Mineralogic constraints on the magmatic history of Volcán Darwin flank lava at Urvina Bay, Islá Isabela, Galápagos Islands

Nusbaum, Robert L.; Colgan, Mitchell W.; Lawton, Donna E.; Glascock, Michael D.

doi:10.1016/0377-0273(91)90011-n

Cited by 3 publications

(2 citation statements)

References 14 publications

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“…Geist et al, 2006;Graham et al, 1993;Handley et al, 2011;K. S. Harpp and White, 2001;Jackson & Carlson, 2012;Koleszar et al, 2009;Kurz & Geist, 1999; M. D. Kurz et al, 2009;Liang et al, 2017;Marty & Humbert, 1997;McBirney & Williams, 1969;Naumann et al, 2002;Nusbaum et al, 1991;Peterson et al, 2017;Pringle et al, 2016;Raquin & Moreira, 2009;Saal et al, 2007;Shimizu et al, 1981;Standish et al, 1998;Teasdale et al, 2005;White et al, 1993) as identified in Figure 1 and shown in detail in Figure 3. Numbers in parentheses are 1 SD of the values used for each average.…”

Section: Seamount Mapping Sampling and Initial Sample Preparationmentioning

confidence: 97%

Monogenetic Near‐Island Seamounts in the Galápagos Archipelago

Schwartz

Wanless

Soule

et al. 2020

Geochem Geophys Geosyst

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Ocean islands form as a consequence of the intermittent eruption of lavas in a localized area as the Earth's lithosphere moves over a hotspot source (Wilson, 1963). Long-lived hotspot volcanism is most succinctly explained by the concept of so-called "plume theory" (Campbell, 2007; Morgan, 1971), which states that upwelling mantle "plumes," originating from the deep Earth, melt as they near the lithosphere, resulting in hotspot volcanism. "Plume theory" predicts linear volcanic chains that age in the direction of plate motion, relative to their fixed plume source. A single island or seamount contains an integrated history of repeated eruptions over a finite period of time (Morgan, 1971), whereas ocean island and seamount chains can collectively record hotspot activity occurring over tens-of-millions of years. As a result, ocean islands Abstract Rarely have small seamounts on the flanks of hotspot derived ocean-island volcanoes been the targets of sampling, due to sparse high-resolution mapping near ocean islands. In the Galápagos Archipelago, for instance, sampling has primarily targeted the subaerial volcanic edifices, with only a few studies focusing on large-volume submarine features. Sampling restricted to these large volcanic features may present a selection bias, potentially resulting in a skewed view of magmatic and source processes because mature magmatic systems support mixing and volcanic accretion that overprints early magmatic stages. We demonstrate how finer-scale sampling of satellite seamounts surrounding the volcanic islands in the Galápagos can be used to lessen this bias and thus, better constrain the evolution of these volcanoes. Seamounts were targeted in the vicinity of Floreana and Fernandina Islands, and between Santiago and Santa Cruz. In all regions, individual seamounts are typically monogenetic, but each seamount field requires multigenerational magmatic episodes to account for their geochemical variability. This study demonstrates that in the southern and eastern regions the seamounts are characterized by greater geochemical variability than the islands they surround but all three regions have (Sr-Nd-He) isotopic signatures that resemble neighboring islands. Variations in seamount chemistry from alkalic to tholeiitic near Fernandina support the concept that islands along the center of the hotspot track undergo greater mean depths of melting, as predicted by plume theory. Patterns of geochemical and isotopic enrichment of seamounts within each region support fine-scale mantle heterogeneities in the mantle plume sourcing the Galápagos hotspot. Plain Language Summary Hotspots are places on Earth where volcanism occurs away from major plate boundaries and are, thus, not explained by the theory of plate tectonics. Instead, "plume theory" predicts that a least a portion of hotspot volcanism is related to the upwelling of hot mantle, which partially melts as it ascends and forms magma that produces ocean-island volcanoes. Chemistry of lavas sourced from these volcanoes are used to test predic...

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Section: Seamount Mapping Sampling and Initial Sample Preparationmentioning

confidence: 97%

Monogenetic Near‐Island Seamounts in the Galápagos Archipelago

Schwartz

Wanless

Soule

et al. 2020

Geochem Geophys Geosyst

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“…However, it is also possible that due to its current quiescence, historical eruptions have not been identified. There is some historical evidence of lateral intrusions near Darwin: Urvina Bay "catastrophically uplifted" by 6 m in 1954, exposing 1.4 km 2 of coral reef [Nusbaum et al 1991] (Figure 15). The magmatic source of the this uplift is unclear; Urvina Bay is closer to Alcedo than Darwin, but uplift there revealed Darwin-derived basalts, though McBirney et al [1985] hint that it may be related to a 1954 lava flow at Alcedo.…”

Section: Dying Activity: Alcedo Darwin and Sierra Negramentioning

confidence: 99%

Craters of habit: Patterns of deformation in the western Galápagos

Reddin,

Ebmeier,

Bagnardi

et al. 2024

Volcanica

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The western Galápagos islands of Fernandina and Isabela comprise six active volcanoes that have deformed since first observed by satellite radar in the early 1990s. We analyse new (2015–2022) displacement time series at Alcedo, Cerro Azul, Darwin, Fernandina, Sierra Negra, and Wolf volcanoes in the context of deformation and unrest since 1992. Previous discussions of volcano deformation have focused on eruptions, major intrusive episodes, and the structure of sub-volcanic systems. We discuss the full geodetic record of deformation and show that the style of eruptions, characteristics of unrest and deformation are distinctive at each volcano. These characteristic differences in deformation and unrest styles between the volcanoes have persisted for at least three decades, since the first satellite radar measurements. These consistent differences in shallow magma storage and eruptive dynamics reflect the influence of “top-down” factors and evolutionary stage, providing a basis to understand volcanic unrest here, and to inform monitoring strategies.

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Fernandina Volcano's evolved, well‐mixed basalts: Mineralogical and petrological constraints on the nature of the Galapagos plume

Allan¹,

Simkin²

2000

J. Geophys. Res.

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MgO. Cr-spinel and glass melt inclusions in plagioclase, together with zoned olivine, give evidence for a range of parental melts in the recent shallow magmatic system, with Mg # as high as 0.62. Extensive, shallow magma mixing is required to explain these variations in mineral and inclusion chemistry, indicating more thermal variation within the shallow magmatic system than is implied by the relatively monotonous whole rock compositions. Apparently, Fernandina's shallow magma chamber has physically blocked passage of more primitive magmas to the surface and homogenized the erupted lavas by extensive mixing. Small variations in lava isotopic and compatible element composition, combined with the need to resupply melt to maintain thermal balance, indicate that replenishment of the magma chamber is semicontinuous, with resupply occurring of the order of a decade or less. Plagioclase-dominated, evolved Fernandina lavas are in sharp contrast to more primitive, olivine-dominated Hawaiian lavas; the total lack of primitive melts in the shallow Fernandina magmatic system implies that substantial fractionation and heat loss occurred during melt transportation from the mantle source to the edifice magma chamber, despite the fact that these melts were transported through relatively warm, young, and thin lithosphere adjacent to the Cocos-Nazca ridge. The diffuse nature of Galapagos volcanism, with 20th century eruptions from eight distinct volcanoes over a 2 20,000 km area, further supports this interpretation and suggests that the Galapagos plume is relatively diffuse, weak, and significantly less thermally intense than the vigorous Hawaiian plume. It may in fact be waning.

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Mineralogic constraints on the magmatic history of Volcán Darwin flank lava at Urvina Bay, Islá Isabela, Galápagos Islands

Cited by 3 publications

References 14 publications

Monogenetic Near‐Island Seamounts in the Galápagos Archipelago

Monogenetic Near‐Island Seamounts in the Galápagos Archipelago

Craters of habit: Patterns of deformation in the western Galápagos

Fernandina Volcano's evolved, well‐mixed basalts: Mineralogical and petrological constraints on the nature of the Galapagos plume

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