Podrobnosti záznamu

Název
    Lausitzer Moldavite und ihre Fundschichten
Údaj o odpovědnosti
    Jan-Michael Lange
Autor
    Lange, Jan-Michael
Jazyk
    německy
Zdrojový dokument - seriál
    Schriftenreihe für Geowissenschaften
Svazek/č.
    Jg. 3
Rok
    1995
Poznámky
    28 obr., 25 tab., 4 pl., 9 s.bibl. + 2
    Anglické resumé
    Zkr. název ser.: Schr.-Reihe Geowiss.
Předmětová skupina
    Český masiv
    datování Ar/Ar
    granulometrie
    izotopy Sr
    kráter impaktní
    kvartér
    moldavit
    neogén
    sedimentace fluviální
    tektity
    těžké minerály
Geografické jméno
    Česká republika
Klíčové slovo
    Fundschichten
    Ihre
    Lausitzer
    Moldavite
Abstrakt (anglicky)
   Over 25 years after the first find of a moldavite in Lusatia ("Lausitz"), Germany (E-Saxony, SE-Brandenburg)there are still no detailed studies of these glasses. This work attempts to make a contribution to the discussion about the origin of the Lusatian moldavites. This was done by sedimentary-petrographical studies of moldavite-bearing sediments and petrographical and geochemical analyses of moldavites. Further studies will invoke the documentation of Lusatian moldavites and the surveying of selected outcrops which yield moldavites. 111 Lusatian moldavites with a total mass of more than 600 g have already been registered. Samples from selected profiles from various localities were used for sedimentary-petrographical analyses. Priority was given to Late tertiary moldavite-bearing sediments: Older Senftenberg Elbe Gravels ("Altere Senftenberger Elbeaschotter")and Upper Gravel Sands ("Obere Kiessande")of the Rauno Formation ("Rauno Folge").
   For comparision further samples were collected from the Lower Gravel Sands ("Untere Kiesssande")of the Rauno Formation and from Quateranry sediments. Studies of the Late Tertiary moldavite-bearing sediments show differences between the Older Senftenberg Elbe Gravels in Upper Lusatia and the Upper Gravel Sands of Rauno Formation in Lower Lusatia: - Sediments of the Older Senftenberg Gravels are usually coarser and less well sorted than those of the Rauno Formation. Within the Rauno Formation the Lower Gravel Sands, which are the probably moldavite-free, are more fine-grained and better sorted than the Upper Gravel Sands. The sedimentary environments of the Older Senftenberg Elbe Gravels and Upper Garvel Sands were quite similar. Both show features of quick and turbulent sedimentation (4.1). - Shape analysis of quartz pebbles from the moldavite-bearing sediments was not sensitive enough to provide good results.
   Differences between average shapes of quartz pebbles and moldavites can be explained by differences in the structure of source materials. Lusatian moldavites have a shape which is between the shape of Bohemian moldavites (4.2). - Older Senftenberg Elbe Gravels and Lower Gravel Sands display a higher content of instable heavy minerals than the Upper Gravel Sands. In the Lower Gravel sands this can be related to reworked marine Tertiary material. In the study area the ratio of staurolite/sillimanite is useful to distinguish the Rauno Formation (4.3). Petrographical and geochemical analyses of Lusatian moldavites confirm previous ideas about the their affinity to Beohemian and Moravian moldavites. Methods, which can distinguish between moldavites from various sub-strewn fields (Bohemia, Moravia, Radomilice area), show within the Lusatian substrewn field an assemblage of moldavites of Bohemian and Moravian type.
   This lead to comparatively wide variations in the physical and chemical characteristics of the Lusatian moldavites: - Lusatian moldavites have in general a lower density and refractiv
Přispěvatel
    Česká geologická služba
Kód přispěvatele
    ČGS (UNM)
Zdrojový formát
    U
Datum vložení
    25. 3. 2008
Datum importu
    8. 8. 2012