Neogene paleoenvironments of the South of the Marañon Basin (Peru) based on palynology of the La Frontera-1 Well

PARRA F.J.; M.M. DI PASQUO; R.E. NAVARRETE; Y. CALDERON; M. RODDAZ; P. BABY

Paraná

Simposio; XVII Simposio Argentino de Paleobotánica y Palinología; 2018

ALPP y UADER

Palynological study was carried out on selected intervals (ditch cu`ngs samples) from La Frontera-1well in the Marañon basin The aim was to determine the relaVve age and deposiVonal environmentof the secVon (ca. 3000 {). The samples are composed of grey to dark grey and brown shale,claystone and siltstone, with intercalaVons of medium-fine grained sandstone beds. The intervalssampled were sealed to avoid contaminaVons with overlying rocks. Assemblage zones in LaFrontera-1 well correspond to early Miocene to early Pliocene age supported by the occurrence ofkey species like Acaciapollenites myriosporites, Cistacearumpollenites rotundiporus, Corsinipollenitesoculusnoc0s, Crototricolpites annemariae, Crassore0triletes vanraadshooveni, Ctenolophiniditessuigeneris, Cyathidites congoensis, Deltoidospora adriennis, Foveotricolporites len0culoides,Ladakhipollenites? caribbiensis, Lanagiopolllis crassa, Malvacipolloides maristellae, Nijssenosporitesfossulatus, Osmundacidites ciliatus, Palaeosantalaceaepites cingulatus, Psilastephanoporitestesseroporus, Re0monocolpites maximus, Siltaria hammenii, S. santaisabelensis and dinoflagellatecysts such as Apteodinium australiense, Bosedinia infragranulata, and Quadrina? condita. Fourmarine incursions are first Vme documented in the Marañon basin by the presence of marinepalynomorphs such as the dinocysts Quadrina condita, Apteodinium australiense, Selenopemphixquanta, Bosedinia infragranulata and Ba0acasphaera spp., foram linings, Fusiformisporites (fungal)and pyriVzaVon of some palynomorphs. Other taxa such as Microthyraceae (fungal), Oedogonium,Prasinophycean (algae), Leiosphaeridia (algae-acritarch?) are related to terrestrial and marginalenvironments (e.g. man-groves), and marine normal condiVons. Apteodinium australiense seems tobe the first record in the early Miocene of South America and could indicate a migraVon route of thistaxon through the Caribbean.*Project supported by IRD and Paleosedes E.U.