquensis (Buch.) Keys.; in the interval 2418-2462 m, brachiopods - Rhynchonella rollieri eltonica Macr., Gissarella assakeaudanica Pojar. From this suite, foraminifers - Praekaraisella usturica Kurb., Trocholina transversani Paslz.

Age

The age of the suite is accepted as late Oxfordian - early Kimmeridgian

Age Span:

Beginning stage:

Oxfordian

Fraction up in beginning stage:

0.65

Beginning date (Ma):

157.14

Ending stage:

Kimmeridgian

Fraction up in the ending stage:

0.5

Ending date (Ma):

152.01

Depositional setting

Depositional pattern:

Additional Information

Compiler:

V.V. Kurbatov – In: GeoGPT translation of: “Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian)”