On the peritidal cycles and their diagenetic evolution in the Lower Jurassic carbonates of the Calcare Massiccio Formation (Central Apennines)

Abstract

This paper shows the environmental changes and high-frequency cyclicity recorded by Lower Jurassic shallow-water carbonates known as the Calcare Massiccio Formation which crop out in the central Apennines of Italy. Three types of sedimentary cycle bounded by subaerial erosion have been recognized: Type I consists of a shallowing upward cycle with oncoidal floatstones to rudstones passing gradationally up into peloidal packstone alternating with cryptoalgal laminites and often bounded by desiccation cracks and pisolitic-peloidal wackestones indicating a period of subaerial exposure. Type II shows a symmetrical trend in terms of facies arrangement with peloidal packstones and cryptoalgal laminites present both at the base and in the upper portion of the cycle, separated by oncoidal floatstones to rudstones. Type III displays a shallowing upward trend with an initial erosion surface overlain by oncoidal floatstones to rudstones that, in turn, are capped by pisolitic-peloidal wackestones and desiccation sheet cracks. Sheet cracks at the top of cycles formed during the initial phase of subaerial exposure were successively enlarged by dissolution during prolonged subaerial exposure. The following sea-level fall produced dissolution cavities in subtidal facies, while the successive sea-level rise resulted in the precipitation of marine cements in dissolution cavities. Spectral analysis revealed six peaks, five of which are consistent with orbital cycles. While a tectonic control cannot be disregarded, the main signal recorded by the sedimentary succession points toward a main control related to orbital forcing. High frequency sea-level fluctuations also controlled diagenetic processes.

Orbital cycles, differential subsidence and internal factors controlling the high-frequency sequence architecture in a Sinemurian shallow carbonate platform (Mallorca island, Spain)

“…The overall vertical facies distribution of the peritidal to shallow subtidal platform carbonates of the early Sinemurian to earliest late Sinemurian Stage-1 of the Es Barraca Member reflects a long-term transgressive (deepening) trend followed by a short time duration of large-scale sequences would be close to that of the long eccentricity cycles (~400 kyr) and, based on the observed mean 1:4 relationship of the large-and medium-scale sequences (e.g., Strasser et al, 2006), the medium-scale sequences would fit the short eccentricity (~100 kyr) cycles. Eccentricity-related sequences in the greenhouse Jurassic climate mode recorded in similar Jurassic shallow-platform successions have been interpreted as reflecting climate-driven, low amplitude sea-level variations (e.g., Crevello, 1991;Strasser et al, 1999;Aurell and Bádenas, 2004;Colombié and Strasser, 2005;Brandano et al, 2015;Pomoni-Papaioannou and Karakitsios, 2016;Strasser, 2018). In particular, in the Lower Jurassic successions of the High Atlas Crevello (1991) recognized bundles of elementary cycles, similar to the medium-scale sequences proposed here, which were driven by short eccentricity-related sea-level variations with amplitude of around 5 m. In the Apennines, Brandano et al (2015) also recognized superbundles and bundles of elementary cycles, similar to the large-and medium-scale sequences described here (Table 2).…”

“…Eccentricity-related sequences in the greenhouse Jurassic climate mode recorded in similar Jurassic shallow-platform successions have been interpreted as reflecting climate-driven, low amplitude sea-level variations (e.g., Crevello, 1991;Strasser et al, 1999;Aurell and Bádenas, 2004;Colombié and Strasser, 2005;Brandano et al, 2015;Pomoni-Papaioannou and Karakitsios, 2016;Strasser, 2018). In particular, in the Lower Jurassic successions of the High Atlas Crevello (1991) recognized bundles of elementary cycles, similar to the medium-scale sequences proposed here, which were driven by short eccentricity-related sea-level variations with amplitude of around 5 m. In the Apennines, Brandano et al (2015) also recognized superbundles and bundles of elementary cycles, similar to the large-and medium-scale sequences described here (Table 2).…”

“…The Lower Jurassic peritidal to shallow marine carbonate platform successions developed around the western Tethys usually display a hierarchical stacking of highfrequency depositional sequences that have been related to allocyclic and/or autocyclic mechanisms. In most of these platforms, a combination of factors controlling the cyclicity and the internal facies stacking has been suggested: orbital-driven sea-level changes, local or regional tectonic subsidence, and variations in local sediment supply and tidal flat progradation (Crevello, 1990(Crevello, , 1991Walkden and De Matos, 2000;Bosence et al, 2000Bosence et al, , 2009Pomoni-Papaioannou and Kostopoulou, 2008;Pomoni-Papaioannou and Karakitsios, 2016;Bádenas et al, 2010;Aurell and Bádenas, 2015;Brandano et al, 2015;Belkhedim et al, 2019). Similar high-frequency depositional sequences have been described in the Sinemurian shallow platform successions of Mallorca (Es Barraca Member, Balearic Islands, Spain) (Barnolas and Simó, 1984;Sevillano et al, 2013).…”

“…described in other Lower Jurassic peritidal and shallow carbonate platforms of the western Tethys (Iberian and Betic Ranges, Spain, Bosence et al 2000, 2009, Bádenas et Journal Pre-proof J o u r n a l P r e -p r o o f 26 al. 2010; High Atlas, Morocco, Crevello 1991; Central Apennines, Italy,Brandano et al 2015; Central western Creta; Greece, Pomoni-Papaioannou andKostopoulou, 2008, Pomoni-Papaioannou andKarakitsios, 2016; Dorsales, Tunisia, Bosence et al, 2009; …”