Nitrogen-rich fluid in the upper mantle: fluid inclusions in spinel dunite from Lanzarote, Canary Islands

1995 ◽  
Vol 120 (1) ◽  
pp. 20-28 ◽  
Author(s):  
T. Andersen ◽  
E. A. J. Burke ◽  
E. -R. Neumann
Keyword(s):  
Canary Islands ◽  
Fluid Inclusions ◽  
Upper Mantle ◽  
Mantle Fluid

First assessment of the noble gas and CO2 isotopic composition of fluid inclusions hosted in mantle xenoliths from El Hierro (Canary Islands) 

2021 ◽  
Author(s):  
Andres Sandoval Velasquez ◽  
Andrea Luca Rizzo ◽  
Alessandro Aiuppa ◽  
Maria Luce Frezzotti ◽  
Samantha Remigi ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Oceanic Crust ◽  
Canary Islands ◽  
Fluid Inclusions ◽  
Upper Mantle ◽  
Noble Gas ◽  
Mantle Metasomatism ◽  
Mantle Xenoliths ◽  
Local Source ◽  
El Hierro

<p>Studying the isotopic composition of fluids trapped in mantle xenoliths opens avenues to understanding the origin and cycling of volatiles in the Earth’s upper mantle. Here, we present the first isotopic results for noble gases and CO<sub>2</sub> in fluid inclusions (FI) trapped in mantle xenoliths from El Hierro the youngest island of the Canarian archipelago. Our results are based on 6 mantle xenolith samples (3 Spinel-lherzolites and 3 Spinel-harzburgites) collected from the El Julan cliff valley (Oglialoro et al., 2017), from which we hand-picked crystals of Ol, Opx, and Cpx. Isotopic determinations were performed at the INGV (Sezione di Palermo) noble gas and stable isotopes laboratories, following the preparation methods and analytical procedures described in Rizzo et al. (2018 and references therein).</p><p>The Ne-Ar isotopic compositions reveal the presence of an atmospheric component in the FI. Most of the samples exhibit <sup>4</sup>He/<sup>20</sup>Ne ratios > 60, <sup>20</sup>Ne/<sup>22</sup>Ne ratios between 9.84 and 10.49, <sup>21</sup>Ne/<sup>22</sup>Ne ratios from 0.0295 to 0.0330, and <sup>40</sup>Ar/<sup>36</sup>Ar > 800, suggesting mixing between MORB-like mantle fluids and an air-derived component. We argue this latter may (at least in part) derive from upper mantle recycling of atmospheric fluids via paleo-subduction event(s). Excluding samples possibly affected by diffusive fractionation processes, the average Rc/Ra ratio (<sup>3</sup>He/<sup>4</sup>He ratio corrected for atmospheric contamination) measured in El Hierro xenoliths is ~7.45 + 0.26 Ra, within the MORB range (8 + 1 Ra; Graham, 2002). The He homogeneous signature of these xenoliths agrees well with the <sup>3</sup>He/<sup>4</sup>He compositions previously reported in lava phenocrysts and cumulates (Day and Hilton, 2011) and is slightly below the maximum ratios measured in groundwater samples during the 2012 volcanic unrest (~8.2 Ra; Padron et al., 2013). All these pieces of evidence argue against a primordial source involved in the local lithospheric mantle. Putting these data in the context of previous literature results for FI and surface gases in the Canary Islands (La Palma, La Gomera, Tenerife, Gran Canaria, and Lanzarote), we identify an eastward <sup>3</sup>He/<sup>4</sup>He decreasing trend that parallels a corresponding increase of the oceanic crust thickness. In addition to the mantle heterogeneity, we propose that part of the <sup>3</sup>He/<sup>4</sup>He east-to-west variation along the archipelago is caused by the variable thickness of the oceanic crust (and hence, different interactions with <sup>4</sup>He-rich crustal fluids during emplacement).</p><p>The FI δ<sup>13</sup>C(CO<sub>2</sub>) isotopic composition ranges from -2.38 to -1.23‰ in pyroxenes and -0.2 to +2.0‰ in olivine. These unusually positive δ<sup>13</sup>C compositions support the existence of a recycled crustal carbon component in the local source mantle, likely pointing to mantle metasomatism (Oglialoro et al., 2017) from fluids carrying carbon from subducted sediments and/or altered oceanic crust (AOC).</p>

Fluid inclusions in upper mantle xenoliths from Northern Patagonia, Argentina: Evidence for an upper mantle diapir

1997 ◽  
Vol 60 (3-4) ◽  
pp. 145-164 ◽  
Author(s):  
M. E. Varela ◽  
E. A. Bjerg ◽  
R. Clocchiatti ◽  
C. H. Labudia ◽  
G. Kurat
Keyword(s):  
Fluid Inclusions ◽  
Upper Mantle ◽  
Mantle Xenoliths ◽  
Northern Patagonia ◽  
Mantle Diapir

Melt and fluid inclusions in dunite xenoliths from La Gomera, Canary Islands: tracking the mantle metasomatic fluids

1994 ◽  
Vol 6 (6) ◽  
pp. 805-818 ◽  
Author(s):  
Maria-Luce Frezzotti ◽  
Jacques L.R. Touret ◽  
Wim J. Lustenhouwer ◽  
Else-Ragnild Neumann
Keyword(s):  
Canary Islands ◽  
Fluid Inclusions ◽  
Melt And Fluid Inclusions ◽  
La Gomera

Multi-stage magma ascent beneath the Canary Islands: evidence from fluid inclusions

1998 ◽  
Vol 132 (1) ◽  
pp. 48-64 ◽  
Author(s):  
Thor H. Hansteen ◽  
Andreas Klügel ◽  
Hans-Ulrich Schmincke
Keyword(s):  
Canary Islands ◽  
Fluid Inclusions ◽  
Magma Ascent ◽  
Multi Stage

Brine inclusions in diamonds: a new upper mantle fluid

2001 ◽  
Vol 187 (3-4) ◽  
pp. 323-332 ◽  
Author(s):  
Elad S. Izraeli ◽  
Jeffrey W. Harris ◽  
Oded Navon
Keyword(s):  
Upper Mantle ◽  
Mantle Fluid

Petrogenesis of spinel harzburgite and dunite suite xenoliths from Lanzarote, eastern Canary Islands: Implications for the upper mantle

Lithos ◽  
1995 ◽  
Vol 35 (1-2) ◽  
pp. 83-107 ◽  
Author(s):  
E.-R. Neumann ◽  
E. Wulff-Pedersen ◽  
K. Johnsen ◽  
T. Andersen ◽  
E. Krogh
Keyword(s):  
Canary Islands ◽  
Upper Mantle
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