Full vector secular variation during the Brunhes Chron in Mexico determined from volcanic hard rocks

我们打算系统地研究来自墨西哥火山带的火山岩，将前一项目所涵盖的时间范围延伸到整个布鲁赫极性年代（-780 ka）。进一步的古地磁数据将有助于增加我们对地磁场变化的了解，包括落入该时间窗的地磁漂移。为了识别这些事件和偏移，已经并将确定古方向和古强度。在低纬度地区发现漂移现象将是非常有意义的，可以将磁场行为与北方和南方高纬度地区的磁场行为进行比较。一些精确的年龄数据已经从墨西哥岩石中获得，作为项目的一部分，将确定更多的数据。绝对古强度与绝对年龄数据一起也将用于改进和校准海洋沉积物报告的相对古强度曲线，这些曲线可能受到剩磁延迟锁定和/或成岩作用以及气候扰动的影响。

We intend to study systematically volcanic rocks from the Transmexican Volcanic Belt, extending the time range covered in the preceding project back through the entire Brunhes polarity chron (-780 ka). Further palaeomagnetic data shall contribute to increase our knowledge of the variability of the geomagnetic field, including geomagnetic excursions falling into that time window. To recognise such events and excursions, palaeodirections and palaeointensities have been and will be determined. The finding of excursions at low latitudes would be of great interest, to compare the field behaviour with that at high northern and southern latitudes. Some precise age data are already available from Mexican rocks, additional ones will be determined as part of the project. Absolute palaeointensities together with absolute age data will be also of use to refine and calibrate relative palaeointensity curves reported from marine sediments, which may be affected by delayed lock-in of remanence and/or by diagenetic as well as climatic perturbations.