Fluid-Assisted Hydration Processes on Chondrite Parent-Bodies: Low-Temperature Experimental Alteration
Year: 2020
Type: conference-abstract
Abstract: The formation of FeO-rich olivine is a first order problem in cosmochemistry and has been the subject of intense debate for more than three decades with nebular and asteroidal scenarios having been proposed [1][2][3][4][5]. Although there are a lot of studies of the occurrence of FeO-rich olivine in chondrites, its origin is poorly understood. Our first preliminary experiments provide clear evidence that hydrothermal growth of elongated, iron-rich olivine can occur during thermal metamorphism in the presence of a fluid (220C, 0.4 W/R mass ratio, 6 days), as described previously in meteorites [3, 6]. So far, hydrothermal alteration experiments have been successful at forming FeO-rich olivines with the compositions and textures observed in the matrices of chondrites only at 220C [6]. Therefore, understanding the formation conditions of FeO-rich olivines at lower temperatures, durations, and water-torock (W/R) mass ratios remains a key problem to understanding the effects of hydrothermal alteration on chondrite matrices. In this study, we performed twelve hydrothermal alteration experiments in an attempt to synthesize FeO-rich olivines at low-temperatures (50C, 100C, and 150C). New minerals were formed in all the experiments analyzed (magnetite, ferrihydrite, and greenalite). Our transmission electron microscopy observations show that the W/R mass ratio controls the abundance of phases; however, the temperature and the duration have an important role in the type of phases formed during the experiments.
Source: Goldschmidt Abstracts
Authors: Elena Dobrica, Joseph Nuth, Adrian Brearley
Institutions: University of New Mexico, Goddard Space Flight Center
Language: English
Topic: Astro and Planetary Science
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W4244821423