ap s ri uchy c c CR2P, UMR 7207, Sorbonne Universités -MNHN, CNRS, UPM a r t i c l e i n f o
Received 14 August 2014
Received in revised form 7 March 2015
Accepted 19 March 2015
Available online 9 April 2015 and fluidisation processes. Their superimposition explains the vuggy and boxwork-like textures, in situ brecciaferent types of carbonironmental conditions from primary carbonditions that have been pigenetic transformaPalaeogeography, Palaeoclimatology, Palaeoecology 429 (2015) 136–162
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Palaeogeography, Palaeocli e lscomplexes that were widely distributed along the margins of the Mediterranean Basin before the onset of the MSC, as well as to stromatolitic and ooid-bearing carbonates belonging to the Terminal Carbonate tions controlled by bio-geochemical processes. The best occurrences can be observed in Sicily and Calabria where these carbonates are classically distinguished into two major groups, i.e. the “Calcare di Base”1. Introduction
Various types of carbonate deposits formed in the Mediterranean
Basin, before, during and near the end of the Messinian Salinity Crisis (MSC). They mostly correspond to carbonate platforms and coral reef et al., 2010). This paper deals with completely dif ate deposits, which are directly linked to the env of the salinity crisis itself. Their formation results ate and evaporite precipitation in hypersaline con affected by a multistaged set of diagenetic and etion and lateral displacement, which are responsible for the chaotic organisation without necessarily involving basin-scale re-sedimentation in the form of debris flows. © 2015 Elsevier B.V. All rights reserved.Complex unit (Rouchy and Saint-Martin, 1992 ⁎ Corresponding author at: Università degli Studi di Pale
Palermo, Italy. Tel.: +39 09123864621.
E-mail address: email@example.com (A. Caruso). http://dx.doi.org/10.1016/j.palaeo.2015.03.035 0031-0182/© 2015 Elsevier B.V. All rights reserved.fibrous silica, anhydrite, secondary gypsum, and native sulphur. The initial accumulation of fine-grained carbonate and gypsum sedimentswas strongly destabilised by volumetric changes resulting frommineral replacementsKeywords:
Messinian Salinity Crisis
Calcare di Base
Bacterial sulphate reductionMarie Curie, 4 Place Jussieu, 75252 ParisCedex 05, France
C-Paris 6, Muséum national d'histoire naturelle, 57 rue Cuvier, CP 48, F-75005, Paris, France a b s t r a c t
The depositional and diagenetic processes involved in the formation of carbonates in the evaporitic environment of the Messinian Salinity Crisis are investigated in Southern Italy (Sicily and Calabria). Strong differences are observed between the studied sections that reflect specific depositional and diagenetic evolution in the interconnected sub-basins resulting from the syn-sedimentary tectonic fragmentation of the Central Sicilian and
Calabrian domains. These carbonates formed diachronously in restricted perched sub-basins between the Tripoli
Formation and the hypersaline settings of the MSC. The Calcare di Base (CdB) that can be interbedded with gypsum layers occurs rhythmically at the transition between the upper part of the Tripoli Formation and themassive gypsum, and at places synchronously with the deposition of the Lower Gypsum unit. It deposited initially as primary peloidal and microbial limestones, but their original structure and mineral composition were modified by the superimposition of early to late diagenetic processes. The first diagenetic step was the development of interstitially grown gypsum and halite crystals from trapped saturated brines that locally led to the formation of salt beds. The Sulphur Limestone (SL) resulted from the activity of sulphate reducing bacteria that occurred locally in the deeper parts of the various basinswhere anoxic bottomwaters favouredmicrobial processes fuelled by biogenicmethane and crude oil, and caused the carbonate replacement of gypsumand the formation of native sulphur. The migration of hydrocarbon and H2S-rich fluids caused the epigenetic dissemination of sulphur and a late diagenetic carbonate replacement of the gypsum. Later influxes of continental freshwaters were responsible for the dissolution of the halite crystals and their replacement by sparry calcite. The vugs, formed during both the gypsum/calcite conversion and the halite dissolution, either remained empty orwere filledwith calcite, celestine,a Dipartimento di Scienze della Terra e del Mare (DiSTeM), Un b UMR CNRS-UPMC-IRD 7159, LOCEAN, Université Pierre etiversità degli Studi di Palermo, Via Archirafi 20-22, 90123 Palermo, ItalyA. Caruso a,⁎, C. Pierre b, M.-M. Blanc-Valleron c, J.M. RoCarbonate deposition and diagenesis in ev evaporative and sulphur-bearing limestone
Messinian Salinity Crisis in Sicily and Calab j ourna l homepage: www.; Esteban, 1996; Bourillot rmo, via Archirafi 20-22, 90123oritic environments: The during the settlement of the a matology, Palaeoecology ev ie r .com/ locate /pa laeo(CdB) and the Sulfifera Limestone (SL), although these groups may be often closely interrelated in some sedimentary successions.
The CdB from Sicily and Calabria constitutes a complex carbonate unit up to 50 m thick, which is irregularly interbedded between the pre-evaporitic diatomite-bearing unit (Tripoli Fm) and the Gypsum 137A. Caruso et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 429 (2015) 136–162formations. The first petrographic description of the CdB was provided by Ogniben (1957) who interpreted these deposits as being the result of chemical precipitation during the first stages of increasing salinity.
Many authors (Decima and Wezel, 1973; Richter-Bernburg, 1973;
Pierre, 1974, 1982, 1988; Schreiber, 1976, 1988; Schreiber et al., 1976;
Rouchy, 1982; McKenzie, 1985; Decima et al., 1988; Bellanca et al., 2001; Rouchy and Caruso, 2006; Ziegenbalg et al., 2010, 2012) have acknowledged, although with some disagreements, the evaporitic origin of these carbonates (“evaporative limestone”) taking into consideration both the abundance of evaporite mineral ghosts and the stable isotope composition of the carbonates.