Field-based constraints on finite strain and rheology of the lithospheric mantle, Twin Sisters, Washington Academic Article

abstract

• We present direct finite strain and rheological estimates of naturally deformed mantle materials using field observations in the Twin Sisters ultramafi c body of Washington State. Folded and elongated (boudinaged or ductilely thinned) orthopyroxenite dikes within the host dunite provide strain markers that allow us to characterize the finite strain over an ~15,000 m 2 area. Using dynamic instability analysis on the folded orthopyroxenite dikes, orthopyroxene is calculated to have ~25 times the effective viscosity of olivine-rich host rocks (based on a power-law exponent of 3.0 for this dislocation creep process). Detailed mapping also indicates that inclusion of up to 15% orthopyroxene in the olivinerich host rocks does not affect their viscosity, constraining the rheological behavior of two-phase, mantle material. 2010 Geological Society of America.

authors

• Newman, Julie

published proceedings

• LITHOSPHERE

author list (cited authors)

• Tikoff, B., Larson, C. E., Newman, J., & Little, T.

citation count

• 15

complete list of authors

• Tikoff, Basil||Larson, Carrie E||Newman, Julie||Little, Timothy

publication date

• December 2010

publisher

• GeoScienceWorld  Publisher

published in

• Lithosphere  Journal

keywords

• 37 Earth Sciences
• 3703 Geochemistry
• 3705 Geology
• 3706 Geophysics

Digital Object Identifier (DOI)

• 10.1130/L97.1

start page

• 418

end page

• 422

volume

• 2

issue

• 6

URL

• http%3A%2F%2Fdx.doi.org%2F10.1130%2Fl97.1