Academic Commons

Articles

Redbeds and thermoviscous magnetization theory

Kent, Dennis V.; Miller, John D.

Thermal demagnetization characteristics of a Brunhes“age viscous overprint in Appalachian redbeds and a thermoviscous component acquired in the laboratory at moderate temperature agree well with relaxation time“blocking temperature relations for hematite proposed by Pullaiah et al. [1975]. Supporting evidence was obtained from redbeds associated with an igneous dike intrusion although the interpretation of these data are complicated by magnetochemical alterations. Paradoxically, experimental data for magnetite in some limestones were shown to agree more closely with an alternative theory of Walton [1980]. The hematite in redbeds is predominantly singledomain (SD) whereas magnetite in the limestones studied extends well into the multidomain (MD) range. Thus experiment and theory could be reconciled if it is assumed that Pullaiah et al. applies strictly to SD material whereas Walton's theory somehow describes thermoviscous effects dominated by larger MD grains.

Subjects

Files

Also Published In

Title
Geophysical Research Letters
DOI
https://doi.org/10.1029/GL014i004p00327

More About This Work

Academic Units
Lamont-Doherty Earth Observatory
Published Here
August 2, 2011
Academic Commons provides global access to research and scholarship produced at Columbia University, Barnard College, Teachers College, Union Theological Seminary and Jewish Theological Seminary. Academic Commons is managed by the Columbia University Libraries.