What is it about?
Holocene and Late-glacial records documenting variations in direction and intensity of the geomagnetic field during the last 16,000 cal. BP are presented for Southern Patagonia. This continuous high-resolution terrestrial record from Laguna Potrok Aike (51°58′S, 70°23′W) was recovered within the SALSA (South Argentinean Lake Sediment Archives and modeling) project. Mineral magnetic measurements indicate that pseudo single-domain magnetite is the major carrier of the remanence allowing the reliable determination of stable natural remanent magnetization inclinations and declinations from alternating field demagnetization and principal component analysis. Paleomagnetic secular variation records reveal most of the familiar features of declination and inclination that have previously been reported in other records from South Argentina but conspicuous centennial-scale differences are also observed. The results illustrate the potential of paleosecular variations records for dating sedimentary sequences in southern South America.
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Why is it important?
The results illustrate the potential of paleosecular variations records for dating sedimentary sequences in southern South America.
Perspectives
The Holocene/Late-Pleistocene PSV records from other Southern Argentinean sites show similarities with Laguna Potrok Aike although some discrepancies in the amplitude and age of the features are obvious. These differences are probably caused by smoothing effects due to different sedimentation rates, different sediment grain sizes, inaccuracies in the various chronologies, as well as different measuring techniques (u-channel versus discrete samples) and/or local non-dipole features. Despite this, the PSV records at these sites, which are located more than 1000 km apart, can be correlated between them and with other PSV records from the same lake. Such reproducibility between holes from the same lake and between lakes validates the quality of the paleomagnetic records and suggests that the PSV and RPI profiles from these new high-resolution and well-dated records from Laguna Potrok Aike could be used as a robust regional correlation tool in Southern South America.
Dr María A Irurzun
CIFICEN
Read the Original
This page is a summary of: High-resolution paleomagnetic records from Laguna Potrok Aike (Patagonia, Argentina) for the last 16,000 years, Geochemistry Geophysics Geosystems, February 2012, American Geophysical Union (AGU),
DOI: 10.1029/2011gc003900.
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