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Pollen analyses from a 50 000-yr rodent midden series in the southern Atacama Desert (25° 300' S)

Journal of Quaternary Science

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Abstract

Precipitation in northern Chile is controlled by two great wind belts—the southern westerlies over the southern Atacama and points south (>24° S) and the tropical easterlies over the northern and central Atacama Desert (16–24° S). At the intersection of these summer and winter rainfall regimes, respectively, is a Mars-like landscape consisting of expansive surfaces devoid of vegetation (i.e. absolute desert) except in canyons that originate high enough to experience runoff once every few years. Pollen assemblages from 39 fossil rodent middens in one of these canyons, Quebrada del Chaco (25° 30' S), were used to infer the history of vegetation and precipitation at three elevations (2670–800 m; 3100–3200 m; 3450–3500 m) over the past 50 000 years. When compared to modern conditions and fossil records to the north and south, the pollen evidence indicates more winter precipitation at >52, 40–33, 24–17 k cal.yrBP, more precipitation in both seasons at 17–14 k cal. yr BP, and more summer precipitation from 14–11 k cal. yr BP. Younger middens are scarce at Quebrada del Chaco, and the few Holocene samples indicate hyperarid conditions comparable to today. The only exception is a pollen assemblage that indicates a brief but significant interlude of increased winter precipitation in the last millennium.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Pollen analyses from a 50 000-yr rodent midden series in the southern Atacama Desert (25° 300' S)
Series title:
Journal of Quaternary Science
Volume
20
Issue:
5
Year Published:
2005
Language:
English
Publisher:
Wiley
Publisher location:
Hoboken, NJ
Contributing office(s):
Branch of Regional Research-Western Region
Description:
15 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Quaternary Science
First page:
493
Last page:
507
Country:
Chile
Other Geospatial:
Atacama Desert