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Journal Article
Gee, JS, Meurer WP, Selkin PA, Cheadle MJ.  2004.  Quantifying three-dimensional silicate fabrics in cumulates using cumulative distribution functions. Journal of Petrology. 45:1983-2009.   10.1093/petrology/egh045   AbstractWebsite

We present a new method for quantifying three-dimensional silicate fabrics and the associated uncertainties from grain orientation data on three orthogonal sections. Our technique is applied to the orientation of crystallographic features and, hence, yields a fabric related to the lattice-preferred orientation, although the method could be applied to shape-preferred orientations or strain analysis based on passive linear markers. The orientation data for each section are represented by their cumulative distribution function, and an iterative procedure is used to find the symmetric second-rank strain tensor that will simultaneously satisfy the cumulative distribution functions observed on each section. For samples with well-developed fabrics, this technique provides a much closer match to the sectional data than do previous techniques based on eigenparameter analysis of two-dimensional orientation data. Robust uncertainty estimates are derived from a non-parametric bootstrap resampling scheme. The method is applied to two cumulates: one with a well-developed fabric and the other with a weak fabric, from the Stillwater complex, Montana. The silicate petrofabric orientations obtained for these samples compare favorably with independent direct estimates of the volume fabric from electron backscatter diffraction and magnetic techniques.

Gee, JS, Lawrence RM, Hurst SD.  1996.  Remanence characteristics of gabbros from the MARK area; implications for crustal magnetization. Proceedings of the Ocean Drilling Program, Scientific Results. 153:429-436.   10.2973/odp.proc.sr.153.042.1997   Abstract

Although the general concept of linear magnetic anomalies generated by seafloor spreading processes is well established, the details of the source distribution responsible for these anomalies remain uncertain. We summarize here magnetic properties from variably altered and deformed olivine gabbro, gabbro, and less abundant troctolite, gabbronorite, and oxide gabbros sam- pled at four sites drilled on the western median valley wall of the Mid-Atlantic Ridge south of the Kane Fracture Zone. The overall mean natural remanent magnetization (NRM) intensity (1.54 ± 2.6 A/m) and Koenigsberger ratio (8.05 ± 15.2) for these samples suggest that lower crustal gabbros are a significant contributor to marine magnetic anomalies. However, dual magnetic polarities were recorded at all four sites, with apparent polarity reversals sometimes occurring over spatial scales of tens of cen- timeters. Detailed demagnetization and rock magnetic studies of one such interval suggest that the complex remanence, dual polarities, and the occurrence of spurious well-defined magnetization components are related to production of magnetite during high-temperature alteration and/or cooling in periods of opposite polarity. These complexities, if generally applicable to oce- anic gabbros, may reduce the integrated contribution from the gabbroic layer to marine magnetic anomalies.