Petrolithology of the Permian melaphyre lavas, Darmstadt, Germany
Al-Malabeh, Ahmad; Kempe, Stephan
published: May 15, 2009
ArtNo. ESP155025202001, Price: 29.00 €
Volcanological, petrographical and geochemical characteristics of Permian melaphyre outcrops in Darmstadt were investigated by thin sections, XRD, XRF and ESEM. Two units of melaphyre occur, each over 2 m thick. The lower unit is hard, vesicular, and composed of decimeter-thick pahoehoe sheets, while the upper micro-doleritic unit is softer, dense with a low vesicularity, and a higher degree of weathering. Petrographically, the melaphyres are composed mainly of plagioclase, olivine, opaque mineral oxides and glass. The rocks underwent different degrees of palagonitization and other alteration processes. The layers appear to be surface flows of two pulses of the same magma and reflect thermal facies indicating overall up-section decrease in temperature and in the volatile content of the magma chamber.