MODEL SYSTEMS AS PROBES OF ORGANIC-MINERAL INTERACTIONS IN ANCIENT ENVIRONMENTS (Invited Presentation)

Complexity is one of the greatest challenges inherent to the study of natural systems, with the interrogation of ancient environments being further convoluted by processes associated with the passage of time. Although the sedimentary rock record is in some sense a collection of snapshots representing past environmental conditions, the recorded images are incomplete and very often blurred by physical and chemical alteration. As such, investigations of ancient systems commonly endeavor to place constraints on environmental conditions and develop plausible models of past system behavior, but are challenged to develop hypotheses that can be unambiguously tested through continued interrogation of the sedimentary record. For instance, the conditions underlying soft tissue preservation in sediments dating to the Proterozoic-Cambrian transition are of geobiological interest, but nearly all modes of fossil preservation during this time are debated. In particular, silicate mineral templates have been implicated as playing a role in several types of soft tissue preservation, including Burgess Shale-type preservation, Bitter Springs-type silicification, as well as with microfossils preserved in phosphate (e.g., Wacey et al., 2014 Scientific Reports); yet, there is still much back and forth over whether these mineral coatings form during early stage burial and diagenesis, or later stage metamorphism. Herein we argue that progress towards resolving such debates may be achieved through the application of model systems that are constructed to address testable hypotheses. Specifically, we discuss the results of experiments designed to determine whether organic surfaces are intrinsically capable of promoting authigenic silicate formation in simulated marine settings.