Eruptive processes and caldera formation in a nested downsagcollapse caldera: Cerro Panizos, central Andes Mountains

Ort, Michael H.

doi:10.1016/0377-0273(93)90018-m

Cited by 84 publications

(85 citation statements)

References 62 publications

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“…Their size is such that many of their vents were only recognized after the advent of satellite imagery (e.g. Baker 1981, Gardeweg & Ramírez 1987, Ort 1993, Sparks et al 1985. The large phenocryst-rich (up to 40-50% crystals) ignimbrites with relatively homogeneous compositions probably erupted from homogeneous magma chambers.…”

Section: Changing Magmatic Patterns Across the Plateaumentioning

confidence: 99%

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The Evolution of the Altiplano-Puna Plateau of the Central Andes

Allmendinger

Jordan²,

Kay³

et al. 1997

Annu. Rev. Earth Planet. Sci.

815

658

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▪ Abstract The enigma of continental plateaus formed in the absence of continental collision is embodied by the Altiplano-Puna, which stretches for 1800 km along the Central Andes and attains a width of 350–400 km. The plateau correlates spatially and temporally with Andean arc magmatism, but it was uplifted primarily because of crustal thickening produced by horizontal shortening of a thermally softened lithosphere. Nonetheless, known shortening at the surface accounts for only 70–80% of the observed crustal thickening, suggesting that magmatic addition and other processes such as lithospheric thinning, upper mantle hydration, or tectonic underplating may contribute significantly to thickening. Uplift in the region of the Altiplano began around 25 Ma, coincident with increased convergence rate and inferred shallowing of subduction; uplift in the Puna commenced 5–10 million years later.

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Section: Changing Magmatic Patterns Across the Plateaumentioning

confidence: 99%

“…• S that extended across the plateau over the early-Miocene volcanically quiescent region , de Silva 1989, de Silva & Francis 1991, Mobarec & Heuschmidt 1994, Ort 1993, Seggiaro 1994. De Silva (1989) assigned these centers to the so-called Altiplano-Puna Volcanic Complex (APVC).…”

Section: Changing Magmatic Patterns Across the Plateaumentioning

confidence: 99%

The Evolution of the Altiplano-Puna Plateau of the Central Andes

Allmendinger

Jordan²,

Kay³

et al. 1997

Annu. Rev. Earth Planet. Sci.

815

658

View full text Add to dashboard Cite

show abstract

“…The K 1 axis is usually interpreted to be parallel to the flow direction and thus plunges towards the source (Knight et al, 1986). The use of the K 1 axis alone as a proxy for flow direction is not always reliable (Seaman et al, 1991;Hillhouse and Wells, 1991;Ort, 1993;Le Pennec et al, 1998) and a different methodology must be used to interpret the magnetic data. The imbrication angle of the magnetic foliation plane, which equivalents the deviation of the K 3 axes from the normal to the macroscopic flow plane, offers another method to distinguish the flow direction of ignimbrite (Henry, 1980;Thompson and Oldfield, 1986) (Fig.…”

Section: Sampling Methods and Ams Measurementsmentioning

confidence: 99%

Hazards from Pyroclastic Density Currents at Mount Bamenda (West-Cameroon, Cameroon Volcanic Line): Mapping and Assessment by AMS Method

Dedzo¹,

Kamgang²,

Njonfang³

et al. 2015

American Journal of Geoscience

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Hazards related to pyroclastic density current continue to raise victims on many volcanoes in our planet. The Cameroon is not spared to this type of hazard because deposits of pyroclastic flows and surges are found on Mount Bamenda; products of this volcano are relatively young (27-0 Ma). Besides Mount Bamenda, Mounts Bambouto and Oku are the only volcanoes located in the central part of the Cameroon Volcanic Line where these ignimbritic deposits are found. Several factors highlight dangerousness and damage that can cause ignimbritic flows on the flanks of this volcano. This is essentially the high aspect ratio of these ignimbrites, the important population (about 750,000 people) that lives on the slopes and around the volcano. In order to have an idea of a nowadays ignimbritic eruption scenario on Bamenda volcano, the Anisotropy of Magnetic Susceptibility (ASM) method is used in this study to highlight the palaeoflow in ancient deposits of ignimbrites which are mostly discontinuous and isotropic. Results of AMS study are used to produce map of hazards and assess risks that may be related with such eruptions in Bamenda volcano.

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“…The maximum axis (K 1 ) is typically interpreted to be parallel to the flow direction and thus plunges towards the source [11]. The use of the K 1 susceptibility axis alone as a proxy for flow direction is not always reliable [11,13,[20][21][22], and a different approach must be used to interpret the AMS data. The imbrication angle of the magnetic foliation plane, which equals the deviation of the K 3 axes from the normal to the macroscopic flow plane, provides an alternative method to discern the flow direction of ignimbrite deposits [23,24].…”

Section: Sampling Methods and Ams Measurementsmentioning

confidence: 99%

Mapping and Assessment of Volcanic Hazards Related to the Ignimbritic Eruption by AMS in Bambouto Volcano (Cameroon Volcanic Line)

Dedzo

Kamgang²,

Njonfang³

et al. 2013

TOGEOJ

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Pyroclastic deposits constitute major components of explosive volcanic activity. To help improve the safety of the population faced with natural disasters, a study is carried out at Bambouto volcano with a view to map potential hazards related to pyroclastic flows. The Bambouto volcano is indeed considered to be still active since the recent discovery of Quaternary basalts (0.5 Ma) at Totap, a locality situated near the Bambouto Caldera. This discovery has led to reclassify Mount Bambouto among active volcanoes of Cameroon and, therefore, considered as potentially dangerous. The dangerousness of this volcano is accentuated by the presence of ignimbrites that are witnesses of ancient pyroclastic flows. Because a map of volcanic hazards is non-existent on the volcano, anisotropy of magnetic susceptibility (AMS) is the method used in this paper to characterize magnetic fabrics and provides an estimate of flow direction of each ignimbrite sheet (represented by massive lapilli tuff and massive lithic breccia facies). Inferred transport directions based on the AMS data and field indicators show that Bambouto Caldera is the source of main pyroclastic deposits of Mount Bambouto. These results have enabled us to produce a new hazard map related to potential future pyroclastic flows.

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Eruptive processes and caldera formation in a nested downsagcollapse caldera: Cerro Panizos, central Andes Mountains

Cited by 84 publications

References 62 publications

The Evolution of the Altiplano-Puna Plateau of the Central Andes

The Evolution of the Altiplano-Puna Plateau of the Central Andes

Hazards from Pyroclastic Density Currents at Mount Bamenda (West-Cameroon, Cameroon Volcanic Line): Mapping and Assessment by AMS Method

Mapping and Assessment of Volcanic Hazards Related to the Ignimbritic Eruption by AMS in Bambouto Volcano (Cameroon Volcanic Line)

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