Biography:

In the past Jaime D. Barnes has collaborated on articles with Timm John and Andrea L. Rizzo. One of their most recent publications is Chorine stable isotope variations in Izu Bonin tephra: Implications for serpentinite subduction. Which was published in journal Chemical Geology.

More information about Jaime D. Barnes research including statistics on their citations can be found on their Copernicus Academic profile page.

Jaime D. Barnes's Articles: (10)

Chorine stable isotope variations in Izu Bonin tephra: Implications for serpentinite subduction

Abstractδ37Cl values were determined for Izu Bonin arc magmas erupted 0–44 Ma in order to better understand the time-dependent processing of volatiles in subduction zones. Pristine ash-sized particles (glass, pumice, scoria, and rock fragments) were handpicked from tephra drilled at ODP Site 782. δ37Cl values for these particles span a large range from − 2.1 to + 1.7‰ (error = ± 0.3‰) vs. SMOC (Standard Mean Ocean Chloride, defined as 0‰). The temporal data extend the previously reported range of δ37Cl values of − 2.6 to 0.4‰ (bulk ash) and − 5.4 to − 0.1‰ (volcanic gases) from the Quaternary Izu Bonin–Mariana volcanic front to more positive values. Overall, the temporal data indicate a time-progressive evolution, from isotopically negative Eocene and Oligocene magmas (− 0.7 ± 1.1‰, n = 10) to Neogene magmas that have higher δ37Cl values on average (+ 0.3 ± 1.1‰; n = 13). The increase is due to the emergence of positive δ37Cl values in the Neogene, while minimum δ37Cl values are similar through time. The range in δ37Cl values cannot be attributed to fractionation during melt formation and differentiation, and must reflect the diversity of Cl present in the arc magma sources. Cl clearly derives from the slab (> 96% Cl in arc magmas), but δ37Cl values do not correlate with isotope tracers (e.g. 207Pb/204Pb and 87Sr/86Sr) that are indicative of the flux from subducting sedimentary and igneous crust. Given the steady, high Cl flux since at least 42 Ma, the temporal variability of δ37Cl values is best explained by a flux from subducting isotopically positive and negative serpentinite formed in the ocean basins that mingles with and possibly overprints the isotopically negative flux from sediment and igneous crust at arc front depths. The change in the δ37Cl values before and after backarc spreading may reflect either a tectonically induced change in the mechanism of serpentinite formation on the oceanic plate, or possibly the integration of isotopically positive wedge serpentinite as arc fluid source during the Neogene. Our study suggests that serpentinites are important fluid sources at arc front depth, and implies the return of isotopically positive and negative Cl from the Earth surface to the mantle.

Mineralogical control on the chlorine isotope composition of altered oceanic crust

AbstractBulk chlorine concentrations and chlorine stable isotope compositions were determined for hydrothermally altered basalt (extrusive lavas and sheeted dikes) and gabbro samples (n = 50) from seven DSDP/ODP/IODP drill sites. These altered oceanic crust (AOC) samples span a range of crustal ages, tectonic settings, alteration type, and crustal depth. Bulk chlorine concentrations range from < 0.01 wt.% to 0.09 wt.%. In general, higher chlorine concentrations coincide with an increase in temperature of alteration and amphibole content. δ37Cl values of whole rock AOC samples range from − 1.4 to + 1.8‰. High δ37Cl values (≥ ~ 0.5‰) are associated with areas of higher amphibole content. This observation is consistent with theoretical calculations that estimate amphibole should be enriched in 37Cl compared to co-existing fluid. Negative to near zero δ37Cl values are found in areas dominated by clay minerals. Chlorine geochemistry is a rough indicator of metamorphic grade and mineralogy. AOC is a major Cl host in the subducting oceanic lithospheric slab. Here we show that bulk chlorine concentrations are ~ 3 times higher than previous estimates resulting in a greater contribution of Cl to the mantle.

Geochemistry of Alpine serpentinites from rifting to subduction: A view across paleogeographic domains and metamorphic grade

Highlights•Geochemistry of serpentinites from the Western Alps is consistent with an abyssal origin in a hyper-extended rifted margin.•Relict spinels have low Cr#s and high Mg#s suggesting low degrees of melt depletion.•Trace element gradients in serpentinites support interaction with sedimentary-derived fluids and mobility of Pb, Ba, Cs, U, Rb during subduction.•Serpentinite-crustal contact is analogous to the slab–mantle interface.

Chlorine isotope evidence for crustal recycling into the Earth's mantle

AbstractSubduction of oceanic lithosphere is a key feature of terrestrial plate tectonics. However, the effect of this recycled crustal material on mantle composition is debated. Ocean island basalts (OIB) provide direct insights into the composition of Earth's mantle. The distinct composition of the HIMU (high 238U/204Pb)- and EM (enriched mantle)-type OIB mantle sources may be due to either recycling of oceanic crust and sediment into the mantle or metasomatic processes within the mantle. Chlorine derived from seawater or crustal fluids potentially provides a tracer for recycled material. Previously reported δ37Cl values for mid-ocean ridge basalts (MORB) range from ca. − 3.0 to near 0‰. In contrast to MORB, we find a larger variation in OIB glasses representing HIMU- and EM-type mantle sources based on replicate SIMS analyses with δ37Cl values ranging from − 1.6 to + 1.1‰ for HIMU-type and − 0.4 to + 2.9‰ for EM-type lavas. These δ37Cl values correlate positively with 87Sr/86Sr ratios for both the HIMU- and EM-type samples. The negative δ37Cl values of some HIMU-type lavas overlap with those of altered oceanic lithosphere, which is assumed to be present in the HIMU source. The EM lavas have high 87Sr/86Sr and primarily positive δ37Cl values. We hypothesize that subducting sediments may have developed high δ37Cl values by expelling 37Cl-depleted pore fluids, thus accounting for the positive δ37Cl values recorded in the EM-type lavas.

Chlorine isotope composition of volcanic gases and rocks at Mount Etna (Italy) and inferences on the local mantle source

Highlights•We investigated the chlorine isotope composition in gases and lavas from Mount Etna (Italy).•The Etnean δ37Cl value for magmatic chlorine is ∼0±0.7‰.•Magma degassing does not modify the isotopic composition of chlorine.•High-temperature gases collected in 2009 were affected by secondary process (i.e., HCl removal).•Mantle source below Mount Etna is characterized by altered oceanic crust added to depleted mantle.

Chlorine stable isotope variations across the Quaternary volcanic arc of Ecuador

Highlights•Stable chlorine isotope data of volcanic rocks of the Ecuadorian arc are presented.•Chlorine isotopes correlate with typical slab fluid indices (Ba/La, Pb/Ce).•Across-arc Cl isotope variation is due to diminishing slab input away from trench.•Intravolcano Cl isotope variability is due to intracrustal magmatic evolution.

Geochemical investigation of Gabbroic Xenoliths from Hualalai Volcano: Implications for lower oceanic crust accretion and Hualalai Volcano magma storage system

Highlights•The lower oceanic crust (LOC) beneath the Hawaiian Islands has undergone minimal hydrothermal alteration.•The hydrothermal alteration history and composition of LOC can provide constraints on the mechanisms of LOC accretion.•A deep magma reservoir existed within or at the base of the LOC during the shield stage of Hualalai Volcano.•Isotopic heterogeneity observed in Hawaiian melts appears to derive from the heterogeneous plume source(s).

On the (mis)behavior of water in the mantle: Controls on nominally anhydrous mineral water content in mantle peridotites

Highlights•We measured NAM water contents in Colorado Plateau peridotite xenoliths via SIMS.•No correlation between NAM water content and melt depletion or metasomatism.•Hydrous mineral bearing and anhydrous xenoliths have the same NAM water content.•Rapid hydrogen diffusion erases NAM water content variability and correlations.•Diffusion of hydrogen explains low variability of NAM water content relative to Ce.

The stable isotope composition of halite and sulfate of hyperarid soils and its relation to aqueous transport

AbstractHalite (NaCl) and gypsum or anhydrite (CaSO4) are water-soluble minerals found in soils of the driest regions of Earth, and only modest attention has been given to the hydrological processes that distribute these salts vertically in soil profiles. The two most notable chloride and sulfate-rich deserts on earth are the Dry Valleys of Antarctica and the Atacama Desert of Chile. While each is hyperarid, they possess very different hydrological regimes. We first show, using previously published S and O isotope data for sulfate minerals, that downward migration of water and sulfate is the primary mechanism responsible for depth profiles of sulfate concentration, and S and O isotopes, in both deserts. In contrast, we found quite different soluble Cl concentration and Cl isotope profiles between the two deserts. For Antarctic soils with an ice layer near the soil surface, the Cl concentrations increase with decreasing soil depth, whereas the ratio of 37Cl/35Cl increases. Based on previous field observations by others, we found that thermally driven upward movement of brine during the winter, described by an advection/diffusion model, qualitatively mimics the observed profiles. In contrast, in the Atacama Desert where rare but relatively large rains drive Cl downward through the profiles, Cl concentrations and 37Cl/35Cl ratios increased with depth. The depth trends in Cl isotopes are more closely explained by a Rayleigh-like model of downward fluid flow. The isotope profiles, and our modeling, reveal the similarities and differences between these two very arid regions on Earth, and are relevant for constraining models of fluid flow in arid zone soil and vadose zone hydrology.

Chlorine isotope composition of volcanic rocks and gases at Stromboli volcano (Aeolian Islands, Italy): Inferences on magmatic degassing prior to 2014 eruption

Highlights•Rocks have δ37Cl values ranging between − 1.0 and + 0.7‰.•Plume gases have δ37Cl values ranging between − 2.2‰ and + 1.5‰.•Isotopic fractionation between gaseous and dissolved chlorine (lnαgas-melt > 0) can happen.

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