Title:
Coupled thermodynamic feedback and organic synthesis in natural nuclear reactors

Abstract:
Energy dissipation processes in abiotic systems is typically unidirectional, ranging from the gentle rain of sunshine to the explosive release of an impactor. However, the thermodynamics of such systems are inherently problematic for origins of life studies. Mass transport, thermal and chemical gradients converge and interact on short systemic scales to freeze reactants into organic matter, but work and information flow rarely result in stable circulatory patterns that link chemical outcomes to energy inputs. This talk will be about a search for thermodynamic feedback in naturally-occurring organic synthesis systems and geologic settings, and the incorporation of feedback analogs into laboratory experiments. Specifically, I will discuss how natural nuclear reactors would have created cyclic temperature oscillations comparable to polymerase chain reaction (PCR) thermal profiles along reactor margins, and gamma radiolysis would have produced nucleobase precursors (pyrimidines, purines and sugars) within the same volumes. The products of initial reactor-on events would participate in later reactions, thus the chemical and energy profiles of reactors would co-evolve over time. Natural nuclear reactors may serve as an instructive scenario for investigating how abiotic energy feedback mechanisms can serve as a thermodynamic template for the simultaneous production and organization of organic matter. It may be fruitful to extend gamma-radiolysis experiments to include solid- and dissolved-phosphate components to evaluate whether reactive phosphate and nucleobase compounds may be produced.