Neogene

Paleogene

Cretaceous

Jurassic

Triassic

Permian

Carboniferous

Devonian

Silurian

Ordovician

Cambrian

Neoproterozoic

Mesoproterozoic

Paleoproterozoic

Main source = Abduazimova, Z.M. (Ed.), 2001. Stratigraphic Dictionary of Uzbekistan. IMR (Institute of Mineral Resources), Tashkent, 580 pp. (In Russian) Translated to English by the GeoGPT group, Zhejiang Lab, Hangzhou, China--see About

East Daristan Formation

East Daristan Fm

Period:

Silurian

Age Interval:

Ludlow-Prídolí, N4

Province:
Nuratau

Type Locality and Naming

Along the Daristan River, N. Nuratau Ridge. P.N. Podkopaev et al. (1964) in the volume of the Ludlow. Stratotype on the left bank of the Daristansay.

Synonym: East Daristan Suite, Восточноаристантауская св.

Lithology and Thickness

Divided into two subsuites.

Upper subsuite (thickness 40-50m) - dark gray to black flaggy clayey limestones, interbedded with thin-bedded argillaceous slates and medium-bedded organogenic-fragmentary limestones

Lower subsuite (thickness 70-80m) - dark gray argillaceous slates and greenish-gray siltstone (aleurolites) with subordinate layers (1-5cm) of fine-grained aleuropelites and organogenic reddish-yellow limestones

Total thickness 110-130m.

Lithology Pattern:

Clayey limestone

Relationships and Distribution

Lower contact

The boundary between the lower and upper subsuites is conformable. The lower boundary presumably is conformable with the Kyzkolysay Fm.

Upper contact

The boundary between the lower and upper subsuites is conformable. The upper boundary is tectonic

Regional extent

Northern Nuratau, Mikhin-Daristan structure, upper reaches of the Mikhin, Daristan, Kyzkoly rivers. It is an age analogue of the Akkayak Fm.

GeoJSON

null

Fossils

Upper subsuite – filled with fragments of thin-walled brachiopods, crinoids, tabulates. Contains graptolites Tamplograptus formosus(Bouček.), Pseudomonoclimacis ultimus (Perner.), Monograptus pridoliensis Přibyl., Skalograptus lochkovensis Přibyl., S. perexiguus Abd., S. rarus Teller. and others.

Lower subsuite – filled with fragments of thin-walled brachiopods, crinoids, and detritus. In the slates, graptolites - Neodiversograptus nilssoni (Lapw.), Colonograptus colonus (Barr.), Saetograptus chimera salweyi (Lapw.), Bohemograptus bohemicus(Barr.), B. bohemicus tenuis (Bouček), Lobograptus crinitus (Wood.) and others; chitinozoa Conochitina intermedia Eis., Linochitina erratica (Eis.), Cingulochitina cingulata (Eis.), Eisenackitina bohemica (Eis.) and others.

Age

The lower corresponds to the Ludlow in the span of graptolite zones Neodiversograptus nilssoni - Saetograptus leintwardinensis; the Upper unites the composition of rocks of Prídolí age in the span of graptolite zones Tamplograptus formosus - Skalograptus lochkovensis. E.V. Chukarov et al. (1966), A.I. Kim et al. (1970), S.K. Piven et al. (1980) attributed the suite to the Ludlow, later I.A. Kim and S.K. Piven (1987) included tectonic scales of the Kyzkolysay Fm in the composition of the suite and began to date the East Darlstan Fm in the interval of late Wenlock to Prídolí. Z.M. Abdouazimova et al. (1989; 11) during specialized stratigraphic studies clarified the lithological span and age of the suite, dating it to the late Silurian in the interval of Ludlow-Prídolí. In the same volume, it is accepted on the State Geolmap-500 of Uzbekistan (460) and in the monograph (165).

Age Span:

Beginning stage:

Gorstian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

426.74

Ending stage:

Pridoli

Fraction up in the ending stage:

1.0

Ending date (Ma):

419.00

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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