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Kathleen Elyse Vander Kaaden

Publications and source records attributed to Kathleen Elyse Vander Kaaden.

Understanding Mercury’s Magmatic History: Geochemical Affinity, Compatibility, & Volatility Changes Due to Reduction

Mercury’s depletion in O and abundance of S substituting in as S2- has fundamental effects on the physicochemical properties of minerals and melts because O2- is the dominant rock-forming anion. These changes exert a first order effect on planetary body evolution, including the initial distribution of elements, crystallization paths, stability of phases, and mineral chemistry. Experimental and empirical data have revealed that most nominally lithophile elements become more chalcophile and/or siderophile at reducing conditions, which can be visualized through a re-interpreted Goldschmidt classification table prepared for McCubbin & Anzures’s Treatises of Geochemistry 3rd edition chapter under review. Additionally, the S bonding environment influences Mercurian phase equilibria by decreasing the stability of forsterite and anorthite while increasing the stability of enstatite, silica, and albite through re-projection of silicate ternaries.

Brendan Anthony Anzures↗

Silicon Partitioning Between Iron-Rich Metal and Silicate Melt: New Constraints From Aerodynamic Laser Levitation Furnace Experiments

The partitioning of light elements (e.g., Si, C, H, etc.) between silicate melts and iron metal alloys as a function of pressure and temperature is a critical constraint in defining the compositional evolution of planetary interiors. While there are a significant number of experimental studies in the literature that examine the various influences of oxygen fugacity, temperature, pressure, and composition on the metal-melt partitioning of silicon, it is difficult to disentangle the effects of each variable due to the nominally independent parameters (e.g., pressure, temperature, composition) being collinear. To better test for the independent effects of pressure, temperature, and melt composition on the partitioning of silicon between iron alloy and silicate melt, new high temperature (1800°–2500°C), rapid quench (~700°C/s) aerodynamic levitation laser-heating experiments in the Fe-Si-Mg-O (En65-Fa5-Si3-Fe27) system were conducted. This high temperature, low pressure method is ideal for these experiments because it eliminates the metal container as a sink for elements of interest to partition into, and it has a rapid quench rate that minimizes potential exsolution of silicon from the metal phase during quench cooling. Given the short run times of the levitation experiments (30–60 seconds), a time series at a lower temperature (1700°C) in a vertical gas-mixing muffle tube furnace was also conducted to assess equilibrium times of the bulk composition. All successful runs were imaged using back-scatter electron imaging and analyzed for phase composition using a JEOL 8530F field emission microprobe. These new data were added to a comprehensive and internally consistent data set created from published experiments, and subsequently modeled using parameters designed to minimize collinearity (e.g., optical basicity is used as a proxy for melt composition). High collinearity is found in the data set however between temperature and oxygen fugacity, precluding any model that contains both as nominally independent variables. The resulting model demonstrates a statistically significant effect of pressure, temperature, and melt composition on the partitioning of silicon in Fe-rich metal, which has implications for the formation of planetary cores in rocky planets and provides important constraints on potential bulk core compositions.

Metal↗

OSIRIS-REx Curation: The First Year with Bennu Samples on Earth

The OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer) sample return capsule landed on the Utah Test and Training Range (UTTR) on September 24, 2023. Preparations for the curation of the sample from asteroid Bennu inside of this capsule spanned more than a decade. On the morning of landing, the sample return capsule was brought to a temporary cleanroom at UTTR for initial de-integration and connection of the sample canister to a nitrogen gas purge to protect the sample from modification by the terrestrial atmosphere. In the week following landing, the sample canister was flown to Houston while on nitrogen purge, transferred to a nitrogen atmosphere glovebox at NASA Johnson Space Center in which the canister lid was removed revealing small amounts of sample on the inside of the canister lid and avionics deck, some of this sample was allocated rapidly to the mission sample analysis team as “quick look” samples. Next, the Touch-and-Go sample acquisition mechanism (TAGSAM) head was disassembled inside of a specially designed glovebox. A challenge arose during one of the last stages of disassembly when two fasteners resisted being loosened. The curation team was able to remove 70.3 grams of asteroid sample from the TAGSAM head with those fasteners in-place and began initial sample processing which supported long-term curation of hermetically sealed and frozen samples, transfer of some samples to remote storage, and allocation of aggregate samples to the mission sample analysis team. Meanwhile, curation engineers developed a tool to remove the stubborn fasteners without contaminating the remaining sample, enabling the remaining bulk sample to be transferred to long-term storage trays in January 2024. With this second part of the bulk sample, the returned bulk asteroid sample reached 121.6 grams. During disassembly and prior to sealing the bulk sample trays into long-term storage containers, archival photographs were collected. Select particles are gradually being XCT scanned while inside of containers that hold a nitrogen atmosphere. The initial OSIRIS-REx sample catalog was released in spring 2024 with an update in fall 2024. The curation team will be busy working to allocate samples to scientists around the world for the foreseeable future.

Curation↗