TEXTURAL, GEOCHEMICAL AND LEACHING STUDY OF VOLCANIC ASH: ENVIRONMENTAL IMPACT OF THE VOLCANO CALBUCO ERUPTION, APRIL 2015 1*
1
1
Benet D. , Carrazana A. , Gimeno D. , Kalmbach R.
2
1
Departament de Mineralogia, Petrologia i Geologia Aplicada. Universitat de Barcelona, Spain. Carrer Martí i Franquès s/n, 08028, Barcelona. 2 Grupo de Estudios Ambientales (GEA). Centro Regional Universitario Bariloche. Universidad Nacional del Comahue, Argentina. *E-mail:
[email protected]
I N T R O D U C T I O N RD
1. THE ERUPTION OF APRIL 23
2015
2. GEOLOGY OF CALBUCO VOLCANO
3. VOLCANIC ASH SAMPLING N
SAM-2 SAM-1
675m
4. OBJECTIVES The aims are (1) to characterize geochemically and texturally the ash samples and (2) to assess the geochemical impact of ash in the local balance.
R E S U L T S 5. TEXTURAL CHARACTERIZATION
7. LEACHING TEST
5.1 GSA: Frequency curves and accumulate frequency curves Accumulate Vol. %
Volume % 100
10
100
SAM-1
SAM-2
9
90
9
90
8
80
8
80
7
70
7
70
6
60
6
60
5
50
5
50
4
40
4
40
3
30
3
30
2
20
2
20
1
10
1
10
0
0
0 0.01
0.10
1.00
10.00
100.00
0 0.01
1000.00
The histogram has bimodal distribution. The main peak at 110 µm diameter and the secondary at 15 µm.
The leaching test is used as a proxy of short-term weathering on ash deposits, e.g. rainfall. The ratio between bulk composition and leachate composition, called RML(%), is indicative of the mobility for each element: leachate composition shows whether is suitable for human consumption comparing to the drinking guideline values.
0.10
1.00
Grain-size (μm)
10.00
100.00
1000.00
Grain-size (μm)
Mobility
RML
Elements
High
>5%
Te
Moderate
5-0,5%
Tl, Mo, Cd, Ni,As, Th, Sb, K, Na, Cu, Sn, Zn, W, Ca, Li, Pb, Rb.
Low
200
9.39 6.70
Fraction (Horwell 2007)
0.25 0.09
Respirable
