Constraining in situ cosmogenic nuclide paleo-production rates using sequential lava flows during a paleomagnetic field strength low

Balbas, Andrea; Farley, K. A.

doi:10.1016/j.chemgeo.2019.119355

Cited by 5 publications

(2 citation statements)

References 44 publications

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“…This local production rate was scaled to sea level and high lati- (Hofmann, 2019) extracted from the same samples as the magnetite studied here. The best-fit model uses the same parameters as in (a), but was optimized for the exposure age and inherited concentration, with a scaled surface 10 Be production rate from the CRONUS-Earth online calculator (Balco et al, 2008). This measurement establishes the surface exposure age used to calibrate the production rate in magnetite.…”

Section: Calibration Of the 3 He Production Rate In Magnetitementioning

confidence: 99%

Exposure dating of detrital magnetite using 3He enabled by microCT and calibration of the cosmogenic 3He production rate in magnetite

et al. 2021

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Abstract. We test whether X-ray micro-computed tomography (microCT) imaging can be used as a tool for screening magnetite grains to improve the accuracy and precision of cosmogenic 3He exposure dating. We extracted detrital magnetite from a soil developed on a fanglomerate at Whitewater, California, which was offset by the Banning strand of the San Andreas Fault. This study shows that microCT screening can distinguish between inclusion-free magnetite and magnetite with fluid or common solid inclusions. Such inclusions can produce bulk 3He concentrations that are significantly in excess of the expected spallation production. We present Li concentrations, major and trace element analyses, and estimated magnetite (U–Th) / He cooling ages of samples in order to model the contribution from fissiogenic, nucleogenic, and cosmogenic thermal neutron production of 3He. We show that mineral inclusions in magnetite can produce 3He concentrations of up to 4 times that of the spallation component, leading to erroneous exposure ages. Therefore, grains with inclusions must be avoided in order to facilitate accurate and precise magnetite 3He exposure dating. Around 30 % of all grains were found to be without inclusions, as detectable by microCT, with the largest proportion of suitable grains in the grain size range of 400–800 µm. While grains with inclusions have 3He concentrations far in excess of the values expected from existing 10Be and 26Al data in quartz at the Whitewater site, magnetite grains without inclusions have concentrations close to the predicted depth profile. We measured 3He concentrations in aliquots without inclusions and corrected them for Li-produced components. By comparing these data to the known exposure age of 53.5 ± 2.2 ka, we calibrate a production rate for magnetite 3He at sea level and high latitude (SLHL) of 116 ± 13 at g−1 a−1. We suggest that this microCT screening approach can be used to improve the quality of cosmogenic 3He measurements of magnetite and other opaque mineral phases for exposure age and detrital studies.

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Section: Calibration Of the 3 He Production Rate In Magnetitementioning

confidence: 99%

Exposure dating of detrital magnetite using 3He enabled by microCT and calibration of the cosmogenic 3He production rate in magnetite

et al. 2021

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“…The production rates of cosmogenic nuclides are usually determined from calibration sites where independent controls on exposure history are available such as 14 C dating from organic materials (e.g., Lifton et al, 2015) or argon ( 40 Ar/ 39 Ar) dating from lava flows (e.g., Balbas and Farley, 2020;Fenton et al, 2019). However, the commonly used estimates of muogenic 14 C production rates (for both negative muon capture and fast muon reactions) were derived through laboratory irradiation of artificial target compounds 105 (Heisinger et al, 2002a(Heisinger et al, , 2002b.…”

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confidence: 99%

Using ice core measurements from Taylor Glacier, Antarctica to calibrate in situ cosmogenic ¹⁴C production rates by muons

Dyonisius

Petrenko

Smith

et al. 2022

Preprint

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Abstract. Cosmic rays entering the Earth’s atmosphere produce showers of secondary particles such as neutrons and muons. The interaction of these neutrons and muons with oxygen-16 (16O) in minerals such as ice and quartz can produce carbon-14 (14C). Analyses of in situ produced cosmogenic 14C in quartz are commonly used to investigate the Earth’s landscape evolution. In glacial ice, 14C is also incorporated through trapping of 14C-containing atmospheric gases (14CO2, 14CO, and 14CH4). Understanding the production rates of in situ cosmogenic 14C is important to deconvolve the in situ cosmogenic and atmospheric 14C signals in ice, both of which contain valuable paleoenvironmental information. Unfortunately, the in situ 14C production rates by muons (which are the dominant production mechanism at depths of > 6 m solid ice equivalent) are uncertain. In this study, we use measurements of in situ 14C in ancient ice (> 50 kilo-annum before present, ka BP) from the Taylor Glacier ablation site, Antarctica in combination with a 2D ice flow model to better constrain the rates of 14C production by muons. We find that the commonly used values for muogenic 14C production rates (Heisinger et al., 2002a, 2002b) in ice are too high by factors of 5.7 (3.6–13.9, 95 % confidence interval) and 3.7 (2.0–11.9 95 % confidence interval) for negative muon capture and fast muon interactions, respectively. Our constraints on muogenic 14C production rates in ice allow for future measurements of 14C in ice cores to be used for other applications and imply that muogenic 14C production rates in quartz are overestimated as well.

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The survival of tracers of primordial mantle heterogeneity investigated through 142Nd/144Nd and 3He/4He isotope decoupling in the Gorgona Island lavas

Hyung,

Ibañez-Mejia,

Rojas-Agramonte

2023

Earth and Planetary Science Letters

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Constraining in situ cosmogenic nuclide paleo-production rates using sequential lava flows during a paleomagnetic field strength low

Abstract: Please cite this article as: Balbas AM, Farley KA, Constraining in situ cosmogenic nuclide paleo-production rates using sequential lava flows during a paleomagnetic field strength low,

Cited by 5 publications

References 44 publications

Exposure dating of detrital magnetite using <sup>3</sup>He enabled by microCT and calibration of the cosmogenic <sup>3</sup>He production rate in magnetite

Exposure dating of detrital magnetite using <sup>3</sup>He enabled by microCT and calibration of the cosmogenic <sup>3</sup>He production rate in magnetite

Using ice core measurements from Taylor Glacier, Antarctica to calibrate in situ cosmogenic ¹⁴C production rates by muons

The survival of tracers of primordial mantle heterogeneity investigated through 142Nd/144Nd and 3He/4He isotope decoupling in the Gorgona Island lavas

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Constraining in situ cosmogenic nuclide paleo-production rates using sequential lava flows during a paleomagnetic field strength low

Abstract: Please cite this article as: Balbas AM, Farley KA, Constraining in situ cosmogenic nuclide paleo-production rates using sequential lava flows during a paleomagnetic field strength low,

Cited by 5 publications

References 44 publications

Exposure dating of detrital magnetite using &lt;sup&gt;3&lt;/sup&gt;He enabled by microCT and calibration of the cosmogenic &lt;sup&gt;3&lt;/sup&gt;He production rate in magnetite

Exposure dating of detrital magnetite using &lt;sup&gt;3&lt;/sup&gt;He enabled by microCT and calibration of the cosmogenic &lt;sup&gt;3&lt;/sup&gt;He production rate in magnetite

Using ice core measurements from Taylor Glacier, Antarctica to calibrate in situ cosmogenic 14C production rates by muons

The survival of tracers of primordial mantle heterogeneity investigated through 142Nd/144Nd and 3He/4He isotope decoupling in the Gorgona Island lavas

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Exposure dating of detrital magnetite using <sup>3</sup>He enabled by microCT and calibration of the cosmogenic <sup>3</sup>He production rate in magnetite

Exposure dating of detrital magnetite using <sup>3</sup>He enabled by microCT and calibration of the cosmogenic <sup>3</sup>He production rate in magnetite

Using ice core measurements from Taylor Glacier, Antarctica to calibrate in situ cosmogenic ¹⁴C production rates by muons