The origin of a large (&gt;3km) maar volcano by coalescence of multiple shallow craters: Lake Purrumbete maar, southeastern Australia

Jordan, Simone Christiane; Fernand, Raymond Alexander; Hayman, Patrick

doi:10.1016/j.jvolgeores.2012.12.019

Cited by 68 publications

(62 citation statements)

References 37 publications

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“…Country rock lithic abundance will be high, approaching 100% in some units, in the tephra ring, and lithic clasts derived from progressively deeper levels may appear upward in the stratigraphy due to the subsurface explosive mixing. Most deposits extend no more than a few kilometers from the craters, which are typically ∼500-1500 m in diameter, although larger ones can be produced due to lateral shifting of explosion sites (e.g., Jordan et al, 2013). The total erupted volume of magma may range to a fraction of cubic kilometer, or rarely a few cubic kilometers in case of polygenetic maars (Table 1).…”

Section: Characteristics Of the End-membersmentioning

confidence: 99%

Maars to calderas: end-members on a spectrum of explosive volcanic depressions

et al. 2015

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We discuss maar-diatremes and calderas as end-members on a spectrum of negative volcanic landforms (depressions) produced by explosive eruptions (note-we focus on calderas formed during explosive eruptions, recognizing that some caldera types are not related to such activity). The former are dominated by ejection of material during numerous discrete phreatomagmatic explosions, brecciation, and subsidence of diatreme fill, while the latter are dominated by subsidence over a partly evacuated magma chamber during sustained, magmatic volatile-driven discharge. Many examples share characteristics of both, including landforms that are identified as maars but preserve deposits from non-phreatomagmatic explosive activity, and ambiguous structures that appear to be coalesced maars but that also produced sustained explosive eruptions with likely magma reservoir subsidence. A convergence of research directions on issues related to magma-water interaction and shallow reservoir mechanics is an important avenue toward developing a unified picture of the maar-diatreme-caldera spectrum.

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Section: Characteristics Of the End-membersmentioning

confidence: 99%

Maars to calderas: end-members on a spectrum of explosive volcanic depressions

et al. 2015

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“…Previous models have relied on host rock lithics to determine the depth of explosions, but it is now clear that these explosions sample material that has been mixed within the vent during an eruption and reflect the cumulative explosion history rather than individual events (Lefebvre et al 2013;Graettinger et al 2015aGraettinger et al , 2016Sweeney and Valentine 2015). There is also ample evidence through stratigraphic relationships, ballistic orientations, and morphology that vent locations within a crater migrate both vertically and laterally throughout an eruption (Ort and Carrasco-Núñez 2009;van Otterloo et al 2013;Jordan et al 2013;Pedrazzi et al 2014;Agustin-Flores et al 2015;Kosik et al 2016). Individual clasts in a tephra ring therefore do not help constrain the depth of the explosion that produced the beds in which the lithics are hosted.…”

Section: Variations In Relative Explosion Position and Energymentioning

confidence: 99%

Evidence for the relative depths and energies of phreatomagmatic explosions recorded in tephra rings

Graettinger

Valentine

2017

Bull Volcanol

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Experimental work and field observations have inspired the revision of conceptual models of how maar-diatreme eruptions progress and the effects of variable energy, depth, and lateral position of explosions during an eruption sequence. This study reevaluates natural tephra ring deposits to test these new models against the depositional record. Two incised tephra rings in the Hopi Buttes Volcanic Field are revisited, and published tephra ring stratigraphic studies are compared to identify trends within tephra rings. Five major facies were recognized and interpreted as the result of different transportation and depositional processes and found to be common at these volcanoes. Tephra rings often contain evidence of repeated discrete phreatomagmatic explosions in the form of couplets of two facies: (1) massive lapilli tuffs and tuff breccias and (2) overlying thinly stratified to crossstratified tuffs and lapilli tuffs. The occurrence of repeating layers of either facies and the occurrence of couplets are used to interpret major trends in the relative depth of phreatomagmatic explosions that contribute to these eruptions. For deposits related to near-optimal scaled depth explosions, estimates of the mass of ejected material and initial ejection velocity can be used to approximate the explosion energy. The 19 stratigraphic sections compared indicate that near-optimal scaled depth explosions are common and that the explosion locations can migrate both upward and downward during an eruption, suggesting a complex interplay between water availability and magma flux. Reverse to normal coarse-tail graded tuff breccias inferred to be the product of closely timed phreatomagmatic explosions, and deposits of magmatic gas-driven explosions, were observed interspersed with discrete explosion deposits. This study not only provides a framework for more detailed interpretations of eruption sequences from tephra rings but also highlights the gap in our understanding of syn-eruptive hydrology and variations in magma flux that enables phreatomagmatic explosions.

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“…20 000 yrs B.P.) are characterized by three temporally separated eruption phases and vent locations, with relatively dry as well as wet phreatomagmatic conditions (Jordan et al, 2013). Ballistic bombs with impact sags are widespread in these deposits, suggesting wet deposits (Jordan et al, 2013).…”

Section: Purrumbete Lake (Victoria Australia)mentioning

confidence: 99%

“…This may be associated with subaqueous eruptions (Fiske, 1963) or subaqueous deposition (Brand and White, 2007;Brand and Clarke, 2009;Jordan et al, 2013), but also importantly, subaerial emplacement (Vazquez and Ort, 2006). Hot-state, plastic deformation including partial deformation of the clasts themselves is referred to as rheomorphism (Branney et al, 2004;Andrews and Branney, 2011).…”

Section: Pdcs and Their Possible Ssd Triggersmentioning

confidence: 99%

“…The high deposition rates also trigger simple load casts (Mattsson and Tripoli, 2011). Blocks ejected ballistically during an eruptive event deform the fresh deposits by landing (Gençalioglu-Kuşcu et al, 2007;Jordan et al, 2013). Post eruptive processes are also common on steep sided volcanic edifices, with freshly deposited material likely to be unstable and slump (Fiske and Tobisch, 1978;Voight et al, 1983;Branney and Kokelaar, 1994;Ward and Day, 2006) as well as inherent contraction and compaction fractures following emplacement (Whelley et al, 2012).…”

Section: Pdcs and Their Possible Ssd Triggersmentioning

confidence: 99%

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