Amazon forest dynamics under changing abiotic conditions in the early Miocene (Colombian Amazonia)
Salamanca Villegas, S.; van Soelen, E.; Teunissen van Manen, M.L.; Flantua, S.G.A.; Santos, R.V.; Roddaz, M.; Dantas, E.L.; van Loon, E.; Sinninghe Damsté, J.S.; Kim, J.-H.; Hoorn, C. (2016). Amazon forest dynamics under changing abiotic conditions in the early Miocene (Colombian Amazonia). J. Biogeogr. 43(12): 2424–2437. dx.doi.org/10.1111/jbi.12769 In: Journal of Biogeography. Wiley-Blackwell: Oxford. ISSN 0305-0270; e-ISSN 1365-2699, more |  |
| Author keywords | Andean uplift; constrained hierarchical clustering; lipid biomarkers; marine incursion; Mauritia swamp; Miocene; non-metric multidimensional scaling; Orinoco; palynology; provenance |
| Authors | | Top | - Salamanca Villegas, S.
- van Soelen, E., more
- Teunissen van Manen, M.L.
- Flantua, S.G.A.
| - Santos, R.V.
- Roddaz, M.
- Dantas, E.L.
- van Loon, E.
| - Sinninghe Damsté, J.S., more
- Kim, J.-H., more
- Hoorn, C.
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| Abstract | Aim We analysed in detail a past marine incursion event in north-westernAmazonia and measured its effect on the forest composition. We also deter-mined the sediment provenance in the ?uvio-estuarine system and recon-structed the overall ?oral composition of the Amazon lowland forest duringthe Miocene climatic optimum.Location A 60-m-thick sedimentary succession situated along the Caquet?aRiver in Colombian Amazonia (0.77° S; 71.97° W).Methods Palynological, geochemical and statistical analyses were performedon samples from organic-rich sediments.Results The lower section was formed by ?uvial ?oodplain deposits of Andeanprovenance rich in pollen of Malvacipolloides maristellae (aff. Abutilon) andRhoipites guianensis (aff. Vasivaea). The middle section was formed by ?uvialchannel and estuarine swamp deposits of central Venezuelan provenance domi-nated by pollen of Mauritiidites franciscoi (Mauritia). Towards the top, theswamp deposits represent an estuarine ?oodplain with aquatic biomarkers,marine palynomorphs and mangrove pollen. The succession ended with ?uvial?oodplain deposits of central to southern Venezuelan origin with R. guianensisas dominant pollen type. Palynological diversity was high throughout the sec-tion with Andean- and Venezuelan-derived sediments each with their charac-teristic taxa. Tropical rain forest taxa, such as Arecaceae, Fabaceae, Sapotaceae,Malpighiaceae and Bombacoideae, were common in these sediments, althoughtaxa adapted to drier conditions also occurred. We provide a ‘?gshare’ link toan image library of selected taxa, as well as the raw counts and processed data.Main conclusions The ?uvio-estuarine system was of mixed origin with sedi-ments and palynomorphs from the emerging Andes, but also from an area sit-uated in the modern Orinoco Basin. Marine in?uence was linked to theVenezuelan source area and thus of indisputable Caribbean origin. Overall, amixed forest with drought-resistant components existed in the drainage systemduring the Miocene climatic optimum. Our data provide a novel insight intothe composition of the tropical lowland forest and the environments in north-western Amazonia prior to the main uplift of the central and northern Andes |
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