Virtual Special Issue: Geoarchaeology at the Micro‐Scale: Recent Advances in Microanalytical Techniques

Over the last few decades, geoarchaeology has witnessed rapid growth in the development and application of microanalytical techniques across a variety of archaeological contexts (Macphail and Goldberg 2018; Karkanas and Goldberg 2018; Weiner 2010). This growth includes both the further refinement of theoretical principles and advances in methodology. To highlight these advances and identify persistent gaps in these geoarchaeological approaches, we convened experts at the 2022 annual meeting of the Geological Society of America in Denver, Colorado. Our session, titled “Geoarchaeology at the Micro-Scale: Recent Advances in Microanalytical Techniques,” featured contributions from around the world encompassing a wide range of case studies. This Virtual Special Issue of Geoarchaeology is dedicated to that session and includes seven papers showcasing the current and future state of the field. As discussed below, these papers present examples of multimethod microanalytical applications in diverse archaeological contexts spanning the last 130,000 years, effectively demonstrating the interpretive power of geoarchaeology for investigating past human behavior across space and time. To begin, Morrissey et al. (2025) incorporate soil micromorphology, µ-XRF, µ-FTIR, and organic petrography to study Middle Stone Age (MSA I) deposits from Cave 1 of the Klasies River Main site (KRM) on South Africa's southern Cape Coast. Researchers working at KRM studied a complex sequence of pre-MSA (> 110 ka) cave deposits formed by natural and cultural processes. Their research identifies nuanced lateral and vertical variations within contemporaneous deposits, largely due to intense human occupations and activity, such as midden and hearth formation and maintenance, as well as physical and chemical post-depositional alterations. Their work highlights the importance of not solely relying on macro-scale observations alone to correlate deposits in caves and rockshelter settings, and sheds light on past behavior of MSA peoples, including how they organized, structured, and maintained living space during a key time and place in our species' evolutionary history. Continuing into the Pleistocene, Meinekat et al. (forthcoming) contribute new perspectives to early coastal lifeways at the archaeological site Quebrada-Jaguay 280 in southern Peru. They incorporate soil and sediment micromorphology with µ-XRF to identify a series of living areas which were postdepositionally altered by salt action and bioturbation. Through this multiscalar approach, the authors were able to pinpoint site maintenance activities, as well correlate the role of halite and gypsum formation to more humid periods, which sheds light on paleoenvironmental conditions which helped form the site's stratigraphy. Their research represents one of the few applications of micro-geoarchaeology in Paleoindian research in Peru and sets a new standard for future research in the region. Familetto et al. (2026) offer unique insight into Early Neolithic tilled fields associated with Swifterbant settlements (4500 and 4200 B.C.E.) now submerged beneath Lake IJssel, Netherlands. They applied soil and sediment micromorphology, portable X-ray fluorescence spectrometry (p-XRF), loss on ignition (LOI), and radiocarbon dating to a series of cores to disentangle a series of lagoonal, coastal, and levee deposits. Importantly, their research identified periods when mature tidal levees would have experienced “windows of suitability” for utilization. Additionally, their multi-analytical approach facilitated the identification of increased anthropogenic activity, such as burning and tilling, for multiple generations between 4525 and 4210 B.C.E. Their research suggests a sustained engagement with the lagoon-rim levee landscape of the Early Neolithic Lake-IJssel area, and exemplifies how geoarchaeology can study human-environment dynamics in wetland settings from the micro-to-landscape scale. Andreaki et al. (2025) also apply soil micromorphology to the study of wetland settings at a Neolithic site at the lakeside settlement of La Draga (Lake Banyoles), Spain (5300–4800 cal B.C.E.). Drawing on microstratigraphic analysis of samples from excavations and supported by robust Bayesian chronological modeling of these contexts, they identify micro‑scale evidence for trampling, burning, construction episodes, and repeated surface maintenance. These data allow the authors to reconstruct domestic practices and waste‑management strategies within a community living in a highly dynamic lacustrine environment. Fluctuating water levels throughout the history of the community not only shaped behavior and spatial organization but also profoundly influenced preservation. Without micro‑scale examination of cultural sediments, lacustrine deposits, and pedogenic traces of changing hydrology, the degree to which inhabitants adapted their lifeways to living with water would remain unresolved. Gaggioli and Van Damme (2025) provide the first study of late Middle Helladic to Late Helladic I period (1700–1550 B.C.E.) mortuary practices associated with a low tumulus and associated built chamber tomb in Eleon, Greece. Micromorphology, combined with granulometry and Fourier transform infrared spectrometry (FTIR), allowed the researchers to identify six microfacies associated with the construction, maintenance, repeated use, and abandonment of a single stable and long-lasting earthen architectural monument. Their findings illuminate the social and ritual logic behind tumulus construction and reuse and show how microstratigraphic approaches help to reveal generational processes of memory and identity in Ancient Greece. Deposits in natural caves are often the subject of geoarchaeological investigations, but formation processes of artificial caves, like mines, are rarely considered. Cereda et al. (2025) present a novel application of micro-scale geoarchaeology to deposits preserved within the Kropfsberg Mine in the Austrian state of Tyrol. By combining traditional stratigraphic analyses with soil micromorphology and µ-XRF elemental mapping, the authors reconstruct not just overlapping phases of mining activity, which extend back to at least the Early Iron Age, but also a pit deposit of Roman coins and charred materials associated with Late Antique Mithraeum cult activities. Their investigations helped confirm the interpretation that the pit filled with coins and the by-products of fires was likely ceremonial, and that the pit was subsequently buried by natural flooding from the Inn River. Their study illustrates how micro‑scale methods can disentangle the intertwined cultural and geomorphic processes that structure historically modified subterranean environments. Finally, Parish (2025) demonstrates that microscalar geoarchaeological approaches can extend from sediments and soils to archaeological materials, such as stone tools. He applied reflectance spectroscopy to chert artifacts at the Carson-Conn-Short (40BN190)—a Pleistocene-aged hunter-gatherer site along the Tennessee River, USA. Specifically, Parish acquired spectral data from 1351 regional geologic samples and 58 artifacts from the site. Multivariate statistical analysis and machine learning was applied to the data set to differentiate between local and non-local chert sources and utilization. His study shows how reflectance spectroscopy data at the nanometer scale using diagnostic atomic, molecular, and structural information can study past forager stone tool resource use, group mobility, and social networks during the late Pleistocene. As pointed out by Shillito et al. (2019), microarchaeology can no longer be considered “new.” However, as the papers in this Special Issue demonstrate, the application of complementary analytical techniques, such as p-XRF, µ-XRF, and µ-FTIR, to resin-impregnated block samples and thin-sections represent the current frontier of microscalar geoarchaeology, allowing researchers to develop multiple lines of evidence to test hypotheses about site formation processes, geochronology, and paleoenvironments across a variety of unique archaeological contexts. Of particular importance is the application of µ-FTIR and µ-XRF to identify allogenic and authigenic minerals at the micro-scale and to generate elemental scans of thin sections, respectively, to reconstruct preservation conditions, evaluate stratigraphic integrity, and reconstruct formation processes. These two microscalar methods are quickly becoming a new standard in microarchaeology. Additionally, although there are no examples in our issue, it's clear that microcontextual approaches to sediments and soils will continue to be a crucial aid to new exciting applications in archeology, such as sedaDNA (Aldeias and Stahlschmidt 2024), fecal biomarker analyses (Rodriguez de Vera et al. 2020; Shillito et al. 2020), and zooarchaeology by mass spectrometry (ZooMS) (Fagernäs et al. 2025). As we continue to refine and develop geoarchaeological approaches, it is clear that microscalar applications will remain central to the study of people and environments in archeology. We hope this Special Issue helps inspire innovations and new applications, especially by the next generation of multiscalar geoarchaeologists. Justin A. Holcomb: conceptualization, writing – review and editing. Michael J. Aiuvalasit: conceptualization, writing – review and editing. Special thanks to Sarah Sherwood, Kevin Walsh, and Lisa Shillito for their support during the publication of this Virtual Special Issue. Justin A Holcomb would like to thank Rolfe Mandel for his continued support in all things geoarchaeology. Michael J Aiuvalasit would like to thank Timothy Pauketat, Kristin Hedman, and the Prairie Research Institute for their support.