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Magnetic techniques applied to the study of rock varnish
Author(s) -
Clayton Jeffrey A.,
Verosub Kenneth L.,
Harrington Charles D.
Publication year - 1990
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl017i006p00787
Subject(s) - varnish , geology , magnetite , paleomagnetism , remanence , rock magnetism , mineralogy , maghemite , magnetization , coating , geophysics , materials science , paleontology , composite material , magnetic field , physics , quantum mechanics
We report the successful application of magnetic techniques to the study of rock varnish, a surficial coating that forms on rocks in arid environments. Using thin wafers of varnished and unvarnished greywacke sandstone, we have detected a stable remanent magnetization that can be unambiguously attributed to the rock varnish. We have also measured several rock magnetic properties of the rock varnish and have shown that the primary magnetic carrier is either magnetite or maghemite. Our results demonstrate the feasibility of applying magnetic techniques to the study of geomorphic surfaces. Subsequent rock magnetic and paleomagnetic studies of rock varnish should provide new information about the geochemical processes involved in the formation of rock varnish and about the validity of a new chronological technique known as rock varnish dating.