VERTICAL VARIABILITY OF MISS MORPHOLOGY IN AN EARLY CRETACEOUS CONTINENTAL SETTING: MILL CANYON DINOSAUR TRACKSITE, MOAB, UTAH

Microbially induced sedimentary structures (MISS) are organo-sedimentary structures (microbialites) produced through binding of siliciclastic sediments by microbial mats. Many recent studies focus on MISS in marine environments and lack documentation of variation in microbial micromorphology with regard to topography in continental environments. This study examines and demonstrates vertical variability in MISS formed within a lacustrine environment of the Early Cretaceous Cedar Mountain Formation at the Mill Canyon Dinosaur Tracksite (MCDT), east-central Utah.

The MCDT records preserved pustulate to rectilinear MISS disrupted by vertebrate tracks on top of a paleotopographic surface with ~60 cm of relief. The MISS are recogniable due to the pliable nature of the micromorphology illustrated in the preserved tracks and binding of coarser clastics at the sediment-mat interface. Detailed measurements of micromorphology and elevation were collected across a high relief portion of the MCDT surface. Photogrammetry of the site was processed in PhotoscanPro and used to produce detailed 3-D images for data visualization. Multivariate statistical methods were applied to the measurements to identify correlations within the MISS substructure versus paleotopography. Normal distributions of morphological measurements converged at an elevation of ~15 cm, suggesting a microenvironment that maximized growth conditions. Empirical patterns within MISS microstructures provide a criterion to identify biogenesis, especially within lacustrine deposits where marine MISS features cannot be applied.