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This study presents 32 high-resolution geomagnetic intensity data points from Mesopotamia, spanning the 3rd to the 1st millennia BCE. These data contribute to rectifying geographic disparities in the resolution of the global archaeointensity curve that have hampered our understanding of geomagnetic field dynamics and the viability of applying archaeomagnetism as a method of absolute dating of archaeological objects. A lack of precise and well-dated intensity data in the region has also limited our ability to identify short-term fluctuations in the geomagnetic field, such as the Levantine Iron Age geomagnetic Anomaly (LIAA), a period of high field intensity from ca. 1050 to 550 BCE. This phenomenon has hitherto not been well-demonstrated in Mesopotamia, contrary to predictions from regional geomagnetic models. To address these issues, this study presents precise archaeomagnetic results from 32 inscribed baked bricks, tightly dated to the reigns of 12 Mesopotamian kings through interpretation of their inscriptions. Results confirm the presence of the high field values of the LIAA in Mesopotamia during the first millennium BCE and drastically increase the resolution of the archaeointensity curve for the 3rd-1st millennia BCE. This research establishes a baseline for the use of archaeomagnetic analysis as an absolute dating technique for archaeological materials from Mesopotamia.

The Earth’s magnetic field (or geomagnetic field) has been measured for hundreds of years, starting with maritime observations from logbooks for navigation purposes to present day real-time recording by satellites. From these records, the geomagnetic field variation throughout recent time is well-understood. In order to study longer term field variations (on the scale of hundreds to thousands of years), it is necessary to use indirect methods of observation of the geomagnetic field, recovered from lavas and burnt archaeological clays. Reconstructions of the geomagnetic field based on such archaeo-/ palaeomagnetic data can be used both to date certain archaeological and geological materials and to study deep Earth processes where the field is generated. However, the currently available archaeo-/ palaeomagnetic data are not geographically nor chronologically well-distributed. The first aim of this thesis is therefore to provide new archaeomagnetic field determinations from locations that are currently under-represented (either spatially or temporally) in the geomagnetic field records, including southern Africa, New Zealand and the Orkney Isles, UK. New geomagnetic field intensities have been collected from each targeted location and in addition, new geomagnetic field directions from New Zealand have also been produced. Archaeomagnetic dating is challenging in data sparse areas such as these, due to large and often unknown uncertainties of either the data (due to non-ideal formation/ preservation conditions) or the geomagnetic reference curves or both. The second aim of this thesis is to address such problems by introducing alternative methodologies for archaeomagnetic dating, (i) accounting for unknown uncertainties and (ii) using alternative constraints, such as the rate of change of the geomagnetic field to be able to provide chronological information.

Here we report a detailed archaeomagnetic and rock-magnetic study of a pottery kiln from Burgos (Spain) to reconstruct its burning conditions and date its last use and abandonment age. During the course of a rescue archaeological excavation carried out in 2015 in the center of Burgos city, a medieval pottery workshop was discovered. Two well-preserved kilns appeared and archaeomagnetic analyses were performed on one of them. In addition to a large amount of pottery remains, some numismatic and documental evidences provided a general chronological estimation, but the abandonment age of the workshop remains unknown. On the basis of the existing archaeological information we carried out an archaeomagnetic study in order to date its last use. 69 archaeomagnetic samples were collected from the combustion chamber and the kiln's fire tunnel. Stepwise alternating field and thermal demagnetization of the natural remanent magnetization (NRM) were carried out to retrieve the mean direction. Additional experiments consisted in the acquisition of isothermal remanence (IRM), low-field magnetic susceptibility and its anisotropy as well as thermomagnetic curves. Despite the high temperatures expected in the combustion chamber, it appeared that the bricks´ samples from the fire tunnel exhibit the most successful directional results. Magnetite and variable contributions of hematite are the main ferromagnetic minerals observed in the thermomagnetic curves. The type of lithology studied, its previous magnetic history and their location in the kiln strongly condition the observed directional and rock-magnetic results. Additionally, AMS data revealed the manufacturing fabric of the fire tunnel's bricks, showing moderately high anisotropy degrees, but not enough to casts doubts on the directional NRM record. In order to test the reproducibility of the dating results, archaeomagnetic dating was carried out using different geomagnetic field models and the Iberian paleosecular variation curv, European Social Fund (Operational Programme for Castilla y León) and the Junta de Castilla y León (Consejería de Educación). Authors also thank the support of the project CGL2016-77560-C2 financed by Spanish Ministry of Economy and Competitiveness (MINECO) and European Fund of Regional Development (EFRD), the project BU235P18 funded by Junta de Castilla y León and EFRD, and the projects PID2019-108753GB-C21 and PID2019-105796GB-I00 financed by Agencia Estatal de Investigación (Spain) [AEI /10.13039/501100011033].

© 2019 the Autors. This work was supported by CONACYT project n° 252149 and partly by UNAM-PAPIIT IN101717., Despite the immense cultural heritage of Mesoamerica, there is still no reference archaeomagnetic curve available for Central Mexico and adjacent areas. The present research has two simultaneous objectives: to obtain finer characteristics of the geomagnetic field elements over archaeological past, and to build up a reliable regional archaeomagnetic dating tool for the time span of 350 BC. to 1500 AD. For these purposes, 72 previous were compiled and analyzed with 40 new data selected from unpublished reports and theses performed in the paleomagnetic laboratories of the Geophysics Institute of UNAM (CDMX and Morelia). Most of the samples carry thermo-remanent magnetization, 31 cases were unburned stuccos, and 3 mural paintings carrying detrital or pictorial remanent magnetization. A total of 112 archaeomagnetic directions constitute the core of the updated catalogue. Special effort should be paid for to the time intervals of 500 BC.—AD. 200 and AD. 1200–325 where there is a major lack of reliable archaeomagnetic results. The present paleosecular variation curve agrees reasonably well with the fluctuation observed in the SW United States area. The differences in the intervals between AD. 600–720, AD. 850 and 1000 and AD. 1200–1325 may be rather attributed to the lack of reliable data than to local non-dipole field. It is urgent to gather a greater number of high-quality data supported by radiometric ages to improve the reference curve in both regions., Aunque el patrimonio cultural de Mesoamérica es cuantioso, aún no se cuenta con una curva de variación secular del campo geomagnético mediante datos arqueomagnéticos para el centro de México y áreas adyacentes. La presente investigación persiguió dos objetivos: obtener características más precisas de los elementos del campo geomagnético en el pasado arqueológico para el lapso 350 aC. a 1500 dC., además de construir una herramienta de datación arqueomagnética confiable para el centro y Sur de México, región que corresponde con la porción central y norte de Mesoamérica. Para ello se compilaron y seleccionaron 72 resultados previamente publicados en revistas arbitradas junto con 40 datos provenientes de informes de proyectos o tesis. La mayoría de las muestras portan magnetización termo-remanente, únicamente 31 son estucos no quemados con magnetización remanente detrítica y 3 pinturas murales con magnetización remanente pictórica. Un total de 112 direcciones arqueomagnéticas constituyen el núcleo del catálogo actualizado. Es necesario un mayor número de datos respaldados por edades radiométricas y de mayor calidad para mejorar la curva de referencia en México, en particular para los lapsos entre 500 aC. y 200 dC. y entre 1200 dC y 1325 dC. La curva de variación paleosecular que se presenta muestra buena correlación con la fluctuación observada en el área SO de Estados Unidos. Las grandes diferencias entre ambas áreas para los lapsos 600–650 dC., 850–1000 dC. y 1200–1325 dC. pueden ser mayormente atribuidas a la falta de datos confiables más que al campo no dipolar local., CONACYT, UNAM-PAPIIT, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

Archaeomagnetic dating was performed on four archaeological structures in Catalonia (NE Spain) using magnetic inclination and declination values from three reference curves: the Iberian SVC and two curves computed using the regional SCHA.DIF.3k model and the global SHA.DIF.14k. The results provide new data for discussions regarding the dating of three archaeological sites from three very different periods: Roman, Medieval and Modern. In addition, some considerations were made regarding the usefulness of the three reference curves and the corresponding geomagnetic models. The Iberian SVC suggests that a Roman limekiln near Tarragona was last fired during the 1st century BC, but the archaeomagnetic models suggest it was last fired during the 1st century AD, i.e. closer to the date of the kiln infillings (2nd-3rd centuries AD). All three-reference curves date two structures from an archaeological site to the north of Barcelona to the 10th or 11th century AD. These ages match those determined using radiocarbon ages. Dating a modern limekiln near Girona with a presumed age of more than 200 years produced an inconsistent age when using the Iberian SVC, but plausible ages in the 17th or 18th centuries AD using the archaeomagnetic models. This suggests that the Iberian SVC has been superseded by the regional SCHA.DIF.3k model and the global SHA.DIF.14k model, both of which exhibit excellent dating capabilities. Older archaeological sites, including prehistoric sites, should be investigated to fully exploit and verify the potential of the new SHA.DIF.14k archaeomagnetic model., We are grateful to Xavier Aguelo, archaeologist at Antequem SL to allow access and sampling into the ‘Camps de Mas Vidal’ site. Boutheina Fouzai is also acknowledged for her support during field work at Forn Teuler. Thanks as well to the Paleomagnetic Laboratory CCiTUB-ICTJA CSIC where the archaeomagnetic measurements were conducted. This research was funded by the Spanish Ministerio de Economía y Competitividad (project CGL2013-42167), Peer Reviewed, Postprint (author's final draft)

[EN] Researchers have related the manufacturing technique of plasters and stucco in the Maya area with their period of production but not with their architectural function. In this paper, we establish a relationship between those three features (manufacturing technique, age, and architectural function) in the plasters of the Maya site of Dzibanche in southern Quintana Roo. Dzibanche has abundant remains of stuccos and plasters found mainly in three buildings (Plaza Pom, Pequena Acropolis, and Structure 2). We used thin sections, SEM and XRD, and archaeomagnetic dating processes. The pictorial layer of Structure 2 was the earliest (AD 274-316 and the stuccoes and plasters of the other two buildings were dated to the Middle Classic (AD 422-531), but we obtained different archaeomagnetic dates for the red pigment layers found in the buildings of the Pequena Acropolis and thus we were able to determine their chronological order of construction. The raw materials and proportions were carefully chosen to fulfil the mechanical necessities of the architectonic function: different proportions were found in plasters of floors, in the external walls, and inside the buildings; differences between earlier and later plasters were also detected.

[EN] Researchers have related the manufacturing technique of plasters and stucco in the Maya area with their period of production but not with their architectural function. In this paper, we establish a relationship between those three features (manufacturing technique, age, and architectural function) in the plasters of the Maya site of Dzibanche in southern Quintana Roo. Dzibanche has abundant remains of stuccos and plasters found mainly in three buildings (Plaza Pom, Pequena Acropolis, and Structure 2). We used thin sections, SEM and XRD, and archaeomagnetic dating processes. The pictorial layer of Structure 2 was the earliest (AD 274-316 and the stuccoes and plasters of the other two buildings were dated to the Middle Classic (AD 422-531), but we obtained different archaeomagnetic dates for the red pigment layers found in the buildings of the Pequena Acropolis and thus we were able to determine their chronological order of construction. The raw materials and proportions were carefully chosen to fulfil the mechanical necessities of the architectonic function: different proportions were found in plasters of floors, in the external walls, and inside the buildings; differences between earlier and later plasters were also detected.

New archaeomagnetic results from three archaeological kilns recovered from one archaeological site in north-east Spain are reported. The abandonment of kilns BC1 and BC2 has been dated by archaeological evidence to between ad 0 and ad 50, whereas kiln BC3 was abandoned later, between ad 50 and ad 150. Mean archaeomagnetic directions and archaeointensities have been obtained from classical Thellier experiments. The new data are consistent with previous archaeomagnetic data for the Iberian Peninsula. They add to and improve the description of palaeosecular variation during Roman times in Iberia. © University of Oxford, 2012.

A Matlab tool for archaeomagnetic dating has been developed in this work. Well-dated palaeosecular variation curves (PSVCs) can be used to date archaeological artefacts with unknown ages. The archaeomagnetic direction (declination and/or inclination) and the archaeointensity obtained from the archaeological artefact are compared with a master PSVC. In addition, historical lava flows with controversial ages can be dated using this methodology. The dating process follows the descriptions given by Lanos (2004), which is based on the combination of temporal probability density functions of the three geomagnetic field elements. Here, we develop an interactive tool in Matlab code to carry out archaeomagnetic dating by comparing the undated archaeomagnetic (or lava flow) data with a master PSVC. The master PSVCs included with the Matlab tool are the different European Bayesian curves and those generated using both regional and global geomagnetic field models. A case study using all the PSVCs available in Europe and some undated archaeomagnetic data has been carried out to analyze how the different PSVCs affect the dating process. In addition, the dating uncertainty and the relocation error have been analyzed in the European region. Results show that some regional Bayesian PSVCs and the regional SCHA.DIF.3K archaeomagnetic model are the best choices to obtain an accurate date in Europe. Moreover, when it is available, the full geomagnetic field vector must be used for archaeomagnetic dating.

A Matlab tool for archaeomagnetic dating has been developed in this work. Well-dated palaeosecular variation curves (PSVCs) can be used to date archaeological artefacts with unknown ages. The archaeomagnetic direction (declination and/or inclination) and the archaeointensity obtained from the archaeological artefact are compared with a master PSVC. In addition, historical lava flows with controversial ages can be dated using this methodology. The dating process follows the descriptions given by Lanos (2004), which is based on the combination of temporal probability density functions of the three geomagnetic field elements. Here, we develop an interactive tool in Matlab code to carry out archaeomagnetic dating by comparing the undated archaeomagnetic (or lava flow) data with a master PSVC. The master PSVCs included with the Matlab tool are the different European Bayesian curves and those generated using both regional and global geomagnetic field models. A case study using all the PSVCs available in Europe and some undated archaeomagnetic data has been carried out to analyze how the different PSVCs affect the dating process. In addition, the dating uncertainty and the relocation error have been analyzed in the European region. Results show that some regional Bayesian PSVCs and the regional SCHA.DIF.3K archaeomagnetic model are the best choices to obtain an accurate date in Europe. Moreover, when it is available, the full geomagnetic field vector must be used for archaeomagnetic dating.

Here we report a detailed archaeomagnetic and rock-magnetic study of a pottery kiln from Burgos (Spain) to reconstruct its burning conditions and date its last use and abandonment age. During the course of a rescue archaeological excavation carried out in 2015 in the center of Burgos city, a medieval pottery workshop was discovered. Two well-preserved kilns appeared and archaeomagnetic analyses were performed on one of them. In addition to a large amount of pottery remains, some numismatic and documental evidences provided a general chronological estimation, but the abandonment age of the workshop remains unknown. On the basis of the existing archaeological information we carried out an archaeomagnetic study in order to date its last use. 69 archaeomagnetic samples were collected from the combustion chamber and the kiln's fire tunnel. Stepwise alternating field and thermal demagnetization of the natural remanent magnetization (NRM) were carried out to retrieve the mean direction. Additional experiments consisted in the acquisition of isothermal remanence (IRM), low-field magnetic susceptibility and its anisotropy as well as thermomagnetic curves. Despite the high temperatures expected in the combustion chamber, it appeared that the bricks´ samples from the fire tunnel exhibit the most successful directional results. Magnetite and variable contributions of hematite are the main ferromagnetic minerals observed in the thermomagnetic curves. The type of lithology studied, its previous magnetic history and their location in the kiln strongly condition the observed directional and rock-magnetic results. Additionally, AMS data revealed the manufacturing fabric of the fire tunnel's bricks, showing moderately high anisotropy degrees, but not enough to casts doubts on the directional NRM record. In order to test the reproducibility of the dating results, archaeomagnetic dating was carried out using different geomagnetic field models and the Iberian paleosecular variation curv, European Social Fund (Operational Programme for Castilla y León) and the Junta de Castilla y León (Consejería de Educación). Authors also thank the support of the project CGL2016-77560-C2 financed by Spanish Ministry of Economy and Competitiveness (MINECO) and European Fund of Regional Development (EFRD), the project BU235P18 funded by Junta de Castilla y León and EFRD, and the projects PID2019-108753GB-C21 and PID2019-105796GB-I00 financed by Agencia Estatal de Investigación (Spain) [AEI /10.13039/501100011033].