COLLABORATIVE ENGINEERING DEVELOPMENT OF A DEVICE FOR MEASURING 3D ANGLES OF PLANAR ORIENTATION IN A TAPHONOMIC STUDY OF MARINE BIVALVES

Taphonomic histories of fossils are important connectors between the life and death of an organism and its paleoecological environment. Events that leave fossil evidence are especially revealing of post-mortem processes such as burial, erosion, and movement. The measurement of taphonomic effects may be as simple, for example, as disarticulation, a degree of abrasion, or the orientation of a fossil in a sedimentary bed.

A collection of bivalves from a Plio-Pleistocene quarry exhibits erosional surfaces that cut through bivalve shells and their steinkerns at various angles.

The measurement of these erosional surfaces presents a problem of mechanics.

An ongoing collaboration with UAB engineering faculty and senior engineering undergraduate students has produced a version 1 device for measuring the three-dimensional (3D) angular difference between an erosional surface and the plane of the biological axis of a fossil bivalve. In a design-to-specifications (constrained by a maximum $100 cost) and build framework the students created an embedded system of fabricated materials with powered hardware and software interfaces. The system sets the planar surface as a 3D angle (X=0,Y=0,Z=0). A manual rotation of the platform to align with the plane of the biological axis generates the angular difference between the two planar surfaces. Angles are displayed and stored on an SD card for later transfer to a computer for statistical analysis.

This system will characterize the statistical distribution of erosional surface orientation in a post-mortem population of marine bivalves to characterize taphonomic processes of burial, sedimention, and erosion.

Other geological processes create planar surfaces in diverse rocks, such as cross-bedding in sedimentary rock and metamorphic lineation and fabric. Our device may also be useful in the measurement and study of angular distributions in these, and other, materials.