Bactrian Gr

Cenozoic

Cretaceous

Jurassic

Triassic

Permian

Carboniferous

Devonian

Silurian

Ordovician

Cambrian

Neoproterozoic

Main source = Baratov, R.B., et al. (1976). Subdivisions of stratified and intrusive rocks of Tajikistan. Publishing House "Donish", Dushanbe, 269 pp. plus tables. Provided by Dr. Jovid Aminov, Nazarbayev University, Astana, Kazakhstan Translated to English by the GeoGPT group, Zhejiang Lab, Hangzhou, China--see About

Select Region(s) to search
Hold Ctrl (Windows/Linux) or Command (Mac) to select multiple

Bactrian Gr

Period:

Neogene

Age Interval:

Pliocene (N2bk), S2, S3

Province:
North Tajik

Type Locality and Naming

Includes in Fergana Valley, Isfara River

Synonym: Bactrian series (Бактрийская серия)

Reference section:

Lithology and Thickness

Lower part - sandstones, upper part – conglomerates. It has a two-membered structure. The Lower part (thin-bedded suite) is composed of alternating light-brown sandstones and reddish-brown siltstones. Near local paleo-uplifts, they contain interlayers of gravelites and conglomerates, far from them - interlayers of clays, marls, and limestones. The thickness of the lower part of the Bactrian series ranges from 1000 m in the north of the South Ferghana region, in the mountains of Akchop - Akbel - Supetau, down to 500 m in the south of this region and down to 100 m in the Turkestan region. The Upper part (thick-bedded suite) near the paleo-uplifts is represented by gray gravelites and conglomerates, far from them - gray and brown coarse-grained sandstones, containing interlayers and lenses of gravelites and conglomerates. Its thickness is the same as the lower part of Bactria. The thickness of the Bactrian series in the north of the South Ferghana region in the mountains of Akchop Akbel - Supetau reaches 2000 m, in the south of this region it decreases to 1000 m. In the Turkestan region, it decreases in the southern direction from 1000 to 200 m.

Lithology Pattern:

Coarse-grained sandstone

Relationships and Distribution

Lower contact

The Bactrian Gr lies on the Miocene Massaget Gr with erosion, and in some places with angular unconformity

Upper contact

Unconformably overlain by deposits of the lower Quaternary Sohsky Gr.

Regional extent

It is widespread in the South Ferghana and Turkestan regions.

GeoJSON

{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[68.81,39.88],[69.03,39.9],[69.45,39.98],[71.41,41.03],[71.78,41.31],[73.02,40.87],[71.84,39.88],[70.94,39.83],[70.1,39.66],[68.92,39.51],[68.44,39.58],[68.41,39.72],[68.54,39.89],[68.81,39.88]]]]}}

Fossils

Gastropod and ostracod remains

Age

The Pliocene age of the described series is determined by the finds in the lower thin-bedded suite of gastropod and ostracod remains of the Pliocene type (Geol. USSR, vol. 24, 1959; Geol. USSR, vol. 23, 1972). Considering contacts are unconformities; then for graphic purposes, assumed that the base is late Zanclean (early Zanclean absent) and upper hiatus is Gelasian.

Age Span:

Beginning stage:

Zanclean

Fraction up in beginning stage:

0.5

Beginning date (Ma):

4.47

Ending stage:

Piacenzian

Fraction up in the ending stage:

1.0

Ending date (Ma):

2.58

Depositional setting

Depositional pattern:

Additional Information

Compiler:

Extracted from Baratov, R. B. (1976). Subdivisions of stratified and intrusive rocks of Tajikistan. Donish, Dushanbe, 276.