Magnetism in Mesoamerian Murals By: Emily Shearin

What is Archaeomagnetic Dating? Two basic principles: Earth's magnetic field changes with time in both intensity and direction (strength and secular variation) Certain events can naturally cause magnetic materials to end up permanently magnetized. This records the magnetic field within the magnetic materials pertaining to the time of the event

My Thesis Archaeomagnetic Dating Reliable and useful That Mesoamerican murals have the correct material to perform Archaeomagnetic dating I will also discuss what I believe is a logical next step in archaeomagnetic research in Mesoamerica would be.

What Materials Can Be Used? In the case of Mesoamerican murals: Hematite and Magnetite As the paint and pigments dry the inclination, declination, and therefore field direction freeze, this leaves the remanent magnetization behind that can be tested The most prevalent of these magnetized minerals are iron oxides including magnetite, and hematite It was previously thought that the magnetized minerals would only get stuck after being heated above the Curie point. The Curie point is also known as the Curie temperature is the point where a material's magnetic parts change direction

The Research: Study 1 Avto Goguitchaichvili and A. Soler Templo Tenohtitlan, Templo de Cacaxtla, Chapulines and Cholula These specific pieces were chosen because they have been well dated in different ways. Also because they have an abundance of red paint Looking to prove that archaeomagnetic dating results were valid A characteristic remanent magnetization is successfully isolated by alternating field demagnetization They found the mean directions of each mural are reasonably determined and hold within the date range previously determined Compared these results to those from rocks and lime plaster Turned out that all the archaeomagnetic dating from the murals and other materials agreed with previous research.

The Research: Study 1 Avto Goguitchaichvili and A. Soler

The Research: Study 2 Hueda-Tanabe and A Soler Archaeomagnetic dating on burned and unburned lime-plaster Lime plaster was chosen because of its frequent occurrence, especially as support for murals Hypothesis: Lime plasters contain enough magnetic materials, and that it is feasible to measure their remanent magnetization Proving Archaeomagnetism is a useful tool in Mesoamerican archeology, allowing the dating of constructive stages

The Research: Study 2 Hueda-Tanabe and A Soler Teopancazco Residential compound Characterized by a series of constructive levels Very well known dating, this is why it was chosen Templo Mayor Large complex structure with several constructive stages Chosen specifically because the chronology of the constructive stages are unclear

The Research: Study 2 Hueda-Tanabe and A Soler Teopancazco Stage 2 both A. dating and c14 have a mean of 350 AD Stage 3 C14 said 575 +/- 80 while A dating says 555 AD Due to secondary tilting of the structure, re- magnetization possibly occurred However showed well grouped magnetization and the group believed with further research and re calibration the dates will hold true

The Next Step...

Why Monte Alban? The murals in Monte Alban are mostly tomb murals They have discovered 177 tombs and more are being found The two tombs I would focus on are Tomb 104 and Tomb 105

Characteristics of the Tombs Tomb 104 Thoroughly researched Can be cross dated Zapotec Red Holds Hematite Remained sealed Tomb 105 Thoroughly researched Some chronological questions remain Zapotec Red Hold Hematite Re-entered

Tomb 105 Mystery Zapotec red is a unique mixture: Organic red lake pigment (either carminic acid from cochineal insects or colorant extracted from annatto seed), cinnabar, hematite Dead technique brought back for these tombs Darker red used for skin color is hematite and water Different technique suggesting re-entrance and re- painting of the mural

The Dream Use archaeomagnetic dating on all the layers of paint Layers of lime plaster Compare these dates to those known before Fill in gaps of construction and culture

Sources De La Fuente B., Flacon T., Ruizgallut M.E., Soilis F., Stainescicero L., Uriarte M.T. 1999, The Pre-Columbian Paining, Murals of Mesoamerica. Milan, Jaca Book Spa Eighmy, Jeffery L., Sternberh, Robert S. 1991, Archaeomagnetic Dating, University of Arizona Press Goguitchaichvili, A., A. M. Soler, E. Zanella, G. Chiari, R. Lanza, J. Urrutia-Fucugauchi, and T. Gonzales 2004, Pre-Columbian Mural Paintings from Mesoamerica as Geomagnetic Field Recorders, Geophysical Research Letters, Volume 31, Issue 12, L12607 Pellizzi F., Wood C., Hay J., Mahaloni D., Guernsey J., Becker, C., Rochette M., Kousser R., Et Al Res:Anthropology and Aethetics, 57/58 Spring/Autumn Pratt, S Magnetic Murals. Geotimes, rals.html Hueda-Tanabe,Y, Soler-Arechalde, A.M., Urrutia- Fucugauchi, J., Barba L., Manzanilla, L., Rebolledo-Vieyra M., Goguitchaichvili, A., 2004 Archaeomagnetic studies in central Mexicodating of Mesoamerican lime-plasters, Physics of the Earth and Planetary Interiors, Volume 147, Issues 2–3, 15 November 2004, Pages , ( ) Lopez, V., E. Romero, A. M. Soler-Arechalde, and G. Espinosa. 2007, "Archaeomagnetic Investigation at Chapultepec, Mexico City: Case Study of Classical Settlers." In AGU Spring Meeting Abstracts, vol. 1, p. 07. Otgeta-Aviles, M., San-German, C.M., Mendoza- Anaya, D., Morales, D., Jose- Yacaman,M., 2001, Characterization of Mural Paintings from Cacaxtla Journal of Materials Science, Valume 36, Issue 9, pp