Investigating the role of differential biotic production on carbonate geometries through stratigraphic forward modelling and sensitivity analysis: the Llucmajor example

Abstract

The geometry of carbonate platforms reflects the interaction of several factors. However, the impact of carbonate producing organisms has been poorly investigated so far. This study applies stratigraphic forward modelling (SFM) and sensitivity analysis to examine, referenced to the Miocene Llucmajor platform, the effect on platform geometry of changes of the dominant biotic production in the oligophotic and euphotic zones. Our results show that the complex interplay of carbonate production rates, bathymetry and accommodation variation controls the platform geometry. The main driver of progradation is the oligophotic production of rhodalgal sediments during the lowstands. This study demonstrates that platform geometry and internal architecture varies significantly according to the interaction of the predominant carbonate producing biotas. The input parameters for this study are based on well-understood Miocene carbonate biotas with characteristic euphotic, oligophotic and photo-independent carbonate production in which it is crucial that each carbonate producing class is modelled explicitly within the simulation run and not averaged with a single carbonate production-depth profile. This is important in subsurface exploration studies based on stratigraphic forward models where the overall platform geometry may be approximated through calibration runs and constrained by seismic surveys and wellbores. However, the internal architecture is likely to be over-simplified, without an in-depth understanding of the target carbonate system and transfer to forward modelling parameters.

Reply to Comment by John J.G. Reijmer on ‘Understanding carbonate factories through palaeoecological and sedimentological signals – Tribute to Luis Pomar’ by Brandano et al. (2022), Sedimentology, 69, 5–23

“…This insightful concept of Pomar has been demonstrated to be crucial for different quantitative analyses of the complex interdependence between factory types, production profiles, inherited topography and resulting platform morphologies that are being explored through stratigraphic forward modelling approaches (i.e. Warrlich et al ., 2008; Williams et al ., 2011; Sultana et al ., 2022; Tella et al ., 2022).…”