There are three distinct zones of recent volcanic activity in the Andean Cordillera: a northern zone in South Colombia and Ecuador, a central zone in South Peru and North Chile, and a southern zone in South Chile (Figure 1). Cenozoic intrusive rocks occur between these areas, and on the coastal margin of the active zones. It is therefore natural to suppose that the igneous processes that take place along the Andean plate margin have simultaneous volcanic and plutonic components and, consequently, that the two kinds of magmatic activity are interrelated. This supposition is expressed in countless diagrams and cross-sections purporting to illustrate destructive plate margin processes.

Margin (machine learning)

10.1007/978-1-4684-0570-5_6

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Citations (33)

Depletion rates of sulfur dioxide in tropospheric volcanic plumes

Geophysical Research Letters (1998)

Clive Oppenheimer P. W. Francis John Stix

The tropospheric sulfur cycle has been closely studied from the standpoint of anthropogenic emissions but less so with respect to volcanic sources. We document here evidence for wide variation in lifetimes of volcanic SO 2 in the troposphere. At one extreme, our observations of the plume associated with the lavadome eruption of Soufriere Hills volcano (Montserrat) suggest loss of gaseous SO 2 at rates exceeding 10 −3 s −1 . While this efficent SO 2 depletion reflects unusual environmental factors, published measurements for Mount Etna's plume approach these rapid rates. In such cases, source strengths of SO 2 must significantly exceed apparent fluxes measured several kilometres downwind. This implies that meteorological and geographic factors, as well as volcanic degassing rates, should be considered in the interpretation of fluxes of SO 2 measured beyond source vents, with ramifications for volcano monitoring and eruption prediction. Furthermore, since most calculations of global volcanic fluxes of sulfur (and other species) to the troposphere are based on extrapolation of SO 2 flux data they may underestimate true source strengths. Finally, we consider that fast sulfur chemistry may also prevail in convecting eruption columns, resulting in partial tropospheric scrubbing of sulfur from stratosphere‐bound plumes.

Volcanic Gases

Panache

10.1029/98gl01988

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Citations (114)

Rates of production of the main magma types in the central Andes

Geological Society of America Bulletin (1976)

P. W. Francis Christopher Rundle

Research Article| March 01, 1976 Rates of production of the main magma types in the central Andes P. W. FRANCIS; P. W. FRANCIS 1Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA England Search for other works by this author on: GSW Google Scholar C. C. RUNDLE C. C. RUNDLE 2Geochemical Division, Institute of Geological Sciences, Gray's Inn Road, London WC1X 8NG England Search for other works by this author on: GSW Google Scholar GSA Bulletin (1976) 87 (3): 474–480. https://doi.org/10.1130/0016-7606(1976)87<474:ROPOTM>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation P. W. FRANCIS, C. C. RUNDLE; Rates of production of the main magma types in the central Andes. GSA Bulletin 1976;; 87 (3): 474–480. doi: https://doi.org/10.1130/0016-7606(1976)87<474:ROPOTM>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Six new K-Ar dates for young volcanic rocks in the area between lat 21° and 22°S in the Andes of northern Chile have been determined. Two groups of volcanic rocks are present: extrusive lava flows and domes of andesitic composition and extensive sheets of ignimbrite. Both groups are less than 10 m.y. old. We estimate that 2 × 103 km3 of andesitic rocks and 1.5 × 103 km3 of ignimbrite lie within the study area. Andesitic rocks have been erupted at an estimated rate of between 1.7 × 10−6 km3 and 2.9 × 10−6 km3/yr/1 km of length of the active belt, and ignimbrite at a rate of 1.3 × 10−6 km3/yr/l km of length. The total volume of ignimbrite is less than is suggested by the huge area covered by ignimbrite sheets.In order to estimate the volume and rate of production of a comparable strip of the Coastal batholith of Peru, two extreme models were used for the shapes of batholiths in depth: one assumes a tabular shape with a thickness of 5 km, the other an inverted teardrop shape extending to a depth of 30 km. Rate of production estimates for these two models range from 2.9 × 10−6 km3/yr/l km to 9.9 × 10−6 km3/yr/l km of length. Whichever model is used, the rate of production is broadly comparable with that of the Sierra Nevada batholith in California.The rate of extrusive volcanism is about two orders of magnitude less than that at the Icelandic constructive plate margin and several times less than the rate of intrusion of batholithic material. Volumetric data do not explicitly support any particular one of the many hypotheses for the genesis of destructive plate margin magma types. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

10.1130/0016-7606(1976)87<474:ropotm>2.0.co;2

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Citations (72)

Ignimbrites of the Cerro Galan caldera, NW Argentina

Journal of Volcanology and Geothermal Research (1985)

R. S. J. Sparks P. W. Francis R. D. Hamer R. J. Pankhurst L.O. O'Callaghan

Caldera

Pumice

Breccia

Basement

Magma chamber

10.1016/0377-0273(85)90071-x

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Citations (145)

Volcanic contribution to crustal growth in the Central Andes: A new estimate and a discussion of uncertainties

Charles A. Wood P. W. Francis

Volcanism above subduction zones is a major mechanism for crustal growth and compared to some other proposed processes calculation of growth rates is relatively easy given accurate volumes and ages of volcanic material. Francis and Rundie (1976) first used this approach in a small region of the Central Andes, and extrapolated their result to the entire Central Andean arc. The derived rate of 3 to 4.2 x 10 to the minus 6th cubic km yr/km of arc length is compared with an independent estimate based upon a reconnaissance census of all major volcanoes in the Central Andes.

Island arc

Volcanic arc

Central Asia

Volcanology

Source

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Citations (2)

Upper Cenozoic volcanism in the Central Andes — Ages and volumes

Earth and Planetary Science Letters (1978)

Mr Baker P. W. Francis

Volcanic plateau

Volcanology

10.1016/0012-821x(78)90008-0

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Citations (115)