Precambrian paleosols on the Great Unconformity of the East European Craton: An 800 million year record of Baltica’s climatic conditions
Introduction
Paleosols, which record the interaction of rocks with the atmosphere and hydrosphere, offer a unique opportunity for studying past climates. Precambrian paleosols are known from many continents, but they are often thin (<50 cm) and developed on sediment (e.g. Ediacara Member paleosols in Australia; Retallack, 2012) or their mineralogical and geochemical composition is affected by various post-weathering processes (e.g. Beukes et al., 2002, MacFarlane and Holland, 1991, Mitchell and Sheldon, 2009, Mitchell and Sheldon, 2010, Wiggering and Beukes, 1990) and thus they are of limited use in climatic reconstructions. The East European Craton (EEC), has preserved exceptionally well-developed paleosol profiles of Meso- and Neoproterozoic age. Up to tens of meters thick paleosol was described previously under the Ediacaran sediments on the crystalline basement in Estonia (Kuuspalu et al., 1971, Vanamb and Kirs, 1990, Liivamägi et al., 2014, Liivamägi et al., 2015, Vircava et al., 2015, Driese et al., 2018). Although kaolinite-dominated lateritic paleosol in Estonia is mature and well preserved/unmetamorphosed, its mineralogical composition is affected by diagenesis, with smectite-rich middle sections having been replaced with illite and illite–smectite with 15–25% of expandable layers (Liivamägi et al., 2015). The Ediacaran paleosols, developed on the Ediacaran flood basalts in Volyn, Ukraine, and covered by the Ediacaran sediments, also show high maturity and preservation, but much lower degree of Paleozoic diagenesis, with 60–90% of smectite in the mixed layer illite–smectite (Liivamägi et al., 2018). In Belarus and Russia, paleosols containing kaolinite and smectite occur under sedimentary cover ranging from the upper Ediacaran to Mezoproterozoic (Vendian and Riphean in Russian nomenclature: Eroshev-Shak et al., 1969, Nesterenko et al., 1969, Makhnach and Levykh, 1973, Levykh, 1999). These reports document that the EEC holds a very unique set of well-preserved/unmetamorphosed Precambrian paleosols and that locally these paleosols are affected by a very low degree of diagenesis, which is also evident from the map of conodont alteration index in the Ordovician rocks (Nehring-Lefeld et al., 1997), deposited a few hundred meters above the crystalline basement. The low degree of diagenesis on the craton has been confirmed by a recent multi-method study of its Proterozoic sedimentary cover (Derkowski et al., 2021).
In this contribution, we investigate 15 weathering profiles/paleosols, developed on the crystalline basement of the EEC in Belarus, Estonia, Lithuania, and Ukraine (Fig. 1). These paleosols offer a chance to examine continental weathering and alteration sequences from early stages of weathering to completely weathered paleosols on a variety of different parent materials during the Meso- to Neoproterozoic. An overview including the parent material, age constraints, mineralogy and geochemistry of all studied paleosol profiles is presented in Table 1. The top surface of the EEC crystalline basement (EEC “Great Unconformity”) is very old. The youngest eroded rocks under the sedimentary cover are 1.5–1.3 Ga old Rapakivi granites (Fig. 1a in Paszkowski et al., 2019). The paleosol ages on this surface are constrained by the ages of overlying sediments (Table 1).
Section snippets
Geological setting and age constraints
The EEC paleosols are developed on different rocks including granitoids, gneiss, amphibolite, and gabbro (Table 1). In the central part of the craton, in the Volyn-Orsha Graben (Fig. 1), the weathered crystalline basement is covered by the continental clastic sediments of different units (called “svita” in the Russian stratigraphic scheme) of the Mesoproterozoic (Riphean in Russian literature), of not well-constrained age: Bortnikov (locally at the bottom; <1350 Ma according to Kruchek et al.,
Macroscopic characteristics
15 weathering profiles were available for this study (Fig. 1): 2 from Estonia (Metspere F261, Kiiu), 5 from Lithuania, (Glukelis 348, Sirvintos 1, Vilkiskiai 68, Tverecius 336, and Šaškai 2), 6 from Belarus (Slonim 3, Slonim 14, Slonim 5, Slonim 18, Pinsk 26, and Lida 43) and 2 from Ukraine (Vyshcheolchedayiv and 1679). 6 were sampled by the authors from core materials, 1 (Vyshcheolchedayiv) from an abandoned quarry, 1 (Metspere) was provided by Kalle Kirsimäe, and 7 (the Belarus profiles,
Whole-rock mineralogy
Whole-rock mineral compositions based on the bulk rock XRD are given in Supplementary Table 1, where the paleosol profiles developed on mafic and felsic rocks are listed separately. The bulk rock XRD patterns for the most complete profiles of both types are presented in Fig. 3.
The assemblage of major minerals typical of magmatic/metamorphic rocks includes quartz, K-feldspars (both orthoclase and microcline), Ca-plagioclases in mafic rocks (gabbro and amphibolite) and some felsic rocks, and
Diagenetic overprint
EEC paleosol profiles investigated in this study have been affected by Paleozoic diagenesis, evidenced to occur over the entire area of the western EEC by the K-Ar dates of clay fractions containing illite–smectite and aluminoceladonite (Liivamägi et al., 2018, Środoń et al., 2002, Derkowski et al., 2021). The presence of aluminoceladonite is indicated by both XRD analysis and SEM observations (Fig. 3, Fig. 5), and illite–smectite by XRD (Fig. 3). Well-constrained ages of paleosols diagenetic
Conclusions
- 1.
Paleosols of the East European Craton, ranging in age from ca. 1350 to ca. 550 Ma, all represent the same type of kaolinite + hematite weathering under a hot and humid climate, preserving - due to variable erosion - different portions of the weathering profile (Fig. 10). Such a climate must have prevailed on the EEC in these times, with the exception of well-documented glaciation periods (e.g. Chumakov, 2003, Paszkowski et al., 2018).
- 2.
Dioctahedral clays: smectite and kaolinite are the main
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
Many thanks to the Republican Unitary Enterprise Belarusian Scientific Geological Survey Institute and Oksana Kuzmenkova, Alla Laptsevich, and Sergei Mankevich personally for providing access to the core material, core descriptions, and the Minsk collection of Nikolay Levykh. Jurga Lazauskiene and Jaunutis Bitinias of the Lithuanian Geological Survey are thanked for providing access to the core material and core descriptions. Kalle Kirsimäe provided the Metspere sample set from Estonia. We
References (74)
- et al.
Quantifying chemical weathering intensity and trace element release from two basalt profiles, Deccan Traps, India
Chem. Geol.
(2014) - et al.
Formation and transformation processes of iron duricrust systems in tropical humid environment
Chem. Geol.
(1993) - et al.
Constitutive mass balance relations between chemical composition, volume, density, porosity, and strain in metasomatic hydrochemical systems: Results on weathering and pedogenesis
Geochem. Cosmochem. Acta
(1987) The role of glaciations in the biosphere
Russ Geol. Geophys.
(2015)A burial diagenesis origin for the Ediacaran Shuram-Wonoka carbon isotope anomaly
Earth Planet. Sci. Lett.
(2010)- et al.
Oxisolic processes and geochemical constraints on duration of weathering for Neoproterozoic Baltic paleosol
Precambr. Res.
(2018) - et al.
Paleolatitude estimation and premises for geomagnetic field instability from the Proterozoic drilling core material of the south-western part of the East European Craton
Precambr. Res.
(2021) - et al.
The room for the Vendian in the International Chronostratigraphic Chart
Russ. Geol. Geophys.
(2015) - et al.
The Sr, C and O isotopic evolution of Neoproterozoic seawater
Chem. Geol.
(1999) - et al.
The oxygen isotope evolution of seawater: a critical review of a long-standing controversy and an improved geological water cycle model for the past 3.4 billion years
Earth Sci. Rev.
(2007)
Neoproterozoic variations in the C-isotopic composition of seawater: stratigraphic and biogeochemical implications
Precambr. Res.
Cyanobacterial-algal crusts from Late Ediacaran paleosols of the East European Craton
Precambr. Res.
Petrology, mineralogy and geochemical climofunctions of the Neoproterozoic Baltic paleosol
Precambr. Res.
Paleosols on the Ediacaran basalts of the East European Craton: a unique record of paleoweathering with minimum diagenetic overprint
Precambr. Res.
Weathering and paleosol formation in the 1.1 Gakeweenawan Rift
Precambr. Res.
The ~1100 Ma Sturgeon Falls paleosol revisited implications for mesoproterozoic weathering environments and atmospheric CO2 levels
Precambr. Res.
An isotopic study of siderites, dolomites and ankerites at high temperatures
Geochim. Cosmochim. Acta
The Ediacaran radiogenic Sr isotope excursion in the Doushantuo Formation in the three Gorges area, South China
Precambr. Res.
Quantitative paleoenvironmental and paleoclimatic reconstruction using paleosols
Earth Sci. Rev.
207Pb/206Pb ages and Hf isotope composition of zircons from sedimentary rocks of the Ukrainian shield: crustal growth of the south-western part of East European craton from Archaean to Neoproterozoic
Precambr. Res.
Origin and paleoenvironmental interpretation of aluminum phosphate–sulfate minerals in a Neoproterozoic Baltic paleosol
Sed. Geol.
Petrography and geochemistry of a 2000–2200-Ma-old hematitic paleo-alteration profile on Ongeluk basalt of the Transvaal Supergroup, Griqualand West, South Africa
Precambr. Res.
IsoplotR: a free and open toolbox for geochronology
Geosci. Front.
Evidence for low or no oxygen in the late Archean atmosphere from the ~2.76 Ga Mt. Roe #2 paleosol, Western Australia: Part 3
Geochim. Cosmochim. Acta
Model for K-bentonite formation: Evidence from zoned K-bentonites in the disturbed belt, Montana
Geology
Silicate weathering and climate
Tropical laterites, life on land, and the history of atmospheric oxygen in the Paleoproterozoic
Geology
Pedogenic siderites fossilizing Ediacaran soil microorganisms on the Baltica paleocontinent
Geology
Global climates of the Vendian
Russ. J. Earth Sci.
Long-distance fluids migration defines diagenetic history of unique Ediacaran sediments in the East European Craton
Basin Res.
Factors responsible for crystal-chemical variations in the solid solutions from illite to aluminoceladonite and from glauconite to celadonite
Am. Mineral.
Unraveling the effects of potassium metasomatism in sedimentary-rocks and paleosols, with Implications for paleoweathering conditions and provenance
Geology
Enigmatic origin of the largest-known carbon isotope excursion in Earth's history
Nat. Geosci.
Toward a Neoproterozoic composite carbon-isotope record
Geol. Soc. Am. Bull.
Constraints on a Late Cretaceous uplift, denudation, and incision of the Grand Canyon region, southwestern Colorado Plateau, USA, from U-Pb dating of lacustrine limestone
Tectonics
Community-derived standards for LA-ICP-MS U-(Th-) Pb geochronology–Uncertainty propagation, age interpretation and data reporting
Geostand. Geoanal. Res.
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