Christopher Vician, “Volcanic and Alkaline Mineralogy of Lake Natron’s Margin: Analogues for Planetary Surface Processes”
Mentor: Lindsay McHenry, Geosciences, Letters & Science (College of)
Poster #100
Lake Natron, a highly saline-alkaline lake on the Tanzania-Kenya border, is one of the most basic lakes on Earth, causing an abundance of carbonate and evaporate minerals to precipitate along the lake margin. A unique feature of the lake system is its proximity to the world’s only active natrocarbonitite volcano, Ol Doinyo Lengai (ODL), 16km to the south. In January and July 2023, Prof. Lindsay McHenry and her team traveled to Lake Natron and collected evaporite and substrate samples from the lake margin on the southern, ODL-facing side, and the northwest shore. The scope of this study is to better understand the effects of ODL on the alkaline Lake Natron sediments. Our primary method of analysis is X-Ray Diffraction (XRD), in which X-rays are diffracted by a powdered rock sample, and the angle of diffraction is measured by the instrument. These unique angles of diffraction are attributed to the crystalline structures of specific minerals and are used to identify mineral assemblages within the sample. By studying the minerals present on the opposite shores of the lake, we can determine the impact of ODL on the shoreline mineralogy of Lake Natron. Results show that the southern shore contained significant amounts of nepheline and pyroxenes (of volcanic origin), along with evaporite minerals gaylussite and calcite. The northern shore lacks these minerals but contains significant amounts of analcime and illite (likely detrital), along with evaporite minerals pirssonite and thermonatrite. Evaporates like trona and halite were omnipresent in both areas. These findings provide insight into how volcanic input influences mineral assemblages in extreme alkaline environments, offering a potential analogue for aqueous alteration processes observed on the recently sampled and analyzed carbonaceous asteroid Bennu. Comparing these systems can help future studies of the role of water-rock interactions in shaping extraterrestrial surfaces.