Dr. Cyrena Goodrich
Dr. Cyrena Goodrich studies meteorites, particularly meteorites of a type known as “primitive achondrites.” Primitive achondrites, such as ureilites or brachinites, are rocks that come from small asteroids rather than any of the larger planets in our Solar System. They are samples that preserve evidence of the earliest geologic processes in our Solar System, around 4.5 billion years ago.
She uses electron microbeam instruments at Johnson Space Center to study the mineralogy and textures of these rocks and determine the chemical compositions of their minerals. She also works with numerous other colleagues who use different techniques to measure properties such as the oxygen isotope compositions, ages, and bulk chemical compositions of these same rocks. Dr. Goodrich then integrates all these data to understand the geologic histories of the parent asteroids from which these meteorites are derived.
She is currently fascinated with a group of meteorities known as polymict ureilites, which are breccias. A breccia consists of many broken fragments of other rocks, all welded together. Polymict ureilites are thought to represent the outer layers of a ureilitic asteroid (or parent body), where numerous impacts of other bodies caused shattering and extensive “gardening” of the debris. Some of the rock fragments left in this debris include pieces of the impactors, which may be totally different kinds of rocks from ureilites. Dr. Goodrich is using these foreign fragments, sometimes known as xenoliths, to reveal chemical and isotopic properties of early solar system materials in the region in which the ureilite parent body formed.