Facies analysis of the Trypali carbonate unit (Upper Triassic) in central‐western Crete (Greece): an evaporite formation transformed into solution‐collapse breccias

Abstract

The Trypali carbonate unit (Upper Triassic), which crops out mainly in central‐western Crete, occurs between the parautochthonous series (Plattenkalk or Talea Ori‐Ida series, e.g. metamorphic Ionian series) and the Tripolis nappe (comprising the Tripolis carbonate series and including a basal Phyllite–Quartzite unit). It consists of interbedded dolomitic layers, represented principally by algally laminated peloidal mudstones, foraminiferal, peloidal and ooidal grainstones, as well as by fine‐grained detrital carbonate layers, in which coarse baroque dolomite crystals and dolomite nodules are dispersed. Baroque dolomite is present as pseudomorphs after evaporite crystals (nodules and rosettes), which grew penecontemporaneously by displacement and/or replacement of the host sediments (sabkha diagenesis). However, portions of the evaporites show evidence of resedimentation. Pre‐existing evaporites predominantly consisted of skeletal halite crystals that formed from fragmentation of pyramidal‐shaped hoppers, as well as of anhydrite nodules and rosettes (salt crusts). All microfacies are characteristic of peritidal depositional environments, such as sabkhas, tidal flats, shallow hypersaline lagoons, tidal bars and/or tidal channels. Along most horizons, the Trypali unit is strongly brecciated. These breccias are of solution‐collapse origin, forming after the removal of evaporite beds. Evaporite‐related diagenetic fabrics show that there was extensive dissolution and replacement of pre‐existing evaporites, which resulted in solution‐collapse of the carbonate beds. Evaporite replacement fabrics, including calcitized and silicified evaporite crystals, are present in cements in the carbonate breccias. Brecciation was a multistage process; it started in the Triassic, but was most active in the Tertiary, in association with uplift and ground‐water flow (telogenetic alteration). During late diagenesis, in zones of intense evaporite leaching and brecciation, solution‐collapse breccias were transformed to rauhwackes. The Trypali carbonate breccias (Trypali unit) are lithologically and texturally similar to the Triassic solution‐collapse breccias of the Ionian zone (continental Greece). The evaporites probably represent a major diapiric injection along the base of the parautochthonous series (metamorphic Ionian series) and also along the overthrust surface separating the parautochthonous series from the Tripolis nappe (Phyllite–Quartzite and Tripolis series). The injected evaporites were subsequently transformed into solution‐collapse breccias.

Early diagenetic dolomitization and dedolomitization of Late Jurassic and earliest Cretaceous platform carbonates: A case study from the Jura Mountains (NW Switzerland, E France)

“…Commonly, evaporite dissolution is a multistage process (Pomoni-Papaioannou and Karakitsios, 2002). Intrastratal collapse breccias in Permian sedimentary rocks, related to Tertiary telogenetic near-surface dissolution of evaporites, are described by Scholle et al (1992Scholle et al ( , 1993.…”

Microfacies and cycle stacking pattern in Liassic peritidal carbonate platform strata, Gavrovo-Tripolitza platform, Peloponnesus, Greece

“…These MF and their association indicate sedimentation in supratidal settings that were exposed to intermittent subaerial conditions (Sattler et al 2005). Although, saddle dolomite usually forms at late-stage diagenesis, indicating higher temperatures and elevated salinity (Radke and Mathis 1980;Warren 2000), the patches of saddle dolomite observed in the supratidal facies are interpreted as pseudomorphic early replacement after evaporite minerals suggesting hypersaline conditions (Assereto and Folk 1980;Pomoni-Papaioannou and Karakitsios 2002). The almost total absence of fauna and the presence of authigenic idiomorphic quartz crystals support increased salinity conditions as well.…”

Gypsiferous carbonates at Honaz Dağı (Denizli): First documentation of Triassic gypsum in western Turkey and its tectonic significance

“…Evaporite formation reached an all time maximum during the Triassic, the late zenith to the break-up phase of Pangea (Gordon, 1975). The main Triassic evaporite deposits are situated in southwestern-central Europe (Germanic and Lorrain basins: Vescei and Duringer, 2003;Fanlo and Ayora, 1998;central-southeast Iberia: Orti, 1987;Jurado, 1990;Salvany, 1990;Serrano and Olmo, 1990;Orti et al, 1996;Zarza et al, 2002), in the Atlas and Saharan platform (Kamoun et al, 2001;Courel et al, 2003), in northern Appennines (Reutter et al, 1983;Lugli, 2001;Lugli et al, 2002), in eastern Europe of the Carpathian Keuper (Marcoux and Baud, 1995), in Israel (Hirsch, 1984), in the Palmirides and Zaros area, northern Arabia (Searle, 1994;Mouty, 1997;Sadooni and Dalqamouni, 1998;Jamal et al, 2000;Makhlouf and El-Haddad, 2006), in the Hellenic Trench (Krahl et al, 1983;Papanikolaou, 1988;Zelilidis et al, 1998;Papaioannou and Karakitsios, 2002), and in Antalya-Tahtalı Dag Unit (Ö zgü l, 1976;Robertson and Woodcock, 1984). These Triassic evaporate-bearing sediments have been separated and moved several kilometers by thrust faults related to the Alpine orogenesis.…”