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Quaternary ecological and geomorphic changes associated with rainfall events in presently semi‐arid northeastern Brazil
Author(s) -
Auler Augusto S.,
Wang Xianfeng,
Edwards R. Lawrence,
Cheng Hai,
Cristalli Patrícia S.,
Smart Peter L.,
Richards David A.
Publication year - 2004
Publication title -
journal of quaternary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.142
H-Index - 94
eISSN - 1099-1417
pISSN - 0267-8179
DOI - 10.1002/jqs.876
Subject(s) - megafauna , quaternary , vegetation (pathology) , arid , pleistocene , younger dryas , ecology , deciduous , fauna , arboreal locomotion , geology , holocene , sclerophyll , geography , physical geography , archaeology , paleontology , mediterranean climate , medicine , pathology , biology , habitat
Abstract Several geomorphic features and palaeobiotic remains in now semi‐arid northeastern Brazil indicate major palaeoenvironmental changes during past periods of increased rainfall. 230 Th mass spectrometric ages of speleothems and travertines have allowed the determination of the timing and duration of wetter than present conditions. The data demonstrate that wet events have occurred throughout much of the Pleistocene, present dry conditions having been established at the end of the Younger Dryas. A markedly different fauna comprising megafaunal elements not adapted to the present low arboreal scrubland caatinga vegetation existed in the area. Palaeobotanical remains embedded in travertine indicate forested vegetation at these wetter intervals, suggesting that the caatinga was then replaced or mixed with a semi‐deciduous forest. Due to the abundance of travertine sites containing fossil botanical remains in northeastern Brazil, it is believed that forest expansion occurred over large areas of the now semi‐arid zone, showing that the long hypothesised forested links between biodiversity‐rich Amazon and Atlantic rainforests may indeed have existed during these moister phases. Copyright © 2004 John Wiley & Sons, Ltd.