The Bag Tephra, a widespread tephrochronological marker in Middle Europe: chemical and mineralogical investigations

Abstract

The Bag Tephra is a widespread tephra layer interbedded in Quaternary loess deposits along the Danubian valley of Hungary and Slovakia. Its age is poorly defined between 788 and 380 ka B.P. The glass and mineral composition -micropumice clasts of phono-tephrite and blocky shards of tephri-phonolite associated with two kinds of clinopyroxene, fassaitic diopside, and salite -is very distinctive. This tephra could be used as a chronological marker, as soon as its age is refined. The probable origin is the middle Italian volcanic area.

Tracages isotopiques de l'origine et de l'évolution des magmas en milieu continental :

“…9a and b). This also supports the previously suggested volcanic source of other volcanic layers found in loess deposits of eastern Europe (the Bag Tephra; Pouclet et al, 1999) which are likely the same as t32 ; this study).…”

“…A paleomagnetic reversal, interpreted as the Brunhes-Matuyama, was found below this tephra layer (Juvigne' et al, 1991). Interestingly, Pouclet et al (1999) concluded, on the basis of trace and major elements chemistry that the most probable magmatic source for this tephrawas the N-RMP and more probably the Sabatini Mts. or the Alban Hills.…”

“…Comparison with trace element contents and radiogenic isotopes would give more constrained indications on the volcanic sources. However, modern tephrochronology tends to be anchored on simple comparisons based on grain morphology and major element chemistry, and it is only recently that a few studies have used trace element geochemistry combined with statistical approaches (e.g., Pearce et al, 1996Pearce et al, , 2008Pouclet et al, 1999;Pinti et al, 2003).…”

Tephrochronological dating of varved interglacial lake deposits from Piànico‐Sèllere (Southern Alps, Italy) to around 400 ka

“…According to the petrological composition, the volcanic complex of Roccamonfina provides the most likely source for tephra T32. Roccamonfina is a Pleistocene stratovolcano located 50 km NNW of Naples in the Campanian region Figure 6 Composition of clinopyroxenes of T32 tephra, the Brown Leucitic Tuff (Luhr and Giannetti, 1987) and 'Bag' tephra (Pouclet et al, 1999) after Morimoto et al (1988) Table 2 Mean electron-microprobe data from single glass shards in T32 tephra. Types a-c indicate different glass populations; n ¼ number of glass shards, ARD ¼ averaged raw data, SD ¼ 1 standard deviation, AWFD ¼ averaged water-free data (normalised to 100 wt %) T32, type a (n ¼ 24) Giannetti and Luhr, 1983), whereas pyroclastic materials and lavas from stage I activity are leucite tephritic to phonolitic in composition.…”

Pleistocene volcaniclastic units from North-Eastern Sicily (Italy): new evidence for calc-alkaline explosive volcanism in the Southern Tyrrhenian Sea

“…Within the Strait of Messina area, similar sequences are also exposed along the Calabrian coast (Kézirian 1992a,b;Calanchi 1988;Leyrit et al 1998Leyrit et al , 1999Toussaint et al 1999) and in several sites of the Ionian and peri-Tyrrhenian Calabria (Cello et al 1983;Toussaint et al 1999;De Rosa et al 2001, 2002Bigazzi & Carobene 2004;Carobene et al 2006;De Rosa et al 2008). Since the Late Tortonian, extensive explosive volcanic activity took place in the Mediterranean area, with dispersion of pyroclastic products over a large portion of the basin and of continental Europe (Keller et al 1978;Paterne et al 1988;Pyle et al 1998;Narcisi & Vezzoli 1999;Pouclet et al 1999;Schmidt et al 2002).…”