Record details

    Modern and Palaeozoic iron ooids - a similar volcanic origin
Statement of responsibility
    U. Sturesson, J.M. Heikoop, M.J. Risk
    Heikoop, J. M.
    Risk, M. J.
    Sturesson, U.
Source title - serial
    Sedimentary geology
    Vol. 136, no. 1-2
    p. 137-146
    3 obr., 2 fot., 2 tab.
    Obsahuje bibliografické odkazy
    Zkr. název ser.: Sedimentary Geol.
Subject group
    geologie mořská
    pražská pánev
    rudy Fe
    sedimentace lagunární
    sedimentace mořská
    sedimentace recentní
    struktura oolitická
Geographical name
    Ejpovice (Rokycany)
    Velká Británie-Wales
Abstract (in english)
   The discovery of an unconsolidated deposit of iron ooids of a kind not previously described, and in the vicinity of a volcanic island in Indonesia has shed new light on the genesis of many ancient iron oolites. The discovery shows that iron ooid formation is geologically a rapid process. The ooids form by chemical precipitation of cryptocrystalline iron oxyhydroxides on available grains on the seafloor, from seawater enriched with Fe, Al and Si. The enrichment can be a result of hydrothermal fluids, volcanic ash falls into shallow basins or rapid weathering of fresh volcanic rocks Ordovician iron ooids from northern Europe are strikingly similar to the modern ooids in chemical composition, REE distribution and internal structures. The differences in mineralogy can be explained as diagenetic transformation reactions under different environments.
   A model for the formation of the Ordovician iron ooids in northern Europe from volcanoclastic material is presented, which could be applicable to other ancient oolites in the world
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    9. 2. 2007
Import date
    8. 8. 2012