A Preisach method for estimating absolute paleofield intensity under the constraint of using only isothermal measurements: 2. Experimental testing
A Preisach method for estimating absolute paleofield intensity under the constraint of using only isothermal measurements: 2. Experimental testing
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DOI：
10.1029/2010jb007844
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发表时间：
2011-04
影响因子：
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通讯作者：
A. Muxworthy;D. Heslop;G. Paterson;D. Michalk
中科院分区：
文献类型：
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作者：
A. Muxworthy;D. Heslop;G. Paterson;D. Michalk
[1]本文报道了一个新的非加热Preisach为基础的协议，确定绝对古磁场强度（paleointensity）使用的合成样品和一个大的现代熔岩和火山碎屑岩样品套件的经验测试。一般来说，Preisach的古强度估计值与预期的场强相比是有利的：（1）对于显示出类似单域行为的合成样本，该方法返回了已知场的正确结果，而多域样本产生了低估，（2）平均168个公元1850年后的熔岩产生的值在预期的场值内<6%。这些Preisach paleointensity估计也进行了比较paleointensity测定同一套样品使用标准的泰勒型加热协议和非加热剩磁（REM）的方法。Preisach的古强度估计比较有利的样品，产生正确的泰勒型的决定，包括合成的单域样样品。此外，Preisach方法为Thellier型估计失败的情况提供了估计。一个可能的选择标准被确定（中值破坏性字段），这被发现，以提高在一些样本套件的paleointensity估计。对于所调查的样品集的Preisach方法被认为是更准确的REM方法。冷却速率的Preisach古强度估计的重要性也进行了研究。
[1] This paper reports an empirical test of a new nonheating Preisach-based protocol for determining the absolute ancient magnetic field intensity (paleointensity) using a selection of synthetic samples and a large suite of modern lavas and pyroclastic lithic samples. Generally, the Preisach paleointensity estimates compare favorably with the expected field intensities: (1) for the synthetic samples displaying single-domain-like behavior, the method returned the correct result for the known field, while multidomain samples yielded an underestimate, and (2) averaging 168 post-1850 A.D. lavas yielded a value <6% within the expected field value. These Preisach paleointensity estimates are also compared with paleointensity determinations made on the same suite of samples using standard Thellier-type heating protocols and the nonheating remanence (REM) method. The Preisach paleointensity estimates compare favorably for samples that yielded correct Thellier-type determinations, including the synthetic single-domain-like samples. In addition, the Preisach method produced estimates for cases where the Thellier-type estimates failed. A possible selection criterion was identified (median destructive field), which was found to improve the paleointensity estimates in some sample suites. For the investigated sample set the Preisach method was found to be much more accurate than the REM method. The importance of cooling rate on the Preisach paleointensity estimate is also examined.