The 720-m-thick succession of the Middle Triassic Latema Ár Massif (Dolomites, Italy) was used to reconstruct the lagoonal facies architecture of a small atoll-like carbonate platform. Facies analysis of the lagoonal sediments yields a bathymetric interpretation of the lateral facies variations, which re¯ect a syndepositional palaeorelief. Based on tracing of lagoonal¯ooding surfaces, the metre-scale shallowing-upward cycles are interpreted to be of allocyclic origin. Short-term sea-level changes led to subaerial exposure of wide parts of the marginal zone, resulting in the development of a tepee belt of varying width. Occasional emergence of the entire lagoon produced lagoon-wide decimetrethick red exposure horizons. The supratidal tepee belt in the backreef area represented the zone of maximum elevation, which circumscribed the sub-to peritidal lagoonal interior during most of the platform's development. This tepee rim, the subtidal reef and a sub-to peritidal transition zone in between stabilized the platform margin. The asymmetric width of facies belts within individual metre-scale cycles was caused by redistribution processes that re¯ect palaeowinds and storm paths from the present-day south and west. The overall succession shows stratigraphic changes on a scale of tens of metres from a basal subtidal unit, overlain by three tepee-rich intervals, separated by tepee-poor units composed of subtidal to peritidal facies. This stacking pattern re¯ects two third-order sequences during the late Anisian to early middle Ladinian.

Sedimentary cycles recorded in young sediments are often attributed to fluctuations of the Earth's climate on a 104−106‐year scale which in turn is governed by periodic variations in solar insolation linked to orbital (Milankovitch) parameters. A spectacular example of cyclic stratal patterns in ancient deposits is the Middle Triassic Latemar carbonate platform (W Dolomites, N Italy). Based on spectral analyses from previous studies, a superimposition of precession (∼20 ka) and eccentricity (∼100 ka) controlled sea‐level fluctuations has been suggested to account for the stacking hierarchy at Latemar, with ∼20 ka being assigned to each highest‐order depositional cycle. Zircon U–Pb isotopic ages from volcanic‐ash layers within the cyclic succession, corroborated by biostratigraphic constraints, suggest that the average time interval for every individual cycle is significantly smaller than the shortest Milankovitch period and therefore challenge previously published interpretations relating distinct spectral peaks to the above mentioned hierarchy. However, our new spectral data indicate that cyclicities resembling Milankovitch characteristics might exist, but on an entirely different scale. Our findings show that frequency spectra should only be interpreted in combination with robust age control. They also encourage the search for complementary mechanisms controlling carbonate deposition.

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The well-known cyclic carbonate succession of the Middle Triassic Latemàr Massif in the Italian Dolomites reveals significant lateral variability in cycle numbers in platform-interior strata. Within an interval of 60 m, a 25% increase in the number of marine flooding surfaces was detected when approaching the several-hundred-meters-wide tepee belt in the backreef area, which represents the maximum elevation of the isolated Latemàr buildup. The impact of high-frequency-low-amplitude sea-level fluctuations on this elevated zone resulted in the development of spatially restricted intermittent emergence and marine flooding surfaces bounding small-scale upward-shallowing cycles. It is postulated that these alternations of submergence and subaerial exposure have favored tepee formation. Sediment collecting in the saucer-shaped tepee megapolygons further expedited upward shallowing of small-scale cycles. Conversely, deeper parts of the lagoon remained largely unaffected by high-frequency, lowamplitude sea-level oscillations: marine flooding surfaces disappear and cycles amalgamate. It is concluded that tepee structures are generally confined to topographically elevated areas where low-amplitude sea-level fluctuations were recorded. Lateral variations in cycle stacking pattern should be commonplace in shallow carbonate buildups throughout the geological record, where paleorelief existed in the platform interior.

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