Dzhalatar Fm
Type Locality and Naming
Along the Say Dzhalatar, N. Nuratau Range. R.R. Usmanov et al. (1978f). Stratotype Along Dzhalatarasai.
Synonym: Dzhalatar Suite, Джалатарская св.
Lithology and Thickness
Lower part - rhythmically interbedded thin-bedded and fine-grained siltstone (aleurolites) and claystone (argillites) of dark gray and dark dirty green color. Thickness 60-70m.
Above, black and dirty green claystone (argillites) containing layers of gray clayey limestones (15-30m)
Overlain by a package of dark gray, black, dirty dark green claystone (argillites) with rare layers of platy fine-grained siltstone (aleurolites). Thickness 10-15m.
The section is topped by a package of "platy cherts" (quartz-chlorite, quartz-siliceous rocks) of black, gray, bluish-gray, green color with thin horizontal and oblique wavy bedding (thickness 20m), on which olive-green, light green, brownish-magenta claystone (argillites) with layers of thin-plate siltstone (aleurolites) (30m) lie. According to R.R. Usmanov (1999), tuff-siltstone (aleurolites) are present in the upper part of the section.
Total thickness over 135-165m.
Relationships and Distribution
Lower contact
Stratigraphic contacts are unknown. It is assumed that it gradually builds up the section of the Karakush Fm.
Upper contact
Stratigraphic contacts are unknown.
Regional extent
South slope of the Northern Nuratau range, Merishkorskaya, Mikhin-Daristanskaya, Koytashskaya structures, along the north slope of the Tamerlanova ridge; S. Nuratau range, Kizyl-Karagai pass area, Uzgarkul village, Kuraev basin. The analog of the Ordovician Akbulak Fm in the Malguzar Mountains, the Kurbanazin Fm in the S. Nuratau, and the Telibay Fm in the S. Bukantau; the upper part is correlated with the Dzhery Fm of the S. Tamdytau.
GeoJSON
Fossils
In the Dzhalatar Fm, there are traces of bottom currents, mechanoglyphs, as well as numerous traces of the activity of various organisms: trilobite tracks, worm burrows, burrows, among which Megagrapton sp., Helminthopsis sp., Dictyodosa cf. scotica Weiss. (Pyanova et al., 1986) have been identified.
The rocks of the suite are filled with radiolarians Entactina sp. (ex gr. elongata Naz.), Pylentonema sp., Entactinosphaera(?) cf. dasysa Naz., Ulcundia sp., etc., chitinozoans - Linochitina pissotensis Paris., Desmochitina minor f. typica Eis., D. minor f. cocca Eis., Lagenochitina deunfi Paris., Conochitina parva Umn., etc.; conodonts - Drepanodus cf. subarcuatus(Br. et Mehl.), Acontiodus cf. rectus Lind., Oistodus cf. lancelatus Pand., Cordylodus spinatus (Had.) etc., characteristic of the upper Lower (Arenig)-Middle Ordovician deposits (Abduazimova et al., 1985, 1993, 1996; Usmanov et al., 1999; 37; 165; 460).
Age
Depositional setting
Additional Information