35 Minerals in Motion: Tracking Mineral Reactions Using In Situ and Synchrotron Techniques, A Celebration of the Career of Peter Heaney (Posters)

In celebration of the career of Dr. Peter Heaney, we invite submissions using in situ, synchrotron, X-ray, neutron, or electron techniques to study rates/mechanisms of mineral reactions, alongside contributions exploring new approaches to mineralogy education.

Sunday, 19 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Investigation of Moganite Phase transition under In-situ Heating / Cooling Using Synchrotron X-ray Diffraction and Pair Distribution Function Analysis

Paper number: 35-0
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

This study investigates the temperature-dependent crystal structure of moganite from the Mogán Formation, Gran Canaria, by combining in-situ synchrotron X-ray diffraction (XRD) and pair distribution function (PDF) analysis. Data collected from 300 K to 900 K were analyzed using both Rietveld and PDF refinement methods. Our analysis revealed a reversible phase transition from the monoclinic I2/a to the orthorhombic Imab space group between 560-580 K, consistent with previous reports. The thermal expansion behavior was notably anisotropic: the a and c lattice parameters increased up to the transition temperature, beyond which their expansion plateaued. In contrast, the b parameter expanded continuously, suggesting a gradual un-kinking of the tetrahedral [010] chains due to polyhedral rotations. Crucially, the PDF analysis provided atomic-scale insight into this process, successfully capturing the subtle local structural rearrangements that accompany the transition. Furthermore, the crystal structure of the high-temperature Imab phase was precisely refined at 900 K, and its structural parameters, including anisotropic atomic displacement parameters (ADPs), are reported. This work highlights the powerful synergy of combining XRD, which probes long-range average structure, with PDF analysis, which is sensitive to local atomic-level changes. This integrated approach proves especially effective for characterizing phase transitions in structurally complex or poorly crystalline materials such as nanominerals and clay minerals.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412533

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