Characterizing magnetofossils from first-order reversal curve (FORC) central ridge signatures

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doi: 10.1002/2014GC005291
Author(s): Heslop, David; Roberts, Andrew P.; Chang, Liao
Author Affiliation(s): Primary:
Australian National University, Research School of Earth Sciences, Canberra, Australia
Volume Title: Geochemistry, Geophysics, Geosystems - G<sup>3</sup>
Source: Geochemistry, Geophysics, Geosystems - G>3`, 15(6), p.2170-2179. Publisher: American Geophysical Union and The Geochemical Society, United States. ISSN: 1525-2027
Note: In English. 57 refs.; illus., incl. sketch map
Summary: The central ridge structure of a first-order reversal curve (FORC) distribution is indicative of uniaxial noninteracting single domain magnetic particles, which provides the opportunity to identify and characterize biogenic magnetic mineral remains (magnetofossils) in sediments. Recent studies have shown that magnetofossils are widespread in the geological record and that they carry useful environmental information and contribute to paleomagnetic recording, which makes it essential to quantify how these biogenic components contribute to the magnetic properties of sediments. We present results from six sedimentary sequences whose magnetic mineral assemblages contain a significant magnetofossil contribution. Using principal component analysis, we find that the central ridge properties exhibit both intra-sequnce and inter-sequence variability that may be ascribed to external environmental factors. While samples from individual sediment sequences tend to cluster together, there is a continuum of inter-sequence behavior that appears to be related to a variety of magnetofossil properties. We demonstrate the complexity of biogenic magnetic components in sedimentary environments, but also the power and potential of FORC central ridges for understanding magnetic mixtures and unraveling environmental information. Abstract Copyright (2014), American Geophysical Union. All Rights Reserved.
Year of Publication: 2014
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Australasia; Australia; Bacteria; Cenozoic; Continental shelf; Core; Electron microscopy data; Eocene; First-order reversal curve; Indian Ocean; Kerguelen Plateau; Leg 113; Leg 119; Magnetic hysteresis; Magnetic minerals; Magnetic properties; Magnetotactic taxa; Marine sediments; Maud Rise; Mediterranean Sea; Mediterranean region; Microfossils; Mineral assemblages; Nannofossils; ODP Site 689; ODP Site 690; ODP Site 738; Ocean Drilling Program; Paleocene-Eocene Thermal Maximum; Paleogene; Paleomagnetism; Plantae; Reversals; Sedimentary rocks; Sediments; Southern Ocean; Strait of Sicily; TEM data; Tertiary; Weddell Sea; Western Australia
Record ID: 2016043622
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom, Reference includes data supplied by, and/or abstract, Copyright, American Geophysical Union

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