Full vector geomagnetic secular variation in central Mexico as derived from volcanic rocks younger than about 50 ka

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The ongoing volcanism within the Transmexican Volcanic Belt provides high-quality archives of the ancient earth's magnetic field, allowing for recovering directional variations as well as absolute palaeointensities. As there are not sufficient dated volcanoes for a detailed secular variation curce, we pretend first to select laca flows on the basis of geomorphological age estimations, from the age range 0-50 ka. These lava flows shall be dated by means of the 14C method, using charcoal produced directly by the volcanic eruptions. Palaeomagnetic studies of these lavas will be carried out to determine the paleodirections and absolute palaeointensities of the geomagnetic field, the latter also by application of the novel microwave paleointensity method. We pretend to study a minimum of 50 independent lava flows, to construct together with already available data as well-defined full-vector secular variation curve. This secular variation curve may be used to calibrate semi-continuous data obtained from lake sediments to construct compound secular variation curves of higher resolution. Such curves are much sougth after as observational input data for models of the geodynamo. The period under concern also includes the geomagnetic Laschamp and Mono Lake events, which have been found so far only in few places in volcanic rocks.