ABSTRACT: Simulation of the Triassic Picco di Vallandro Section of the Dolomite Alps

WHITTLE, GREGORY, CHRISTOPHER G. ST. C. KENDALL, and PHILIP MOORE, University of South Carolina, Columbia, SC, and KEVIN BIDDLE, Exxon Company International, Houston, TX

The Picco di Vallandro section of the Dolomite Alps is an Upper Triassic (Carnian) sequence of carbonate beds (Schlern carbonates) that prograded into the basin and interfingered with the marl and shale units of the Cassian Formation. These two formations are overlain by the thinly bedded carbonates of the Durrenstein Formation. Using cross-sectional data, this platform to basin setting was modeled with a two-dimensional computer program called SEDPAK, which simulates the filling of a basin. In recreating the geometries of this section, the interaction between sea level, tectonic behavior, and rates of carbonate accumulation were tested. The progradation observed in the Picco di Vallandro section was found to be a product of carbonate accumulation rates that exceed the rate of subside ce and rising sea level. Also, the rate of carbonate accumulation with depth was found to be uniform.

In addition to the ramped margin of Picco di Vallandro, SEDPAK was used to discover what would have caused the margin to become rimmed or backstep. It was found that an increase in the rate of carbonate accumulation in shallow water creates a rimmed margin. Backstepping could be caused in three ways: (1) a decrease in the rate of carbonate accumulation throughout the water column, (2) a rapid rate of sea level rise, (3) a rapid rate of subsidence. Thus, rate of sediment accumulation, sea level, and rate of subsidence are the primary factors in causing a margin to prograde, vertically aggrade, or backstep.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)