2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 19-14
Presentation Time: 11:15 AM

RESPONSE OF SHALLOW-WATER CARBONATES AND REEF SYSTEMS TO THE TOARCIAN OCEAN ANOXIC EVENT (183 MA) ON THE DINARIC CARBONATE PLATFORM (SLOVENIA)


MARTINDALE, Rowan C., Jackson School of Geosciences, University of Texas at Austin, 1 University Station C1100, Austin, TX 78712 and KO҆IR, Adrijan, Research Center of the Slovenian Academy of Arts and Sciences, Ivan Rakovec Institute of Palaeontology, Novi trg 2,, Ljubljana, SI-1000, Slovenia, martindale@jsg.utexas.edu

With rising concerns regarding the persistence of coral reefs through the 21stcentury, there is a crucial need to understand how these ecosystems will respond to future environmental deterioration (e.g. ocean warming, acidification, and decreased oxygenation). Several ancient events, such as the end-Permian and end-Triassic carbon cycle perturbations, have been identified as good analogues for modern ecological changes, however, most of these correspond to catastrophic extinctions and complete ecosystem reordering. By studying carbon cycle perturbations that caused more minor ecosystem collapse, such as the Toarcian Ocean Anoxic Event (T-OAE), the key physiological, ecological, and environmental features that correlate with species and community survival can be assessed.

The Dinaric Carbonate Platform, which extends from northeastern Italy to northwestern Albania, is one of the few platforms in Europe that captures an almost continuous shallow-water record of Pliensbachian and Toarcian strata. Specifically, this comparatively poorly studied platform captures the T-OAE in shallow-water carbonates. One such outcrop on the Trnovski Gozd karst plateau in western Slovenia contains both Pleinsbachian lithiotid (bivalve) biostromes and coral bioherms (i.e. coral reefs). The occurrence of both lithiotid and coral buildups in one section is extremely rare and provides the opportunity to study the response of both communities, as well as the carbonate system as a whole, to the T-OAE. This research focuses on the lithology and chemostratigraphy from this locality, particularly identifying the T-OAE horizon more precisely. Additionally, microfacies analyses and paleontological analyses of the reefs and level-bottom communities themselves will be presented. These data will establish the paleoenvironmental conditions that favored reef growth in the Pliensbachian, as well as what conditions changed at the stage boundary and T-OAE to cause the collapse of the shallow-water carbonates and reef systems.