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The magnetization and relative paleointensity of experimentally deposited natural sediment

Posted on:2018-02-12Degree:M.SType:Thesis
University:University of MinnesotaCandidate:Molinek, Frank R., IIIFull Text:PDF
GTID:2440390002495775Subject:Geophysics
Abstract/Summary:
The magnetization of a sediment occurs when ferromagnetic detrital particles align with a depositional magnetic field. The geomagnetic field can be approximated by a dipole that averages to share an axis with the rotation of the Earth. This field exerts a magnetic torque on ferromagnetic particles such as magnetite. However, processes including flocculation, contact with the substrate, bioturbation, and compaction disrupt this alignment, leading to shallowed remanent inclinations and biased intensities. The dependence of paleointensity on the inclination of the depositional field leads to complications in interpretations, despite the relative continuity and ubiquity of the global sedimentary record. We present a series of 12 deposition experiments in varying field strengths and inclinations, and attempt to correct relative paleointensity estimates using the anisotropy of anhysteretic remanence. We find experimentally that this correction reduces the inclination dependence of relative paleointensity, suggesting that it should also improve those estimates in naturally occurring sediments.
Keywords/Search Tags:Relative paleointensity, Field
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