--> ABSTRACT: Tracing Lateral Metre-Scale Cycle Variability across the Latemar Platform (Dolomites, Italy) Using Digital Outcrop Modeling, by Amour, Frédéric; Mutti, Maria; Christ, Nicolas; Immenhauser, Adrian; Agar, Susan; Yose, Lyndon A.; Benson, Gregory; #90135 (2011)

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Tracing Lateral Metre-Scale Cycle Variability across the Latemar Platform (Dolomites, Italy) Using Digital Outcrop Modeling

Amour, Frédéric 1; Mutti, Maria 1; Christ, Nicolas 2; Immenhauser, Adrian 2; Agar, Susan 3; Yose, Lyndon A.4; Benson, Gregory 3
(1)Institute of Earth and Environmental Science, Potsdam-Golm, Germany. (2) Institute for Geology, Mineralogy und Geophysics, Bochum, Germany. (3) ExxonMobil Upstream Research Company, Houston, TX. (4) ExxonMobil Exploration Company, Houston, TX.

The identification of the auto- or allocyclic factors controlling the stacking patterns of metre-scale carbonate cycles and their temporal significance are a key issue in the Latemar controversy. Previous studies have focused on the vertical facies and stratigraphic changes throughout the 700 m thick interval of the platform and provided a fundamental contribution towards the understanding of the mechanisms controlling the carbonate deposition. However, the lateral facies and cycle changes from the interior platform to the tepee belt are critical issues to be considered in this discussion.


The study was aimed at characterizing cycle continuity across critical turning points in the stratigraphic evolution, such as at the transition between Lower Cyclic Facies (LCF), Middle Tepee Facies (MTF) and Upper Cyclic Facies (UCF). The lateral facies and cyclic variability in “Cima de Forcellone“ was documented in sections with spacings as close as 25 m. The field data were supported by d-GPS and LiDAR survey mapping. The outcrop morphology allows a 2.5D view, 1 km long and 110 m thick along the depositional profile of the platform.


The investigation of the lateral variability of the cycles shows two major scales of change. The first observation reveals an increasing number of cycles (up to 50% more) along a transect from the lagoon toward the tepee belt within the MTF unit. The tepees being interpreted as topographic highs, this observation indicates that autocyclic mechanisms seem to play a more important role within tepee units than within cyclic units, where increases of only 25% have been documented. At the second scale, the d-GPS mapping of key surfaces allows the identification of topographic changes of the tepee belt from cyclic units and tepee units, indicating changes in the deposition profile through time. The transition between LCF and MTF, which comes along with an expansion of the tepee as described previously, is characterized also by a progressive progradation of a topographic high representing the tepee belt. Maximum progradation is associated with the flooding surface at the middle of MTF. The elevation difference between the lagoon and the tepee belt ranges from 1 to 3 m.


The present study reveals that the Latemar platform facies, previously interpreted as highly continuous throughout the platform, actually shows significant lithological, cyclic and topographic lateral changes from the tepee belt to the lagoon and from cyclic to tepee units.

 

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.