Volcanological and magmatological evolution of Stromboli volcano (Aeolian Islands): The roles of fractional crystallization, magma mixing, crustal contamination and source heterogeneity

1989 ◽  
Vol 51 (5) ◽  
pp. 355-378 ◽  
Author(s):  
Lorella Francalanci ◽  
Piero Manetti ◽  
Angelo Peccerillo
Keyword(s):  
Fractional Crystallization ◽  
Magma Mixing ◽  
Crustal Contamination ◽  
Stromboli Volcano ◽  
Aeolian Islands ◽  
Source Heterogeneity

Relative roles of source composition, fractional crystallization and crustal contamination in the petrogenesis of Andean volcanic rocks

1984 ◽  
Vol 310 (1514) ◽  
pp. 675-692 ◽  
Keyword(s):  
Subduction Zone ◽  
Continental Crust ◽  
Fractional Crystallization ◽  
Magma Mixing ◽  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Oceanic Lithosphere ◽  
Alkaline Basalt ◽  
Complex Process ◽  
Heterogeneous Mantle

There are well established differences in the chemical and isotopic characteristics of the calc-alkaline basalt—andesite-dacite-rhyolite association of the northern (n.v.z.), central (c.v.z.) and southern volcanic zones (s.v.z.) of the South American Andes. Volcanic rocks of the alkaline basalt-trachyte association occur within and to the east of these active volcanic zones. The chemical and isotopic characteristics of the n.v.z. basaltic andesites and andesites and the s.v.z. basalts, basaltic andesites and andesites are consistent with derivation by fractional crystallization of basaltic parent magmas formed by partial melting of the asthenospheric mantle wedge containing components from subducted oceanic lithosphere. Conversely, the alkaline lavas are derived from basaltic parent magmas formed from mantle of ‘within-plate’ character. Recent basaltic andesites from the Cerro Galan volcanic centre to the SE of the c.v.z. are derived from mantle containing both subduction zone and within-plate components, and have experienced assimilation and fractional crystallization (a.f.c.) during uprise through the continental crust. The c.v.z. basaltic andesites are derived from mantle containing subduction-zone components, probably accompanied by a.f.c. within the continental crust. Some c.v.z. lavas and pyroclastic rocks show petrological and geochemical evidence for magma mixing. The petrogenesis of the c.v.z. lavas is therefore a complex process in which magmas derived from heterogeneous mantle experience assimilation, fractional crystallization, and magma mixing during uprise through the continental crust.

scholarly journals Geology and Petrology of Ruapehu Volcano and Related Vents

2021 ◽  
Author(s):  
◽  
William Robert Hackett
Keyword(s):  
Fractional Crystallization ◽  
Magma Mixing ◽  
Bulk Composition ◽  
Crustal Contamination ◽  
Lava Flows ◽  
Taupo Volcanic Zone ◽  
Bulk Rock ◽  
Compositional Diversity ◽  
New Formation ◽  
Ruapehu Volcano

<p>Ruapehu Volcano is an active, multiple-vent, andesite composite volcano at the southern terminus of the Taupo Volcanic Zone, central North Island, New Zealand. The present-day volume of Ruapehu is estimated at 110 km3, and construction of the massif probably occurred during the past 0.5 m.y. Geologic mapping and stratigraphic studies have led to the recognition of four periods of cone construction, each occurring over 104-105 year time intervals. On the basis of lithologic/petrographic differences, and conspicuous unconformities which separate the deposits of each cone-building period, four new formations are defined, comprises the Ruapehu Group. Te Herenga formation (new formation name) comprises the oldest deposits of Ruapehu (upper lavas ca. 0.23 Ma) and is exposed as planeze surfaces and aretes on N and NW Ruapehu. The formation includes lava flows, tuff breccias, and small intrusive bodies surrounded by zones of hydrothermal alteration. There is little petrographic and compositional diversity; most lavas are porphyritic titanomagnetite- augite- hypersthene- plagioclase basic andesites. Wahiance Formation (new formation name) is younger than Te Herenga Fm,. but of unknown age. It is well exposed on SE Ruapehu, and comprises mostly lava flows and tuff breccias. The lavas comprise acid and basic andesites. Mangewhero Formation (new formation name) is well exposed everywhere except SE Ruapehu, and the upper lavas and pyroclastics (ca. 0.02 Ma) form the present high peeks and main cone of Ruapehu. The lavas are petrographically and geochemically diverse, ranging from basalt to decite in bulk composition. Some of the lower lavas are olivine-beering andesites of hybrid orgin. Whakapapa Formation (new formation name; ca 15,000 years to present) comprises conspicuously young lava flows, tuff breccias, airfall pyroclastics and minor pyroclastic flows of acid- and basic andesite. The deposits of these post-glacial summit and flank eruptions are subdivided into the lwikau, Rangataua, Tama and Crater Lake Members. 'Related vents' produced Heuhungatahi Andesite Fm. (> 0.5 Ma?), and Holocene deposits of basalt and basic andesite at isolated, monogenetic centres comprising Ohakune Andesite Fm., Pukeonake Andesite Fm., and Waimarino Basalt Fm. (new formation name). Most Ruapehu lavas are medium-K acid and basic andesites (mean of 144 bulk rock analyses is 57.8 wt % SiO2), but rare basalt and minor decite are present. Nearly all lavas are porphyritic in plagioclase, augite and hypersthene [plus or minus] olivine, with titanomagnetite micro- phenocrysts, and contain abundant metamorphic and igneous rock inclusions. Petrography, mineral chemistry and bulk rock chemistry indicate fractional crystallization series from parental basalts (52-53 % SiO2, Q-normative, low-alumina) to medium-K basic- and acid andesites (58-59 % SiO2). Early fractionating minerals are olivine and clinopyroxene with minor chrome spinel and plagioclase, followed by plagioclase, orthopyroxene, clinopyroxene and minor titanomagnetite in later stages of differentiation. Thus, basalt differentiation to produce andesites involves 'POAM-type' (Gill, 1981) fractional crystallization. Three second-order differentiation processes operate concurrently with frational crystallization: (1) Crystal accumulation involves addition of co-genetic plutonic rock fragments and crystals derived from them. These inclusions are common and few rocks represent liquid compositions. (2) Magma mixing involves mingling of magmas in repeatedly-occupied conduits. End members are as diverse as basalt and decite, yielding petrogaphically and chemically distinctive high-Mg andesites of the upper cone complex and parasitic centres. (3) Selective crustal assimilation is suggested by partially fused metamorphic inclusions, positive correlation of 87Sr/86Sr with SiO2, and failure of simple 'POAM' fractionation to explain decites (63-65 % SiO2). Petrogenesis of Ruapehu andesites takes place under open-system condition, involving production of parental Q-normative basalts in the mantle wedge, concurrent fractional crystallization and crustal contamination, entrainment of co-genetic plutonic rocks, and mixing of magmas in common conduits.</p>

scholarly journals Geology and Petrology of Ruapehu Volcano and Related Vents

2021 ◽  
Author(s):  
◽  
William Robert Hackett
Keyword(s):  
Fractional Crystallization ◽  
Magma Mixing ◽  
Bulk Composition ◽  
Crustal Contamination ◽  
Lava Flows ◽  
Taupo Volcanic Zone ◽  
Bulk Rock ◽  
Compositional Diversity ◽  
New Formation ◽  
Ruapehu Volcano

<p>Ruapehu Volcano is an active, multiple-vent, andesite composite volcano at the southern terminus of the Taupo Volcanic Zone, central North Island, New Zealand. The present-day volume of Ruapehu is estimated at 110 km3, and construction of the massif probably occurred during the past 0.5 m.y. Geologic mapping and stratigraphic studies have led to the recognition of four periods of cone construction, each occurring over 104-105 year time intervals. On the basis of lithologic/petrographic differences, and conspicuous unconformities which separate the deposits of each cone-building period, four new formations are defined, comprises the Ruapehu Group. Te Herenga formation (new formation name) comprises the oldest deposits of Ruapehu (upper lavas ca. 0.23 Ma) and is exposed as planeze surfaces and aretes on N and NW Ruapehu. The formation includes lava flows, tuff breccias, and small intrusive bodies surrounded by zones of hydrothermal alteration. There is little petrographic and compositional diversity; most lavas are porphyritic titanomagnetite- augite- hypersthene- plagioclase basic andesites. Wahiance Formation (new formation name) is younger than Te Herenga Fm,. but of unknown age. It is well exposed on SE Ruapehu, and comprises mostly lava flows and tuff breccias. The lavas comprise acid and basic andesites. Mangewhero Formation (new formation name) is well exposed everywhere except SE Ruapehu, and the upper lavas and pyroclastics (ca. 0.02 Ma) form the present high peeks and main cone of Ruapehu. The lavas are petrographically and geochemically diverse, ranging from basalt to decite in bulk composition. Some of the lower lavas are olivine-beering andesites of hybrid orgin. Whakapapa Formation (new formation name; ca 15,000 years to present) comprises conspicuously young lava flows, tuff breccias, airfall pyroclastics and minor pyroclastic flows of acid- and basic andesite. The deposits of these post-glacial summit and flank eruptions are subdivided into the lwikau, Rangataua, Tama and Crater Lake Members. 'Related vents' produced Heuhungatahi Andesite Fm. (> 0.5 Ma?), and Holocene deposits of basalt and basic andesite at isolated, monogenetic centres comprising Ohakune Andesite Fm., Pukeonake Andesite Fm., and Waimarino Basalt Fm. (new formation name). Most Ruapehu lavas are medium-K acid and basic andesites (mean of 144 bulk rock analyses is 57.8 wt % SiO2), but rare basalt and minor decite are present. Nearly all lavas are porphyritic in plagioclase, augite and hypersthene [plus or minus] olivine, with titanomagnetite micro- phenocrysts, and contain abundant metamorphic and igneous rock inclusions. Petrography, mineral chemistry and bulk rock chemistry indicate fractional crystallization series from parental basalts (52-53 % SiO2, Q-normative, low-alumina) to medium-K basic- and acid andesites (58-59 % SiO2). Early fractionating minerals are olivine and clinopyroxene with minor chrome spinel and plagioclase, followed by plagioclase, orthopyroxene, clinopyroxene and minor titanomagnetite in later stages of differentiation. Thus, basalt differentiation to produce andesites involves 'POAM-type' (Gill, 1981) fractional crystallization. Three second-order differentiation processes operate concurrently with frational crystallization: (1) Crystal accumulation involves addition of co-genetic plutonic rock fragments and crystals derived from them. These inclusions are common and few rocks represent liquid compositions. (2) Magma mixing involves mingling of magmas in repeatedly-occupied conduits. End members are as diverse as basalt and decite, yielding petrogaphically and chemically distinctive high-Mg andesites of the upper cone complex and parasitic centres. (3) Selective crustal assimilation is suggested by partially fused metamorphic inclusions, positive correlation of 87Sr/86Sr with SiO2, and failure of simple 'POAM' fractionation to explain decites (63-65 % SiO2). Petrogenesis of Ruapehu andesites takes place under open-system condition, involving production of parental Q-normative basalts in the mantle wedge, concurrent fractional crystallization and crustal contamination, entrainment of co-genetic plutonic rocks, and mixing of magmas in common conduits.</p>

Aeromagnetic constraints on the subsurface structure of Stromboli Volcano, Aeolian Islands, Italy

2009 ◽  
Vol 478 (1-2) ◽  
pp. 19-33 ◽  
Author(s):  
Shigeo Okuma ◽  
Christian Stotter ◽  
Robert Supper ◽  
Tadashi Nakatsuka ◽  
Ryuta Furukawa ◽  
...  
Keyword(s):  
Subsurface Structure ◽  
Stromboli Volcano ◽  
Aeolian Islands

scholarly journals Tracking precursors and degassing by radon monitoring during major eruptions at Stromboli Volcano (Aeolian Islands, Italy)

2005 ◽  
Vol 32 (12) ◽  
pp. n/a-n/a ◽  
Author(s):  
C. Cigolini ◽  
G. Gervino ◽  
R. Bonetti ◽  
F. Conte ◽  
M. Laiolo ◽  
...  
Keyword(s):  
Stromboli Volcano ◽  
Aeolian Islands ◽  
Radon Monitoring
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