Mailisay Formation

Mailisay Fm

Period:

Neogene

Age Interval:

Lower-Middle Miocene, F2

Province:
Fergana

Type Locality and Naming

Along the Maylisai River, Fergana Depression. M.N. Gramm, 1958 (467, p.170). It is included in the Chatkal-Kuramin Gr of the 1:50,000 sheets, 1998.

Synonym: Maylisay Fm, Maylisai Suite, Mailisaaiskaya Fm, Майлисайская св.

Lithology and Thickness

Brick-red clays and siltstone (aleurolites), pinkish and brownish-gray sandstones, gravelites, and conglomerates. Thickness 280-690m.

Lithology Pattern:

Sandy_claystone

Relationships and Distribution

Lower contact

With erosion, it lies on the Sumsar-Paleog Fm

Upper contact

It is also overlain by the Obchak Fm

Regional extent

Fergana Depression. Exposed in its flanks and uncovered in the central part. B.I. Pinhasov correlated with the Agitmin Fm of the Kyzylkum, into which it transitions through the intermediate Chulin Fm of the Golodnostepskoye Depression.

GeoJSON

null

Fossils

Contains ostracods - Eucypris excistus Gr., E. aggeratus Gr., E. medius Gr., E. validus Gr., Limnocythere kuschnari Gr., L. depressa Schn., Cyprinotus baturini Schn., Iliocypris errabundis Mand.

Age

According to A., the age is Oligocene. V.I. Popov et al. (166) correlated it with the Shurysai Fm and considered it Oligocene. O.S. Vyalov included the Mailisay Fm in the lower part of the Oligocene-Miocene Massaget Gr he distinguished. Yu.R. Smolnikov et al. (1973) assigned their lower Maylisai sub-suite (Maylisai suite of M.N. Gramm) to the Lower Miocene. B.I. Pinhasov accepts the age of the suite as Lower-Middle Miocene based on its position on the Sumsar-Paleog Fm. In the Khorezm region, the continental red beds of the Agitmin Fm are initially interbedded, and to the west, they are completely facially replaced by marine deposits of the Kotsakhur-Middle Sarmatian. Given that the main volume of the Sarmatian is assigned to the Middle Miocene, the upper age boundary of the red beds of the Tien-Shan molasses, which never rose above the Lower Miocene, is limited to the Middle Miocene.

Age Span:

Beginning stage:

Burdigalian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

20.45

Ending stage:

Tortonian

Fraction up in the ending stage:

0.0

Ending date (Ma):

11.63

Depositional setting

Depositional pattern:

Additional Information

Compiler:

B.I. Pinhasov – In: GeoGPT translation of: “Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian)"