Paleogene-Neogene astronomical timescale of a well-log from the western South Atlantic (Espírito Santo Basin)@en

Here we present natural gamma ray (NGR) measured continously through a well-log drilled at the western South Atlantic (Espirito Santo Basin) named ES-2. Biostratigraphic and sequence stratigraphic interpretation identify the well-log as a Paleogene to Neogene section bounded by global sequences Sel1 (Selandian) and Ser4/Tor1 (Serravalian/Tortonian). Within this interval a high-resolution cyclostratigraphic framework was conducted to build an astronomical time scale. The identification of the orbital spectral conented is made through null-hypothesis test, such as Average Spectral Misfit (ASM), Correlation Coefficient (COCO) and Time Optimization (TimeOpt). Integrated prediction error filter (INPEFA) is used to recognize main depositional sequences. When INPEFA is tuned to the high-resolution orbital age model a very coherent astronomical deposition is revealed forced by long (405-kyr) and short (~100-kyr) eccentricity and periods of obliquity (~41-kyr). Very long amplitude modulation (AM) of eccentricity and obliquity are identified. These set of orbital forcing likely appear as a result of sea-level fluctuation and determine the stacking pattern.