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Title: Contribution of multidomain titanomagnetite to the intensity and stability of Mars crustal magnetic anomalies
Abstract Two basalts with compositions relevant to the crusts of Mars and Earth were synthesized at igneous temperatures and held at 650°C for 21 to 257 days under quartz‐fayalite‐magnetitefO2buffer conditions. The run products are germane to slowly cooled igneous intrusions, which might be a significant volumetric fraction of the Martian crust and carriers of magnetic anomalies in the Southern Highlands. Both basalts acquired intense thermoremanent magnetizations and intense but easily demagnetized anhysteretic remanent magnetizations carried by homogeneous multidomain titanomagnetite. Hypothetical intrusions on Mars composed of these materials would be capable of acquiring intense remanences sufficient to generate the observed anomalies. However, the remanence would be easily demagnetized by impact events after the cessation of the Mars geodynamo. Coercivity enhancement by pressure or formation of single domain regions via exsolution within the multidomain grains is necessary for long‐term retention of a remanence carried exclusively by multidomain titanomagnetite grains.  more » « less
Award ID(s):
0521069 0619402 0948262
PAR ID:
10530279
Author(s) / Creator(s):
; ; ; ; ;
Publisher / Repository:
American Geophysical Union
Date Published:
Journal Name:
Geophysical Research Letters
Volume:
41
Issue:
22
ISSN:
0094-8276
Page Range / eLocation ID:
7997 to 8005
Subject(s) / Keyword(s):
Mars crustal magnetic anomalies synthetic basalt titanomagnetite Fe-spinel Coercivity
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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