Precisiones estratigráficas sobre el Neógeno de la cuenca de Azua (República Dominicana)

Abstract

The Azua basin is located at the eastern end of the Hispaniola Neogene basins, which had a marked shallowing and coarsening upwards history, evolving from deep marine conditions in Early Miocene time, to continental environments in Upper Pliocene. This evolution was conditioned directly by the uplift and advance of the Cordillera Central over the Azua basin, providing a great contribution of terrigenous deposits and the restriction of basin surface, with inicial basin division, forming the Enriquillo and San Juan-Azua basins during Pliocene time. Int this setting, the Azua sector exhibits some peculiar features caused by its marginal location and geodynamic processes from Upper Pliocene time onwards. The Neogene section is composed of the following formations: Sombrerito (Miocene), not outcroping; Trinchera (Upper Miocene-Pliocene) deposited under deltaic influence; Quita Coraza (Pliocene), showing a bay context; Arroyo Blanco (Pliocene) developed in connection with littoral and alluvial environments; and Arroyo Seco/Vía (Pliocene-Pleistocene), deposited in continental ambits. The Miocene outcrops surrounding the Ocoa bay are the consequence of allochthonous processes of several hundred kilometres, which should be treated separately from the autochthonous series.