El sitio arqueologico de Dzibanche, en Quintana Roo, tieneuna gran cantidad de restos de estuco e... more El sitio arqueologico de Dzibanche, en Quintana Roo, tieneuna gran cantidad de restos de estuco en diferentes complejos de edificios con diversos problemas de conservacion. Estos vestigios fueron analizados con distintos metodos para conocer su tecnica de manufactura, dando como resultado que no solo la evolucion tecnica influye en la manera de hacer mezclas de cal, sino tambien su funcion y ubicacion en las estructuras. Asi, los estucos que estan en el exterior, en los vanos y el interior de un edificio difieren en proporciones e incluso en composicion tanto en los distintos estratos como en los materiales constitutivos.
PRESENTACIÓN La serie Cuadernos del Instituto de Geofísica de la UNAM se creó con el propósito de... more PRESENTACIÓN La serie Cuadernos del Instituto de Geofísica de la UNAM se creó con el propósito de llevar fuera de los muros universitarios las experiencias y conocimientos del personal académico de este instituto sobre los diversos programas y proyectos de investigación. Escritos en ...
Recent investigations have demonstrated that motor-vehicle gas contains particles with potentiall... more Recent investigations have demonstrated that motor-vehicle gas contains particles with potentially toxic elements. These contaminating particles accumulate on the soil surface or overlying material (asphalt, stone and concrete pavements) and they are usually mixed with urban dust. In this work we RESEARCH PAPER Published on behalf of Latin American Association of Paleomagnetism and Geomagnetism by the Instituto de Geofisica, Universidad Nacional Autónoma de México 1 Latinmag Letters Volume 5, number 5 (2015), LL15-0502Rs, 1-16 Cejudo, R. et al. / Latinmag Letters 5 (2015), LL15-0502Rs, 1-16 2 determine the magnetic threshold values using urban dust and leave samples collected from different type of urban land-use soil along the metropolitan area of Mexico City and identify potentially dangerous areas considering potentially toxic elements. 89 urban dust samples deposited on the streets and same number of Ficus benjamina leaves were collected from different land-use zones (residentia...
Trabajo presentado en la Reunion Anual de la Union Geofisica Mexicana, celebrada en Jalisco (Mexi... more Trabajo presentado en la Reunion Anual de la Union Geofisica Mexicana, celebrada en Jalisco (Mexico), del 30 de octubre al 4 de noviembre de 2016
Paleomagnetic declinations for volcanic units within the Acambay graben, are rotated counterclock... more Paleomagnetic declinations for volcanic units within the Acambay graben, are rotated counterclockwise by various amounts with respect to expected references directions. The average overall mean rotation is from -18.5 ± 7.5 to -15.8 ± 7.2 degrees, assuming the region behaves as a coherent rigid tectonic domain. Deformation on a local scale seems more complex and several tectonic domains can be identified. Site-mean rotation estimates are as high as -49 degrees, with rotations within the graben around -40 degrees. The angular differences among the site-mean paleomagnetic directions mainly result from: (a) paleosecular variation, (b) differential rotation of small tectonic domains, (c) internal deformation within the rotated domain, (d) age differences and timing of rotation, (e) sampling and measurement effects, (f) local structural complexities, apparent rotations due to improper structural correction, and (g) a combination of these factors. The paleomagnetic results are analyzed for...
Abstract Earth’s Magnetic Field variation strength may provide crucial information to understand ... more Abstract Earth’s Magnetic Field variation strength may provide crucial information to understand the geodynamo mechanism and elucidate the conditions on the physics of the Earth’s deep interiors. Aimed to reveal the fine characteristics of the geomagnetic field during the last three millennia in Mesoamerica, we analyzed the available absolute geomagnetic intensities associated to absolute radiometric dating as well some ages provided by historical documents. This analysis is achieved using thermoremanent magnetization carried by volcanic lava flows and burned archaeological artefacts. A total of 106 selected intensities from Mesoamerica and other 100 from the southern part of the United States represent the main core of the dataset to construct the variation curve using both combined bootstrap method and temporal penalized B-spline methods. The obtained intensity paleosecular variation curve for Mesoamerica generally disagrees with the values predicted by the global geomagnetic field models. There is rather firm evidence of eastward drift when compared to similar reference curves in Western Europe, Asia and Pacific Ocean. The recent hypothesis about the relationship between the geomagnetic field strength and paleoclimate is also critically analyzed in the light of this new data compilation.
Paleomagnetic declinations for volcanic units within the Acambay graben, are rotated counterclock... more Paleomagnetic declinations for volcanic units within the Acambay graben, are rotated counterclockwise by various amounts with respect to expected references directions. The average overall mean rotation is from -18.5 ± 7.5 to -15.8 ± 7.2 degrees, assuming the region behaves as a coherent rigid tectonic domain. Deformation on a local scale seems more complex and several tectonic domains can be identified. Site-mean rotation estimates are as high as -49 degrees, with rotations within the graben around -40 degrees. The angular differences among the site-mean paleomagnetic directions mainly result from: (a) paleosecular variation, (b) differential rotation of small tectonic domains, (c) internal deformation within the rotated domain, (d) age differences and timing of rotation, (e) sampling and measurement effects, (f) local structural complexities, apparent rotations due to improper structural correction, and (g) a combination of these factors. The paleomagnetic results are analyzed for geographic distribution within the graben, relative position of sampling sites with respect to fault scarps, etc. Factors (a), (b), (c) and (d) are considered important. Results support the occurrence of a counterclockwise rotation of a large domain, possibly related to regional sinistral shear and transtension within the magmatic arc. Locally, deformations within the graben seem distributed among various small domains, which show different amounts of counterclockwise rotation.
Red colored paintings contain small amount of antiferromagnetic hematite grains. When the red pig... more Red colored paintings contain small amount of antiferromagnetic hematite grains. When the red pigment is applied to the wall, these grains are free to move and they align their magnetic moment with the Earth's magnetic field. The resulting magnetization is called pictorial remanence. Here, we evaluate the usefulness of natural rem-anent magnetization carried by mural paintings in archaeomagnetism in order to try to estimate whether it may be used as a reliable dating tool. Moreover, we report a first ever attempt to analyze samples of cave paintings.
Abstract We carried out a detailed mineral magnetic and archaeomagnetic investigation on wattle a... more Abstract We carried out a detailed mineral magnetic and archaeomagnetic investigation on wattle and daub (locally known as Bajareque) building remains recovered at Teuchitlan archeological site (Jalisco, Mexico) in order to estimate the suitability of such material for Thellier double heating absolute geomagnetic intensity determinations and to contribute to the still incipient archaeomagnetic database for Mesoamerica. The single-domain Ti-poor titanomagnetite and hematite seem to be main magnetic carriers in most of samples. Although the presence of hematite is confirmed for all samples, its contribution to the remanent magnetization seems negligible and the most part of remanent magnetization is carried by almost magnetite phase. All 42 analyzed Bajareque samples yielded technically acceptable archaeointensity determination, which is probably a unique case since a 100% of success rate is reached. Present study underlines the exceptional magnetic properties of Bajareque samples and their high suitability for absolute geomagnetic intensity determinations. Selected mean archeointensity data currently available for Mesoamerica show unusually high dispersion, which makes it difficult to make any firm conclusion about the evolution of Earth's magnetic field through archeological time.
An integrated magnetic survey was carried out on key places within the La Quemada archaeological ... more An integrated magnetic survey was carried out on key places within the La Quemada archaeological complex, built over a hill on the northern frontier of Classic period Mesoamerica. Samples were collected from the Plaza of Sacrifices and Hall of Columns in an attempt to precisely determine the age intervals corresponding to the decline and abandonment of the site, apparently due to the intentional firing as a closure ritual. Well-defined char- acteristic remanent magnetizations were retrieved from 23 of 32 samples. Moreover, twelve samples belonging to two areas yielded reliable determinations under criteria curtailed in this study. In any case, a primary re- manent magnetization is carried by pseudo-single-domain Ti-poor titanomagnetite, as evidenced by hysteresis and continuous thermomagnetic curves. The archaeomagnetic dating was performed using full geomagnetic vector (directions and absolute intensity) using the last SHADIF14k model. The Plaza of Sacrifices seems to been burned between a time interval from 854 to 968 CE, while a late interval from 1018 to 1163 CE is assigned to the samples collected in the Hall of Columns, which suggest the gradual abandonment of the site. The first aban- donment stage is almost synchronous to the same phenomena observed for other sites at the Bajío area (central and western Mesoamerica) region. Under these circumstances, it cannot be discarded that La Quemada was burned in its entirety during the first stage of abandonment, but the Hall of Columns was again burned later.
El sitio arqueologico de Dzibanche, en Quintana Roo, tieneuna gran cantidad de restos de estuco e... more El sitio arqueologico de Dzibanche, en Quintana Roo, tieneuna gran cantidad de restos de estuco en diferentes complejos de edificios con diversos problemas de conservacion. Estos vestigios fueron analizados con distintos metodos para conocer su tecnica de manufactura, dando como resultado que no solo la evolucion tecnica influye en la manera de hacer mezclas de cal, sino tambien su funcion y ubicacion en las estructuras. Asi, los estucos que estan en el exterior, en los vanos y el interior de un edificio difieren en proporciones e incluso en composicion tanto en los distintos estratos como en los materiales constitutivos.
PRESENTACIÓN La serie Cuadernos del Instituto de Geofísica de la UNAM se creó con el propósito de... more PRESENTACIÓN La serie Cuadernos del Instituto de Geofísica de la UNAM se creó con el propósito de llevar fuera de los muros universitarios las experiencias y conocimientos del personal académico de este instituto sobre los diversos programas y proyectos de investigación. Escritos en ...
Recent investigations have demonstrated that motor-vehicle gas contains particles with potentiall... more Recent investigations have demonstrated that motor-vehicle gas contains particles with potentially toxic elements. These contaminating particles accumulate on the soil surface or overlying material (asphalt, stone and concrete pavements) and they are usually mixed with urban dust. In this work we RESEARCH PAPER Published on behalf of Latin American Association of Paleomagnetism and Geomagnetism by the Instituto de Geofisica, Universidad Nacional Autónoma de México 1 Latinmag Letters Volume 5, number 5 (2015), LL15-0502Rs, 1-16 Cejudo, R. et al. / Latinmag Letters 5 (2015), LL15-0502Rs, 1-16 2 determine the magnetic threshold values using urban dust and leave samples collected from different type of urban land-use soil along the metropolitan area of Mexico City and identify potentially dangerous areas considering potentially toxic elements. 89 urban dust samples deposited on the streets and same number of Ficus benjamina leaves were collected from different land-use zones (residentia...
Trabajo presentado en la Reunion Anual de la Union Geofisica Mexicana, celebrada en Jalisco (Mexi... more Trabajo presentado en la Reunion Anual de la Union Geofisica Mexicana, celebrada en Jalisco (Mexico), del 30 de octubre al 4 de noviembre de 2016
Paleomagnetic declinations for volcanic units within the Acambay graben, are rotated counterclock... more Paleomagnetic declinations for volcanic units within the Acambay graben, are rotated counterclockwise by various amounts with respect to expected references directions. The average overall mean rotation is from -18.5 ± 7.5 to -15.8 ± 7.2 degrees, assuming the region behaves as a coherent rigid tectonic domain. Deformation on a local scale seems more complex and several tectonic domains can be identified. Site-mean rotation estimates are as high as -49 degrees, with rotations within the graben around -40 degrees. The angular differences among the site-mean paleomagnetic directions mainly result from: (a) paleosecular variation, (b) differential rotation of small tectonic domains, (c) internal deformation within the rotated domain, (d) age differences and timing of rotation, (e) sampling and measurement effects, (f) local structural complexities, apparent rotations due to improper structural correction, and (g) a combination of these factors. The paleomagnetic results are analyzed for...
Abstract Earth’s Magnetic Field variation strength may provide crucial information to understand ... more Abstract Earth’s Magnetic Field variation strength may provide crucial information to understand the geodynamo mechanism and elucidate the conditions on the physics of the Earth’s deep interiors. Aimed to reveal the fine characteristics of the geomagnetic field during the last three millennia in Mesoamerica, we analyzed the available absolute geomagnetic intensities associated to absolute radiometric dating as well some ages provided by historical documents. This analysis is achieved using thermoremanent magnetization carried by volcanic lava flows and burned archaeological artefacts. A total of 106 selected intensities from Mesoamerica and other 100 from the southern part of the United States represent the main core of the dataset to construct the variation curve using both combined bootstrap method and temporal penalized B-spline methods. The obtained intensity paleosecular variation curve for Mesoamerica generally disagrees with the values predicted by the global geomagnetic field models. There is rather firm evidence of eastward drift when compared to similar reference curves in Western Europe, Asia and Pacific Ocean. The recent hypothesis about the relationship between the geomagnetic field strength and paleoclimate is also critically analyzed in the light of this new data compilation.
Paleomagnetic declinations for volcanic units within the Acambay graben, are rotated counterclock... more Paleomagnetic declinations for volcanic units within the Acambay graben, are rotated counterclockwise by various amounts with respect to expected references directions. The average overall mean rotation is from -18.5 ± 7.5 to -15.8 ± 7.2 degrees, assuming the region behaves as a coherent rigid tectonic domain. Deformation on a local scale seems more complex and several tectonic domains can be identified. Site-mean rotation estimates are as high as -49 degrees, with rotations within the graben around -40 degrees. The angular differences among the site-mean paleomagnetic directions mainly result from: (a) paleosecular variation, (b) differential rotation of small tectonic domains, (c) internal deformation within the rotated domain, (d) age differences and timing of rotation, (e) sampling and measurement effects, (f) local structural complexities, apparent rotations due to improper structural correction, and (g) a combination of these factors. The paleomagnetic results are analyzed for geographic distribution within the graben, relative position of sampling sites with respect to fault scarps, etc. Factors (a), (b), (c) and (d) are considered important. Results support the occurrence of a counterclockwise rotation of a large domain, possibly related to regional sinistral shear and transtension within the magmatic arc. Locally, deformations within the graben seem distributed among various small domains, which show different amounts of counterclockwise rotation.
Red colored paintings contain small amount of antiferromagnetic hematite grains. When the red pig... more Red colored paintings contain small amount of antiferromagnetic hematite grains. When the red pigment is applied to the wall, these grains are free to move and they align their magnetic moment with the Earth's magnetic field. The resulting magnetization is called pictorial remanence. Here, we evaluate the usefulness of natural rem-anent magnetization carried by mural paintings in archaeomagnetism in order to try to estimate whether it may be used as a reliable dating tool. Moreover, we report a first ever attempt to analyze samples of cave paintings.
Abstract We carried out a detailed mineral magnetic and archaeomagnetic investigation on wattle a... more Abstract We carried out a detailed mineral magnetic and archaeomagnetic investigation on wattle and daub (locally known as Bajareque) building remains recovered at Teuchitlan archeological site (Jalisco, Mexico) in order to estimate the suitability of such material for Thellier double heating absolute geomagnetic intensity determinations and to contribute to the still incipient archaeomagnetic database for Mesoamerica. The single-domain Ti-poor titanomagnetite and hematite seem to be main magnetic carriers in most of samples. Although the presence of hematite is confirmed for all samples, its contribution to the remanent magnetization seems negligible and the most part of remanent magnetization is carried by almost magnetite phase. All 42 analyzed Bajareque samples yielded technically acceptable archaeointensity determination, which is probably a unique case since a 100% of success rate is reached. Present study underlines the exceptional magnetic properties of Bajareque samples and their high suitability for absolute geomagnetic intensity determinations. Selected mean archeointensity data currently available for Mesoamerica show unusually high dispersion, which makes it difficult to make any firm conclusion about the evolution of Earth's magnetic field through archeological time.
An integrated magnetic survey was carried out on key places within the La Quemada archaeological ... more An integrated magnetic survey was carried out on key places within the La Quemada archaeological complex, built over a hill on the northern frontier of Classic period Mesoamerica. Samples were collected from the Plaza of Sacrifices and Hall of Columns in an attempt to precisely determine the age intervals corresponding to the decline and abandonment of the site, apparently due to the intentional firing as a closure ritual. Well-defined char- acteristic remanent magnetizations were retrieved from 23 of 32 samples. Moreover, twelve samples belonging to two areas yielded reliable determinations under criteria curtailed in this study. In any case, a primary re- manent magnetization is carried by pseudo-single-domain Ti-poor titanomagnetite, as evidenced by hysteresis and continuous thermomagnetic curves. The archaeomagnetic dating was performed using full geomagnetic vector (directions and absolute intensity) using the last SHADIF14k model. The Plaza of Sacrifices seems to been burned between a time interval from 854 to 968 CE, while a late interval from 1018 to 1163 CE is assigned to the samples collected in the Hall of Columns, which suggest the gradual abandonment of the site. The first aban- donment stage is almost synchronous to the same phenomena observed for other sites at the Bajío area (central and western Mesoamerica) region. Under these circumstances, it cannot be discarded that La Quemada was burned in its entirety during the first stage of abandonment, but the Hall of Columns was again burned later.
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Papers by Ana María Soler Arechalde