First Paleomagnetic Results from Holocene Alluvial Sediments in the Iberian Peninsula
Abstract
We present the first paleomagnetic results from Holocene alluvial sediments that crop out in the western sector of the Ebro basin at the Bardenas Reales de Navarra natural park (N Spain). The Holocene alluvial record in this area is characterized by a sequence of four morphopedosedimentary units arranged in a cut-and- fill and nested fill terrace system. We have sampled the lowermost two units in order to test the reliability of these sediments for secular variation studies. Unit 1, which is 17 meters thick and ranges between 7150-5300 BC in age, has been sampled with a mean resolution of 25 cm. The lowermost 6 meters of Unit 2, with ages between 1700-1000 BC, have been sampled with a mean resolution of 50 cm. Thermal demagnetization of the natural remanent magnetization has enabled identification of a low-temperature component carried by magnetite. In most of the samples, an additional high-temperature component carried by hematite has been identified. Although both components are affected by inclination shallowing, they give similar secular variation trends. A comparison of these results with secular variation data derived from European lacustrine sediments and with available global geomagnetic models is presented. Our results suggest that the studied alluvial sediments might provide secular variation data of comparable quality to those of lacustrine sediments. Although these results are preliminary, they constitute the first step towards the extension of the Holocene secular variation curve for the Iberian Peninsula beyond archeomagnetic data.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2009
- Bibcode:
- 2009AGUSMGP11C..07G
- Keywords:
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- 1522 Paleomagnetic secular variation