Título del libro: Volcaniclastic Sedimentation In Lacustrine Settings
Título del capítulo: Late Pleistocene-Holocene Volcanic Stratigraphy and Palaeoenvironments of the Upper Lerma Basin, Mexico
MARGARITA ERNA CABALLERO MIRANDA; MARIA DEL SOCORRO LOZANO GARCIA;
Autores externos:
Idioma:
Inglés
Año de publicación:
2009
Palabras clave:
Late Pleistocene-Holocene volcanic stratigraphy and palaeoenvironments of the upper Lerma basin, Mexico; Loss on ignition (LOI) and ash-flow deposit (AFD); Low lake-level conditions during early to middle Holocene times; Magnetic and microfossil analys
Resumen:
Detailed analysis of a series of subaerial and lacustrine volcaniclastic sequences in the upper Lerma basin provides evidence of the eruptive history of Nevado de Toluca volcano. These data, together with magnetic susceptibility and microfossil analyses from the studied sequences, are used to document the environmental evolution of this area during the last 40 kyr. The activity of Nevado de Toluca includes three well-documented dome destruction events that occurred at c. 37 000, c. 28 000, and c. 15 000 yr BP, and two Plinian eruptions at c. 24 000 yr BP (Lower Toluca Pumice) and c. 11 600 yr BP (Upper Toluca Pumice), the latest having the most extensive effect in the upper Lerma and neighbouring basins. Monogenetic volcanism at the Tres Cruces volcano by c. 8500 yr BP is also recorded in the upper Lerma basin. Volcanic activity had a great influence on lacustrine sedimentation, as thick packets of volcanic material were repeatedly deposited in the lake basin. Pollen data from a highland pond indicate extensive grasslands and cold, dry conditions during the last interstadial (> 30 000 yr BP). The diatom record from the lowlands indicates that a shallow, freshwater lake covered the area during the last 15 kyr. An episode of lower lake level followed by a trend towards slightly higher water level is recorded during late Pleistocene time (c. 14 000-11 600 yr BP). Relatively dry early Holocene conditions, followed by a recovery of the lake level after c. 5000 yr BP are recorded in the upper Lerma basin; this lake-level pattern is also recorded in the neigh-bouring Lake Chalco basin. Throughout these periods, emplacement of volcanic material resulted in changes to lake geometry and, in part, to lake levels. © 2001 by Blackwell Science Ltd. All rights reserved.
Entidades citadas de la UNAM:
ISBN:
9781444304251
Editorial:
Wiley-Blackwell Publishing Ltd Nombre de la publicación:
Late Pleistocene-Holocene Volcanic Stratigraphy and Palaeoenvironments of the Upper Lerma Basin, Mexico
Página inicial:
247
Página final:
261
