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

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Darshay Formation

Darshay Fm

Period:

Archean

Age Interval:

Paleoarchean (AR? dr), Sh1

Province:
SE Tajik (SW Pamir)

Type Locality and Naming

Includes in Shadarlan and Schugnan ranges.

Delineated by B. Ya. Khorova and K. T. Budanova (1965). Within the volumes accepted in this work, these suites were delineated in 1957-1970 by V. P. Bulin, K. T. Budanova, G. S. Volos, and A. G. Davydchenko during geological mapping. In somewhat different volumes, and sometimes under different names, these suites or those close to them were previously delineated by S. I. Klunnikov, V. A. Maslennikov, and M. I. Rabkin (Geol. USSR, vol. 24, 1959; Barhatov, 1963). This is the lower formation in Shakhdaryn Gr

Synonym: Darshay suite

Reference section:

Lithology and Thickness

It is composed of various rocks, the composition of which varies along their strike. The thickness of the suite is 1500 - 2000 m.

In different quantitative proportions, it alternates biotite-garnet, amphibole-garnet-biotite, disthene, sillimanite, and two-pyroxene-garnet gneisses, migmatites, calcite and dolomite marbles. The thicknesses of the layers vary from tens of centimeters to tens of meters. There are lenses and planar deposits of garnet granulites, garnet amphibolites, and eclogite-like rocks. Among the migmatites, there are lenses of two-pyroxene alkali-feldspar-plagioclase granitoids and granodiorite gneisses of the charnockite series. Gneisses with subordinate layers of biotite gneisses, migmatites, and marbles. The thickness of the suite is 1500 m. Its peculiarity is the prevalence of garnet-bearing varieties of gneisses (garnet up to 50-70% of the rock volume), which distinguishes it from other suites of the Shakhdarinsk series, in which the number of garnets is much less.

Lithology Pattern:

Gneiss

Relationships and Distribution

Lower contact

The schematic stratigraphic column indicates the conformable lower contact as Khoreg Fm

Upper contact

The schematic stratigraphic column indicates the conformable upper contact as Wrang Fm

Regional extent

It is widespread in the Southwest Pamir.

GeoJSON

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Fossils

Age

Paleoarchean

Age Span:

Beginning stage:

Paleoarchean

Fraction up in beginning stage:

0.0

Beginning date (Ma):

3,600.00

Ending stage:

Paleoarchean

Fraction up in the ending stage:

1.0

Ending date (Ma):

3,200.00

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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