Advanced Aqueous Alteration in Primitive Meteorites: Micro- to Nano-scale Studies of CR1 Sulfides and Metals

• Applicant: Dr. Sheryl Singerling
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 545422732

In the proposed work, I aim to study two groups of minerals in meteorites that have not changed much since they formed in the early Solar System, nearly 4.56 billion years ago. These meteorites are called the CR chondrites, and they contain information on the Solar System in its earliest stages. The minerals I aim to study are the iron sulfides (mostly containing iron and sulfur) and metals (mostly containing iron and nickel in their metallic forms). Both types of minerals are sensitive to water and change very readily from even small amounts of the fluid. Water is present in relatively high abundances in the small bodies (asteroids) like those that the CR chondrites come from. These small bodies are the most likely source for the water we have on Earth today. By studying the minerals that were changed by the water, we can, in turn, learn about the water itself. The proposed work is most concerned with studying sulfides and metals in CR chondrites that have been changed by water to a large extent. These are the CR1 chondrites. Only one CR1 chondrite is present in all the world’s meteorite collections, and to date, no studies have analyzed the sulfides and minerals in it. I will use electron microscopes to study the minerals from the micrometer- to the nanometer-scale. The instruments include an electron probe microanalyzer (EPMA) and a transmission electron microscope (TEM). Many features are only visible on such small scales, but these same features can tell researchers much about larger-scale processes; such as heating, impacts, space weathering, and the interaction of water with rocky materials; as well as the conditions present; such as temperature, pressure, and fluid compositions. In addition to containing water, the CR1 chondrites are also similar to the rocky materials present on asteroids Ryugu and Bennu. Both of these asteroids were the targets of recent missions by the Japanese and American space agencies (JAXA and NASA, respectively). These missions actually retrieved samples from the asteroid surfaces and delivered them back to Earth for detailed laboratory-based studies. Analyses of the CR1 chondrites using similar techniques and instruments to those used for these returned samples allow for better comparisons and ground-truth.

• DFG Programme: Research Grants