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Vol. 29 (2026 year), No. 1, DOI: 10.21443/1560-9278-2026-29-1

Kozlov N. E., Mudruk S. V., Sorokhtin N. O.
New approaches to lithological and stratigraphic research and mapping of the early Precambrian complexes (using an example of the Paleoproterozoic and Archean structures of Keivy, Kola Peninsula)

Previously, the team of authors proposed a new method for the comparative analysis of geological objects. Its foundation is an assessment of the proximity of statistically significant petrogeochemical characteristics. The key advantage of this approach is the ability to quantitatively determine the degree of similarity for heterogeneous samples, which favorably distinguishes it from many classical geochemical methods. The successful application of the technique for comparing geological objects has allowed its adaptation for solving lithological-stratigraphic tasks in complexly structured Early Precambrian complexes, where traditional methods often prove insufficiently effective. In the present work, the method has been tested on supracrustal formations of the Keivy Domain. At the first stage, it was used for the correlation of Paleoproterozoic strata. The results confirmed existing stratigraphic schemes: Serpovidny complex Formation (Pestsovokeivskaya Formation, Serpovidny Ridge area) demonstrates the greatest similarity with formations of the Umba (Imandra-Varzuga Belt) and Kuetsyarvi Formations (Pechenga Structure). At the next stage, the method was applied to older complexes, the correlation of which had previously been problematic. The research has established that the deposits of the upper part of the Lebyazhinskaya Formation and the Chervurta Subformations were formed throughout the entire Keivy structure primarily due to the reworking and redeposition of underlying rocks. The analysis has also revealed differences in the geological history of the two main regional structures – the Bolshie and Malye Keivy. The formation of strata within them occurred in different settings. In the Bolshie Keivy, stable sedimentation conditions persisted until the accumulation of the Vykhchurta Formation. Active tectonic reorganization began later, during the formation of the Peschtsovotundrovsky complexes, when clastic material from the surrounding areas, primarily from the Murmansk Domain, began to enter the sedimentary basin. In the Malye Keivy, this activation occurred earlier, as recorded in the composition of the rocks of the Snezhnoborskaya Formation. The reconstruction of the geological history of the Keivy Domain, proposed based on petrogeochemical correlation, offers a solution to previously existing contradictions in correlating the supracrustal complexes of the Bolshie and Malye Keivy.

(in Russian, стр.12, fig. 4, tables. 3, ref 20, AdobePDF, AdobePDF 0 Kb)

Vol. 29 (2026 year), No. 2, DOI: 10.21443/1560-9278-2026-29-2

Kozlov N. E., Sorokhtin N. O.
Chervurt formation of the Kolmozero-Voron'ya belt and Keivy domain: A geodynamic reference point for spatial and temporal heterogeneity during the formation of the ancient median massif

The paper considers the possible correlation of the rocks of the Chervurt Formation in the Kolmozero-Voron'ya zone with its constituent supracrustal complexes and the formations of the adjacent Keivy domain, as well as the role that metasedimentary rocks of the upper part of this zone's section played in the formation history of the Keivy median massif. The study has employed the authors' original method for assessing statistically significant patterns in petrogeochemical characteristics, which has yielded good results in solving such problems, as previously demonstrated by the authors in a number of publications devoted to the correlation of supracrustal complexes of the Bolshiye Keivy and Malyye Keivy structures. The presented data allow us to conclude that the Chervurt rocks of the Kolmozero-Voron'ya zone are most similar to the metasedimentary complexes of the Keivy domain, and within them, to the rocks of the Upper Chervurt Subformation. This is also indicated by other clearly manifested patterns previously noted by the authors for the Upper Chervurt Subformation of the Keivy structure. It is also shown that the rocks of the Chervurt formation of the Kolmozero-Voron'ya belt are compositionally most distant from other complexes constituting this zone, primarily the Lyavozero complex, with which some researchers have attempted to correlate them. Taking into account these data, as well as information on the age of the rocks composing the Keivy domain and the Kolmozero-Voron'ya greenstone belt, and the authors' previously obtained data on the possible formation settings of certain Keivy formations, a model for the final stage of the formation of the Keivy median massif has been proposed.

(in Russian, стр.9, fig. 2, tables. 1, ref 16, AdobePDF, AdobePDF 0 Kb)