Archeomagnetism of Metallurgical Slag Deposits in Israel and Jordan: Constraints for Secular Variation Models for the last 7000 Years

地球磁场的起源及其过去的行为仍然是地球科学中长期存在的问题之一。古地磁学是对古代地磁场的研究，是了解地球内部深处过去过程的最有用的信息来源之一。几十年来的巨大努力已经产生了大量的古代地磁场数据。这些数据已被纳入日益复杂的地磁场模型。除了将地磁场的近期行为置于某种历史背景中之外，它在全新世的行为也引起了包括考古学家，历史学家和古气候研究人员在内的各种研究人员的兴趣。 地磁场是控制放射性碳产生的主要因素之一，因此对放射性碳校准曲线有很大的影响。 对磁场变化进行分类是解释过去太阳活动的关键。 此外，地磁场变化的精确模型最终可以提供期待已久的基于长期变化的时间尺度。 为了进一步实现这些不同的目标，我们将结合考古学和古地磁学的联合收割机专业知识，从以色列和约旦的铜矿矿渣中获得新的古强度数据。 考古学和古地磁学的共生关系有着悠久而卓越的历史。 古地磁场的研究需要在人类测量之前保留磁场矢量记录的材料，这些材料可以在实验室中检索和校准。 反过来，将磁矢量与先前建立的磁场变化进行比较，可以对日期不确定的考古材料提供年龄限制。 目前地球磁场数据库的主要缺点之一是相对缺乏有关矢量强度的数据。 这是因为很难获得合适的材料，既在实验室实验中表现良好，又可以用辐射测量方法准确地确定年代。 实验室实验的进展和对快速冷却的古代冶金炉渣作为古强度研究的潜在理想材料的认识表明，我们对地球磁场随时间变化的理解可以大大提高。 反过来，改进的地磁场模型可以应用于缺乏精确考古背景的考古冶金炉渣沉积物的定年问题（例如，从表面收集的材料）。该项目涉及从主要位于约旦的古代铜金属生产遗址收集新材料，这些遗址跨越公元前4000年至公元前1000年。 考古材料将于2007年夏天从积极的考古发掘中收集 并分析了放射性碳年龄和古磁场强度。 根据这项赠款收集的数据将有助于我们对古长期变化的一般知识，并影响放射性碳校准曲线，太阳活动的变化，长期变化时间尺度等更广泛的问题。 此外，该提案将加强地球物理学和考古学之间的跨学科研究，包括为Erez ben Yosef提供资金，Erez ben Yosef正在与UCSD的两位P.I.s合作进行地球物理学和考古学相结合的跨学科研究。 他将成为这两个领域的专家。

The origin of Earth's magnetic field and its past behavior remain among the long standing problems in the Earth sciences. Paleomagnetism, the study of the ancient geomagnetic field, is one of the more useful sources of information on past processes in the deep interior of the planet. Enormous effort over many decades has produced a huge amount of data for the ancient geomagnetic field. These data have been incorporated into increasingly sophisticated models of the geomagnetic field. Apart from placing the recent behavior of the geomagnetic field into some sort of historical context, its behavior over the Holocene is also of interest to a wide variety of investigators including archaeologists, historians, and paleoclimate researchers. The geomagnetic field is one of the primary controls of radiocarbon production hence strongly effects the radiocarbon calibration curves. Sorting out field variations are key to interpretations of past solar activity. Moreover, an accurate model of geomagnetic field variations could ultimately provide the long awaited time scale based on secular variation. To further these disparate goals, we will combine expertise from archaeology and paleomagnetism to obtain a new paleointensity data from well dated material from copper mining slags in Israel and Jordan. The symbiosis of archaeology and archeomagnetism has a long and distinguished record. The study of the ancient geomagnetic field requires materials that retain a record of the magnetic field vector prior to human calendrical measurements that can be retrieved and calibrated in the laboratory. In turn, comparison of the magnetic vector with previously established variations of the magnetic field can provide age constraints on poorly dated archeological material. One of the major drawbacks with the current database for the Earth's magnetic field is the relative lack of data concerning the strength of the vector. This is because it is quite difficult to obtain suitable material that both behaves well during the laboratory experiment and also can be accurately dated with radiometric methods. Advances in the laboratory experiment and recognition of quickly cooled ancient metallurgical slag as a potentially ideal material for paleointensity study suggest that our understanding of the changes in the Earth's magnetic field over time can be much improved. In turn the improved geomagnetic field model could be applied to the problem of dating archaeo-metallurgical slag deposits that lack precise archeological context (e.g., material collected from the surface). This project involves collecting new material from ancient sites of copper metal production primarily in Jordan spanning the 4th through 1st millennia BCE. The archaeometallurgcal material will be collected from active archeological excavations in the summer of 2007 and analyzed for both radiocarbon age and the ancient magnetic field strength. The data assembled under this grant will contribute to our general knowledge of paleosecular variation and impact the broader issues of radiocarbon calibration curves, variability of solar activity, secular variation time scales and so on. Moreover, this proposal will enhance interdisciplinary research between geophysics and archeology Including provide funding for Erez ben Yosef who is working with both P.I.s at UCSD in an interdisciplenary study combining geophysics and archeology. He will become expert in both fields.