Absolute geomagnetic intensity determinations on Formative potsherds (1400–700 BC) from the Oaxaca Valley, Southwestern Mexico

Abstract

New Thellier-Coe archeointensity determinations have been measured on 15 potsherds from the Oaxaca Valley belonging to three of the four Formative Periods (Pre-Classical) of Mesoamerica, spanning 1400–700 BC. Seven of these are considered to be reliable and indicate a geomagnetic field strength of about 30 μT. This value is some 75% of the present geomagnetic field strength but is in agreement with the absolute intensities predicted from global models for this time and location, and consistent with coeval published determinations. These data thus provide significant evidence for the geomagnetic field strength in an area and for a time that was previously poorly constrained, thus providing an important contribution towards establishing a local master curve for the last 3500 yr. When established, such a curve would be a useful dating tool and also enable establishing for field strength correlations with climatic events and civilization evolutions in a region that is particularly strong in archeological and geological features. Such potential is examined for aridity events, although such observations can only be considered tentative at this stage.

An integrated archeomagnetic and C14study on pre‐Columbian potsherds and associated charcoals intercalated between Holocene lacustrine sediments in Western Mexico: Geomagnetic implications

“…As already suggested by Pétronille et al . [], the main tendencies, given by both the few available archeointensity data from Central and South Mesoamerica and the model predictions, are anticorrelated with the main tendencies given by oxygen isotope record from Lake Punta Laguna.…”

“…(a) Currently available absolute intensity data from Mesoamerica (relocated to Arraro) derived from archeological artifacts and historic lava flows (This study and Pétronille et al ., ). Also shown are the data derived from model prediction from CALS3K.4 for the past 3 ka (Korte and Constable, ) and CALS10K.1b for the past 10 ka [ Korte et al ., ].…”

“…We tried however to compare the archeointensity data compiled by Pétronille et al . [] shown in Figure with the δ 18 O record obtained on Vienna PeeDee Belemnites in sediment cores from Lake Punta Laguna, northeastern Yucatan Peninsula, Mexico [ Curtis et al ., ; Rosenmeier et al ., ; deMenocal , ]. As already suggested by Pétronille et al .…”

Secular Variation of the Intensity of the Geomagnetic Field in Mexico During the First Millennium BCE

“…In Mexico, a large number of archaeomagnetic studies on baked clays or lava flows have been published in the last 10 years (e.g., Fanjat et al, 2013;Mahgoub et al, 2017;Mahgoub et al, 2019bMahgoub et al, , 2019aMahgoub et al, 2019aMahgoub et al, , 2019bPétronille et al, 2012;Rodriguez-Ceja et al, 2009;Rodriguez-Trejo et al, 2019;Terán et al, 2016), but a recent critical analysis of the Mexican dataset showed that around 70% of these data cannot be considered as high quality, according to basic selection criteria. Two local secular variation curves have been recently proposed using only Mexican data (Mahgoub et al, 2019a) or also some from the southwestern United States (Goguitchaichvili et al, 2018).…”

First Full Vector Archeomagnetic Data From Northern Mexico

“…There has been a long tradition of archeomagnetic studies in Northern and Central America, with the first studies in the mid 60s (e.g., Bucha et al, 1970;Lee, 1975 for Mexico and see Jones et al, 2021 for USA) and continuous improvements since (e.g., Alva-Valdivia et al, 2020Dubois, 1989;Hagstrum & Champion, 2002;Hervé, Perrin, Alva-Valdivia, Tchibinda Madingou, et al, 2019;Jones et al, 2020Jones et al, , 2021Lengyel & Eighmy, 2002;Mahgoub, Juárez-Arriaga, Böhnel, Manzanilla, & Cyphers, 2019;Morales et al, 2009;Pétronille et al, 2012;Rodríguez-Trejo et al, 2019;Schaafsma et al, 2002;Soler-Arechalde et al, 2019;Sternberg, 1989;Wolfman, 1990). For the past 2 kyrs, around 325 intensities and 690 directions, respectively 11% and 12% of the worldwide archeomagnetic data set (GEOMAGIA50.v3.4; Brown et al, 2021), have been published.…”