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Metadata Files

Data Publication

Activation of dissolution-precipitation creep causes weakening and viscous behaviour in experimentally-deformed antigorite

André Rik Niemeijer

Utrecht University

(2024)

Descriptions

Antigorite occurs at seismogenic depth along plate boundary shear zones, particularly in subduction and oceanic transform settings, and has been suggested to control a low strength bulk rheology. To constrain dominant deformation mechanisms, we perform hydrothermal ring-shear experiments on antigorite and antigorite-quartz mixtures at temperatures between 20 and 500 ◦C and 150 MPa effective normal stress. Pure antigorite 20 is strain hardening, with frictional coefficient (μ) > 0.5, and developed cataclastic microstructures. In contrast, antigorite-quartz mixtures (10 % quartz) are strain weakening with μ decreasing with temperature from 0.36 at 200◦C to 0.22 at 500◦C. Antigorite-quartz mixtures developed foliation similar to natural serpentinite shear zones. Although reaction between antigorite and quartz is expected to form mechanically weak talc, we only find small, localised amounts of talc in our deformed samples, and mechanical data are inconsistent with reaction-dependent weakening. Instead, we propose that the observed weakening primarily results from silica dissolution leading to a lowered pore-fluid pH that increases antigorite solubility and dissolution rate and thus the rate of dissolution-precipitation creep. We suggest that under our experimental conditions, efficient dissolution-precipitation creep coupled to grain boundary sliding results in a mechanically weak frictional-viscous rheology. Antigorite with this rheology is much weaker than antigorite deforming frictionally, and strength is sensitive to effective normal stress and strain rate. The activation of dissolution-precipitation in antigorite may allow steady or transient creep at low driving stress where antigorite solubility and dissolution rate are high relative to strain rate, for example in faults juxtaposing serpentinite with quartz-bearing rocks. Data is from hydrothermal ring shear experiments on simulated gouges of antigorite and antigorite-quartz. The data is provided in 12 subfolders for 10 experiments/samples. Detailed information about the files in these subfolders as well as information on how the data is processed is given in the explanatory file Data-Documentation_Antigorite.pdf.

Keywords


Originally assigned keywords
Rock and melt physical properties
Antigorite
seismogenic depth
plate boundary shear zones
subduction and oceanic transform settings
low strength bulk rheology
hydrothermal ring-shear experiments
EPOS
multi-scale laboratories
rock and melt physics properties
Powder Mixture
Rotary Shear
Friction

Corresponding MSL vocabulary keywords
antigorite
rotary shear apparatus
rotary shear apparatus
friction coefficient
frictional deformation
friction coefficient

MSL enriched keywords
minerals
silicate minerals
phyllosilicates
serpentine
antigorite
Apparatus
deformation testing
shear testing
rotary shear apparatus
Apparatus
characterization of modelling material
frictional property determination
rotary shear apparatus
Measured property
friction - controlled slip rate
friction coefficient
Inferred deformation behavior
deformation behaviour
frictional deformation
Measured property
friction - controlled slip rate
friction coefficient
microphysical deformation mechanism
time-dependent mechanism
metamorphic rock
serpentinite
clay - smectite
talc
tectosilicates
quartz
strain
strain
tectonic plate boundary
convergent tectonic plate boundary
subduction
measured property
pH
silicon
silicon dioxide
Analyzed feature
deformation microstructure
brittle microstructure
fault gouge microstructure
Y shear
generic deformation microstructure
foliation

MSL enriched sub domains i

rock and melt physics
analogue modelling of geologic processes
geochemistry
microscopy and tomography

Source

https://public.yoda.uu.nl/geo/UU01/94P4HL.html

Source publisher

Utrecht University


DOI

10.24416/uu01-94p4hl


Creators

André Rik Niemeijer

Utrecht University

ORCID:

https://orcid.org/0000-0003-3983-9308


Contributors

ten Thij, Lotte

DataCollector

Utrecht University

ORCID:

https://orcid.org/0009-0008-9970-2139


Citation

Niemeijer, A. R. (2024). Activation of dissolution-precipitation creep causes weakening and viscous behaviour in experimentally-deformed antigorite (Version 1.0) [Data set]. Utrecht University. https://doi.org/10.24416/UU01-94P4HL


Dates

Updated:

2024-03-04T11:31:10

Collected:

2020-10-02/2023-08-04


Language

en


Funding References

Funder name: European Union’s Horizon 2020 research and innovation program


Rights

Open - freely retrievable

Creative Commons Attribution 4.0 International Public License


Datacite version

1.0