Christoph Breitkreuz, TU Bergakademie Freibergphysics...Christoph Breitkreuz, TU Bergakademie...
Transcript of Christoph Breitkreuz, TU Bergakademie Freibergphysics...Christoph Breitkreuz, TU Bergakademie...
Physical Volcanology
Christoph Breitkreuz,
TU Bergakademie Freiberg
55
Structure:
– Introduction
– Reology and deformation of magma and lava
– Eruption processes and types
– Volcano forms
– Emplacement of lava flows, domes and subvolcanic bodies
– Pyroclastic fragmentation
– Pyroclasts: Types and classification
– Pyroclastic transport und deposition
– Subaquatic and phreatomagmatic processes and resulting textures
– Cooling textures in SiO2-rich (sub-)volcanic bodies
– Volcanic hazards: Assessment and monitoring
exercises: Wednesdays, even weeks, 11.00 – 12.30, CVT
GP Osteifel: 1. – 3.7.2011
Test 18.7.2011
Recommended literature
BRANNEY, M. & KOKELAAR, P. (2002): Pyroclastic density flows and the sedimentation of
ignimbrites.- Geol. Soc. London, Mem., 27, 143 pp.
CAS, R.A.F. & WRIGHT, J.V. (1987): Volcanic successions - Modern and ancient.-
Allen & Unwin, London, 528S.
CHAPIN, C. E. and ELSTON, W. E. (eds.)(1979): Ash-flow tuffs.- Geol. Soc. Amer.
Spec. Pap. 180, 211S.
CHESTER, D.K., DUNCAN, A.M., GUEST, J.E. & KILBURN, C.R.J. (1985): Mount
Etna: Anatomy of a volcano.- Chapman and Hall, London, 404S.
DRUITT, T.H. (1999): Santorini volcano.- Geol. Soc. London, Mem. 19, 165 pp.
DRUITT, T.H. & KOKELAAR, B.P. (eds.)(2002): The eruption of Soufrière Hills
Volcano, Montserrat, from 1995 to 1999.- Geol. Soc. Mem. 21, 645S.
FISHER, R.V. & SCHMINCKE, H.-U. (1984): Pyroclastic rocks.- Springer-Verlag,
Berlin, 472S.
FISHER, R.V. and SMITH, G.A. (eds.)(1991): Sedimentation in volcanic settings.-
Soc. Econ. Paleont. Mineral., Vol. 45.
FRANCIS, P. (1993): Volcanoes - A planetary perspective.- Oxford Univ. Press,
Oxford, 1-443.
FREUNDT, A. & ROSI, M. (Hrsg.)(1998): From magma to tephra – modelling
physical processes of explosive volcanic eruptions.- Developments in Volcanol. 4,
Elsevier, 318S.
GIFKINS, C. , HERRMANN, W. & LARGE, R. (2005): Altered Volcanic Rocks: A
guide to description and interpretation.- Univ. Tasmania, Centre for Ore Deposits
and Exploration Studies, Hobart, 275S.
LATTER, J. (ed.)(1989): Volcanic hazards.- Springer, 625S.
LIPMAN, P.W. & MULLINEAUX, D.R. (eds.)(1981): The 1980 eruptions of Mount St.
Helens, Wash., USA.- U.S. Geol. Surv. Prof. Pap., 1250, ca. 850S.
MARTÍ, J. & ERNST, G.G. (eds.)(2005): Volcanoes and the environment.- Cambridge
University Press, 471 pp.
McCLELLAND, L. et al. (eds.)(1989): Global volcanism, 1975-1985.- Amer. Geophys.
Union, Wash. D.C., 655S.
McPHIE, J.M., DOYLE, M. & ALLEN, R. (1993): Volcanic textures - A guide to the
interpretation of textures in volcanic rocks.- Univ. Tasmania, Centre for Ore
Deposits and Exploration Studies, 1-196, Hobart.
ORTON, G.J. (1996): Volcanic environment. - in: READING, H.G. (Hrsg.):
Sedimentary Environments: Processes, facies and stratigraphy. - Blackwell
Science, Oxford, 3. Aufl., 485-567.
SCHMINCKE, H.-U. (2004): Volcanism.- Springer, Heidelberg, 324 pp.
SIGURDSON, H. et al. (eds.)(1999): Encyclopedia of volcanoes.- Academic Press.
SIMKIN, T. and FISKE, R.S. (1983): Krakatau 1883 - The eruption and its effects.-
Smithsonian Inst. Press. 464S.
THOMPSON, D. (2000): The volcano cowboys - The rocky evolution of a dangerous science.-
St. Martin‘s Press, New York, 326 pp.
WHITE, J.D.L., SMELLIE, J.L. & CLAGUE, D.A. (eds.)(2003): Explosive Subaqueous
volcanism.- Geophys. Monogr., 140, 1-379.
Journal of Volcanology and Geothermal Research (Elsevier)
Bulletin of Volcanology (International Association of Volcanology and Chemistry of
the Earths Interior, IAVCEI), www.iavcei.org
http://vulcan.wr.usgs.gov/home.html
www.geo.tu-freiberg.de/dynamo/Abbildungen_Lehre.htm
Physical volcanology Petrology Sedimentology
Natural Hazards
Mineral deposits
e.g. VHMS Raw material
Agriculture
Engineering
Geology
Hydrology
Health
Fields of work and position within Geosciences
History of
volcanology –
Historic eruptions
Encyclopedia of Volcanoes 1999
Aristotheles
Plato
A.G. Werner
J. Hutton
Santorini, Ägäis
Forque 1879
Dietrich, ETH Zürich
1650 B.C...
Encyclopedia of Volcanoes 1999
History of
volcanology –
Historic eruptions
Vesuv 79 A.D.
Pompei
Encyclopedia of Volcanoes 1999
History of
volcanology –
Historic eruptions
Krakatau 1883 in Indonesia:
Tsunami caused by a shallow marine caldera eruption:
36 000 fatalities
Encyclopedia of Volcanoes 1999
History of
volcanology –
Historic eruptions
Lacroix 1904
Mt. Pelee, Martinique: 1902-3
St. Pierre
Lassen Peak, 1915,
California
Encyclopedia of Volcanoes 1999
History of
volcanology –
Historic eruptions
Mt. St. Helens, Washington
June 1980
Pinatubo 1991
Smithsonian Institute
Schmincke 1986
Bahlburg & Breitkreuz 2004
Plate tectonics and
magma generation
Irvine & Baragar 1971
Geochemical
classification
older classifications
Required: Norm
calculation
(e.g. CIPW)
Al2O3 content
Reology and
Deformation of Magma
and Lava
Christoph Breitkreuz,
TU Bergakademie Freiberg
Sill, Estratos El Bordo, Chile
Mt. St. Helens
Glass Mtns, California
welded ignimbrite,
St. Francis Mtns, Missouri,
Proterozoic
Reology, deformation and fragmentation are controlled by
many parameters. The following are important:
- Ambient pressure (in the magmatic conduit
system, in subaquatic environment)
- Viscosity of Magma/Lava
- Density of Magma/Lava
- Temperature
- Deformation rate
- Magma ascent rate
Just to remember…
Types of fluids: Newtonian Fluid: water,
certain pyroclastic flows
Bingham Fluid:
(with yield strength)
Debris flows, lava / magma
certain pyroclastic flows
Fig. 1.1 Relationship between viscosity
and temperature for some magmas. The
rhyolite was glassy or liquid through the
entire temperature range (From Cas &
Wright 1987, after Murase & McBirney
1973).
VISCOSITY depends on:
- composition
(SiO2 , Al2O3 )
(H2O, other volatiles, Na, K etc. )
- temperature
- phenocryst content
- microlith content,
- vesicle content
Table 1.1 Estimates of eruption temperatures for some common magmas (After Cas & Wright 1987).
Fig. 1.2 The effect of H2O on the viscosity
of (a) granitic and (b) basaltic melts at
varying temperatures (From Cas & Wright
1987, after Murase 1962).
H2O content and Viscosity:
e.g. foaming up of magma during ascent
(first boiling)
Basalt
Rhyolite
Fig. 1.3 Densities of some molten volcanic
rocks with varying temperature at atmospheric
pressure (From Cas & Wright 1987, after
Murase & McBirney 1973).
Density depends on:
composition
temperature
pressure
content of phenocrysts
and vesicles
Fig. 1.5 Relation between super cooling (T) and
crystal nucleation and growth rate in a granitic melt
(Swanson et al. 1989)
T = supercooling
(below liquidus)
Formation of crystals and vesicles depends on:
- temperature
- presuure
- time (Nucleation and diffusion!)
Fig. 1.6 Bubble growth and water oversaturation in an ascending rhyolitic magma. The curves
define oversaturation in % as a function of the depth in the system during magma ascent. The
labels on the curves refer to the ascent or rise rates. The initial conditions are 4 km (a) and 1 km
(b), which correspond to initial water concentrations dissolved in the magma of 3.72 and 1.86
wt.%, respectively. Reproduced from Proussevitch and Sahagian (1996) (From Dingwell 1998).
FIRST BOILING:
- ascent rate
- supersaturation (e.g., with respect to H2O)
(m
)
Embayments in quartz phenocrysts
Embayments form by:
- growth impediment
- skeletal growth
(quenching)
Growth zonation
Cathodoluminescence
image of a quartz
phenocryst
Quartz broken during first boiling
Ignimbrite with crystal fragments
Fig. 1.4 Relation between deformation rate and
deformation style of magma or lava depending
on temperature; Tg = glass transition temperature
Fig. 1.7 Temperature profiles of the Ben Lomond
flow at different time steps as derived by numerical
modelling with the emplacement temperature of
850°C; Tg = glass transition temperature, FVP =
finely vesicular pumice, U.OBS = upper obsidian,
TZ = transition zone, RHY = stony rhyolite, L.OBS
= lower obsidian, BRX = breccia (from Stevenson et
al. 2001)
Land surface
Tg = glass transition temperature
c. 2/3 of the liquidus temperature
Glass (above Tg) oozes out of a fracture plain
Panum Crater, Mono Lake, California