Helium-carbon systematics of groundwaters in the Lassen Peak Region

Barry, Peter H.; Bekaert, David V.; Krantz, John A.; Halldórsson, Sæmundur A.; Moor, J. Marten de; Fischer, Tobias P.; Werner, C. A.; Kelly, P. J.; Seltzer, Alan M.; Franz, B.; Kulongoski, Justin T.

doi:10.1016/j.chemgeo.2021.120535

Cited by 7 publications

(6 citation statements)

References 77 publications

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“…The fraction (f) of carbon loss can be calculated for any observed δ 13 C o value can be calculated using Eq. 9 (Holloway and Blank, 1994;Barry et al, 2021).…”

Section: Precipitation Of Calcitementioning

confidence: 99%

The Helium and Carbon Isotope Characteristics of the Andean Convergent Margin

et al. 2022

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Subduction zones represent the interface between Earth’s interior (crust and mantle) and exterior (atmosphere and oceans), where carbon and other volatile elements are actively cycled between Earth reservoirs by plate tectonics. Helium is a sensitive tracer of volatile sources and can be used to deconvolute mantle and crustal sources in arcs; however it is not thought to be recycled into the mantle by subduction processes. In contrast, carbon is readily recycled, mostly in the form of carbon-rich sediments, and can thus be used to understand volatile delivery via subduction. Further, carbon is chemically-reactive and isotope fractionation can be used to determine the main processes controlling volatile movements within arc systems. Here, we report helium isotope and abundance data for 42 deeply-sourced fluid and gas samples from the Central Volcanic Zone (CVZ) and Southern Volcanic Zone (SVZ) of the Andean Convergent Margin (ACM). Data are used to assess the influence of subduction parameters (e.g., crustal thickness, subduction inputs, and convergence rate) on the composition of volatiles in surface volcanic fluid and gas emissions. He isotopes from the CVZ backarc range from 0.1 to 2.6 RA (n = 23), with the highest values in the Puna and the lowest in the Sub-Andean foreland fold-and-thrust belt. Atmosphere-corrected He isotopes from the SVZ range from 0.7 to 5.0 RA (n = 19). Taken together, these data reveal a clear southeastward increase in 3He/4He, with the highest values (in the SVZ) falling below the nominal range associated with pure upper mantle helium (8 ± 1 RA), approaching the mean He isotope value for arc gases of (5.4 ± 1.9 RA). Notably, the lowest values are found in the CVZ, suggesting more significant crustal inputs (i.e., assimilation of 4He) to the helium budget. The crustal thickness in the CVZ (up to 70 km) is significantly larger than in the SVZ, where it is just ∼40 km. We suggest that crustal thickness exerts a primary control on the extent of fluid-crust interaction, as helium and other volatiles rise through the upper plate in the ACM. We also report carbon isotopes from (n = 11) sites in the CVZ, where δ13C varies between −15.3‰ and −1.2‰ [vs. Vienna Pee Dee Belemnite (VPDB)] and CO2/3He values that vary by over two orders of magnitude (6.9 × 108–1.7 × 1011). In the SVZ, carbon isotope ratios are also reported from (n = 13) sites and vary between −17.2‰ and −4.1‰. CO2/3He values vary by over four orders of magnitude (4.7 × 107–1.7 × 1012). Low δ13C and CO2/3He values are consistent with CO2 removal (e.g., calcite precipitation and gas dissolution) in shallow hydrothermal systems. Carbon isotope fractionation modeling suggests that calcite precipitation occurs at temperatures coincident with the upper temperature limit for life (122°C), suggesting that biology may play a role in C-He systematics of arc-related volcanic fluid and gas emissions.

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“…The fraction (f) of carbon loss can be calculated for any observed δ 13 C o value can be calculated using Eq. 9 (Holloway and Blank, 1994;Barry et al, 2021).…”

Section: Precipitation Of Calcitementioning

confidence: 99%

The Helium and Carbon Isotope Characteristics of the Andean Convergent Margin

et al. 2022

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“…It is not known if diffuse CO 2 degassing occurs from Taranaki's upper flanks above the staturated zone. The inset shows the expected range of CO 2 emission from Taranaki's springs (in gray) compared to emissions from cold springs on Mammoth Mountain (Evans et al., 2002), individual cold springs in the Cascades (James et al., 1999), Lassen volcano (Barry et al., 2021; Rose & Davisson, 1996), and Iwate volcano in Japan (Ohwada et al., 2012).…”

Section: Discussionmentioning

confidence: 99%

“…The air corrected 3 He/ 4 He (R C /R A ) is also consistent with a magmatic contribution to Arawhata spring (5.13 R A ). It is common for magmatic helium to be observed at large distances from active volcanoes (Barry et al., 2013, 2019, 2021, 2022). This signature differs from sedimentary basin fluids in the Taranaki region that have air corrected 3 He/ 4 He values of 0.17–1.4 R A and δ 13 C‐CO 2 from −8 to −16.6‰, Giggenbach, 1997; Hilton et al., 2002).…”

Section: Discussionmentioning

confidence: 99%

“…In particular, carbon dioxide (CO 2 ) dissolves in cold groundwaters in the subsurface, but is rapidly lost to the atmosphere near the point of discharge, providing a long-term, cryptic mechanism for deep CO 2 transfer to the surface. The magnitude of magmatic CO 2 released from cold springs on dormant volcanoes is globally unconstrained (e.g., Barry et al, 2021;Werner et al, 2019), and it is rarely used as a monitoring tool. Documenting how such emissions vary in time could provide important new insights into the magmatic vitality of long-dormant volcanoes.Taranaki is a 2518-m-high stratovolcano in the west of the North Island of New Zealand (NZ).…”

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confidence: 99%

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Magmatic Carbon and Helium in Springs Reveals the Vitality of a Dormant Volcano, Taranaki, New Zealand

Werner

Schipper

Cronin

et al. 2022

Geophysical Research Letters

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A challenge in monitoring long‐dormant volcanoes is to discover early signs of reawakening. Mineral springs on Taranaki volcano (2,518 m, New Zealand) have elevated carbonate concentrations, δ13CDIC ∼ −5‰ (VPDB) and He isotopes from 5.13 to 5.92 RA, indicating a magmatic volatile source. Stable isotopes demonstrate water recharge occurs near the volcano's summit. Volatile anions and silica are low in a cold (5oC) flank spring at 1,000 m a.s.l., yet elevated in warm springs (25–32oC) associated with travertine deposits at 250–300 m, suggesting a weak hydrothermal component along the flow path. Tritium dating of the cold spring water yields a mean residence time of 7.8 years. This short residence time and magmatic volatile signatures suggest magmatic CO2 persistently flushes Taranaki's upper edifice. Cold spring geochemistry thus reveals volcanic activity at this dormant volcano that otherwise lacks obvious geophysical signs of unrest.

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“…Carbon isotopes are likewise fractionated during gas-water interactions (Randazzo et al, 2021 and references therein). Thus, both elemental ratios and δ 13 C can be severely modified by secondary processes such as gas dissolution in water and solidphase (carbonate) precipitation (Gilfillan et al, 2009;Barry and Bekaer, 2021;Randazzo et al, 2021).…”

Section: Secondary Processesmentioning

confidence: 99%

Active degassing of crustal CO2 in areas of tectonic collision: A case study from the Pollino and Calabria sectors (Southern Italy)

Randazzo

Caracausi²,

Aiuppa³

et al. 2022

Front. Earth Sci.

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Carbon dioxide (CO2) is released from the Earth’s interior into the atmosphere through both volcanic and non-volcanic sources in a variety of tectonic settings. A quantitative understanding of CO2 outgassing fluxes in different geological settings is thus critical for decoding the link between the global carbon budget and different natural processes (e.g., volcanic eruption and earthquake nucleation) and the effects on the climate evolution over geological time. It has recently been proposed that CO2 degassing from non-volcanic areas is a major component of the natural CO2 emission budget, but available data are still sparse and incomplete. Here, we report the results of a geochemical survey aimed at quantifying CO2 emissions through cold and thermal springs of the tectonically active Pollino Massif and Calabrian arc (Southern Italy). The chemical ad isotopic (He and C) composition of fifty-five dissolved gas samples allows to identify two different domains: 1) a shallow system dominated by gas components of atmospheric signature (helium, hereafter He) and biogenic origin (C), and 2) a deeper system in which crustal/deep fluids (CO2 and He) are dominant. The measured He isotope ratios range from 0.03 to 1.1 Ra (where Ra is the He isotopic ratio in the atmosphere) revealing a variable atmospheric contamination. Furthermore, the He isotopic data indicate the presence of traces of mantle He contributions (2%–3%) in the thermal groundwater. The prevailing low R/Ra values reflect the addition of crustal radiogenic 4He during groundwater circulation. Using helium and carbon isotope data, we explore the possible sources of fluids and the secondary processes (dissolution/precipitation) that act to modify the chemistry of pristine volatiles. For the thermal springs, we estimate a deep C output of 2.3 x 107 to 6.1 x 108 mol year−1. These values correspond to deep CO2 fluxes per square km comparable with those estimated in several active and inactive volcanic areas and in continental regions affected by metamorphic CO2 degassing (e.g., the southern margin of the Tibetan Plateau).

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Helium-carbon systematics of groundwaters in the Lassen Peak Region

Cited by 7 publications

References 77 publications

The Helium and Carbon Isotope Characteristics of the Andean Convergent Margin

The Helium and Carbon Isotope Characteristics of the Andean Convergent Margin

Magmatic Carbon and Helium in Springs Reveals the Vitality of a Dormant Volcano, Taranaki, New Zealand

Active degassing of crustal CO2 in areas of tectonic collision: A case study from the Pollino and Calabria sectors (Southern Italy)

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