Rock Magnetic Properties and RPI Stack between 13 to 24 kyr. from Sediment Cores, Lake Moreno (Arg)

What is it about?

We conducted a detailed study of natural remanence and rock magnetic properties on three sediment cores from Lake Moreno (Patagonia, Argentina). Based on these measurements, we constructed a relative paleointensity stack for the period 13 - 24 kyr. calibrated ages. Rock magnetic properties of the sediment cores showed uniform magnetic mineralogy and grain size, suggesting that they were suitable for relative paleointensity studies. The remanent magnetisation at 20mT (NRM20mT) was normalised using the anhysteretic remanent magnetisation at 20mT (ARM20mT), the saturation of the isothermal remanent magnetisation at 20mT (SIRM20mT) and the low field magnetic susceptibility (k). Spectral analysis showed that the normalised records were not affected by local environmental conditions. The recorded pseudo-Thellier paleointensity was compared with records obtained from conventional normalising methods. Comparing the paleointensity curves with others obtained previously in other lakes in the area has allowed us to reach reliable conclusions about centennial-scale features.

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Why is it important?

we compare the paleointensity obtained by the standard normalising method and the results obtained from one core with the pseudo-Thellier method. In addition, we perform rock magnetic analyses to study possible environmental influences on the sediment in the studied cores. Improved knowledge about relative variations of the geomagnetic field over the last few hundred thousand years has allowed the construction of global reference paleointensity curves, which are useful for defining high-resolution age models in appropriate sedimentary sequences. The research presented in this paper helps mitigate the extremely uneven global distribution of data.

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