Hembree, Daniel I.1, Stephen T. Hasiotis1
(1) University of Kansas, Lawrence, KS
ABSTRACT: Casts of Modern Continental Burrows as Trace Fossil Analogs in the Reconstruction of Paleoenvironment and Paleoclimate
Ichnofossils are an important source of paleoenvironmental and paleoclimatic data through their assemblages and morphology. Understanding what information trace fossils provide requires the study of modern fossorial organisms and their traces. By doing so, the tracemakers and their trace morphologies may be correlated to: 1) climatic factors such as temperature and precipitation, 2) depositional environments, and 3) substrate conditions, including grain size, moisture level, and organic content.
Casts of modern burrowing invertebrates and vertebrates were made with polyurethane resin in field and laboratory settings. From the University of Kansas Field Station and Ecological Reserve burrows of various beetles, crayfish, moles, and ground squirrels were cast. Burrows of caecilians and skinks housed in a temperature-controlled laboratory at the University of Kansas were also cast.
Burrow morphology varied predictably with changes in the environment, even when constructed by the same type of organism. The post-depositional conditions of continental environments controlled the type of burrowing organisms present. Precipitation and temperature primarily controlled the maximum depth of the burrow. Substrate conditions influenced the burrow architecture, including the number of entrances, sinuosity of the burrow passages, the verticality of the burrow, and the overall complexity, whether a single tunnel or a network of interconnecting tunnels. Surficial morphology was produced by the tracemaker, but it also resulted from associated biotic and abiotic processes within the substrate. Results of the field and laboratory studies enhance our understanding of the significance of ancient burrow morphologies as they relate to organism behavior, environment settings, and climatic factors.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.