Collaborative Research: Levantine geomagnetic field spike: How high, how fast, how far?

在过去的七千年里，采矿活动在欧洲和亚洲的许多地方留下了大量的材料。由于铜冶炼需要在熔炉中高温熔化矿石，因此有大量的木炭与铜渣密切相关，从而能够直接确定考古碎片的年代。 事实证明，冶金碎片可以保留古代地磁场强度的良好记录。 这一点，再加上前所未有的能力，以日期的材料，意味着高分辨率的记录变化的磁场强度现在可以提供给我们。 我们已经记录了约旦（公元前世纪）的一段时间，那里的磁场强度非常高，几乎是现在磁场的三倍。 这种地磁场“尖峰”一定发生得非常快。 这些数据与附近的研究在希腊的比较表明，有一个显着的差异之间的希腊主曲线和约旦的数据。为了评估这种差异的各种可能原因（例如，地磁场中的极短波长特征、地磁场中的极高频时间变化遗漏等），我们正在挖掘第二个遗址，它靠近并与包含“钉子”的遗址和塞浦路斯的一个具有可比材料的遗址共同存在。考古学和古地磁场（古地磁学）研究的结合本质上是跨学科的，在两个学科中具有广泛的影响。跨学科研究在实践中是困难的，因为研究生需要成为自己领域的专家，并冒着以牺牲深度为代价而变得过于广泛的风险。 在我们的研究中，我们通过让两名研究生密切合作来处理这个问题，每个人都牢牢扎根于一个学科，但从另一个学生那里学到了很多关于另一个学科的知识。 这种跨学科努力的好处是广泛的。 从研究地磁场的角度来看，在全球范围内准确描绘强度变化（本项目有助于实现这一目标，但本身并不能解决）对于“地面实况”数值模型和了解放射性碳产生的变化以及放射性碳时标的校准等不同努力至关重要。 从考古学的角度来看， 在一个紧密的时间框架中寻找考古材料一直是一个挑战，我们的工作已经被用来解决考古计量学中的日期难题。

Mining activity has left enormous piles of material in numerous places around Europe and Asia spanning the last seven millennia. Because copper smelting requires melting of ore at high temperatures in furnaces, there is abundant charcoal intimately associated with the copper slag, enabling the direct dating of the archaeological debris. It turns out that metallurgical debris can retain an excellent record of the ancient geomagnetic field strength. This, combined with unprecedented ability to date the material, means that high resolution records of changes in field strength are now available to us. We have already documented a period of time in Jordan (10th century BCE) of extraordinarily high magnetic field strengths, nearly three times the present field. This geomagnetic field "spike" must have happened very quickly. Comparison of these data with those from nearby studies in Greece suggest that there is a significant discrepancy between the Grecian master curve and the data from Jordan. To assess the various possible causes for this discrepancy (e.g., extremely short wavelength features in the geomagnetic field, extremely high frequency temporal changes in the geomagnetic field missed, etc.), we are excavating a second site near to and co-eval with the site containing the "spike" and a co-eval site in Cyprus that has comparable material. The combination of archaeology and the study of the ancient geomagnetic field (paleomagnetism) is inherently interdisciplinary, with broad impacts in both disciplines. Interdisciplinary research is difficult in practice because graduate students need to become expert in their own fields and run the risk of becoming too broad at the expense of depth. We are handling this problem in our research by having two graduate students work closely together, each firmly rooted in one discipline but learning a great deal about the other discipline from the other student. The benefits of such interdisciplinary efforts are wide ranging. From the point of view of studying the geomagnetic field, an accurate picture of intensity changes on a global scale (a goal to which this project contributes but does not solve by itself) is essential for such different endeavors as "ground truthing" numerical models and understanding variations in the production of radiocarbon and the calibration of the radiocarbon time scale. From the archaeological perspective, placing archaeological materials in a tight temporal framework is always a challenge and our work is already being put to use to solve dating puzzles in archaeometallurgy.