Bedrock and Quaternary sediment geochemistry and biodiversity in Eastern Fennoscandia and Estonia

Ylo Systra

doi:10.2478/v10132-011-0088-4

Abstract

Bedrock and Quaternary sediment geochemistry and biodiversity in Eastern Fennoscandia and Estonia Crystalline bedrock and Quaternary sediments are the parent materials for soil, which is a substrate for plant roots and also a supplier of nutrients. Through interactions within the bedrock-soil-plant-animal-human beings system, bedrock geology and geochemistry influence all forms of life on the planet. There are 11 major elements or macronutrients that are nutritionally essential for plants and animals in constructing and maintaining cells and tissues, and up to 43 trace elements or micronutrients involved in the regulation of metabolic processes. Element concentrations in soils reflect those of parent rocks, but for healthy growth and development of plant and animal tissues there are very strict constraints on trace element concentrations. Chemical analysis of different organic materials shows that all forms of life, marine and terrestrial plants and animals, and bacteria consist of comparable proportions of the of macronutrients: O, H, C, N, P, S, Ca, Mg, K, Na, Cl, as well as trace elements. Some differences are noted in elements that are more available in sea water (Mg, I, Br, Sr, Fe, Pb) or are essential for life outside of water (terrestrial animals need more Ca and P for stronger skeletons, etc.). Limestone and dolostone of northern and central Estonia are rich in Ca and Mg, whereas the sandstones that predominate in southern Estonia consist mainly of quartz (SiO2) and contain very few nutrients. Glacial activity in Fennoscandia transported predominantly Si-rich granite rock material to Estonia, in which trace element concentrations are very low, as in the local bedrock. The bedrock geochemistry, Quaternary cover and their influence on vegetation in some selected areas in Fennoscandia and Estonia are discussed.

Highlights

The distribution of chemical elements in the Earth crust is controlled by their physical and chemical properties, which are becoming progressively better understood with progress in geochemistry and laboratory study methods
The exposed part of the Karelian Craton is 600 km long and 300 km wide, with its southeastern edge being covered by Ediacaran and Paleozoic sediments, which are contiguous with those in Estonia
The Karelian Craton formed during two distinct orogenic events, the first of which is represented by the Archean (3.8–2.5 Ga) basement, composed of Paleoarchean gneiss, gneissose diorite and migmatites, and narrow Neoarchean greenstone belts, consisting of volcanic-sedimentary rocks

Summary

Introduction

The distribution of chemical elements in the Earth crust is controlled by their physical and chemical properties, which are becoming progressively better understood with progress in geochemistry and laboratory study methods. Of the 90 (Albarède, 2009) naturally occurring stable elements, only 9 have abundances (in atomic weight) exceeding 1% (Table 1). The first 14 elements in order of the abundance comprise 99.81% of the earth’s crust in terms of atomic weight. The remaining 76 elements, known as trace elements, represent only 0.19%, with a mean abundance of only 0.025 atomic weight per cents; some of them are referred to as rare earth elements. Copper, and nickel, which are commonly found in everyday use, are included in these trace elements.

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