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Using Syntectonic Calcite Veins to Reconstruct the Strength Evolution of an Active Low‐Angle Normal Fault, Woodlark Rift, SE Papua New Guinea

Mizera, Marcel and Little, Tim and Boulton, Carolyn and Katzir, Yaron and Thiagarajan, Nivedita and Prior, David J. and Biemiller, James and Smith, Euan G. C. (2021) Using Syntectonic Calcite Veins to Reconstruct the Strength Evolution of an Active Low‐Angle Normal Fault, Woodlark Rift, SE Papua New Guinea. Journal of Geophysical Research. Solid Earth, 126 (8). Art. No. e2021JB021916. ISSN 2169-9313. doi:10.1029/2021JB021916. https://resolver.caltech.edu/CaltechAUTHORS:20210910-211046870

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Abstract

Quantifying the strength evolution of faults that cut the lithosphere is essential to better understand seismicity in continental regions. We estimate differential stresses and principal stress orientations driving rapid slip of ∼10 mm/yr on the active Mai'iu low-angle normal fault (LANF), SE Papua New Guinea. The fault's mafic footwall hosts a well-preserved sequence of mylonite, (ultra-)cataclasite, and gouge. In these fault rocks, we combine stress inversion of fault-slip data and paleostress analysis of syntectonically emplaced calcite veins with microstructural and clumped-isotope geothermometry to constrain a syn-exhumational sequence of deformation stresses and temperatures, and to construct a stress profile through the exhumed footwall of the active Mai'iu LANF. This includes: (a) at ∼12–20 km depth (T ≈ 275–370°C), mylonites accommodated slip on the Mai'iu fault at low differential stresses (>25–135 MPa) before being overprinted by localized brittle deformation at shallower depths; (b) at ∼6–12 km depth (T ≈ 130–275°C) differential stresses in the foliated cataclasites and ultracataclasites were high enough (>150 MPa) to drive slip on a mid-crustal portion of the fault (dipping 30–40°), and to trigger brittle yielding of mafic footwall rocks in a zone of mixed-mode seismic/aseismic slip; and (c) at shallower crustal depths (T < 150°C; depth <6 km) on the most poorly oriented segment of the Mai'iu LANF (dipping ∼22°), slip occurred on frictionally weak clay-rich gouges (μ ≈ 0.15–0.38). Subvertical σ1 and subhorizontal σ3 parallel to the extension direction, with σ1 ≈ σ2 (constriction), reflect vertical unloading and 3-D bending strain during rolling-hinge style flexure of the footwall.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1029/2021jb021916DOIArticle
https://dx.doi.org/10.17632/mkpgbs4hf3.4DOIData
http://hdl.handle.net/10063/8666Related ItemData
ORCID:
AuthorORCID
Mizera, Marcel0000-0002-6439-0103
Little, Tim0000-0002-5783-6429
Boulton, Carolyn0000-0003-0597-6152
Katzir, Yaron0000-0003-1999-3746
Prior, David J.0000-0002-4653-2112
Biemiller, James0000-0001-6663-7811
Additional Information:© 2021 American Geophysical Union. Issue Online: 11 August 2021; Version of Record online: 11 August 2021; Accepted manuscript online: 28 July 2021; Manuscript accepted: 22 July 2021; Manuscript revised: 25 June 2021; Manuscript received: 18 February 2021. Marsden Fund grant VUW1310 provided financial support to conduct this research. We are grateful to Hugh Davies (University of Papua New Guinea) and Ian Smith (University of Auckland) for providing field book scans and discussions. We thank Susan Ellis, Samuel Webber, Jürgen Österle, Laura Wallace, Kevin Norton, and Daniel Stockli for field support and discussions. Insightful reviews by Isabelle Manighetti, Bob Holdsworth, an anonymous reviewer and an expert Associate Editor (anonymous) improved the manuscript. Special thanks go to the many landowners, oral chiefs, elders, and citizens who granted us permission to study their land. We also thank our guides and carriers without whom this work would not have been possible. Data Availability Statement: All structural data from the Suckling-Dayman Metamorphic Core Complex, raw EBSD data of analyzed calcite veins and MATLAB codes used in this study can be obtained from the Data Repository (Mizera et al., 2021: https://dx.doi.org/10.17632/mkpgbs4hf3.4). Additional information on fault rocks analyzed in this study can be found in the research archive of Victoria University of Wellington (http://hdl.handle.net/10063/8666, Mizera, 2019).
Funders:
Funding AgencyGrant Number
Marsden Fund of the Royal Society of New ZealandVUW1310
Subject Keywords:low-angle normal fault; paleopiezometry; paleostress; crustal strength; brittle-ductile transition; calcite
Issue or Number:8
DOI:10.1029/2021JB021916
Record Number:CaltechAUTHORS:20210910-211046870
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210910-211046870
Official Citation:Mizera, M., Little, T., Boulton, C., Katzir, Y., Thiagarajan, N., Prior, D. J., et al. (2021). Using syntectonic calcite veins to reconstruct the strength evolution of an active low-angle normal fault, Woodlark rift, SE Papua New Guinea. Journal of Geophysical Research: Solid Earth, 126, e2021JB021916. https://doi.org/10.1029/2021JB021916
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110812
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:13 Sep 2021 20:24
Last Modified:13 Sep 2021 20:24

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