Types of volcanoes. Christoph Breitkreuz, TU Bergakademie Freiberg. Monogenetic and complex volcanoes

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Relative sizes are only approximate (From Orton 1996, after Simkin

1 Types of volcanoes Christoph Breitkreuz, TU Bergakademie Freiberg Monogenetic and complex volcanoes Fig. 3.1 Types of volcanic landforms. Vertical exaggeration 2 to 1 (polygenetic) and 4 to 1 (monogenetic). Relative sizes are only approximate (From Orton 1996, after Simkin et al., 1981). Scoria cones: most abundant volcanic land form - high viscosity, basaltic (high microlith content!) Stromboli 2001

2 Typical eruption styles: - strombolian fallout - minor phreatomagmatic fallout and surge - small lava flows Mt. Tarawera, New Zealand Schmincke km Typical horse shoe shape due to erosion by lava

3 Maar tuff ring tuff cone: typical land forms of phreatomagmatic eruptions of SiO 2 -poor magma Ukinrek maar (formed 1977; Lorenz) Malha Maar, Meidob Hills, NW Sudan

4 Lorenz 2004 Phreatic tuff breccia, Neogene, Eifel, W Germany Southern Slovakia: Neogene Diatreme Field

5 Bedded diatreme facies Unbedded diatreme facies

6 Urach diatreme field, Neogene SW Germany Iceland 1995

7 Rootless phreatic land forms Litoral cones, Myvatn, Iceland Rootless phreatic craters in 1980 tuff deposit Mt. St. Helens volcanic ring plain SiO 2 -rich Lava flows and domes Mt. Pelee, Martinique, 1902/3

8 Mt. St. Helens, More about this in the next lecture Shield volcanoes: - low-viscosity basaltic magma - longlasting magma production at one place Complex volcanoes Olympus Mons, Mars Isabela, Galapagos

9 SW Tenerife: cross section through a Cenozoic shield volcano: Lava pile cross cut by numerous dykes SW Tenerife: cross section through a Cenozoic shield volcano: Two overlapping scoria cones preserved

10 Depth [m] SiO 2 -rich lava flows Profile (this project) Lithology developement of paleosoils at the top of andesite lava flows coarse grained clastics of the Parchim Fm. sandflat, mudflat and playa lake deposits aktive strike-slip (NW-SE) faulting under slightly extensional (N-S) regime lake and fan deposits of the Grüneberg Fm. aktive extrusive and intrusive volcanism, andesitic and rhyolithic (e.g. in well Tuchen 1/74) conglomerate exclusively with clasts of Carboniferous sediments developement of paleosoils last rhyodacitic ash fall activities Depth [m] CS Lava Lava Lava Lava B-Tuff B-Tuff B-Tuff B-Tuff??? Importance of volcanotopographic hiati: Spacially differentiated! and lava domes PhD project Marion Geißler Mg-andesite shield volcano complex in Brandenburg PhD project Marion Geißler Drilling Oranienburg (Ob) 1/68 CS * sediments of a playa-environment, with anhydritic blasts sandstones and 3750 mostly andesitic conglomerates SW E Ob 1/68 flat landscape, covered by playa sediments E Gür 3/76 E Am 1/68 NE U.Rotlieg. Time Fig.1: Schematic modell of the volcano-sedimentary evolution of the area NE of Berlin (from the well Ob 1/68 in the SW through Grüneberg (Gür) 3/76 to Am 1/68 in the NE) Drilling Angermünde (Am) 1/68 * Profile (this project) 4000 andesite lava flows, mostly vesicular; with interbedded "block-lava", breccias and few paleo-soils x x x x? C x SW NE Mg-andesite shield volcanoes create a high topography L.Rotlieg sediments of a playa-environment, with anhydritic blasts thin conglomerate horizont and sandst. andesite lava flows, mostly vesicular; with interbedded breccias and paleo-soils B x x x x x several intermediate lava flows, partly vesicular 4500 SW post-variscan flat landscape, covered by tuff and ignimbrite NE 4500 conglomerates and?sandstones with rhyodacite (?andesite) fragments and interbedded tuff =?ignimbrite (no cores available) 4750 vitric rhyodacitic tuff } conglomerates Carbonif. sediments * = core segments A preignimbritic x x porphyric x rhyodacitic lava, lava dome or sill-intrusion 4750 * = core segments ash fall deposits rhyodacitic sequence of massflows (ignimbrite) and tuffs conglomerates Carbonif. sediments Inundation of shield volcano topography by playa sediments during Upper Rotliegend II Katzung 1995

Iguazú Cascades Stratovolcanoes: - longlasting

11 Plateau basalts Alias trapp basalt or flood basalt Typically hot spot-related Typically fissure eruptions Iguazú Cascades Stratovolcanoes: - longlasting intermediate to SiO 2 -rich magmatism Lincancabur, N Chile Mt. Shasta, California

12 Cone facies - volcanic ring plain facies Sector collapse: oversteepening, hydrothermal alteration, incompetent substrate, active faulting, earthquakes, eruption Mt. Egmont, New Zealand Mt. Egmont, debris avalanche deposit

CALDERA types: Mike Branney -piston(sio 2 -rich

) - trap door - piece meal - resurgent -

4 General caldera cycle (after Lipman, 1984).

of small intermediate stratovolcanoes, Stage 2

Ash flow tuffs interfinger with caldera collapse

13 Mt. St. Helens Socompa, N Chile Sector collapse Main CALDERA types: Mike Branney -piston(sio 2 -rich and poor!) - trap door - piece meal - resurgent - non-resurgent Fig. 3.4 General caldera cycle (after Lipman, 1984). Stage 1 precaldera volcanism develops clusters of small intermediate stratovolcanoes, Stage 2 eruption of zoned magma chamber develops caldera. Ash flow tuffs interfinger with caldera collapse breccia whereas a thin outflow sheet extends outward from the caldera, Stage 3 postcaldera deposition of volcanics and sediment and resurgent doming (From Orton 1996).

14 Crater Lake, Oregon Non-resurgent caldera Cerro Galan NW Argentina Resurgent calderas Valles Caldera, Jemez Mtns, New Mexico

15 Piece meal Caldera Ordovician Lake district, W England Fig. 3.5 Evolution of Scafell Caldera, English Lake District (after Branney & Kokelaar, 1994). The caldera developed atop basaltic to andesitic lavas (e.g. Lingcove Fm.) that formed a composite low-profile shield-like volcano. Schematic section from the Langdale area shows relative thickness of facies from the various stages. These are: A emplacement of Whorneyside ignimbrite and initial subsidence; B inundation of vent leads to phreatoplinian eruptions of Whorneyside bedded tuff; C onset of widespread piecemeal subsidence and eruption of Long Top Tuffs; D continued subsidence and deformation of hot ignimbrites; E eruption of high-grade ignimbrites of Crinkle Crags tuffs; F development of a caldera lake, with subaqueous volcaniclastic sediments and tuffs, and intrusion of rhyolite domes (From Orton 1996).

Types of volcanoes. Christoph Breitkreuz, TU Bergakademie Freiberg

Types of volcanoes. Christoph Breitkreuz, TU Bergakademie Freiberg Types of volcanoes Christoph Breitkreuz, TU Bergakademie Freiberg Monogenetic and complex volcanoes Fig. 3.1 Types of volcan landforms. Vertical exaggeration to 1 (polygenetic) and 4 to (monogenetic).