Pulgon Formation

Pulgon Fm

Period:

Silurian

Age Interval:

Lower-Upper (Wenlock-Prídolí), F10b

Province:
Fergana

Type Locality and Naming

Along the village of Pulygon, Alai ridge. G.S. Porshnyakov, A.D. Miklouho-Maclay, 1955 (356, p. 24). Stratotype in the Kadzhi-Say area.

Synonym: Pulgonian suite, Pulgon Suite, Пульгонская св.

Lithology and Thickness

Sandy-clayey, clayey slates with layers of polymictic sandstones, lenses of limestones, cherts, and basalt and diabase covers are present. In the lower parts - clayey quartzitic sandstones (formerly the Arkhakar suite). Thickness 225-1000 m.

Lithology Pattern:

Sandy_claystone

Relationships and Distribution

Lower contact

Conformably overlies the Syuget Fm

Upper contact

It is unconformably overlain by the Arpalyk Fm, or less commonly, conformably by Upper Silurian-Devonian strata (Matchay series) (Bolgari et al., 1982; 165; 460).

Regional extent

In the territory of Uzbekistan, it is observed as small outcrops in South Ferghana (Turkestan-Alai Mountain region).

GeoJSON

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Fossils

In the lower part of the suite, slates contain late Wenlock graptolites Monograptus flemingi Salter., Testograptus testis Barr. and others; in the upper parts, Ludlow graptolites Bohemograptus bohemicus (Barr.), Neodiwersograptus nilssoni (Lapw.), Colonograptus colonus (Barr.), Saetograptus chimaera (Barr.) and others; in limestones, cephalopods - Orthoceras nobile Barr., O. poccelum Barr., O. transiensis Barr., O. michelini Barr, and others.

Age

A.A. distinguished two suites in the considered age interval: the Arkhakar (sandstone) and Pulygon (slate) suites, but as they moved away from the stratotypes, it became difficult to distinguish these suites, so D.A. Starshinin (1994) proposed to combine them into one Pulygon suite (379). It belongs to the Wenlock, Ludlow, and Prídolí stages of the Silurian. (165; 460).

Age Span:

Beginning stage:

Sheinwoodian

Fraction up in beginning stage:

0.2

Beginning date (Ma):

432.47

Ending stage:

Pridoli

Fraction up in the ending stage:

1.0

Ending date (Ma):

419.00

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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