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| Titel |
Climatic variability and human impact during the last 2000 years in western Mesoamerica: evidence of late Classic (AD 600–900) and Little Ice Age drought events |
| VerfasserIn |
A. Rodríguez-Ramírez, M. Caballero, P. Roy, B. Ortega, G. Vázquez-Castro, S. Lozano-García |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 11, no. 9 ; Nr. 11, no. 9 (2015-09-30), S.1239-1248 |
| Datensatznummer |
250117407
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| Publikation (Nr.) |
 copernicus.org/cp-11-1239-2015.pdf |
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| Zusammenfassung |
| We present results of analysis of biological (diatoms and ostracodes) and
non-biological (Ti, Ca / Ti, total inorganic carbon, magnetic
susceptibility) variables from an 8.8 m long, high-resolution (~ 20 yr sample−1)
laminated sediment sequence from Lake Santa María del Oro
(SMO), western Mexico. This lake lies at a sensitive location between the dry
climates of northern Mexico, under the influence of the North Pacific subtropical
high-pressure cell and the moister climates of central Mexico, under
the influence of the seasonal migration of the intertropical convergence zone
and the North American monsoon (NAM). The sequence covers the last 2000 years
and provides evidence of two periods of human impact in the catchment, shown
by increases in the diatom Achnanthidium minutissimum. The first
from AD 100 to 400 (Early Classic) is related to the shaft and chamber tombs
cultural tradition in western Mexico, and the second is related to
Post-Classic occupation from AD 1100 to 1300. Both periods correspond to
relatively wet conditions. Three dry intervals are identified from increased
carbonate and the presence of ostracodes and aerophilous Eolimna
minima. The first, from AD 500 to 1000 (most intense during the late
Classic, from AD 600 to 800), correlates with the end of the shaft and
chamber tradition in western Mexico after ca. AD 600. This late Classic dry
period is the most important climatic signal in the Mesoamerican region
during the last 2000 years, and has been recorded at several sites from
Yucatan to the Pacific coast. In the Yucatan area, this dry interval has been
related with the demise of the Maya culture at the end of the Classic (AD 850
to 950). The last two dry events (AD 1400 to 1550 and 1690 to 1770)
correspond with the onset of, and the late, Little Ice Age, and follow largely the
Spörer and Maunder minima in solar radiation. The first of these
intervals (AD 1400 to 1550) shows the most intense signal over western
Mexico; however this pattern is different at other sites. Dry/wet intervals
in the SMO record are related with lower/higher intensity of the NAM over
this region, respectively. |
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