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。古地磁学是对古代地磁场的研究，是关于地球内部过去过程的更有用的信息来源之一。几十年来的巨大努力为古代地磁场产生了大量的数据。这些数据已经被纳入越来越复杂的地磁场模型中。除了把地磁场最近的行为放在某种历史背景下，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。地磁场是放射性碳生产的主要控制因素之一，因此对放射性碳刻度曲线有很大影响。理清磁场变化是解释过去太阳活动的关键。此外，一个准确的地磁场变化模型最终可以提供基于长期变化的期待已久的时间尺度。为了推进这些不同的目标，我们将结合考古学和古地磁学的专业知识，从以色列和约旦的铜矿渣中获得新的古强度数据。考古学和考古磁学的共生有着悠久而杰出的记录。对古代地磁场的研究需要在人类日历测量之前保留磁场矢量记录的材料，这些记录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，可以提供对年代较差的考古材料的年龄限制。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。这是因为很难获得既能在实验室实验中表现良好，又能用辐射测量方法准确测得年代的合适材料。实验室实验的进展和对快速冷却的古代冶金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的变化的理解可以得到很大的提高。反过来，改进的地磁场模型可以应用于缺乏准确考古背景(例如，从地表收集的材料)的考古冶金矿渣矿床的年代测定问题。该项目包括从主要位于约旦的铜金属生产古迹收集新材料，时间跨度从公元前4千年到公元前1千年。这些考古冶金材料将于2007年夏天从活跃的考古发掘中收集，并对放射性碳年龄和古代磁场强度进行分析。在这笔赠款下收集的数据将有助于我们对古分子变化的一般知识，并影响更广泛的问题，如放射性碳校准曲线、太阳活动的可变性、长期变化时间尺度等。此外，这项建议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，后者正与加州大学圣迭戈分校的两位私人投资者合作，进行一项结合地球物理学和考古学的跨学科研究。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.