Urubulak Formation

Urubulak Fm

Period:

Silurian

Age Interval:

Llandovery (Lower-Middle Substages), CK9c

Province:
Chatkal-Kuramin Region

Type Locality and Naming

Along Urubulak stream, Mogoltay Mountains. B.N. Nasledov in 1935 (169, p.61, 88). Stratotype Along Urubulak stream, Mashrapsay basin.

Synonym: Urubulak Suite, Урублакская св.

Lithology and Thickness

Flyschoid interbedding of argillites, siltstone (aleurolites), and green sandstones with rare carbonate nodules. Thickness 600-800m.

Lithology Pattern:

Siltstone

Relationships and Distribution

Lower contact

Lower boundary is normal with Kayrak-Ord Fm. or sharply unconformable with Kalcanatin Fm.

Upper contact

It is overlain with erosion by Mazorbobin Fm. or with angular unconformity by volcanogenic formations of Agadjol (= Katrangin Fm)

Regional extent

Almalyk district, Sardobsay, middle course of Karakiyasay.

GeoJSON

null

Fossils

Contains numerous imprints of micromedusae and graptolites Akidograptus acuminatus (Nich.), A. ascensus Davies, Cystograptus praepenna Obut et Sobol., Climacograptus vesiculosus (Nich.), C. ex gr. normalis Tőrnq., Orthograptus cf. sinitzini Chal. and others

Age

Fossil data characterizes the early Llandovery (Rhuddanian-Telychian) age of the deposits. A. considered Urubulak Fm Ordovician based on the find of a trilobite, possibly Ogygites sp. Attempts to reidentify this sample were unsuccessful due to the loss of the sample. (165; 443; 460).

Age Span:

Beginning stage:

Rhuddanian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

443.07

Ending stage:

Telychian

Fraction up in the ending stage:

1.0

Ending date (Ma):

432.93

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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