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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

Madzherum Formation

Madzherum Fm

Period:

Proterozoic

Age Interval:

Lower Proterozoic (?), N6

Province:
Nuratau

Type Locality and Naming

Along the Madjerum ridge, northern slope of the N. Nuratau ridge. First identified and mapped by P.N. Podkopaev et al. in 1961 (1964) as the Ittynusai suite, conditionally of Early Paleozoic age, V.N. Ognev et al., 1968 (337, p.21-30) formations of this suite were named Madjerum and attributed to the Lower Proterozoic. Since then, both of these names have appeared in geological documents.

Synonym: Madzherum (Ittynusai) Suite, Маджерумская (иттынусайская) св., Makjerum Fm

Lithology and Thickness

Mainly greenstone volcano-sedimentary rocks, metamorphosed into epidote-amphibolite facies into amphibolites, garnet-biotite-amphibolite gneisses, clinzoisite-albitic rocks. Along the lithological composition, they are subdivided into two sub-suites

Upper conformably overlies the Lower and is represented by greenish-gray metasandstones, platy greenish-gray epidote-sericite-chlorite meta-aleuritic sandstones, coarse-clastic apotuffitic rocks, and thin-bedded microslates of ferruginous quartzites and quartz-hematite rocks. Thickness 500-1000 m.

Lower - initially volcano-sedimentary, represented by alternating albite-vitrite-chlorite-epidote, albite-quartz-epidote-vitrite, albite-epidote-actinolite slates (436). Thickness 600-900m.

Lithology Pattern:

Sandstone

Relationships and Distribution

Lower contact

Upper contact

Regional extent

Rocks of the suite form several isolated sublatitudinal tectonic blocks extending along the northern slope of the North Nuratau ridge from the district center of Farish to Sopsay, in the basin of the Andygen-Uhum-Madjerum rivers. From the north, the suite is limited by the North Nuratau deep fault, from the south by the large Madjerum fault (351). The Makzherum Fm is an equivalent of the Uchquduktau Fm (North Tamdytau) and the Kumbulak Fm (North Bukantau). Under the name Itgynusay Formation, it is known in archival and published literature (Chukarov et al., 1966f., 1968f; Asatullaev et al., 1972f., 75; 122; 351). In the latest geological maps of the S. Nuratau range (Usmanov et al., 1984f., 1999f., Korsakov et al., 1993f.; Gosgeolcarkta500 of Uzbekistan (460)), it is referred to as Madzherum Fm. O.I. Kim et al. (1976f.) described the lower part of the formation section as Ovruk Fm.

GeoJSON

null

Fossils

Age

The age of the suite is conditionally considered Early Proterozoic based on the specific type of metamorphism, the earliest, according to N.L. Dobretsov, compared to other types of metamorphism, characteristic of the most ancient formations, as well as the development of a unique ferruginous-quartz formation, characteristic mainly of ancient rocks. The earliest stage of diaphthoresis manifested itself during the Baikal cycle of tectogenesis, as absolute age data by the potassium-argon method range from 718 to 631 million years (435). Madzherum Fm was studied in detail by O.A. Starcev and I.V. Mushkin (436), O.A. Starcev (435), who determined the glaucophane type of metamorphism for its rocks and dated the Fm as Riphean. A.K. Bukharin et al. (122) express the opinion of its Ordovician-Silurian age based on finds of Paleozoic chitinozoa, which Z.M. Abdazimova et al. (16) refer to abiogenic formations. A.V. Pokrovsky et al. (351) distinguish rocks of various genetic types in the Madzherum Fm: metavolcanites, including metabasites and metagraywackes (coarse-clastic apotuffaceous rocks), quartzites, consisting of 90-95% quartz, in which associations with manganese garnet, hematite, and piedmontite (group of ferruginous quartzites; according to O.A. Starcev and I.V. Mushkin (436)), metasandstones and metasiltstone (aleurolites), intensely metamorphosed and recrystallized with the new formation of muscovite, biotite, etc.; age - conditionally late Riphean-early Paleozoic. I.M. Mirhodzhaev, V.A. Kholodov et al. (307) attributed the Fm to the middle-late Riphean, L.N. Belkova (99) - to the Riphean, in the Strat. sl. (442) and on the Gosgeolcarkta-500 of Uzbekistan (460) it is dated conditionally as Proterozoic.

Age Span:

Beginning stage:

Ectasian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

1,400.00

Ending stage:

Ectasian

Fraction up in the ending stage:

1.0

Ending date (Ma):

1,200.00

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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