Cruz, Francisco W.
Santos, Roberto V.
Sawakuchi, Andre O.
Pessenda, Luiz C. R.
Novello, Valdir F.
Strauss, Andre M.
Borella, Ana Claudia
Strikis, Nicolas M.
Guedes, Carlos C. F.
Dias De Andrade, Fabio Ramos
[9, 10, 11]
Edwards, R. Lawrence
 Univ Sao Paulo, Inst Geociencias, Rua Lago 562, BR-05508090 Sao Paulo, SP - Brazil
 Univ Brasilia, Dept Geol, Brasilia, DF - Brazil
 Beijing Normal Univ, Interdisciplinary Res Ctr Earth Sci Frontier, Beijing - Peoples R China
 Univ Sao Paulo, 14C Lab, Piracicaba, SP - Brazil
 SUNY Albany, Dept Atmospher & Environm Sci, Albany, NY - USA
 Univ Sao Paulo, Museu Arqueol & Etnol, Sao Paulo, SP - Brazil
 Univ Fed Fluminense, Dept Geoquim, Niteroi, RJ - Brazil
 Univ Fed Parana, Dept Geol, Curitiba, Parana - Brazil
 Xi An Jiao Tong Univ, Inst Global Environm Change, Xian 710054 - Peoples R China
 Chinese Acad Sci, Inst Earth Environm, State Key Lab Loess & Quaternary Geol, Xian 710061 - Peoples R China
 Inst Karst Geol, Key Lab Karst Dynam, MLR, CAGS, Guilin 541004 - Peoples R China
 Univ Minnesota, Dept Earth Sci, Minneapolis, MN - USA
Total Affiliations: 12
QUATERNARY SCIENCE REVIEWS;
DEC 15 2020.
Web of Science Citations:
Changes in insolation driven by precession and obliquity are considered the major driver of tropical precipitation on orbital time scales, and responsible for vegetation and physical landscape changes during the Late Holocene over tropical South America. Here we investigate the environmental changes in the karst region of Chapada do Apodi - Northeastern Brazil (NEB), using a multi-proxy approach including carbon (delta C-13), oxygen (delta O-18) and strontium (Sr-87/Sr-86) isotopic analyses on speleothems from different caves, carbonate bedrock, and clastic cave deposits. This approach reveals that the balance between soil formation and erosion and their alternating impact on vegetation and precipitation changes occurred in response to variations in the position and intensity of the Intertropical Convergence Zone (ITCZ) over the region. The high delta C-13 and delta O-18 and low Sr-87/Sr-86 values at 4,200 yrs BP indicate a massive episode of soil erosion, resulting in the exposure of carbonate bedrocks over a large area of the karst terrain. This event marks the beginning of the Meghalayan chronozone, characterized as the aridification of this region, decline in soil production, drying out of underground drainages, and increased dominance of dry-adapted flora species, characteristic of a more open vegetation (caatinga). We investigated if the Holocene climatic changes affected human occupation in the NEB and found that the overall demographic course is virtually identical to the well-established curve characterized by population deflation during Middle Holocene. (C) 2020 Elsevier Ltd. All rights reserved. (AU)