Magnetism in Mesoamerian MuralsBy: 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 1Avto Goguitchaichvili and A. Soler

Templo Rojo @ Tenohtitlan, Templo de Venus @ Cacaxtla, Chapulines and Estrellas @ 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 1Avto Goguitchaichvili and A. Soler

The Research: Study 2Hueda-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 2Hueda-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 2Hueda-Tanabe and A Soler

Results @ 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

SourcesDe 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.

2010 Res:Anthropology and Aethetics, 57/58 Spring/Autumn

Pratt, S.

2004. Magnetic Murals. Geotimes, <http://www.geotimes.org/sept04/NN_magneticmurals.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 Mexico—dating of Mesoamerican lime-plasters, Physics of the Earth and Planetary Interiors, Volume 147, Issues 2–3, 15 November 2004, Pages 269-283,

(http://www.sciencedirect.com/science/article/pii/S0031920104002742)

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 222702236