Recent developments in micro- to nano-scale analytical techniques have enabled unique observations of physical and chemical complexities in geological materials. The interaction of trace components with crystal defects can control the distribution/ redistribution of elements, as well as provide a record of meso- to tectonic-scale processes that govern Earth systems. This session focuses on the integration and development of structural and chemical analytical techniques for investigations of nano- to atomic-scale structural and geochemical processes. Studies involving transmission electron microscopy, high resolution electron backscatter diffraction, electron channeling contrast imaging, transmission Kikuchi diffraction, laser ablation – inductively coupled plasma – mass spectrometry, secondary ion mass spectrometry, and atom probe tomography are particularly welcomed. We encourage contributions with new insights on trace element heterogeneities, their presence/absence, detection, origin, and preservation, as well as the broader implications (and applications) in understanding geochemistry, economic geology, geochronology, and structural geology.