Constraints on lithospheric mantle and crustal anisotropy in the NoMelt area from an analysis of long-period seafloor magnetotelluric data
MetadataShow full item record
Despite strong anisotropy seen in analysis of seismic data from the NoMelt experiment in 70 Ma Pacific seafloor, a previous analysis of coincident magnetotelluric (MT) data showed no evidence for anisotropy in the electrical conductivity structure of either lithosphere or asthenosphere. We revisit the MT data and use 1D anisotropic models of the lithosphere to demonstrate the limits of acceptable anisotropy within the data. We construct 1D models by varying the thickness and the degree of anisotropy within the lithosphere and conduct a series of tests to investigate what types of electrical anisotropy are compatible with the data. We find that electrical anisotropy is possible in a sheared and/or hydrous mantle within the lower lithosphere (60–90 km depth). The data are not compatible with pervasive electrical anisotropy in the crust. Causes of anisotropy within the highly resistive upper and mid-lithosphere, as seen seismically, are not expected to cause measurable impacts on MT response.
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Earth, Planets and Space 69 (2017): 138, doi:10.1186/s40623-017-0724-1.
Suggested CitationArticle: Matsuno, Tetsuo, Evans, Rob L., "Constraints on lithospheric mantle and crustal anisotropy in the NoMelt area from an analysis of long-period seafloor magnetotelluric data", Earth, Planets and Space 69 (2017): 138, DOI:10.1186/s40623-017-0724-1, https://hdl.handle.net/1912/9320
The following license files are associated with this item:
Showing items related by title, author, creator and subject.
High-resolution constraints on pacific upper mantle petrofabric inferred from surface-wave anisotropy. Russell, Joshua B.; Gaherty, James B.; Lin, Pei-Ying Patty; Lizarralde, Daniel; Collins, John A.; Hirth, Greg; Evans, Rob L. (American Geophysical Union, 2018-12-26)Lithospheric seismic anisotropy illuminates mid‐ocean ridge dynamics and the thermal evolution of oceanic plates. We utilize short‐period (5–7.5 s) ambient‐noise surface waves and 15‐ to 150‐s Rayleigh waves measured across ...
Global mantle flow and the development of seismic anisotropy : differences between the oceanic and continental upper mantle Conrad, Clinton P.; Behn, Mark D.; Silver, Paul G. (American Geophysical Union, 2007-07-26)Viscous shear in the asthenosphere accommodates relative motion between Earth's surface plates and underlying mantle, generating lattice-preferred orientation (LPO) in olivine aggregates and a seismically anisotropic fabric. ...
Zietlow, Daniel W.; Sheehan, Anne F.; Molnar, Peter H.; Savage, Martha K.; Hirth, Greg; Collins, John A.; Hager, Bradford H. (John Wiley & Sons, 2014-02-05)New shear wave splitting measurements made from stations onshore and offshore the South Island of New Zealand show a zone of anisotropy 100–200 km wide. Measurements in central South Island and up to approximately 100 km ...