Changi Formation

Changi Fm

Period:

Triassic, Jurassic

Age Interval:

Rhaetian – Hettangian, CK2, CK5a, CK8, CK9

Province:
Chatkal-Kuramin Region

Type Locality and Naming

Along the village of Changi, Parkent district, foothills of the Chatkal Range. V.V. Kurbatov in 1989; V.I. Troitsky, V.V. Kurbatov, 1998 (165, p.127). Stratotype along borehole 1 Kyzylkisaksay, village of Changi. Parastratotype at the Karankul pass.

Synonym: Changi Suite, Чангиская св.

Lithology and Thickness

Variegated breccias, conglomerates, gravelites, sandstones (on kaolinite cement), clays, siltstone (aleurolites), and one or two layers of bauxite-like rocks, characterizing deposits of a lake and alluvial plain. Thickness 6-145m.

Lithology Pattern:

Aus Conglomerate

Relationships and Distribution

Lower contact

The suite transgressively overlies the Paleozoic

Upper contact

It is also overlain by the Angren or Azatbash suite.

Regional extent

Exposed in discontinuous outcrops in the Chatkal-Kuramin Mountains (Changi, Karankul, Aksagat) and intersected by boreholes in the Parkent district, Angren coal mine, and Prishakhtinsky Chuly. Previously distinguished as the Mansuratin Fm

GeoJSON

null

Fossils

Organic remains not found.

Age

Based on position in the section and analogy with the Sandjar, Ravat, Kamysbashin, and Naut suites, containing bauxite-like rocks and re-deposited weathering crusts, the age of the Ch. suite is conditionally determined as Late Triassic (?) - Early Jurassic (?).V.S. Zimmermann (494) considered it Middle Upper Jurassic, O.A. Fedorov (477) Valanginian, R.Yu. Muzafarova (312) Early Albian, and the Samarkand Stratigraphic Conference (383, table 5, p.2) Late Jurassic. In 1987, at the III Kazakhstani Stratigraphic Conference, the Mansuratin suite in the Priyshimkent district was recognized as invalid.

Age Span:

Beginning stage:

Rhaetian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

205.74

Ending stage:

Hettangian

Fraction up in the ending stage:

1.0

Ending date (Ma):

199.46

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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