Caracterização estratigráfica do preenchimento do vale inciso do Baixo Rio Doce durante o pleistoceno superior-holoceno

Abstract

Completion of the item is worth the Basin of the Lower Rio Doce, located in the city of Linhares - Espírito Santo, is analyzed through the integration of geological data for surface and subsurface, including the interpretation of satellite imagery, geophysical survey, borehole geophysics nine wells, a total of 1032.5 meters drilled, where he collected a total of 1037 samples and 22 dating performed by the method 14C and 21 luminescence. The interpretation was performed according to the concepts of sequence stratigraphy and variations in sea level in the Quaternary. Filling the valley item occurred in two phases, the lower portion of upper Pleistocene and Holocene. The excavation and filling Pleiscênicos, lower portion, is interpreted as the result of the penultimate regression (with your most regressive in 145,000 years AP), trenching, and penultimate transgression (120,000 years BP), filling the valley. During the transgression the sea level rose by two big swings down to its most regressive, about 120,000 years BP, when it reached about 4 meters above the present level. The final excavation of the valley began after the last transgression, when the relative sea level began to fall. While sea level fluctuations degrading passed through to reach its maximum regressive at 18,000 years BP, reaching 120 meters below the current level, generating an incision of about 100m depth on the Pleistocene sedimentation. With the end of the beginning of regression and transgression, the valley begins to fill. The relative sea level rises rapidly until about 7,000 years BP, when rising sea coast to reach the current level. There are about 5,600 years BP the sea level reached its maximum transgressive, reaching 5 meters higher than today. From this moment we have the origin of the system ilhas-barreiras/lagunas thus has initiated the formation of delta intralagunar. There are approximately 5,600 years BP the relative sea level begins to decline, through oscillations to reach the current level.