Eesti rahvuskivi dekoratiivsusest I. Organismide osast paekivi dekoratiivsuse kujunemisel

EESTI RAHVUSKIVI DEKORATIIVSUSEST I ORGANISMIDE OSAST PAEKIVI DEKORATIIVSUSE KUJUNEMISEL Rein Einasto, PhD, TTK professor Kokkuvõte Kokkuvõttes tuleb rõhutada organismide elutegevuse jälgede ja skeletse materjali kuhjumite olulist osa paekivi – Eesti rahvuskivi – dekoratiivsete omaduste kujunemises. Järgnevates artiklites võtame luubi alla kivimi hilismuutustega – dolomiidistumisega, ränstumisega, murenemisega seotud dekoratiivsed omadused Eesti paekivis. Summary The Decorative Aspects of Limestone – the Estonian National Stone especially in terms of varied internal patterns, their uniqueness and formation. The traces of life maintained in stone are at first observed in stone, then in bedand discontinuity surfaces, and finally in the skeleton’s direct locality in stone. The results of bioturbation -- the general process of sedimentary relocation emerging from the digging and feeding of the organisms in mud – are expressed in bioturbed pyritic patterns, worm tracks and partial mixture of neighbouring layers of different composition. Discontinuity surfaces provide many Estonian limestone types of important applicability with a unique intrernal pattern. The specificity that designs this decorativeness emerges from the peculiarities of the micro-relief of the surfaces, especially from the borings made by digging organisms on the one hand, and from the colour of the compounds impregnating these surfaces on the other hand. In the compounds the dominating colours are black pyritic and light brown phosphatic tones. In the lowest greenish grey glauconitic limestones we find discontinuity surfaces of bright impregnation belt with tones varying from dark red chematitic and dark green glauconitic to rust brown and yellow limonitic. In Kunda stage lower boundary to the Kukruse stage upper broundary the dominating patterns are phosphatic discontinuities and pyritic in the higher stages. The stratigraphic levels of disontinuity series with applicable value are the following: BI\BII, BII\BIII, BIIIb\c, CIbcV\CIbcK, CII\CIII, FIc\FII, FII\G1-2, J2Ma, K1Vsa, K2Sna, K2Ua. The stone groups that make higher decorativeness in our limestone are by frequency: echinoderms – cystoids and crinoids; corals and stromatoporoids, algae forming biochermal, brachiopods, stromatolites and oncolites, less frequently nautiloids), lamellibranchiata, gastropods), and very rarely also trilobites.