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6 resultados encontrados para: AUTOR: Roy, Priyadarsi D
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2.
- Artículo con arbitraje
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Climate forcings on vegetation of the southeastern Yucatán Peninsula (Mexico) during the middle to late Holocene
Aragón Moreno, Alejandro Antonio ; Islebe, Gerald A. (coaut.) ; Roy, Priyadarsi D. (coaut.) ; Torrescano Valle, Nuria (coaut.) ; Mueller, Andreas D. (coaut.) ;
Contenido en: Palaeogeography, Palaeoclimatology, Palaeoecology Vol. 495 (April 2018), p. 214-226 ISSN: 0031-0182
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Resumen en: Inglés |
Resumen en inglés

Climate and vegetation history from the Yucatán Peninsula, southeastern Mexico, are inferred from a mangrove sediment core deposited between the middle and late Holocene (~5600–1700 cal yr B.P.) in the Rio Hondo Delta. Fossil pollen and concentrations of Ca and Fe and Ca/Fe ratio in sediments are used to record changes in vegetation and climate. Palaeoecological and palaeoclimatic interpretations obtained from pollen abundances and associations and Fe/Ca ratio coincide with dynamics of major global forcings of climate change like ITCZ, ENSO and global cooling. Mesic conditions enabled tropical forest expansion during the middle Holocene (~5600–3650 cal yr B.P.), although there were periodic dry episodes at ~5200 cal yr B.P. and at ~4300 cal yr B.P. that caused disturbance and enabled herbaceous vegetation to expand. Changes in sedi- mentation and a gradual change from semi-evergreen to dry tropical forest occurred at ~3650 cal yr B.P., with increasing ENSO activity and southward migration of the ITCZ during transition of the middle to late Holocene. The driest period and lowest forest cover occurred between ~2600 and 2000 cal yr B.P. Data show that over the last two millennia, influence of the ENSO on southeastern Mexico is stronger compared to other proxy-records of climate variability from the Caribbean region.


3.
- Artículo con arbitraje
Comparison of elemental concentration in near-surface late Holocene sediments and precipitation regimes of the Yucatán Peninsula (Mexico): a preliminary study
Roy, Priyadarsi D. (autor) ; Torrescano Valle, Nuria (autora) ; Escarraga Paredes, Diana del Socorro (autora) ; Vela Pelaez, Alejandro Antonio (autor) ; Lozano Santacruz, Rufino (autor) ;
Disponible en línea
Contenido en: Boletín Geológico y Minero Vol. 129, no. 4 (octubre-diciembre 2018), p. 693-706 ISSN: 0366-0176
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Resumen en: Español | Inglés |
Resumen en español

La investigación paleoclimática en la Península de Yucatán (YP) de México involucra principalmente el polen fósil preservado en archivos sedimentarios, mientras que la geoquímica ha recibido menos atención. En este estudio, se compararon las concentraciones de K, Ti, Fe, Ca y Sr, en 35 muestras superficiales de sedimento del Holoceno tardío, colectadas en un gradiente de precipitación entre 600-1600 mm/a, a lo largo de la YP, con el objetivo de establecer un testigo de la paleo-precipitación para la región. El origen calcáreo tiene un efecto de dilución en las concentraciones elementales, provocando que los sedimentos presenten baja cantidad de K, Ti y Fe (elementos asociados con clásticos) y mayor cantidad de Ca y Sr (elementos asociados con carbonato y evaporitas), en comparación con la corteza continental superior. Los elementos individuales y las relaciones de K/Ca, Ti/Ca y Fe/Ca en muestras con cantidades mínimas de clástico, no muestran una relación con la precipitación. Los valores promedio de la relación elemental en sedimentos con más clásticos, muestra tendencias positivas con la precipitación. No obstante, el protocolo de muestreo y la presencia de un mayor número de cuerpos de agua investigados en un simple aglomerado (p. ej. 1200-1400 mm/a) no permitió completar la evaluación de la correlación potencial entre precipitación y la relación elemental. Considerando que la concentración de Ti en los sedimentos ricos en calizas de la PY es bajo y el Fe es móvil en ambientes de depositación anóxicos, la relación K/Ca puede ser utilizada como un testigo preliminar para reconstruir la variación de la paleo-precipitación.

Resumen en inglés

Paleoclimate research in the Yucatán Peninsula of Mexico has mainly involved fossil pollen preserved in sedimentary archives whilst geochemistry has received limited attention. In this study, we compared concentrations of K, Ti, Fe, Ca and Sr in 35 near-surface late Holocene sediments collected from different permanent and seasonal water bodies across the peninsula with mean annual precipitation of 600-1600 mm in order to explore the relationship between concentrations of inorganic elements and precipitation. The calcareous provenance has a diluting effect and sediments have less K, Ti and Fe (associated with clastics) and more Ca and Sr (associated with carbonate and evaporite) compared to the Upper Continental Crust. Individual elements and ratios of K/Ca, Ti/Ca and Fe/Ca in samples with minimal clastics did not show any relationship with precipitation. Average values of elemental ratios in sediments with more clastics increase as the mean annual precipitation increases. However, the sampling protocol and presence of most of the sampled water bodies being in a single precipitation cluster (i.e. 1200-1400 mm/year) did not allow a complete evaluation of the potential correlation between precipitation and elemental ratios. Considering that the concentration of Ti is low in sediments of the limestone-rich Yucatán Peninsula and Fe is mobile in anoxic depositional environments, the K/Ca ratio can be used as a preliminary proxy to evaluate precipitation in sedimentary records.


4.
Libro
The holocene and anthropocene environmental history of Mexico: a paleoecological approach on Mesoamerica / editors: Nuria Torrescano Valle, Gerald A. Islebe, Priyadarsi D. Roy
Torrescano Valle, Nuria (editora) ; Islebe, Gerald A. (editor) ; Roy, Priyadarsi Debajyoti (editor) ;
Cham, Switzerland : Springer International Publishing , c2019
Disponible en línea
Clasificación: EE/577 / H6
Bibliotecas: Campeche , San Cristóbal
Cerrar
SIBE Campeche
ECO040007071 (Disponible)
Disponibles para prestamo: 1
Cerrar
SIBE San Cristóbal
ECO010019867 (Disponible)
Disponibles para prestamo: 1
Resumen en español

This book provides essential information on Mexico’s Holocene and Anthropocene climate and vegetation history. Considering the geography of Mexico – which is home to a variety of climatic and environmental conditions, from desert and tropical to high mountain climates – this book focuses on its postglacial paleoecology and paleoclimatology. Further, it analyses human intervention since the middle Holocene as a major agent of environmental change. Offering a valuable tool for understanding past climate change and its relationship with present climate change, the book is a must-read for botanists, ecologists, palaeontologists and graduate students in related fields.

Índice

1 Introduction: The Holocene and Anthropocene Environmental History of Mexico
References
2 Paleoclimate of the Gulf of California (Northwestern Mexico) During the Last 2000 Years
Introduction
Regional Settings
Processes Responsible for the Sedimentation Cycle
Hydrological Processes Linked to Climate and Anthropogenic Changes
Integrated Water–Vertical Settling Studies in the Alfonso Basin
Climate Variations: Interannual, Centennial, and Millennial Scales
Centennial–Scale Variability
Climate Modeling
Conclusions
References
3 Holocene Hydroclimate of the Subtropical Mexico: A State of the Art
Introduction
Modern Climate
Register and Hypothesis
Vegetation Composition
Hydrological Variation and Climate Forcing
Conclusions
References
4 The Environment of Ancient Cloud Forests in the Mexican Pacific
The Mexican Pacific
The Past Environments in the Mexican Pacific
The Present Cloud Forest
The Ancient Cloud Forests
Methods
Results
Discussion
Conclusion
References
5 Sea Level Change and Its Influence on the Coastal Landscape in the Gulf of Mexico During the Holocene
Introduction
Vegetation Types in the Gulf of Mexico
Vegetation Response to Sea Level
Human Impact on Coastal Vegetation
Conclusion
References
6 Insights into the Holocene Environmental History of the Highlands of Central Mexico
Introduction
Central Mexico
Holocene Environment
References
7 Integration of Landscape Approaches for the Spatial Reconstruction of Vegetation
Introduction
Methods
Results
Discussion
References
8 Volcanic Activity in Mexico During the Holocene
Introduction
Distribution of Volcanoes in Mexico
Holocene Eruptions from Volcanoes in Mexico
Active Stratovolcanoes and Calderas
Monogenetic Volcanic Fields
Outlook of Holocene Volcanism
References


5.
- Artículo con arbitraje
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Late Holocene hydroclimate of the western Yucatan Peninsula (Mexico)
Priyadarsi, D. Roy ; Torrescano Valle, Nuria (coaut.) ; Islebe, Gerald A. (coaut.) ; Gutiérrez Ayala, Luz Verónica (coaut.) ;
Contenido en: Journal of Quaternary Science Vol. 32, no. 8 (Noviembre 2017), p. 1112–1120 ISSN: 0267-8179
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Resumen en: Inglés |
Resumen en inglés

Chemical composition, magnetic susceptibility and texture of sediments in a swamp from the Los Petenes Biosphere Reserve provide information about late Holocene hydrological variations on the western margin of the Yucatan Peninsula, Mexico. Periods of lower than average amounts of K-bearing clastics during 2580–2050, 1100–825 and 700–160 cal a BP represent drought intervals. Magnetic minerals were better preserved during these arid intervals, as the swamp was not perennially anoxic. Hydroclimate was unstable during 2580–2050 cal a BP, as several storm-surge events occurred within an overall arid interval. The drought of 1100–825 cal a BP was contemporary with the Terminal Classic Period and the drought of 700–160 cal a BP was characterized by the lowest erosion as well as highest abundance of authigenic carbonate. Comparison with other climate proxy records from the region suggests that droughts had different geographic coverage. We attribute the different geographic coverage of droughts to variable strengths of polar continental air masses as well as dynamics of the Caribbean Low Level Jet and tropical cyclones that brought precipitation into different parts of the peninsula.


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Índice

Introducción general
1 Cambio climático: contexto histórico, paleoecológico y paleoclimático. Tendencias actuales y perspectivas
2 Impacto de las actividades humanas en la biodiversidad y en los ecosistemas
3 Cambios en la biodiversidad y sus consecuencias en el funcionamiento de los ecosistemas y sus servicios
4 Los servicios ecosistémicos
5 Herramientas y estrategias para el estudio y la conservación de los ecosistemas y su biodiversidad
Conclusiones generales