Abstract

Ichnofossil tiering, the vertical partitioning of ichnofossil communities of organisms within substrates, describes organism-substrate interactions from Pangean Triassic continental deposits in northwestern New Mexico. The tiers, informally numbered I through IV, are defined by the cross-cutting and conterminous relations of distinct burrow morphologies that represent different organisms. Each tier reflects inter-related aspects of the paleobiologic and paleohydrologic regime: nutrient availability, organism interactions, soil moisture content and water table level.

Paleoecological tiering in continental rocks records information about the paleohydrologic regime of deposits, enhancing Pangean paleoclimatic and paleogeographic interpretations of Triassic rocks. The paleohydrologic regime recorded by ichnofossil tiering can be compared on local and regional paleogeographic scales to reconstruct the amount of water in the substrate, which reflects trends in Pangean seasonal and annual precipitation. Tiering relationships can be evaluated through time in the continental rock record in conjunction with the depositional and tectonic histories to better comprehend paleo-orographic, paleolatitudinal and paleoclimatic effects across Pangea.