ISSN:
1432-0819
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Geologie und Paläontologie
Notizen:
Abstract During the entire life of Cantal volcano, the main lava types were emitted during rather separated stages of activity. Basalts are scarce in the trachyandesitic complexes, whereas latites are very uncommon in the basaltic units. In both cases, incomplete mechanical mixing would have been active in their genesis as it is suggested by field and microscopic observations. Sanissage composite dome is formed of poorly mixed acid and basic lavas, with still clearly observable reaction relationship between components. Combe de Saure plug shows a dispersion of tiny (smaller than 1 cm) trachyandesitic relics within a prevalent basaltic groundmass, the result of which being a nearly homogeneous melt, so called « leucobasalt », with D.I. similar to that of a hawaiitic rock. From these observations it is suggested that a large part of intermediate Cantal lavas (D.I similar to those from hawaiites-mugearites-benmoreites) may derive from homogeneized mixing, when new basaltic magma entered the chamber filled with differentiated melt.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF01952345
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