Imperial College London
Portrait Picture

Professor Adrian Muxworthy

Faculty of Engineering, Department of Earth Science & Engineering

Professor of Earth and Planetary Magnetism
 
 
 
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Contact

 

+44 (0)20 7594 6442adrian.muxworthy

 
 
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Location

 

4.48Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Evans:2018:gji/ggy111,
author = {Evans, ME and Muxworthy, AR},
doi = {gji/ggy111},
journal = {Geophysical Journal International},
pages = {1744--1750},
title = {A re-appraisal of the proposed rapid Matuyama–Brunhes geomagnetic reversal in the Sulmona Basin, Italy},
url = {http://dx.doi.org/10.1093/gji/ggy111},
volume = {213},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - An extremely sharp magnetic reversal observed in lacustrine sediments in central Italy has been interpreted as a record of the Matuyama-Brunhes geomagnetic polarity reversal that may represent less than a decade (Sagnotti et al., 2014. 2016). Here, we report new results from the same Sulmona Basin outcrop that question this interpretation. In particular, we find evidence of reversed (Matuyama) directions well above the proposed Matuyama-Brunhes Boundary (MBB). Coercivity spectra of anhysteretic remanent magnetization (ARM) imply a 3-component magnetic mineralogy: low-, intermediate-, and high-coercivity. The low-coercivity component is found in all but one of the samples and carries a strong modern overprint seen throughout the section. The high-coercivity component is dominated by volcanic material which is prone to remagnetization. Since it is much more magnetic than the surrounding lacustrine sediments, it may influence the remanence signal even when present at very low concentrations. The intermediate-coercivity component is the main carrier of any true primary remanence, but whether or not this can be isolated depends on the blocking-temperature and coercivity spectra of individual samples, and on the demagnetization method used. The complexity of the magnetization, the reversed zones above the proposed MBB, and the normal zones that Sagnotti and 2 colleagues found below it, lead to the conclusion that this section does not carry a reliable high-resolution record of the geomagnetic field. Thus, we feel that inferences about the stratigraphic position and duration of the MBB are premature.
AU  - Evans,ME
AU  - Muxworthy,AR
DO  - gji/ggy111
EP  - 1750
PY  - 2018///
SN  - 0956-540X
SP  - 1744
TI  - A re-appraisal of the proposed rapid Matuyama–Brunhes geomagnetic reversal in the Sulmona Basin, Italy
T2  - Geophysical Journal International
UR  - http://dx.doi.org/10.1093/gji/ggy111
UR  - http://hdl.handle.net/10044/1/58436
VL  - 213
ER  -
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