Mineralogy of the Dehner and Jungferweiher maar tephras (Eifel, Germany)

This study reports on the mineral assemblages of two long cores from the Eifel volcanic field covering the Upper Pleistocene and the Holocene. Pyroxene is the most abundant mineral followed by olivine, but amphibole, leucite and sphene as well as other minerals are also randomly present in different amounts. The mineral assemblage titanoaugite (mg# about 90) ± olivine is typical of the foidite and olivine-nephelinite and basanite suite while the assemblage titanaugite (mg# lower than 90) ± olivine ± amphibole ± leucite ± sphene could be representative of the less common tephrite and phonolites suites. The presence of aegirine-augitic and enstatitic pyroxene in two samples suggests the presence of tephras with further different signature. These observations might be very important in better correlating and chronologically define the Eifel volcanic episodes which occurred during the Late Quaternary. Moreover, it seems possible to correlate the JW30 layer at about 90ka to the Rocourt Tephra.