Release of radiogenic noble gases as a new signal of rock deformation

Bauer, Stephen J.; Gardner, W. Payton; Lee, Hyun–Woo

doi:10.1002/2016gl070876

Cited by 17 publications

(26 citation statements)

References 25 publications

(25 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When the shale was cored perpendicular to bedding, a much larger increase in matrix permeability was required to match observations. This finding was consistent with postdeformation analysis of the cores which showed a single, clean fracture in the bedding-parallel core and a wider deformation zone in the bedding-perpindicular core (Bauer, Gardner, & Lee, 2016).…”

Section: Discussionsupporting

confidence: 89%

“…The average porosity is around 5%. Full details of the experimental setup and procedures can be found in Bauer, Gardner, and Lee (2016).…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Radon emanation decreases during early elastic deformation as porosity is decreased during compaction, begins to increase at about one third of the elastic yield stress due to the production of microfractures, and remains permanently higher after failure (Holub & Brady, 1981;Mollo et al, 2011;Nicolas et al, 2014;Tuccimei et al, 2010). Bauer, Gardner, and Lee (2016) and Bauer, Gardner, and Heath (2016) show that accumulated helium in porespace and mineral grains is also liberated during deformation. Radiogenic helium follows a repeatable sequence during deformation similar to radon, with decreasing helium flow rate during early compaction, increase in helium flow rate at about one third of the yield strength, a sharp increase during macroscopic failure, and a subsequent long-term decline in gas flow.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling Dynamic Helium Release as a Tracer of Rock Deformation

et al. 2017

Self Cite

View full text Add to dashboard Cite

We use helium released during mechanical deformation of shales as a signal to explore the effects of deformation and failure on material transport properties. A dynamic dual-permeability model with evolving pore and fracture networks is used to simulate gases released from shale during deformation and failure. Changes in material properties required to reproduce experimentally observed gas signals are explored. We model two different experiments of $^4$He flow rate measured from shale undergoing mechanical deformation, a core parallel to bedding and a core perpendicular to bedding. We find that the helium signal is sensitive to fracture development and evolution as well as changes in the matrix transport properties. We constrain the timing and effective fracture aperture, as well as the increase in matrix porosity and permeability. Increases in matrix permeability are required to explain gas flow prior to macroscopic failure, and the short-term gas flow post failure. Increased matrix porosity, is required to match the long-term, post-failure gas flow. Our model provides the first quantitative interpretation of helium release as a result of mechanical deformation. The sensitivity of this model to changes in the fracture network, as well as to matrix properties during deformation, indicates that helium release can be used as a quantitative tool to evaluate the state of stress and strain in earth materials.Comment: 8 figure

show abstract

Section: Discussionsupporting

confidence: 89%

“…The average porosity is around 5%. Full details of the experimental setup and procedures can be found in Bauer, Gardner, and Lee (2016).…”

Section: Experimental Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modeling Dynamic Helium Release as a Tracer of Rock Deformation

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…Transport of gases occurs within the rock grain, along grain boundaries, in the pore fluid, and within the micro-to macrofracture network. Their release during natural and manmade stress and strain changes represents a signal of deformation (e.g., [2][3][4][5][6]).…”

Section: Introductionmentioning

confidence: 99%

“…Noble gas emission and its relationship to crustal processes have been studied for many years in the geologic community including correlations to tectonic velocities [7], origin of crustal fluids [8], qualitative estimates of deep permeability from surface measurements [7,9], study of hydrothermal systems (e.g., [10]), and fingerprints of nuclear weapon detonation [11]. Increases in radiogenic gas at lab and field scales have been observed and related to preseismic stress, dilatancy, and/or fracturing of the rock and as potential precursory signals to earthquakes attributed to gas release due to preseismic stress [2,3,12,13]. Radon release has been observed relative to earthquake activity [14,15].…”

Section: Introductionmentioning

confidence: 99%

Noble Gas Release from Bedded Rock Salt during Deformation

2019

Self Cite

View full text Add to dashboard Cite

Geogenic noble gases are contained in crustal rocks at inter- and intracrystalline sites. In this study, bedded rock salt from southern New Mexico was deformed in a variety of triaxial compression states while measuring the release of naturally contained helium and argon utilizing mass spectrometry. Noble gas release is empirically correlated to volumetric strain and acoustic emissions. At low confining pressures, rock salt deforms primarily by microfracturing, rupturing crystal grains, and releasing helium and argon with a large amount of acoustic emissions, both measured real-time. At higher confining pressure, microfracturing is reduced and the rock salt is presumed to deform more by intracrystalline flow, releasing less amounts of noble gases with fewer acoustic emissions. Our work implies that geogenic gas release during deformation may provide an additional signal which contains information on the type and amount of deformation occurring in a variety of earth systems.

show abstract