The archaeointensity of the earth's magnetic field retrieved from Pampean ceramics (South America)
The archaeointensity of the earth's magnetic field retrieved from Pampean ceramics (South America)
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从潘皮亚陶瓷（南美洲）中检索到的地球磁场的考古强度
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
A. Acosta
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作者：
A. Goguitchaichvili;D. Loponte;J. Morales;A. Acosta
绝对强度测定使用的Coe变体的Thellier方法已进行了一些选定的陶器碎片收集在湿地的下巴拉那（Pamelia地区，阿根廷），以构建第一个archaeotensity主曲线南美洲。相关的放射性年龄介于1640 ± 70和730 ± 70 bp之间。研究的46个样品（8个碎片）中有21个样品（5个碎片）提供了成功的绝对强度测定。本研究中获得的碎片平均古强度值范围为21.9 ± 2.3至42.6 ± 5.4 μT，相应的虚拟轴向偶极矩（VADMs）范围为4.0 ± 0.5至8.1 ± 1.0 x 1022 Am2。这相当于平均VADM为（6.4 ± 1.8）× 1022 Am2。从阿根廷南部和巴西检索的合成记录包括17个平均archaeointensities分布在公元700和公元1700之间。数据集显示了几个不同时期的波动相当大的强度。然而，大多数数据集中在从广告950到广告1300的相对窄的时间段内。可以检测到三个一般特征：从公元950年至1130年和1350年至1480年的时间间隔的特点是相当单调的地磁强度增加，而从公元1150年至1280年观察到一些下降。这些变化可能与几十年时间尺度上的气候变化相关。观测到的数据与根据最近报告的全球模型得出的地磁场预测之间存在重大差异，这加强了区域参考曲线对测年目的的重要性。
Absolute intensity determinations using the Coe variant of the Thellier method have been carried out on some selected pottery fragments collected in the wetlands of the lower Parana (Pampean region, Argentina) in order to construct the first archaeointensity master curve for South America. Associated radiometric ages range between 1640 ± 70 and 730 ± 70 bp. Twenty-one samples (five fragments) out of 46 studied (eight fragments) provided successful absolute intensity determinations. The fragment-mean archaeointensity values obtained in this study range from 21.9 ± 2.3 to 42.6 ± 5.4 μT, with corresponding virtual axial dipole moments (VADMs) ranging from 4.0 ± 0.5 to 8.1 ± 1.0 x 1022Am2. This corresponds to a mean VADM of (6.4 ± 1.8) × 1022 Am2. The synthetic record retrieved from southern Argentina and Brazil consists of 17 mean archaeointensities distributed between approximately ad 700 and ad 1700. The data set shows several distinct periods of fluctuations of quite large intensity. However, most data are concentrated into a relatively narrow time period from ad 950 to ad 1300. Three general features may be detected: the time intervals from about ad 950 to 1130 and 1350 to 1480 are characterized by quite monotonic increases of geomagnetic intensity, while some decrease is observed from ad 1150 to 1280. These variations may be speculatively correlated to climate changes over multi-decadal time scales. Important differences are observed between the data and the geomagnetic field predictions derived from recently reported global models, which reinforces the importance of regional reference curves for dating purposes.