Alay Formation

Alay Fm

Period:

Paleogene

Age Interval:

Middle Eocene (Lutetian), F2, F3

Province:
Fergana

Type Locality and Naming

Along the Alay ridge. O.S. Vyalov, 1935 (155, p.280). Stratotype in the area of the city of Isfara, Fergana Depression.

Synonym: Alay Suite, Alai Fm, Алайская св, Alay mountain, Alay layers, Alay horizon

Lithology and Thickness

Limestones, dolomites, marls, clays, sandy-clayey, sandy-calcareous deposits, sometimes variegated and gypsum-bearing with lenses and veins of chalcedony (Tashsai, Parlisai, Kyzylalma), with organic remains filled with siliceous material (Fergana, South-Eastern Gissar). Thickness is 0-160m.

Lithology Pattern:

Dolomitic limestone

Relationships and Distribution

Lower contact

Lies conformably on the Suzak Fm, Givar Fm, Sulyuktin Fm, Akkum Fm, Syurenatin Fm, Opichek Fm

Upper contact

Conformably overlies the Turkestan Fm, Gulizindan Fm

Regional extent

Fergana Depression, South-Eastern Gissar, Pre-Tashkent region, plain areas of Uzbekistan. S.N. Simakov (413) in the Fergana Depression to the Alay Fm attributed the "k" horizon (upper part of the Bukhara horizon and variegated gypsum-bearing deposits of the Suzak horizon).

GeoJSON

null

Fossils

Contains foraminifera - Acarinina pentacamerata Subb., A. bullbrooki (Bolli), A. interposita Subb.; marine bivalve mollusks - Ostrea turkestanensis Rom., Lucina consobrina Desh., Venericardia viquesneli Arch., Cardium porulosum Sol., Pitar gumberensis Arch., Pteria elytracea Rom. and others; gastropods - Turritella alaica Vial. et Soloun.; ostracods - Schuleridea ampulla Mand., Ehinocythereis vialovi alaensis Mand., Eocytheropteron kalickyi Mand.

Age

Belongs to the Middle Eocene (lower part of the Lutetian Stage)

Age Span:

Beginning stage:

Lutetian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

48.07

Ending stage:

Lutetian

Fraction up in the ending stage:

0.5

Ending date (Ma):

44.55

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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