Národní geovědní bibliografie - GeoLib: Podrobnosti záznamu

This aper refers to new localities of moldavites in the region west of Ivančice (Fig.1). The moldavite-bearing sediments are coarse-grained gravels, in which, besides quartz (accompanied by rock crystal, smoky quartz and zonal amethyst), metamorphic rocks (granulite, amphibolite, serpentinite and eclogite) from the neighbourhood dominate. According to the relative ekevation of the gravel depositions above the present level of the Jihlava river (table 1), the relics of the fluvial sediments are classified as of the Pleistocene, belonging to the higher (70-102 m) and lower (40-68 m) level. The morphology and physical properties of moldavites are summarized in Table 2. The size of moldavites expressed as mean size ranges from 10.3 to 48.3 mm - average value 25.1 mm (aritmetic mean) or from 9.7 to 43.6 mm - average value 23.9 mm (geometric mean). The longest moldavite is 83 mm long.

The sphericity of moldavites expressed according to Zingg (1935) as F Franges from 0.39 to 2.21 (average value 0.95) and according to Sneed and Folk (1958) as 3VT2/(L.B) ranges from 0.45 to 0.93 (average value 0.68). The moldabites are most frequently olive green (46%), specimens of brown-green colour are also not rare (28.5%), 11 specimens (17.5%) are bottle green, 3 specimens (4.8%) are brown and 2 specimens (3.2%) are pale green in colour. The weight of moldavites eanges from 1.1 to 106.0 g (the average weight is 33 g). Typical features of these moldavites are the very poorly preserved original sculptation (sculpture) and numerous minute crescentic to circular bodies that cover their surface. Some moldavites display a newly formed fine sculptation

Přispěvatel

Česká geologická služba

Kód přispěvatele

ČGS (UNM)

Zdrojový formát

Datum vložení

7. 2. 2008

Datum importu

8. 8. 2012