We explore developments in tephra science that consider more than chronology, using case studies of morphological transformations of tephra deposits. Volcanic processes and prevailing weather conditions determine the distribution of tephra deposits immediately after an eruption, but as these freshly fallen tephra become part of the stratigraphic record, the thickness, morphology and definition of the layers they form changes, reflecting the interplay of the tephra, climate, Earth surface processes, topography and vegetation structure, plus direct or indirect modification caused by people and animals. Once part of the stratigraphic record, there can be further diagnostic changes to the morphology of tephra layers, such as the creation of over folds by cryoturbation. Thus, tephra layers may contain proxy evidence of both past surface environments and subsurface processes. Transformations of tephra deposits can complicate the reconstruction of past volcanic processes and make the application of classical tephrochronology as pioneered by Thorarinsson (Sigurður Þórarinsson in Icelandic) challenging. However, as Thorarinsson also noted, novel sources of environmental data can exist within transformed tephra sequences that include the spread or removal of tephra, variations in layer thickness and internal structures, the nature of contact surfaces and the orientation of layers.
We explore the effect small‐scale surface features have on influencing the morphology and grain‐size distribution (GSD) of tephra layers within the Quaternary stratigraphy of sub‐polar landscapes. Icelandic thúfur, small cryogenic earth mounds, are used to assess how and why the morphology and GSD of tephra layers vary over such formations. Through measurement of tephra layer thickness and GSD, Hekla 1947 and Grímsvötn 2011 tephra layers are analysed. Results indicate that such microtopographic features do indeed alter the form of tephra deposits and therefore the tephra layer that is preserved in the stratigraphy. Tephra thickness is significantly greater in hollows than on the thúfur crests. There is greater variation in tephra thickness measurements from thúfur in comparison to control measurements from a surface where thúfur are absent. Thúfur crests contain larger grain sizes than hollows, for both H1947 and G2011 tephras; however this was only statistically significant for the G2011 tephra. Such morphological patterns are thought to arise from an interplay of tephra characteristics, altered topography from the thúfur formations and earth surface processes operating at the sites. This study provides insight into the potential of tephra layer morphology and internal structures as indicators of Quaternary landforms and processes. Additionally, it provides important context for the appropriate sampling of tephra layers to infer volcanological processes, as the characteristics of preserved layers do not necessarily reflect those of the original fall‐out.
The North Atlantic Biocultural Organization (NABO) community initiated dataARC to develop digital research infrastructures to support their work on long-term human-ecodynamics in the North Atlantic. These infrastructures were designed to address the challenges of sharing research data, the connections between those data and high-level interpretations, and the interpretations themselves. In parallel, they were also designed to support the reuse of diverse data that underpin transdisciplinary synthesis research and to contextualise materials disseminated widely to the public more firmly in their evidence base. This article outlines the research infrastructure produced by the project and reflects on its design and development. We outline the core motivations for dataARC's work and introduce the tools, platforms and (meta)data products developed. We then undertake a critical review of the project's workflow. This review focuses on our understanding of the needs of stakeholder groups, the principles that guided the design of the infrastructure, and the extent to which these principles are successfully promoted in the current implementation. Drawing on this assessment, we consider how the infrastructure, in whole or in part, might be reused by other transdisciplinary research communities. Finally, we highlight key socio-technical gaps that may emerge as structural barriers to transdisciplinary, engaged, and open research if left unaddressed.
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