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S. Todaro et al. / Sedimentary Geology 333 (2016) 70–83 73
4. Sedimentological and Stratigraphical Background Up-section, cycles with different subtidal facies are randomly dis-
tributed. In particular, coral bafflestones (Fig. 4A) are implanted on
The Upper Triassic limestone at Monte Sparagio consists of bored firmgrounds that suggest episodic higher-energy conditions
shallowing-upward, peritidal cycles in which it is possible to distinguish within the lagoon. Alternatively thick mud/wackestone beds with ben-
three typical facies (Fig. 3A). thic foraminifera, calcareous algae and characean gyrogonites (Fig. 4D),
lacking or with rare mollusks, indicate a more restricted and lower en-
• A subtidal unit that consists of about 1 m of mudstones–wackestones ergy environment. The thickness of individual cycles is very irregular,
with large Megalodont shells (up to 30 cm of diameter) often in ranging from three or more meters, down to less than 1 m. Frequent
growth position (Fig. 3B). erosional surfaces capped by black pebble lags cut across cycles making
• The intertidal facies, on average 60 cm thick, mainly of stromatolitic it difficult to define cycle-stacking.
limestones with a typical fenestral fabric. Besides the large Megalodonts, the upper part of the Triassic suc-
• Finally, the supratidal facies comprises flat-pebble breccias, rare tee- cession records the presence of Triasina hantkeni (MAJZON)
pee structures and locally black pebble horizons capped in turn by (Cacciatore et al., 2010)(Fig. 4C) among other foraminifers such as
thick Terra Rossa paleosols of about 40 cm (Fig. 3C). The lateral conti- Ophtalmidium sp., Aulotortus sp. and Dasycladacean algae such as
nuity of these paleosols is irregular and in places, they thin or Griphoporella curvata (GüMBEL) that confirm a latest Norian–
disappear. Raethian age for these strata.
Within the Upper Triassic cycles it is possible to distinguish a variety
of dissolution morphologies that are indicative of a complex evolution
On top of the supratidal facies is a basal lag that highlights a new ma- of platform emergence and diagenetic modification (Todaro et al.,
rine transgression and the beginning of another cycle (Fig. 4B). The 2012). Well-developed microkarstic cavities filled with sediments
presence of faults cutting across the section, coupled to an intense net- and/or cements are observable in thin-section. On a mesoscale it is com-
work of bedding-parallel and transverse stylolites, complicates the anal- mon to observe either moldic porosity, formed by dissolution of arago-
ysis of the cyclic stacking pattern. nitic shells of megalodonts, or the spongy-like and vuggy porosity

Fig. 3. A) Composite image showing a typical shallowing upward peritidal cycle from the studied succession. B) Mudstone–wackestone with Megalodont shells partly in growth position
(subtidal unit). C) Cryptalgal laminites with fenestral fabric (intertidal), capped by black pebble conglomerates grading to a “Terra Rossa” paleosol.