scholarly journals TIME CONSTRAINTS ON THE FORMATION OF THE KANDALAKSHA AND KERETSK GRABENS OF THE WHITE SEA PALEO-RIFT SYSTEM FROM NEW ISOTOPIC GEOCHRONOLOGICAL DATA

2021 ◽  
Vol 12 (3) ◽  
pp. 570-607
Author(s):  
N. B. Kuznetsov ◽  
A. S. Baluev ◽  
E. N. Terekhov ◽  
S. Yu. Kolodyazhnyi ◽  
E. S. Przhiyalgovskii ◽  
...  
Keyword(s):  
White Sea ◽  
Weighted Average ◽  
Rift System ◽  
The White Sea ◽  
Formation Cross Section ◽  
East European ◽  
Secondary Sources ◽  
Study Results ◽  
Basic Magmatism ◽  
Stratigraphic Position

Initially, the age and stratigraphic position of the Tersk formation were determined with respect to the fact that this formation overlaps the Early Proterozoic granitoids. Its top was marked by the rocks penetrated by the Late Devonian alkaline intrusions, including explosion pipes.This article presents the U-Pb isotopic dating of detrital zircon grains (dZr) from sandstones of the Tersk formation. It describes the geochemical compositions of the rocks and the Sm-Nd study results. In our study, the weighted average age of four youngest dZr grains from the sandstones of the Tersk formation is 1145±20 Ma, which suggests that the rocks above the studied rock layer (see the Tersk formation cross-section) are is not older than the end of the Middle Riphean. The U-Pb isotopic ages of dZr grains (provenance signals) from the sandstones of the Tersk formation were compared to the ages of other Upper Precambrian clastic strata in the northeastern East European platform (EEP) and adjacent areas. Our comparative analysis shows that these rocks significantly differ in age. This conclusion is in good agreement with the idea that at the end of the Middle and during the Late Riphean, several small (mainly closed) basins separated by uplifts dominated in the paleogeographic setting of the area wherein the White Sea rift system (WSRS) formed and developed. Temporal connections of these basins with the ocean were possible. Such paleogeographic setting does not favour the development of large rivers; this is why the grabens are mainly filled with local rock materials. The Keretsk and Kandalaksha grabens (WSRS) are filled with marine sediments eroded from the grabens walls. The local sediment sources include eclogite complexes (~1.9 Ga), which basic magmatism is dated at ~2.4–2.5 and ~2.7–2.9 Ga. Any potential primary sources for dZr grains are lacking in the area near the Keretsk graben. We suggest that such grains occurred due to recycling of the secondary sources of zircon, i.e. originated from ancient local sedimentary formations.

scholarly journals Comparative tectonics of the White Sea paleorift system and other continental rifting systems

LITOSFERA ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 469-490
Author(s):  
A. S. Baluev ◽  
S. Yu. Kolodyazhny ◽  
E. N. Terekhov
Keyword(s):  
East European Platform ◽  
Rift Zone ◽  
White Sea ◽  
Geophysical Methods ◽  
Normal Fault ◽  
Baikal Rift Zone ◽  
Rift System ◽  
Extensive Literature ◽  
The White Sea ◽  
East European

Research subject. The Riphean paleorift system of the White Sea, most of which is overlain by the waters of the White and Barents Seas and the platform cover of the East European Platform. This allowed numerous researchers to classify it as an aulacogen. The system was revealed by geophysical methods in the relief of the crystalline basement of the platform in the form of a frame of deep extended trenches of northwestern strike, subparallel to the edge of the East European platform.Materials and methods. Personal observations of the authors within the Onega-Kandalakcha paleorift, Baikal rift zone; a detailed study of seismostratigraphic sections of these zones; extensive literature data on the structure of modern rift zones. A comparative analysis of the structure of the most studied and currently active Baikal and East African rift systems, as well as the Karoo rift system of the Late Paleozoic origin with the paleorift system of the White Sea.Results. The following types of structural parageneses, which are characteristic of both modern rift systems and ancient paleorift systems, were identified. 1. Genetic relationship (inheritance?) of riftogenic structures with more ancient basement structures. 2. Structural paragenesis of concentric complexes in rift propagation zones. 3. Comparability of the area of horizontal extension of the lithosphere of the White Sea paleorift system with extension zones of modern continental rifts. 4. The fundamental similarity of the structure: the complex of paleorifts of the White Sea with modern continental rift systems: the presence of long deep trough segmentation of grabens and semi-grabens separated by bridges, which were accommodation zones with polarity reversal along the strike of the rift zone, displacement of the rift relative to the mantle ledge, the existence of a gently dipping normal fault (detachment), etc.Conclusion. The riftogenic nature of the aulacogens in the northeastern segment of the East European Platform has been confirmed.

The Community of the White Sea Microbenthos as an Indicator of the Sate of the Aquatic Environment

2001 ◽  
Vol 37 (3) ◽  
pp. 10
Author(s):  
V. L. Burkovskiy ◽  
A. K. Kashunin ◽  
A. I. Azovskiy
Keyword(s):  
Aquatic Environment ◽  
White Sea ◽  
The White Sea

Hydrological and hydrochemical research of the mouths of the small rivers flowing to the White sea in the winter low water season of 2019

2019 ◽  
Vol 59 (6) ◽  
pp. 1089-1092
Author(s):  
I. V. Miskevich ◽  
A. V. Leshchev ◽  
D. S. Moseev ◽  
A. S. Lokhov
Keyword(s):  
White Sea ◽  
Small Rivers ◽  
The White Sea ◽  
Hydrochemical Parameters ◽  
Catchment Basin ◽  
Onega Bay ◽  
Short Period ◽  
Tidal Estuaries ◽  
Hydrochemical Studies ◽  
River Mouths

In the winter low water season in March and the first week of April 2019, complex hydrological and hydrochemical studies were carried out at the mouths of two small rivers of the White Sea catchment basin (the Mudyuga river, which flows into the Dvina Bay, and the Tamitsa river, which flows into the Onega Bay). The results indicate significant differences in the short-period variability of hydrological and hydrochemical parameters in the winter in the studied river mouths compared with the characteristics observed in the tidal estuaries of large and medium rivers, as well as in the mouths of small rivers of the southern seas.

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