High-quality intensity data from Argentina: archeomagnetic study of pottery fragments from the Guayatayoc-Miraflores basin (Puna de Jujuy, Northwest Argentina)

Abstract:

Improving geomagnetic field reconstructions clearly poses a high-priority challenge in geomagnetic research today. A better characterization of the geomagnetic field strength in the southern hemisphere is particularly crucial as the limited number of reliable intensity records from this area hamper a meaningful analysis of dipole moment past variations. Here we present the first archeointensity results obtained from several collections of pottery fragments from four agropastoral sites from the Puna of Jujuy (Northwest Argentina), an area never studied before. The ages of the studied sites, dated by radiocarbon analysis, range from the XIII to the XVII centuries. The classical Thellier method with regular partial Thermoremanent magnetization (pTRM) checks and TRM anisotropy and cooling rate corrections has been used for archeointensity determination. From the 82 specimens analysed, 63 gave reliable results. This high success rate indicates that potteries from agropastoral sites of the Puna of Jujuy provide a unique opportunity to further recover past geomagnetic field intensity changes in Northwest Argentina. The new data obtained are the first archeointensity data from this region. The differences observed between the new data, other available archeointensity data from nearby regions, and archeointensity variation curves derived from global models (ARCH3k and SHA.DIF.14), highlights the need for new high-quality data to better constrain the evolution of the Earth magnetic field strength in central South America.