Undergraduate Honors Theses

Thesis Defended

Spring 2019

Document Type


Type of Thesis

Departmental Honors


Geological Sciences

First Advisor

Carolyn Crow


The majority of 40Ar/39Ar analyses involving extraterrestrial samples were collected from bulk rock samples due to fine grain sizes. This present challenges in modeling the diffusion kinetics and thermal histories of these samples because of the presence of multiple-diffusion domains. Since Lovera et al. (1989) developed the multi-diffusion domain (MDD) method of modeling, many attempts have been made to automate the modeling process. However, existing software to model diffusion parameters and thermal histories falls short in that it is either restricted in availability, restricted in flexibility, or is cumbersome to use. I have created a new program, OPTIMuM (Optimize Parameters To Interpret Multiple Minerals), that models bulk samlpe diffusion kinetics and thermal histories through a simple graphical user interface (GUI). In this paper, I present the theory behind OPTIMuM as well as modeling results of samples from three extraterrestrial bodies. These results have important implications for the impact history and the dynamical evolution of the early solar system.