Dr. Rachel Kirby - Honours Projects

A new meteorite group – investigating and defining the “F chondrite” meteorite group

In 2025, we proposed that there is evidence for a new group of meteorite – the “F chondrites”, named after the forsterite content of their olivine. This finding was based on previous literature data, and a more comprehensive study is required to answer the question – are these meteorites related, and did they form on the same parent asteroid? To answer this question, a selection of individual meteorites from the proposed “F chondrites” will be comprehensively studied, including their petrology (i.e. mineral and textural relationships) and chemistry. This will be done through the use of optical microscopy, EPMA, and LA-ICP-MS.

Recrystallisation and thermal metamorphism in the planetary nebula

Type 3 chondrites are relatively pristine meteorites that do not show significant degrees of either thermal or aqueous alteration. Chondrules in type 3 chondrites are well preserved and display a wide array of compositions, morphologies and sizes within a single meteorite sample. Variability is also seen within each chondrule as to the degree of recrystallisation and thermal metamorphism each has experienced.  This process seeks to a) survey and quantify the diversity of thermal metamorphic indicators in individual chondrules within a meteorite, and b) determine whether or not this diversity can occur during a single heating event or if it requires individual chondrules to have experienced distinct thermal histories. This will be done through the use of optical microscopy, EPMA, and SEM analyses.

Metamorphism of carbonaceous asteroids

CK chondrites are a group of oxidised meteorites that formed in the early solar system. A perplexing characteristic noted in many CK chondrites is that they have quite distinct chondrules, which generally is interpreted as not being highly metamorphosed, however the matrix shows evidence of highly recrystallised phases, which generally is interpreted to have formed through high degrees of metamorphism. What process/es result in CK chondrites forming a coarse-grained matrix whilst still retaining distinct chondrules? What does this tell us about early solar system conditions? This project seeks to address these questions through comprehensive studies of CK chondrites using both petrological (i.e. mineral and textural relationships) and geochemical techniques. Key techniques include optical microscopy, EPMA, SEM, and EBSD.

For further information contact Dr. Rachel Kirby