The moldavite strewn field

The greatest number of moldavites have been found in Southern Bohemia (Cesk e Budejovice-Trebon area), corresponding to about 77.3% of all finds. Morav ian moldavites constitute 19.5% of all moldavite finds, while Radomilice ar ea in Southern Bohemia possesses only 3.1% of moldavites of the whole molda vite strewn field and the Lusatian area only 111 pieces found up to day, th e Cheb area 38 and Austrian area about 15 moldavites. The fall of moldavites 15 million years ago (at the boundary between the Mi ddle and Upper Badenian) was not homogeneous and this inhomogeneity has bee n preserved in the moldavite strewn field in spite of later redeposition in to younger sediments. The main differences in the chemical composition, tra ce element contents and a number of other parameters, e.g. colour distribut ion, bubble frequency, lechatelierite content, the presence of other minera l grains in the glass matter, the variance in oxygen isotopes and maximum p rojection sphericity values, have remained preserved for several groups of localities and led to the distinguishing of moldavite partial strewn fields or subfields. It can be stated that certain areas with moldavites of simil ar properties are encountered and the rough zonation of the strewn field ob served. These are the moldavites from the Radomilice area (most acidic, low alkalies content), the moldavites from the Ceske Budejovice - Trebon area as well as the Cheb area and moldavites found in Austria with frequent bubb les and lechatelierite grains and the moldavites from Moravia and Lusatia ( low CaO + MgO contents, relatively high total iron and alumina). Stratigraphically, the moldavite-bearing sediments belong to the Lower Sarm atian (greenish-grey sandy clayes with montmorillonite, loc.: Vrabce-Nova h ospoda, Jankov, Besednice-brickyard), to Lower Romanian (Formation of molda vite-bearing sandy gravels and/or feldspathic sandy gravels, loc.: Chlum na d Malsi, Locenice, Koroseky, Slavetice, moldavites from Cheb area and Lusat ian occurrences), to Pleistocene gravels (Radomilice, localities in the sur rounding of Znojmo) and slope loams and scree (Brusna) or Holocene alluvia along present-day rivers. Moldavites from the Horn region in Austria most p robably could have been transported from the southern part of the Trebon Ba sin by Pliocene or Pleistocene streams or they could belong to a small inde pendent strewn subfield.