The Odivelas Limestone: evidence for a Middle Devonian reef system in western Ossa-Morena Zone (Portugal)

Abstract

Abstract:The Odivelas Limestone constitutes one of the few records of Middle Devonian sedimentation in the western Ossa-Morena Zone. Although deformed and metamorphosed the limestones have an abundant fossil content which allows their positioning as late Eifelian/early Givetian in age and to relate the reef fauna with the typical Rhenish facies for the same time period. Magnetic susceptibility analysis was attempted and is in agreement with the biostratigraphy, but the limited extent of sections and the metamorphism precludes firm correlations. The field evidence, petrographic and geochemical analysis point to a close paleogeographical relation and dependence of the reef system on volcanic structures which are included in the Beja Igneous Complex. The age of part of the volcanic and sub-volcanic suite of this complex is thus constrained.

Application of magnetic susceptibility as a paleoclimatic proxy on Paleozoic sedimentary rocks and characterization of the magnetic signal – IGCP-580 projects and events

“…First results were published in high quality peer reviewed publications and were mostly related to the application of MS, with a focus on the impact of sea-level variations and depositional setting on MS signal from the Devonian from Belgium (Da Silva et al, 2009a) and Canada (Da Silva et al, 2009b); on the influence of atmospheric dust during the punctata conodont Zone interval in the Czech Republic (Hladil et al, 2009) and on the influence of volcanic admixture on the MS signal from Devonian carbonates in Portugal (Machado et al, 2009).…”

The multistage crystallization of zircon in calc-alkaline granitoids: U–Pb age constraints on the timing of Variscan tectonic activity in SW Iberia

“…As a result, Gondwana continental margin experienced extensional tectonics that led to the opening of the Rheic Ocean through the Ordovician-Silurian and Lower Devonian Gutierrez-Marco 1990, 2004;Linnemann et al 2008). Carboniferous syn-orogenic sedimentary and bimodal volcanic rocks are well preserved in the OssaMorena Zone, and there are some outcrops of mid-upper Devonian sedimentary rocks that may represent or not olistoliths within the Carboniferous turbidites (Pereira et al 2006(Pereira et al , 2012aMachado et al 2009). …”

Prasinophyte bloom and putative fungi abundance near the Kačák event (Middle Devonian) from the Odivelas Limestone, Southwest Iberia

“…In the SW domains of the OMZ, plutonic and volcanic rocks cover vast areas, ranging from Emsian to Pennsylvanian (Andrade et al 1976;Fonseca et al 1999;Jesus et al 2003;Jesus et al 2007Jesus et al , 2016Pin et al 2008;Ribeiro et al 2010;Moreira et al 2010Moreira et al , 2014 and constitute the Beja Igneous Complex (BIC). Within the BIC, sedimentary rocks are scarce, with the notable exception of geographically restricted reefal and peri-reefal limestone occurrences-the Odivelas Limestone (Conde and Andrade 1974;Machado et al 2009Moreira et al 2010;Oliveira et al 2019). These have been dated as latest Early to Middle Devonian using corals, crinoids, and conodonts (Boogaard 1973;Machado et al 2009.…”

“…Within the BIC, sedimentary rocks are scarce, with the notable exception of geographically restricted reefal and peri-reefal limestone occurrences-the Odivelas Limestone (Conde and Andrade 1974;Machado et al 2009Moreira et al 2010;Oliveira et al 2019). These have been dated as latest Early to Middle Devonian using corals, crinoids, and conodonts (Boogaard 1973;Machado et al 2009. This is one of the few areas where Middle Devonian sedimentation is recorded in the OMZ Gutiérrez-Marco 1990, 2004;Oliveira et al 1991Oliveira et al , 2019.…”