Record details

Title
    "Cave pearls" as a by-product of building constructions
Author
    Buřival, Zbyněk
    Faimon, Jiří
    Schwarzová, Monika
    Štelcl, Jindřich
    Vávra, Václav
Language
    anglicky
Publication type
    článek v periodiku
Source title - serial
    Slovenský kras (Acta Carsologica Slovaca)
Vol./nr.
    Roč. 46, č. 1
Pages
    3
Year
    2008
Thesaurus term
    adit
    calcite
    concrete
    dripwater pool
    growth
    microstructure
    pearl
    percolating water
    rock fragment
Keyword
    Building
    By-product
    Cave
    Constructions
    Pearls
Abstract (in english)
   Cave pearls are frequently found in disused adit leading bellow the Špilberk Hill in Brno (Czech Republic). Each pearl consists of (1) a core comprised of an extraneous rock fragment and (2) a body organized into light and dark calcite layers. The number of the main layers roughly corresponds to 30 years of the total adit age. The darker layers occasionally show a sub-structure consisting of 2-3 extremely fine layers of various gray tones. Dendrite-like structures were observed in some cases. Conditions, necessary for pearl formation, were recognized as follows: (1) percolating waters supersaturated with respect to calcite, (2) free rock fragments as a basis for calcite nucleation, and (3) turbulent water circulation in dripwater pools preventing the fragments to fix at pool bottom during calcite growth. Initial bigger irregular rock fragments (10-15 mm in diameter) lead to formation of pearls of irregular shape. Tiny fragments (1-3 mm in diameter) lead to near spherical pearls.
Contributor
    MU Brno, Přírodovědecká fakulta
Contributor code
    MU, PřF
Source format
    R
Import date
    8. 8. 2012