INTRODUCTION

 

PYRITIZATION

The reason for the undying interest in Beecher's Trilobite Bed is the preservation found within. Fossils from this deposit have been pyritized, a preservational method whereby pyrite (fool's gold) replaces organic material. Pyritization within the fossil record is not uncommon, however, the extensive pyritization of soft-tissue (e.g. antennae, digestive tract, musculature) is extraordinarily rare and offers valuable insight into many aspects of the organism's biology.

Under the right conditions pyritization occurs through a series of reactions that rely on the presence of sulfate-reducing bacteria as well as a low-oxygen setting. The bacteria use the organic matter of a trilobite to produce sulfide that then reacts with iron minerals present in the sediment to create pyrite, an iron sulfide mineral (FeS2). Long after this process is completed and the surrounding sediment has been lithified (turned to rock) the pyritized remains of the trilobite can still be seen (below).

Photos by Tom Whiteley

The predominant organism within the Bed is the trilobite, Triarthrus eatoni, a bottom-dwelling species that thrived in oxygen-poor conditions (pictured above). The T.eatoni specimens used in this study varied from 6 to 25 mm in length and were betweeen 3 and 8 mm wide at the cephalon (head). For more on the specific research goals and methods used in my research click below.

 

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