High-frequency, moderate to high-amplitude sea-level oscillations during the late Early Aptian: Insights into the Mid-Aptian event (Galve sub-basin, Spain)

Abstract

This paper presents a field-based stratigraphic architecture research from the Aptian of Spain in which high-frequency (7cycles/Ma), moderate to high-amplitude (8–127m) sea-level oscillations are evidenced by the repeated incision of palaeovalleys in a carbonate platform developed during the late Early Aptian in a rift setting. Global eustacy, tectonic uplift and mantle dynamic topography are considered as potential mechanisms to explain the observed relative sea-level record. Glacioeustacy is interpreted as the most reliable mechanism to drive the observed sea-level oscillations, however, other mechanisms as oscillations of the groundwater capacity of sedimentary basins and sudden flooding of major a basin as the south Atlantic rift are also considered. A major cooling event is proposed to occur during the late Early Aptian as a response to a large-scale episode of ignimbritic volcanism, increased burial of organic carbon during the Aptian OAE-1a, and a significant demise of carbonate platforms. This cooling event is interpreted as the origin for glacioeustatic sea-level oscillations during the Mid-Aptian.