Unblocking temperatures of viscous remanent magnetism in displaced granitic boulders, Icicle Creek glacial moraines (Washington, USA)
Unblocking temperatures of viscous remanent magnetism in displaced granitic boulders, Icicle Creek glacial moraines (Washington, USA)
复制标题
冰柱溪冰川冰碛中移位的花岗岩巨石中粘性剩磁的解锁温度（美国华盛顿）
DOI：
10.1002/2015gl066381
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发表时间：
2015
影响因子：
5.2
通讯作者：
B. Housen
中科院分区：
文献类型：
--
作者：
J. Crider;D. Globokar;R. Burmester;B. Housen
Viscous remanent magnetization (VRM) may partially overprint original magnetization in rocks displaced by geomorphic events. An established theoretical relationship between the time and temperature of acquisition of VRM and the time and temperature of demagnetization suggests that laboratory demagnetization (unblocking) of VRM can be used to estimate the displacement age of rocks. We test this hypothesis at four nested glacial moraines in the Icicle Creek drainage of central Washington, the ages of which were previously determined by cosmogenic surface exposure dating. The moraines are composed primarily of granodiorite boulders, and magnetic remanence is carried dominantly by magnetite. Both the maximum and average pVRM demagnetization temperatures (TD) increase with relative age of the moraines. For the three younger moraines, the average TD yields an age comparable to the cosmogenic age, within uncertainty of pVRM acquisition temperature. Uncertainty in the acquisition and demagnetization temperatures can limit the utility of pVRM for absolute dating.
