Abstract
Stalagmite data from Anjohibe Cave in northwest Madagascar suggest six distinct climate periods from 9.1 to 0.94 ka. Periods I and II (9.1–4.9 ka) were wetter and punctuated by a series of prominent droughts. Periods IV-VI (4–0.94 ka) were much drier and less variable. Period III (4.9-4 ka) marks the transition between wetter and drier conditions and consists of two significant droughts: the first (4.8–4.6 ka) coincides approximately with the end of the African Humid Period and the second (4.3–4.0 ka) may be the expression of the Northern Hemisphere 4.2 ka dry event in northwest Madagascar. Strong positive correlations between δ 13 C and δ 18 O values in Periods I-IV (r = 0.63–0.91) suggest that both isotopes were influenced by natural climate changes indicating that humans may not have been present in the area. In contrast, during Periods V (r = 0.07) and VI (r = −0.12) the “decoupling” of δ 13 C and δ 18 O might signal an impact from human activities starting around 2.5 ka. Rapid changes in climate during the early and middle Holocene, with prominent droughts lasting up to 800 years, did not kill off Madagascar's megafauna, and neither did a human population, present since the early Holocene if evidence from south Madagascar is reliable. However, many extinctions occurred under the more stable climatic conditions of the late Holocene, despite an antiphase climate relationship between northern and southcentral Madagascar. This suggests that initial human colonization, or significant increase in human population, triggered the megafaunal extinctions by hunting and destruction of megafaunal habitats.
Original language | English (US) |
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Pages (from-to) | 136-153 |
Number of pages | 18 |
Journal | Quaternary Science Reviews |
Volume | 210 |
DOIs | |
State | Published - Apr 15 2019 |
Bibliographical note
Funding Information:This research was supported by NOAA grant NA56GP0325 (Brook, Railsback, Thill and Meltzer), NSF grants 8912046 (Brook, Burney and Cowart) and 9908415 (Brook and Railsback), and NSFC grant 41888101 (Cheng). We thank the government and people of Madagascar for their assistance in making this work possible. Fieldwork in Madagascar was carried out under the auspices of the Cenozoic Research Group, a Malagasy-American collaboration sanctioned by the Service de Paléontologie and the Musée d'Art et d'Archéologie of the Université d'Antananarivo.
Funding Information:
This research was supported by NOAA grant NA56GP0325 (Brook, Railsback, Thill and Meltzer), NSF grants 8912046 (Brook, Burney and Cowart) and 9908415 (Brook and Railsback), and NSFC grant 41888101 (Cheng). We thank the government and people of Madagascar for their assistance in making this work possible. Fieldwork in Madagascar was carried out under the auspices of the Cenozoic Research Group, a Malagasy-American collaboration sanctioned by the Service de Paléontologie and the Musée d’Art et d’Archéologie of the Université d’Antananarivo.
Publisher Copyright:
© 2019 Elsevier Ltd
Keywords
- Holocene
- Human colonization
- Megafaunal extinction
- Paleoclimatology
- Southern hemisphere
- Stalagmite