Dugald Carmichael wrote:
> At 12:07 PM 21/01/2005 +0000, Roger Musson wrote:
> >...
> >... If you believe the word "earthquake" perforce means the shaking of the
> >earth, then the location of the recent great earthquake is actually the
> >entire planet (ground displacement in the UK was about 5 mm).
ACCORDING TO SOME NEWSPAPER MESSAGES QUOTING GEOPHYSICal DATA IN AUSTRIA WE HAD A
LIFTED AND SHIFTED DISPLACEMENT ALL OVER EUROPE RELATED TO THE SUMATRA QUAKE.
WHAT DOES THIS MEAN TO ACTIVE VOLCANO-SYSTEMS I:E: WITHIN EUROPE? WHO GOT DATA
WHAT REALLY CHANGED; before/AFTER?
WE ACTUALLY CONTINUED SAMPLING AND ANALYSIS AND PROVIDE THE ATTACHED ABSTRACT TO
THE NEXT MEETING: WE WOULD BE GRATEFUL IF OTHER GROUPS ARE GOING TO JOIN DATA
LINKED TO OUR ABSTRACT (i.e. to [log in to unmask]).
Nucleation of particles on single glass fibers, metal transport within particles
and barite nucleation on fibers - a case study at a fumarole of La Fossa volcano,
Vulcano island, Italy
Obenholzner, J.H. (*), Reichmann, A. (**), Mitsche, S. (**), Poelt, P.(**)
(*) Naturhistorisches Museum/Mineralogy, Postfach 417, A-1014 Vienna, Austria,
[log in to unmask] ; (**) Institute for Electron Microscopy (ZFE), Graz
University of Technology, Steyrerg. 17, A-8010 Graz, Austria, www.felmi-zfe.at
Filter experiments and subsequent FESEM/EDS analysis of particles collected on
filters esposed to the fumarole F0 (ca. 300°C, highly acidic), La Fossa volcano,
Vulcano island, Italy reveal that single fibers of fibrous filters collect
particles or trigger particle nucleation on fibers in a highly heterogeneous mode.
On individual fibers a great number of particles of the same chemical type can be
found, with none of these particles present on neighbouring fibers. No difference
in the morphology or chemical compostion of these fibres compared to the bulk of
the filter could be found. Sampling had been performed in 08-2004 (1) and 01-2005
(2) for four hours. Technical glass fibers of a +/- basaltic (RW-A1+B2; A=high
density of fibers, B = low density of fibers) and a +/- high-Si rhyolitic
composition (GW-1+2; low density of fibers) had been applied in a parallel mode
by clogging the fumarole hole with them. RW-A1 showed patchy alteration phenomena
of the glass. GW-1 collected cancrinite-group-like particles (diameter ca. 5 µm)
scattered on many fibers. Their composition was analysed by EDS: C, O, Na[low],
Mg[low], Al, Si, Cl, K[low], Ca[low]). Additionally Au, Ag and Pb are
concentrated in regions within these particles. Available data allow no conclusion
whether these particles nucleated on the fibers or had been deposited. RW-A1 in a
filter holder collected 2 Au-Cl particles. Typically, particles of one specific
metal chloride are nucleating preferentially on a single fiber or on two fibers
attached to each other. Data comprise GW-1: Bi-Cl; GW-2: Mn-Cl, Pb-Cl; RW-A1:
Pb-Cl; RW-B2: Tl-(Pb)-Cl, Pb-Cl. Simultaneous gas sampling (2) could have caused a
contaminating Mn flux. Sulfides, mostly Pb-S and Bi-S nucleate in a scattered mode
throughout the fibrous filter materials. These phenomena are still waiting for
physcial and chemical interpretation. However, preliminary data suggest that the
nucleation of i.e. metal chloride particles on single fibers could be used to
detect changes of the element flux of F0. Several other types of filter materials
(borosilicate glass fiber (BS), polycarbonate, glass wool, rock wool in a filter
holder with an exposure time of one hour and natural quartz sand (in silicon hoses
or freely exposed) were used for sampling. It could be shown that particles
containing Ba nucleate mainly as BaSO4 on BS, rarely on RW-B2. A BS sample
(01-2005) shows aggregates of BaSO4 and NaCl, additionally euhedral and anhedral
Tl-Cl nucleated on BS. It is important to note that BaSO4 particles did not
nucleate at all sampling campaigns despite technically similar sampling conditions
(2001-2005). A BS sample (4 h) in 09-2003 did not reveal any BaSO4 particles. The
barite nucleation on BS seems to be a detector of changes of pH, Eh and/or T of
the F0. As-bearing particles do not exhibit any indication of nucleation on fibers
or sand and were collected as aggregates with a variety of other elements on all
kinds of filter materials. Heating and quenching of GW-1 and RW-A1 in H2O dest.
produced a particle spectrum different from randomly picked fiber samples. At GW-1
could additionally Pb-Cl (+As, +F), Pb-S (+As, +P) and Bi-S (+F, +As, +I, +P), at
RW-A1 BaSO4 be detected. Quartz grains added onto RW-A1 commonly show nucleation
of Pb-, Tl- and Al-chlorides (-bromides), Ca- and Al-sulfates and Fe-oxides.
Currently the cinetics of nucleation (sampling time versus crystal size) is
investigated. Statistical evaluation of data is still poor. It should be tested if
fibrous filters can reduce the flux of toxic elements to the environment. We would
appreciate cooperation with groups working continuously at fumaroles.
Nucleation of crystals on fibers might be new to the tectonics group, however we
live according to general opinion in the multidisciplinary world.
All the best
JHO
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