Revision of Scheumann?s classification of melilitic lamprophyres and related melilitic rocks in light of new analytical data
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Type = Article
Cím:
Revision of Scheumann?s classification of melilitic lamprophyres and related melilitic rocks in light of new analytical data
Létrehozó:
ULRYCH, J.
ADAMOVIČ, J.
KRMÍČEK, L.
ACKERMAN, L.
Balogh, Kadosa
Dátum:
2014
Téma:
QE05 Historical geology. Stratigraphy / Földtörténet, rétegtan
Tartalmi leírás:
Dykes of the Late Cretaceous to Early Tertiary (79.5 ± 3.5 to 60.7 ± 2.4 Ma) melilitic rock series of the Ose?ná Com-
plex and the Devil?s Walls dyke swarm, including ultramafic lamprophyres ? polzenites ? of Scheumann (1913) occur
dispersed in the entire Upper Plou?nice River basin in northern Bohemia.
Polzenites and associated melilitic rocks are characterized by the mineral association of olivine + melilite ± nephe-
line, haüyne, monticellite, phlogopite, calcite, perovskite, spinels and apatite. New data on their mineral and chemical
compositions from original Scheumann?s localities (the Vesec, Modlibohov, Luhov types) argue against the abolition
of the group of ultramafic lamprophyres and the terms ?polzenite? and ?alnöite? by the Le Maitre (2002) classification.
Marginal facies and numerous flat apophyses of the lopolith-like body known as the Ose?ná Complex show an olivine
micro-melilitolite composition (lamprophyric facies). The porphyritic texture, chemical composition and the presence of
characteristic minerals such as monticellite and phlogopite point to their affinity with ultramafic lamprophyres ? polze-
nites of the Vesec type. Melilite-bearing olivine nephelinites to olivine melilitites (olivine + clinopyroxene + nepheline
+ melilite ± haüyne and spinels with apatite) form a swarm of subparallel dykes known as the Devil?s Walls.
The Scheumann?s non-melilite dyke rock ?wesselite?, spatially associated with polzenites and often erroneously attributed
to the polzenite group, is an alkaline lamprophyre of monchiquite to camptonite composition (kaersutite + phlogopite
+ diopside + olivine phenocrysts in groundmass containing clinopyroxene, phlogopite, haüyne, analcime, titanian mag-
netite, apatite ± glass/plagioclase). First K?Ar data show Oligocene ages (30.9 ± 1.2 to 27.8 ± 1.1 Ma) and an affinity to
the common tephrite?basanite rock series.
Típus:
Article
PeerReviewed
Formátum:
text
Azonosító:
ULRYCH, J. and ADAMOVI?, J. and KRMÍ?EK, L. and ACKERMAN, L. and Balogh, Kadosa (2014) Revision of Scheumann?s classification of melilitic lamprophyres and related melilitic rocks in light of new analytical data. Journal of Geosciences, 59. pp. 47-66. ISSN 1802-6222
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