scholarly journals U-Pb (SHRIMP) age of zircons from granitoid pebbles of Kukkarauk conglomerates of Vendian asha series in the Alatau anticlinorium (Southern Urals)

2019 ◽  
Vol 486 (5) ◽  
pp. 598-602
Author(s):  
A. A. Krasnobaev ◽  
V. N. Puchkov ◽  
N. D. Sergeeva ◽  
S. V. Busharina
Keyword(s):  
Lower Boundary ◽  
Southern Urals ◽  
The Southern Urals ◽  
Radiometric Data

The absence of reliable radiometric data in Vendian deposits of the Uralian and other regions resulted in uncertainty of the ideas of the age of the lower boundary of Vendian. According to the decision of the Interdepartment Stratigraphic Committee, it is located at 600 ±10 Ma. Analysing zircons of granitoid pebbles from Kukkarauk Formation of the standard sections of Vendian in the Alatau anticlinorium, the authors obtained a concordant SHRIMP date - 713.6 ± 6.1 Ma; practically, it is up to now the only reliable date that can be used as a reference for the rocks in the provenance area of the Vendian basin in the Southern Urals which witness for a Vendian erosion of granites which are alike the granites of the Mazara and Barangulovo massifs, situated in the northern part of the Uraltau zone of the Southern Urals, to the east of the area of Vendian sedimentation.

The Lower Boundary of the Vendian in the Southern Urals as Evidenced by the Rb–Sr Age of Glauconites of the Bakeevo Formation

2019 ◽  
Vol 27 (5) ◽  
pp. 573-587 ◽  
Author(s):  
T. S. Zaitseva ◽  
A. B. Kuznetsov ◽  
V. M. Gorozhanin ◽  
I. M. Gorokhov ◽  
T. A. Ivanovskaya ◽  
...  
Keyword(s):  
Lower Boundary ◽  
Southern Urals ◽  
The Southern Urals

scholarly journals Polychronous zircons of volcanics of the Navysh complex of the Lower Riphean Ai Formation (Southern Urals)

Georesursy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 101-112
Author(s):  
Artur A. Krasnobaev ◽  
Victor N. Puchkov ◽  
Nina D. Sergeeva ◽  
Sofia V. Busharina
Keyword(s):  
Age Groups ◽  
Lower Boundary ◽  
Complex Form ◽  
Southern Urals ◽  
Primary Sources ◽  
The Southern Urals ◽  
Geochemical Properties ◽  
Previous Cycle ◽  
Lower Riphean ◽  
Frequent Presence

The volcanics of the Navysh complex of the Lower Riphean Ai Formation in the Southern Urals are well studied petrochemically and dated by several methods. In 2013 zircons from a trachybasalt porphyrite (sample 2152) gave a concordant SHRIMP date 1752±11 Ma, which was used as a fundamental for the lower boundary of the Riphean with no special arguments against it. The later attempts to repeat this date for the Navysh volcanics were not successful: the collected zircons were either more ancient (> 2500 Ma), or more young (< 500 Ma). From the beginning, the zircons with such ages were regarded as xenogenic or secondary metasomatic, or belonging to paleozoic dykes intruding the Riphean volcanics. However, the clearly expressed mineralogical properties of the Paleozoic zircons and their frequent presence in volcanics, not dykes, led to a conclusion that the zircons and Navysh volcanics, containing them, and exposed within the area of development of the Ai Formation, are polychronous. To support this conclusion, the authors studied in more detail the zircons of the Navysh trachybasalts, developed in the Ai Formation. The main conclusion, obtained from this new data, was that the volcanics attributed to the Navysh complex, form a polychronous system, including both the Lower Riphean (1750 Ma) and Paleozoic (450 Ma) rocks. The zircons of these age groups differ in their mineralogical and geochemical properties supporting the idea that they belong to different primary sources which may be due to repeating plume processes, which partly reanimated – heated and melted-rocks of the previous cycle and/or created new sources of melts.

The first data on possible Mezozoic magmatism within the Western slope of the Southern Urals

2018 ◽  
pp. 24-34
Author(s):  
A. O. Khotylev ◽  
N. B. Devisheva ◽  
Al. V. Tevelev ◽  
V. M. Moseichuk
Keyword(s):  
Southern Urals ◽  
Western Slope ◽  
Isotopic Age ◽  
The Southern Urals ◽  
Early Proterozoic ◽  
Carbonate Formations ◽  
Two Bodies

Within the Western slope of the Southern Urals, there are plenty of basite dyke complexes of Riphean to Vendian among Precambrian terrigenous-carbonate formations. In metamorphic formations of the Taratash complex (Archean to Early Proterozoic, the northern closure of the Bashkirian meganticlinorium) there was observed the andesitic dyke with isotopic age of 71±1 Ma (U-Pb SHRIMP II on zircons) and near Bakal two bodies of gabbroids with zircons of similar ages were found. These are the first evidence of possible Mezozoic magmatism in this region.

ABOUT THE PHYTOCENOTIC ROLE OF THE DARKNOUS SPECIES IN THE SOUTHERN URALS

2017 ◽  
Vol 212 (12) ◽  
pp. 48-50
Author(s):  
Ju.P. Gorichev ◽  
◽  
A.N. Davydychev ◽  
A.Yu. Kulagin ◽  
◽  
...  
Keyword(s):  
Southern Urals ◽  
The Southern Urals

Syntaxonomy of mid-successional stages of secondary forests of the central elevated part of the Southern Urals

2012 ◽  
pp. 109-134
Author(s):  
P. S. Shirokikh ◽  
A. M. Kunafin ◽  
V. B. Martynenko
Keyword(s):  
Boreal Forests ◽  
Floristic Composition ◽  
Southern Urals ◽  
Secondary Forests ◽  
Natural Forests ◽  
The Southern Urals ◽  
Active Growth ◽  
Tree Layer ◽  
Shade Tolerant Species ◽  
Successional Stages

The secondary birch and aspen forests of middle stages of succession of the central elevated part of the Southern Urals are studied. 4 subassociations, 1 community, and 7 variants in the alliances of Aconito-Piceion and Piceion excelsae are allocated. It is shown that the floristic composition of aspen and birch secondary forests in the age of 60—80 years is almost identical to the natural forests. However, a slight increase the coenotical role of light-requiring species of grasslands and hemiboreal forests in the secondary communities of the class Brachypodio-Betuletea was noticed as well as some reduction of role the shade-tolerant species of nemoral complex and species of boreal forests of the class Vaccinio-Piceetea. Dominant tree layer under the canopy of secondary series is marked by an active growth of natural tree species.

Caragano fruticis—Pinion sylvestris, the new alliance of xerophillous pine-larch forests of the Southern Urals

2002 ◽  
pp. 42-62 ◽  
Author(s):  
A. I. Solomeshch ◽  
V. B. Martynenko ◽  
O. Yu. Zhigunov
Keyword(s):  
Southern Urals ◽  
The Southern Urals ◽  
Larch Forests ◽  
Steep Slopes

Xerophillous pine-larch forests of the Southern Ural have been described as a new alliance Caragano fruti­cis—Pinion sylvestris. They occur on steep slopes of upper parts of mountain ridges with poorely developed stony soils. Alliance asigned to the class Brachypodio pinnati—Betuletea pendulae, order Chamaecytiso ruthe­nici—Pinetalia sylvestris. Associations Carici caryophyl­leae—Pinetum sylvestris and Ceraso fruticis—Pinetum sylvestris with four subassociations are described. Eco­logical and floristical peculiarities of new alliance in comparison with another alliances of the order Cha­maecytiso-Pinetalia and with siberian class Rhytidio rugosi—Laricetea sibiricae have been discussed.

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