Dr. Cyrena A. Goodrich
Dr. Cyrena Goodrich studies meteorites, particularly meteorites known as “primitive achondrites.” Primitive achondrites come from asteroids and preserve evidence of the earliest geologic processes that occurred in our solar system, around 4.6 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 colleagues who use different techniques to measure oxygen and chromium isotope compositions, ages, and bulk chemical compositions of these same rocks. Dr. Goodrich then integrates all these data to understand the formation and geologic histories of the parent asteroids from which these meteorites are derived. She also works with laboratory reflectance spectra of meteorites to help establish connections between meteorites and asteroid taxonomic types.
Selected Current Research Projects:
Asteroid 2008 TC3 and the Almahata Sitta Meteorite: The Almahata Sitta meteorite fell in 2008 when asteroid 2008 shattered over the desert of Northern Sudan. 2008 TC3 was the first Near-Earth Object to be detected before it impacted Earth, which made it a milestone in planetary protection. Almahata Sitta, a collection of >600 cm-sized stones, is the first meteorite to be derived from an asteroid that had been tracked and studied in space before impact. Dr. Goodrich is leading a team of diverse experts that include meteorite petrologists and geochemists, spectroscopists, meteor astronomers, and physicists to study the University of Khartoum (Sudan) collection of Almahata Sitta stones, which is curated by team member Professor Muawia Shaddad. They are using the analyzed properties of the stones, combined with pre-impact observations of the asteroid, to understand the composition, structure, fragmentation behavior, and origin of this asteroid.
Goodrich C.A., Zolensky M., Fioretti A.M., Shaddad M.H., Downes H., Hiroi T., Kohl I., Young E., Kita N., Hamilton V.E., Riebe M., Busemann H., Macke R.J., Ross D.K. and Jenniskens P. (2019) The First Samples from Almahata Sitta Showing Contacts Between Ureilitic and Chondritic Lithologies: Implications for the Structure and Composition of Asteroid 2008 TC3. Submitted to Meteoritics and Planetary Science, February 2019.
Xenoliths in Meteoritic Breccias: Some meteorites are breccias (rocks that consist of broken fragments of other rocks welded together) that represent the regolith, or outermost layers, as an asteroid, where numerous impacts of other bodies caused shattering and extensive “gardening” of the debris. Some of the rock fragments in this debris include pieces of the impactors. Dr. Goodrich studies the mineralogy, petrology, and geochemical properties of these foreign fragments, known as xenoliths, to reveal chemical and isotopic properties of early solar system materials that may not be represented by known meteorite types.
Goodrich C.A., Zolensky M., Kohl I., Young E.D., Yin Q.-Z., Sanborn M.E. and Shaddad M.H. (2019) Carbonaceous chondrite-like xenoliths in polymict ureilites: A large variety of unique outer solar system materials. Lunar and Planetary Science Conference 50, abstract #1312.
Goodrich C.A., Kita N.T., Zolensky M., and Shaddad M.H. (2019) Oxygen isotope compositions of magnetite in CC-like clasts from Almahata Sitta and other polymict ureilites. Lunar and Planetary Science Conference 50, abstract #1551.