%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Louterbach, M.
%A Roddaz, M.
%A Bailleul, J.
%A Antoine, P. O.
%A Adnet, S.
%A Kim, J. H.
%A van Soelen, E.
%A Parra, F.
%A Gerard, J.
%A Calderon, Y.
%A Gagnaison, C.
%A Damste, J. S. S.
%A Baby, Patrice
%T Evidences for a Paleocene marine incursion in southern Amazonia (Madre de Dios Sub-Andean Zone, Peru) [plus corrigendum]
%D 2014
%L fdi:010062987
%G ENG
%J Palaeogeography Palaeoclimatology Palaeoecology
%@ 0031-0182
%K Paleogene ; Marine incursion ; Amazonian foreland basin ; Tidal deposits ; Madre de Dios basin ; Peru
%K PEROU ; AMAZONIE
%M ISI:000345202500037
%P 451-471 + corrigendum vol. 418,  386
%R 10.1016/j.palaeo.2014.09.027
%U https://www.documentation.ird.fr/hor/fdi:010062987
%> https://www.documentation.ird.fr/intranet/publi/depot/2015-05-05/010062987.pdf
%V 414
%W Horizon (IRD)
%X This article presents new biostratigraphic dating, facies analysis, organic geochemical data and Nd-Sr isotopic provenance from five outcrops of southern Amazonia (MD-85, MD-177 MD-184, MD-255 and MD-256) to document for the first time the presence of a shallow marine ingression in the Paleocene of southern Amazonia basin. The co-occurrence of a selachian assemblage encompassing Potobatis sp., Ouledia sp., and Pristidae indet with the ostracod Protobuntonia sp. and the charophytes Peckichara cf. varians meridionalis, Platychara perlata, and Feistiella cf. gildemeisteri suggests a Paleocene age for the studied deposits (most likely Thanetian but potentially Danian). Fifteen fades have been recognized and have been grouped into three facies assemblages. Facies association A corresponds to the sedimentary filling of a tide-influenced meandering channel formed in the fluvial-tidal transition zone. Facies association B is related to more distal tidal-flats, little channelized tidal inlets and saltmarsh deposits. Facies association C corresponds to a stressed shallow marine environment such as a bay or a lagoon. The delta C-13(TOC) value (- 23.4%) of MD-184 is enriched in C-13 compared to the other samples suggesting the presence of substantial amounts of marine organic matter in MD-184. The delta C-13(TOC) values of samples from other outcrops ( - 27.3 to - 29.8%) indicate a mixed organic matter origin, from terrestrial to brackish environments. The analyzed sediments have similar Nd-Sr isotopic compositions as those of the Cenozoic sediments of the Altiplano (epsilon Nd(0) values from - 6.2 to - 10.7 and Sr-87/Sr-86 compositions from 0.712024 to 0.719026) indicating a similar volcanic source. This multidisciplinary dataset documents the presence of a tide-dominated estuary sourced by the proto-Westem Cordillera debouching into a shallow marine bay during Paleocene times. This transgression might be explained by subsidence created in response to the proto-Western Cordillera loading. Similar to Miocene marine incursions affecting the Pebas megawetland, Paleogene marine incursions in the Amazonian foreland basin associated with Andean uplift may have played a role in the Neotropical biodiversity dynamics in favoring biogeographical isolation and promoting allopatric speciation for terrestrial organisms.
%$ 064