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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/   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.

Gee, J, Varga R, Gallet Y, Staudigel H.  1993.  Reversed-polarity overprint in dikes from the Troodos ophiolite: Implications for the timing of alteration and extension. Geology. 21:849-852.: Geological Society of America   10.1130/0091-7613(1993)021<0849:rpoidf>;2   AbstractWebsite

Paleomagnetic analysis of dikes from the Troodos ophiolite indicates the presence of a well-defined reversed-polarity overprint, an unexpected result given the currently accepted Cenomanian-Turonian age (88-91 Ma) suggesting formation during the Cretaceous Long Normal Period (83-118 Ma). This reversed- polarity component was apparently acquired prior to tectonic tilting of the dikes, implying that extensional tectonism occurred significantly (>5 m.y.) off axis. Alternatively, the paleomagnetic and field observations may be reconciled if parts of the ophiolite are significantly younger.