GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 172-10
Presentation Time: 10:30 AM

SPATIO-TEMPORAL DIVERSITY DYNAMICS IN NORIAN (LATE TRIASSIC) GOSAUKAMM PATCH REEFS IN AUSTRIA


GODBOLD, Amanda Lynn1, HOHMANN, Niklas2, JAROCHOWSKA, Emilia2, KIESSLING, Wolfgang2 and BOTTJER, David J.1, (1)Earth Science, University of Southern California, 3709 Trousdale Pkwy., Los Angeles, CA MHP 106, (2)GeoZentrum Nordbayern, Friedrich-Alexander-University Erlangen-Nuremberg, Loewenichstra├če 28, Erlangen, 91054, Germany

During the Late Triassic, the Northern Tethys Ocean was a semi-enclosed ocean basin with numerous large carbonate platforms. At this time, warm water circulated from tropical latitudes towards the Northern Tethys Ocean, making this an ideal location for carbonate accretion and reef growth. Today, sediments that were deposited along the northern margin of the Tethys Ocean can be found in the Northern Calcareous Alps, which are known for their extensive reef deposits made by scleractinian corals and hypercalcified sponges. Gosaukamm mountain, located ~7 km south of Gosau, Austria, is one of the most well studied reef localities in the Northern Calcareous Alps. This mountain belongs to the Dachstein Formation which consists of lagoon, reef rim and slope deposits. The reef framework at this locality is restricted to patch reefs that are irregularly distributed across a vast spatial range. The aim of this study is to determine spatio-temporal diversity dynamics in Norian (Late Triassic) Gosaukamm patch reefs in Austria. Quadrats were constructed on each reef and samples were collected every two metres along transects. Samples were processed to create polished slabs that were used for equal area quadrat counts in order to quantify the diversity and abundance of reef building organisms. In order to test for significance differences in taxonomic composition, Bray-Curtis dissimilarities were subject to the ANOSIM (analysis of similarities) and PERMONOVA (analysis of variance) procedures. Results show no significant difference in taxonomic composition between the two patch reefs found at Gosaukamm. However, there appears to be spatio-temporal differences in taxonomic composition within each reef. Since the Norian was a time of optimal reef growth, the dataset generated from this study allows us to establish a baseline of reef functionality that can be compared with reefs deposited during times of environmental stress, such as the current reef crisis.