%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Jaillard, Etienne
%A Bengtson, P.
%A Ordonez, M.
%A Vaca, W.
%A Dhondt, A.
%A Suarez, J.
%A Toro, J.
%T Sedimentary record of terminal Cretaceous accretions in Ecuador : the Yunguilla Group in the Cuenca area
%D 2008
%L fdi:010042546
%G ENG
%J Journal of South American Earth Sciences
%@ 0895-9811
%K Ecuador ; latest Cretaceous ; Paleocene ; accretions ; uplift ; clastic sedimentation
%M CC:0002550824-0001
%N 2
%P 133-144
%R 10.1016/j.jsames.2007.08.002
%U https://www.documentation.ird.fr/hor/fdi:010042546
%> https://www.documentation.ird.fr/intranet/publi/2008/05/010042546.pdf
%V 25
%W Horizon (IRD)
%X A reappraisal of the "Late Cretaceous Yunguilla Formation" of the Cuenca area enables the definition of four distinct formations, correlatable with those of southwestern Ecuador. A mid- to late-Campanian marine transgression (Jadan Formation) is overlain by quartz-rich conglomerates of fan-delta to turbiditic fan environment (Quimas Formation) of latest Campanian-earliest Maastrichtian age, which Lire interpreted as evidence of the accretion of a first oceanic terrane (San Juan). Disconformable, arkosic turbidites and cherts (Tabacay Formation) of early Maastrichtian age are thought to represent the erosion of the newly accreted oceanic terrane. A major unconformity of late Maastrichtian age, caused by the accretion of a second oceanic terrane (Guaranda), is followed by the deposition of quartz-rich micaceous shelf sandstones (Saquisili Formation) of Paleocene age. A third accretion event (late Paleocene) is recorded in coastal Ecuador. Each accretion event correlates with the uplift and erosion of the Eastern Cordillera and with a sedimentary hiatus in the eastern areas. In Ecuador, accretion of oceanic terranes contributed to the build up of the Andes through tectonic underplating of low-density material, and the eastern areas did not behave as flexural foreland basins during late Cretaceous-Paleogene times.
%$ 064