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3 resultados encontrados para: AUTOR: Mueller, Andreas D
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1.
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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.


Resumen en: Inglés |
Resumen en inglés

We employed paleolimnological methods to investigate tropical forest recovery and soil stabilization that followed abandonment of agricultural systems associated with disintegration of Classic Maya polities ca. A.D. 800–1000. We used lithological, geochemical, magnetic, and palynological data from sediment cores of Lake Petén Itzá in the Maya Lowlands of northern Guatemala. Sediment core chronology was developed using radiocarbon dates on terrestrial wood and charcoal fragments. Our results indicate that in the absence of large human populations and extensive farming activities, Petén forests recovered under humid climate conditions within a span of 80–260 yr. Soil stabilization postdates pollen evidence of forest regrowth stratigraphically, and required between 120 and 280 yr. We conclude that the tropical forest ecosystem in the watershed of Lake Petén Itzá had been reestablished by the early Postclassic Period (A.D. 1000–1200).


3.
Artículo
Resumen en: Inglés |
Resumen en inglés

Palynological studies document forest disappearance during the late Holocene in the tropical Maya lowlands of northern Guatemala. The question remains as to whether this vegetation change was driven exclusively by anthropogenic deforestation, as previously suggested, or whether it was partly attributable to climate changes. We report multiple palaeoclimate and palaeoenvironment proxies (pollen, geochemical, sedimentological) from sediment cores collected in Lake Petén Itzá, northern Guatemala. Our data indicate that the earliest phase of late Holocene tropical forest reduction in this area started at not, vert, similar 4500 cal yr BP, simultaneous with the onset of a circum-Caribbean drying trend that lasted for not, vert, similar 1500 yr. This forest decline preceded the appearance of anthropogenically associated Zea mays pollen. We conclude that vegetation changes in Petén during the period from not, vert, similar 4500 to not, vert, similar 3000 cal yr BP were largely a consequence of dry climate conditions. Furthermore, palaeoclimate data from low latitudes in North Africa point to teleconnective linkages of this drying trend on both sides of the Atlantic Ocean.