Paleomagnetism and tectonics from the late Pliocene to late Pleistocene in the Xalapa monogenetic volcanic field, Veracruz, Mexico

2019 ◽  
Vol 131 (9-10) ◽  
pp. 1581-1590 ◽  
Author(s):  
L.M. Alva-Valdivia ◽  
A. Agarwal ◽  
B. García-Amador ◽  
W. Morales-Barrera ◽  
K.K. Agarwal ◽  
...  
Keyword(s):  
Magnetic Domain ◽  
Volcanic Belt ◽  
Domain Size ◽  
Volcanic Field ◽  
Magnetic Mineralogy ◽  
Monogenetic Volcanic Field ◽  
The Past ◽  
Mexican Volcanic Belt ◽  
Reflected Light

Abstract The Xalapa monogenetic volcanic field, Veracruz, Mexico is located at the eastern end of the Trans-Mexican Volcanic Belt. This study uses specimens from 0.8 ka to 5.96 ± 0.156 Ma Xalapa lava deposits and from 4.5 ± 0.028 Ma La Concha ignimbrite. The study identifies the magnetic mineralogy by reflected light microscopy, thermomagnetic curves, and coercivity estimates. It further defines the magnetic domain size distribution by hysteresis plots, Day diagrams, and first-order-reversal-curves. Characteristic remanent directions and virtual geomagnetic poles are also calculated. The characteristic remanent directions are used to establish the magnetostratigraphy and to identify the net rotation experienced, at each site, since the emplacement. The results allow the identification of the rotation domains, and R′-, P-, and Y-shears, active since the past ∼2.5 m.y. in the region and a better characterization of the displacement along the Río Actopan fault, active in the Xalapa monogenetic volcanic field.

scholarly journals Paleomagnetism and Aeromagnetic Survey From Tancitaro Volcano (Central Mexico) - Paleo-Secular Variation at Low Latitudes During the Past 1 Ma

2017 ◽  
Vol 56 (3) ◽  
Author(s):  
Rafael García-Ruiz ◽  
Avto Goguitchaichvili ◽  
Hector-López Loera ◽  
Miguel Cervantes-Solano ◽  
Jaime Urrutia-Fucugauchi ◽  
...  
Keyword(s):  
Volcanic Belt ◽  
High Standard ◽  
Volcanic Field ◽  
Positive Anomaly ◽  
Aeromagnetic Survey ◽  
The Past ◽  
Mexican Volcanic Belt ◽  
Paleomagnetic Study ◽  
Low Latitudes ◽  
Normal Polarity

The Tancitaro volcano (TV) is part of the Michoacan-Guanajuato monogenetic volcanic field (MGVF) in the central-western sector of the Trans-Mexican Volcanic Belt (TMVB). Results of a paleomagnetic study of radiometrically dated lava flows from Tancitaro volcano were used to investigate the paleosecular variation (PSV) and time averaged field (TAF) at low latitudes. Ar-Ar dates range from ~70 to 960 kyr spanning the Brunhes and Matuyama polarity chrons. All samples yielded well defined normal polarity magnetization. Two flows are correlated to the Jaramillo polarity event, which provide a useful marker for the volcanic activity in the MGVF. For the PSV and TAF analysis, paleodirections were combined with previously reported high standard results. The aeromagnetic survey around the Tancitaro volcano was characterized by a trend of regional anomalies over the volcanic structures. The residual field showed several positive and negative anomalies. The Tancitaro volcano is marked by a broad positive anomaly suggesting the presence of a large underground source. Spectral analysis of this anomaly field gives an average estimate to the top of the source bodies between 2-3 km.

Past and recent biodiversity profiling in ancient Lake Chalco Mexico by a metagenomics analysis

2021 ◽  
Author(s):  
Bárbara Moguel ◽  
Liseth Pérez ◽  
Luis David Alcaraz ◽  
Socorro Lozano-García ◽  
Luis Herrera-Estrella ◽  
...  
Keyword(s):  
Volcanic Belt ◽  
Environmental Dna ◽  
Radiocarbon Dates ◽  
The Past ◽  
Mexican Volcanic Belt ◽  
History Of ◽  
High Throughput Dna Sequencing ◽  
High Altitude Lake ◽  
Taxonomic Groups ◽  
The Relationship

<p>For decades, paleoecological studies in lake sediments have focused on reconstructing the environments of the past and explaining phenomena linked to climatic variations. Recent advances in high-throughput DNA sequencing have allowed access to environmental DNA (eDNA) and ancient sedimentary DNA (sedaDNA) as a new and efficient proxy for past and present biodiversity. The basin of Mexico (BM) is located in the central part of the Trans-Mexican Volcanic Belt at 2,200 m a.s.l.; with the southern portion harboring the Chalco sub-basin. Lake Chalco is one of the last remaining natural aquatic ecosystems within the ever-expanding urban area surrounding Mexico City. The paleoenvironmental history of this lake has been previously characterized using sedimentological and geochemical proxies, as well as preserved microfossils (diatoms, pollen) with a temporal framework based on multiple radiocarbon dates. However, information for the remaining taxonomic groups and metabolic pathways remained unexplored. Here, we present the first metagenomics-based study for the Holocene in a high-altitude lake in Central Mexico –Lake Chalco. We explored the relationship between the lake’s paleoenvironmental condition and estimations of taxonomic and metabolic profiles across the sedimentary sequence (2.5 meters long). Multiple biological and abiotic variables revealed three main environmental phases: 1) a cool freshwater lake (FW1: 11,500-11,000 cal years BP), 2) a warm hyposaline lake (HS2: 11,000-6,000 cal years BP), and 3) a temperate, subsaline lake (SS3, <6,000 cal years BP). We describe the structure of the microbiota community and taxonomy richness turnover in the three Holocene paleoenvironmental phases. During the past 12 000 years BP the most abundant domains in Lake Chalco sediments were Bacteria, followed by Archaea, and Eukarya (36,722 genera). The analysis of functional proteins showed high biodiversity with a total of 27,636,243 proteins identified, but it was only possible to annotate 3,227,398 of them. Also, we identified several genes associated with some relevant pathways, such as methanogenesis. Altogether, this study allowed us to reconstruct the natural history of lake Chalco and its surroundings.</p>

Stratigraphy and radiocarbon ages of late-Holocene Las Derrumbadas rhyolitic domes and surrounding vents in the Serdán-Oriental basin (Mexico): Implications for archeology, biology, and hazard assessment

The Holocene ◽  
2019 ◽  
Vol 30 (3) ◽  
pp. 402-419 ◽  
Author(s):  
Corentin Chédeville ◽  
Marie-Noëlle Guilbaud ◽  
Claus Siebe
Keyword(s):  
Late Holocene ◽  
Volcanic Belt ◽  
Volcanic Hazards ◽  
Volcanic Field ◽  
Human Populations ◽  
Crater Lakes ◽  
Piedras Negras ◽  
Mexican Volcanic Belt ◽  
Rare Endemic ◽  
The Impact

The Serdán-Oriental lacustrine basin in the eastern part of the Trans-Mexican Volcanic Belt holds a volcanic field of >30 monogenetic vents. Among them, the ~1000-m-high, ~11 km3 Las Derrumbadas rhyolite twin domes dominate the interior of the basin and are surrounded by smaller scoria cones, lava flows, shields, tuff rings, and maars. Of interest in this area are rare endemic species encountered in some of the maar lakes, as well as the large number of pre-Hispanic archeological sites indicating that the lacustrine environment became attractive as a dwelling hub during the late Holocene. We conducted a stratigraphic and radiocarbon dating study to reconstruct the volcanic history, assess the impact of past eruptions on the environment and pre-Hispanic populations, and evaluate future volcanic hazards. Accordingly, at least 10 volcanoes were identified to be < 25,000 BC of which eight are Holocene in age (Alchichica, Tecuitlapa, Atexcac, Cerro El Brujo, Tepexitl, Aljojuca, Derrumbadas, Piedras Negras). Hence, the central part of the Serdán-Oriental basin should be considered potentially active and new eruptions are likely to occur in the future. Furthermore, we show that the ~AD 20 Las Derrumbadas eruption is one of the most voluminous silicic effusive eruptions during the Holocene worldwide. This eruption possibly triggered a migration of human populations from dispersed rural hamlets in the central part of the basin toward fewer larger urban sites (e.g. Cantona) at its margins. Finally, the young ages of the maars imply that the unique biodiversity of their crater lakes must have developed over remarkably short timescales.

scholarly journals Analysis of geomagnetic secular variation for the last 1.5 Ma recorded by volcanic rocks of the Trans Mexican Volcanic Belt: new data from Sierra de Chichinautzin, Mexico

2019 ◽  
Vol 219 (1) ◽  
pp. 594-606 ◽  
Author(s):  
A Rodríguez-Trejo ◽  
L M Alva-Valdivia ◽  
M Perrin ◽  
G Hervé ◽  
N López-Valdés
Keyword(s):  
Secular Variation ◽  
Volcanic Rocks ◽  
Quality Criteria ◽  
Volcanic Belt ◽  
Volcanic Field ◽  
Virtual Geomagnetic Pole ◽  
Mexican Volcanic Belt ◽  
Cooling Unit ◽  
Earth Magnetic Field ◽  
Trans Mexican Volcanic Belt

Summary The great wealth of volcanism along the Trans Mexican Volcanic Belt (TMVB) and the need to improve the secular variation curve of the Earth magnetic field of the region is the aim of this research. 300 oriented cores from 33 sites and 21 individual cooling units were acquired from Sierra de Chichinautzin volcanic field (ChVF) and Sierra de Santa Catarina (SSC). Directional analysis and rock magnetic experiments were performed (e.g. thermal demagnetization, hysteresis loop, susceptibility vs temperature), achieving 21 new averaged palaeomagnetic directions. New results are consistent with the previous studies on the same cooling unit. We compiled all the palaeomagnetic studies performed on the ChVF, updating age and calculating an average direction per cooling unit and estimating an overall mean direction for the ChVF (Dec = 359.1°, Inc = 35.3°, N = 33, k = 21.6, α95 = 5.5°, Plat = 87.7° N, Plong = 227.4° E, K = 31.8, A95 = 4.5°). Afterwards, we compiled all the previous palaeomagnetic studies along the whole TMVB with age ranging from 0 to 1.5 Ma, and constrained the directional analyses by specific quality criteria such as well-defined age, number of samples and quality of kappa) on the cooling unit consistency. The mean direction and virtual geomagnetic pole (VGP) estimated for the TMVB, during the periods 0–40 ka and 0–1.5 Ma, are close to the geographic pole, supporting the validity of the geocentric axial dipole hypothesis. The directional results of this study also fit well with the predictions at Mexico City of the models SHA.DIF.14k and CALS10k2 calculated for the last 14 ka. The dispersion of the VGP's on the TMVB are also consistent with the expected values proposed by different models of palaeosecular variation. However, large gaps in the temporal record remain that should be filled by further palaeomagnetic studies.

scholarly journals Effective mapping of large ignimbrites by using a GIS-based methodology; case of the Xáltipan ignimbrite from Los Humeros caldera, Mexico

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
Jaime Alberto Cavazos Álvarez ◽  
Gerardo Carrasco-Núñez
Keyword(s):  
Flat Surface ◽  
Volcanic Belt ◽  
Field Measurements ◽  
Volcanic Field ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Eruptive History ◽  
Map Construction ◽  
Mexican Volcanic Belt ◽  
Trans Mexican Volcanic Belt

The Xáltipan ignimbrite (XI) records the largest single-eruption of the Trans-Mexican Volcanic Belt up to date (≥344 km3 uncompacted volume). As most large ignimbrites, the XI presents common challenges when mapping. These are abrupt welding variations, burial by younger units near other volcanic sources, and highly eroded deposits in active-water valleys. In this work, we deal with these issues by integrating classical cartographic techniques such as field measurements, geometric projections of energy lines and construction of geologic sections, with a GIS-based methodology that quantifies the eroded bulk. As a result, we obtained a map with the main XI features that is presented in an interactive format. Furthermore, we discuss the resources used for the map construction and how the results contributed to the interpretation of the eruptive history. These contributions include: 1) the energy lines point to a low-height pyroclastic density currents source, typical of caldera-forming, boiling-over eruptions; 2) the landscape of the XI, coupled with the geologic sections, indicate that in the proximal facies the ignimbrite filled a volcanic field, leaving a radially shaped distribution with a flat surface, while in the distal facies it channelized into a steep mountainous ground; and 3) the geologic sections in the valley areas, where the active rivers highly eroded the original XI deposits, revealed the preferential development of welded zones along channel centers.

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