Smart-Geology for the World’s largest fossil oyster reef

The application of modern data processing and visualization technologies in geology and paleontology is still in its infancy. Within the proposed project we will open a new field we call "Smart Geology", which is characterized by automation and large volumes of data. This will be performed in a key-study focussing on the world`s largest fossil oyster biostrome, which is the highlight of the geo-edutainment park "Fossilienwelt Weinviertel" at Stetten in Lower Austria. The dimension of the protected site and the enormous number of individual shells (c. 15.000) makes a classical paleontological survey of its internal architecture and orientation very difficult, time consuming and highly subjective. Therefore, despite the impressive amount of publications that deal with the flora and fauna of this Early Miocene estuary in which the oyster biostrome was formed, a comparable analysis of the spectacular shell accumulation is still missing so far. No quantification of the shells was performed and the taxonomic inventory and taphonomic features were only cursorily documented during excavation. In this project, we will investigate, if the appropriate application of state-of-the-art 3D digitizing, data processing, and visualization technologies allows for a significant automation in paleontological analyses, making an evaluation of huge areas economically feasible in both, time and costs. The major topics to be dealt with are evaluating available laser scanning and image acquisition systems for optimized 3D digitizing, increasing automation and objectivity in geological an paleontological data analysis and interpretation, and investigating the applicability of smart devices (esp. TabletPCs) to support the on-site accessibility and evaluation of paleontologically relevant data. For the evaluation of the proposed methods, we formulate two scientific hypotheses postulating that the shell-bed was formed by a tsunami or a major storm and that pre- and post-event processes can be reconstructed. To ensure reliable reference data for evaluating the proposed "Smart Geology approach", a complete interactive survey of the whole site will be performed, which allows for a cross-validation of the results. This validation will comprise three steps namely 1. evaluating the reliability and especially the completeness and correctness of the automated processing, 2. evaluating the reliability of the conventional, operator driven data processing especially with respect to local variations in these results, possibly caused by variations in the behaviour of the operator and by variations in the quality of the input data and 3. evaluating variations of the automated results caused by variations in the given data. By this, this project mediates between the two scientific disciplines Photogrammetry and Geology.

Aim of this project was the digital documentation of the worlds largest fossil oyster reef, formed by the giant oyster Crassostrea gryphoides at Stetten north of Vienna (Austria) combining methods of photogrammetry and paleontology. The shell bed covers an excavated area of 459 m and comprises more than 50.000 shells. For the first time, terrestrial laser scanning (TLS) was applied for the analysis of such a huge paleontological data set, captured as georeferenced 3D point cloud of 1 billion data-points. In addition to TLS measurements, more than 300 photographs were produced and an orthophoto mosaic was generated with a ground sampling distance of 0.5 mm. Major goals were the taphonomic and paleoecological analysis of the shell bed and to develop methods of automated object detection. More than 10,280 objects were manually outlined based on the Digital Surface Model (DSM) within two transects. These data served as reference data-set for the quality control of automatic object detection. This resulted in a data set on taxonomy (which species are involved in which amount?), taphonomy (how are shells preserved?) and various physical properties (size of shells, 3D-orientation, distribution of objects). The shell bed is an event deposit, formed by a tsunami or an exceptional storm in an early Miocene estuary. Disarticulated shells of the giant oyster are the most frequent objects along with other bivalves and gastropods. The contradicting ecological requirements and different grades of preservation of the various taxa mixed in the shell bed, along with a statistical analysis of the correlations of occurrences of the species, reveal an amalgamation of at least two pre- and two post-event phases of settlement under different environmental conditions. In addition, we present the first analysis of population structure and cohort distribution in a fossil oyster shell bed based on more than 1121 shells. Correlation between shell-centerline-lengths and shell-weight allowed to establish a growth model, which gives insights into carbonate production of a Miocene oyster reef. TLS technology faces challenges in the presence of the irregular geometry of the oyster shells and reef. Within that complex setting, we developed techniques for an automatic analysis method for identifying and enumerating convex parts of shells. Object surfaces were detected with a completeness of over 69% and a correctness of over 75% using a fully automatic workflow. The detected number of objects gave 98% accuracy. The unique oyster reef is a protected site and part of the geopark Fossilienwelt. Therefore, the unprecedented accuracy of documentation is a major step for conservational issues in natural heritage sites. Finally, we documented the difficulties in detecting potential tsunami signatures in shallow marine settings even in exceptionally preserved shell beds due to taphonomic bias by post-event processes.