Helium isotope ratios in mafic phenocrysts and geothermal fluids from La Palma, the Canary Islands (Spain): implications for HIMU mantle sources

2000 ◽  
Vol 64 (12) ◽  
pp. 2119-2132 ◽  
Author(s):  
D.R Hiltona ◽  
C.G Macphersona ◽  
T.R Elliottb
Keyword(s):  
Canary Islands ◽  
Isotope Ratios ◽  
Helium Isotope ◽  
La Palma ◽  
Geothermal Fluids ◽  
Mantle Sources

Heterogeneous mantle-derived helium isotopes in the Canary Islands and other ocean islands

Geology ◽  
2020 ◽  
Author(s):  
James M.D. Day ◽  
David R. Hilton
Keyword(s):  
Canary Islands ◽  
Temporal Variability ◽  
Good Correspondence ◽  
La Palma ◽  
Enriched Mantle ◽  
Geothermal Fluids ◽  
Co2 Output ◽  
Mantle Sources ◽  
Heterogeneous Mantle ◽  
Cumbre Vieja

Consistent 3He/4He ratios have been measured for >25 years in geothermal fluids and gases from Cumbre Vieja, La Palma (9.4 ± 0.1RA, where RA is the 3He/4He of air), and Teide, Tenerife (6.8 ± 0.3RA), Canary Islands. Both locations are characterized by similar CO2/3He (~2 to 4 × 109), mantle-like δ13C (–3.3‰ to –4.4‰) and CO2 output (0.1–0.2 × 1010 mol yr–1). Helium isotopic differences between the islands cannot be explained by differential aging and 4He ingrowth in their mantle sources. Instead, distinct He reservoirs exist, with a high-μ (HIMU)–type mantle source for La Palma and a more enriched mantle, with possible lithospheric mantle influence, for Tenerife. Geothermal samples from the Canary Islands record a present-day He distribution distinct from higher 3He/4He in olivine from older eastern Canary Island lavas, indicating temporal variability in sources. Comparison of geothermal sample data versus olivine, pyroxene, and glass He isotope data for the Canary Islands, Azores, Cape Verde, Hawaiian islands, and Iceland reveals generally good correspondence, even across >1 m.y. of stratigraphy. However, in addition to the Canary Islands, there are examples of inter-island heterogeneity for He isotopes at Hawaii, the Azores, and within Iceland, preserved in hydrothermal samples, minerals, and glasses. In particular, in northwest Iceland, olivine separates from older lavas preserve higher 3He/4He than present-day geothermal samples from the same region. This difference likely reflects a reduced mantle-derived 3He input to Icelandic magmatism since the Miocene. Temporal variability in 3He/4He, assessed using geothermal and geological materials in conjunction, offers a powerful tool for examining heterogeneity and temporal evolution of mantle sources at intraplate volcanoes.

scholarly journals Paleomagnetism and40Ar/39Ar ages from La Palma in the Canary Islands

2000 ◽  
Vol 1 (9) ◽  
pp. n/a-n/a ◽  
Author(s):  
Lisa Tauxe ◽  
Hubert Staudigel ◽  
Jan R. Wijbrans
Keyword(s):  
Canary Islands ◽  
La Palma

Grazing effects on species composition in different vegetation types (La Palma, Canary Islands)

2011 ◽  
Vol 37 (3) ◽  
pp. 230-238 ◽  
Author(s):  
J.R. Arévalo ◽  
L. de Nascimento ◽  
S. Fernández-Lugo ◽  
J. Mata ◽  
L. Bermejo
Keyword(s):  
Species Composition ◽  
Canary Islands ◽  
Vegetation Types ◽  
La Palma ◽  
Grazing Effects

Diffuse H2 degassing studies: a useful geochemical tool for monitoring Cumbre Vieja volcano, La Palma, Canary Islands

2021 ◽  
Author(s):  
Nemesio M. Pérez ◽  
Gladys V. Melián ◽  
Pedro A. Hernández ◽  
María Asensio-Ramos ◽  
Eleazar Padrón ◽  
...  
Keyword(s):  
Canary Islands ◽  
Emission Rate ◽  
Monitoring Program ◽  
Hydrothermal Systems ◽  
Sequential Gaussian Simulation ◽  
Homogeneous Distribution ◽  
La Palma ◽  
Soil Degassing ◽  
Geothermal Activity ◽  
Cumbre Vieja

<p>Hydrogen (H<sub>2</sub>) is one of the most abundant trace species in volcano-hydrothermal systems and is a key participant in many redox reactions occurring in the hydrothermal reservoir gas. Although H<sub>2</sub> can be produced in soils by N<sub>2</sub>-fixing and fertilizing bacteria, soils are considered nowadays as sinks of molecular hydrogen (Smith-Downey et al. 2006). Because of its chemical and physical characteristics, H<sub>2</sub> generated within the crust moves rapidly and escapes to the atmosphere. These characteristics make H<sub>2</sub> one of the best geochemical indicators of magmatic and geothermal activity at depth. Cumbre Vieja volcano (La Palma, Canary Islands) is the most active basaltic volcano in the Canaries with seven historical eruptions being Teneguía eruption (1971) the most recent one. Cumbre Vieja volcano is characterized by a main north–south rift zone 20 km long, up to 1950 m in elevation and covering an area of 220 km<sup>2</sup> with vents located at the northwest and northeast. Cumbre Vieja does not show any visible degassing (fumaroles, etc.). For that reason, the geochemical volcano monitoring program at Cumbre Vieja volcano has been focused on soil degassing surveys.  Here we show the results of soil H<sub>2</sub> emission surveys that have been carried out regularly since 2001. Soil gas samples were collected in about 600 sampling sites selected to obtain a homogeneous distribution at about 40 cm depth using a metallic probe and 60 cc hypodermic syringes and stored in 10 cc glass vials. H<sub>2</sub> content was analysed later by a VARIAN CP4900 micro-GC. A simple diffusive emission mechanism was applied to compute the emission rate of H<sub>2</sub> at each survey. Diffuse H<sub>2</sub> emission values were used to construct spatial distribution maps by using sequential Gaussian simulation (sGs) algorithm, allowing the estimation of the emission rate from the volcano. Between 2001-2003, the average diffuse H<sub>2</sub> emission rate was ∼2.5 kg·d<sup>−1</sup> and an increase of this value was observed between 2013-2017 (∼16.6 kg·d<sup>−1</sup>), reaching a value of 36 kg·d<sup>−1</sup> on June 2017, 4 month before the first recent seismic swarm in October, 2017 at Cumbre Vieja volcano. Six additional seismic swarms had occurred at Cumbre Vieja volcano (February 2018, July-August 2020; October 8-10, 2020; October 17-19, 2020, November 21, 2020 and December 23-26, 2020) and changes of diffuse H<sub>2</sub> emission related to this unrest had been observed reaching values up to ∼70 kg·d<sup>−1</sup>. Diffuse H<sub>2</sub> emission surveys have demonstrated to be sensitive and excellent precursors of magmatic processes occurring at depth in Cumbre Vieja. Periodic diffuse H<sub>2</sub> emission surveys provide valuable information to improve and optimize the detection of early warning signals of volcanic unrest at Cumbre Vieja volcano.</p>

scholarly journals Geochemical and Volcanological Evolution of La Palma, Canary Islands

2017 ◽  
Vol 58 (6) ◽  
pp. 1227-1248 ◽  
Author(s):  
Andreas Klügel ◽  
Karsten Galipp ◽  
Kaj Hoernle ◽  
Folkmar Hauff ◽  
Simon Groom
Keyword(s):  
Canary Islands ◽  
La Palma

scholarly journals 523676 (2013 UL10): the first active red centaur

2018 ◽  
Vol 620 ◽  
pp. A93 ◽  
Author(s):  
E. Mazzotta Epifani ◽  
E. Dotto ◽  
S. Ieva ◽  
D. Perna ◽  
P. Palumbo ◽  
...  
Keyword(s):  
Production Rate ◽  
Canary Islands ◽  
Colour Index ◽  
Nucleus Size ◽  
Dust Production ◽  
La Palma ◽  
Upper Limit ◽  
Nucleus Surface ◽  
Perihelion Passage

Aims. We present observations of 523676 (2013 UL10), a centaur orbiting between Jupiter and Uranus that is dynamically similar to the few tens of active centaurs that are currently known. Methods. We analysed visible BVR images of the centaur obtained at the Telescopio Nazionale Galileo (La Palma, Canary Islands, Spain) to investigate the weak comet-like activity and to derive information on the nucleus surface colours and size. Results. Centaur 523676 (2013 UL10) is the only centaur known so far that has both comet-like activity and red surface colours: its nucleus has a colour index [B – R] = 1.88 ± 0.11. The nucleus R magnitude (R = 20.93 ± 0.09) allowed us to derive an upper limit for its nucleus size of D ≤ 10 km. We estimated its dust production rate to be Qd ~ 10 kg s−1 at 6.2 au (just after its perihelion passage), resulting in a timescale for the surface blanketing process τB of approximately tens of years, which is very short with respect to typical dynamical lifetime inside the group. Future monitoring of 523676 (2013 UL10) is needed to further constrain the blanketing model for active centaurs and its timescale.

Migration Processes of Geothermal Fluids in the Beppu Geothermal System, Japan, Estimated from Stable Isotope Ratios

1993 ◽  
Vol 35 (4) ◽  
pp. 287-305 ◽  
Author(s):  
Koichi KITAOKA ◽  
Yuki YUSA ◽  
Kokichi KAMIYAMA ◽  
Shinji OHSAWA ◽  
Michael K. STEWART ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotope Ratios ◽  
Geothermal System ◽  
Stable Isotope Ratios ◽  
Geothermal Fluids
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