Vegetation history along the eastern, desert escarpment of the Sierra San Pedro Mártir, Baja California, Mexico

Quaternary Research
By: , and 

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Abstract

Plant macrofossils from 38 packrat middens spanning the last ~ 33,000 cal yr BP record vegetation between ~ 650 and 900 m elevation along the eastern escarpment of the Sierra San Pedro Mártir, northern Baja California. The middens span most of the Holocene, with a gap between ~ 4600 and 1800 cal yr BP, but coverage in the Pleistocene is uneven with a larger hiatus between 23,100 and 14,400 cal yr BP. The midden flora is relatively stable from the Pleistocene to Holocene. Exceptions include Pinus californiarum, Juniperus californica and other chaparral elements that were most abundant > 23,100 cal yr BP and declined after 14,400 cal yr BP. Despite being near the chaparral/woodland-desertscrub ecotone during glacial times, the midden assemblages reflect none of the climatic reversals evident in the glacial or marine record, and this is corroborated by a nearby semi-continuous pollen stratigraphy from lake sediments. Regular appearance of C4 grasses and summer-flowering annuals since 13,600 cal yr BP indicates occurrence of summer rainfall equivalent to modern (JAS average of ~ 80–90 mm). This casts doubt on the claim, based on temperature proxies from marine sediments in the Guaymas Basin, that monsoonal development in the northern Gulf and Arizona was delayed until after 6200 cal yr BP.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Vegetation history along the eastern, desert escarpment of the Sierra San Pedro Mártir, Baja California, Mexico
Series title Quaternary Research
DOI 10.1016/j.yqres.2011.01.008
Volume 75
Issue 3
Year Published 2011
Language English
Publisher Cambridge University Press
Contributing office(s) Branch of Regional Research-Western Region
Description 11 p.
First page 647
Last page 657
Country Mexico
Other Geospatial Baja California, Sierra San Pedro Mártir