I am writing a manuscript on new textural, mineralogical and chemical results
on volcanic ash and aerosols: SEM and FE SEM examinations. All data are from
the recent activity of Popocatepetl volcano, Mexico. One part is dedicated to
the occurrence of Fe-rich wollastonite, hercynite and buchites (glasses with an
origin of contact metamorphism [CM]) as a population of fragments of the
volcanic ash. The wollastonite is not homogeneous, it shows Fe-rich and Fe-poor
parts which are intergrown. Some grains show vesiculation-like textures.
Does anybody know SEM studies of similar wollastonites etc.? Also the buchites
are highly heterogeneous.
The main question is: Are these fragments products of ongoing CM underneath
Popocatepetl, or are they fragments of an old aureol. Popocatepetl is situated
on a ca. 3 km thick sequence of lime/dolostones/evaporites etc. of Cretaceous
Buchites show wild compositions, they are rich in S, Cl and P. Anhydrite and
inheritated zircons are enbedded in this glassy/devitrified matrix.
Ideas, references and coauthorship for essential contributions are welcome.
Thanks and best wishes
Johannes H. Obenholzner, PhD
email: [log in to unmask]