Comparative geochemistry of Early Carboniferous marine red beds (MRBs) and their significance for deep time paleoceanographic reconstructions

Marine red beds (MRBs), also known as oceanic (ORBs), are reddish colored sediments deposited within the marine realm that have been stained during deposition and/or early diagenesis because of changes in ocean water chemistry response to paleoceanographic and paleoclimatological factors. Although common throughout Phanerozoic, mostly investigated Upper Cretaceous successions CORBs (Cretaceous Oceanic Red Beds) - their occurrence context Paleozoic has yet be studied detail. Here we describe interpret high-resolution litho- chemofacies Early Carboniferous (Late Viséan) from northern coast Menorca (Balearic Islands, Spain) mark a rapid transition siliceous radiolarian chert re-worked carbonate debrites followed by typical European Culm facies. The succession was strait-like narrow basin formed part Alboran-Kabylian-Peloritan-Calabrian terrane Western Paleotethys Ocean prior onset Variscan Orogeny. bed geochemistry is described terms three geochemical endmembers Al-MRBs (clayey), Ca-MRBs (calcareous) Si-MRBs (siliceous) using XRF-derived Al2O3, CaO, SiO2 concentrations. This study finds Viséan predominantly with subordinate Ca-MRBs. Furthermore, compare bulk rock this data Paleozoic, Mesozoic Cenozoic available existing literature (Cambrian, Silurian, Jurassic, Cretaceous, Paleogene recent Pacific clays) highlight significance occurrences relation (paleo-)bioproductivity fluctuations, deep-water oxygenation redox transitions. Phanerozoic dominantly Ca-MRBs, whilst less common. present were distal, deeper-marine environment under oxic-suboxic, oligotrophic conditions. A lack any significant Fe2O3T enrichment points towards more complex diagenetic process for origin color imparted MRBs.