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The carbon isotopic signature inherited from soil and epikarst processes may be modified by degassing and prior calcite precipitation (PCP) before its imprint on speleothem calcite. Despite laboratory demonstration of PCP effects on carbon isotopes and increasingly sophisticated models of the governing processes, to date, there has been limited effort to deconvolve the dual PCP and soil-epikarst components in measured speleothem isotopic time series. In this contribution, we explore the feasibility, advantages, and disadvantages of using trace element ratios and δ⁴⁴Ca to remove the overprinting effect of PCP on measured δ¹³C to infer the temporal variations in the initial δ¹³C of drip water prior to degassing and PCP. In nine examined stalagmites, the most widely utilized PCP indicators Mg/Ca and δ⁴⁴Ca covary as expected. However, Srg/gCa does not show consistent relationships with δ⁴⁴Ca so PCP is not the dominant control on Srg/gCa. From δ⁴⁴Ca and Mg/Ca, our calculation of PCP as f_Ca, the fraction of initial Ca remaining in solution at the time the stalagmite layer is deposited, yields multiple viable solutions depending on the assumed δ⁴⁴Ca fractionation factor and inferred variation in DMg. Uncertainty in the effective fractionation of δ¹³C during degassing and precipitation contributes to uncertainty in the absolute value of estimated initial δ¹³C. Nonetheless, the trends in initial δ¹³C are less sensitive to these uncertainties. In coeval stalagmites from the same cave spanning the 94 to 82 ka interval, trends in calculated initial δ¹³C are more similar than those in measured δ¹³C and reveal a common positive-Anomaly initial δ¹³C during a stadial cooling event. During deglaciations, calculated initial δ¹³C implies a trend of greater respiration rates and higher soil CO₂, although the higher interglacial drip water saturation favors more extensive PCP. Initial δ¹³C can be estimated for active and fossil speleothems from a range of settings, wherever there is confidence that Mg/Ca and/or δ⁴⁴Ca provides a quantitative indication of past changes in PCP. Further study of Mg partitioning in speleothems will improve the robustness of Mg/Ca as a PCP proxy. Climate of the Past, 19 (12) ISSN:1814-9332 ISSN:1814-9324

The last decade has seen a steady increase in the application of virtual 3D approaches in cultural heritage research. Although a large literature exists about the advantages of 3D methods in this field, here we go one step further and elucidate a) how image-based 3D reconstructions can be displayed in virtual reality (VR) space using freeware game engine software and low-cost VR hardware and b) highlight the relative benefits and advantages with a focus on interactive museum displays of relatively large archaeological objects. Specifically, we present three 3D models of different stone grave structures from the Neolithic necropolis of Lenzburg (Northern Switzerland, 4450-3500 BCE). The site has been excavated in 1959/60 and certain graves were subsequently preserved for museum display. By means of VR applications, it is now possible to experience these approximately 6000-year-old tombs with an innovative approach circumventing various barriers or constraints and offering interactive display options.

Abstract. The East African Rift System (EARS) represents a major tectonic feature that splits the African continent between the Nubian Plate situated to the west and the Somalian Plate to the east. The EARS comprises various rift segments and microplates and represents a key location for studying rift evolution. Researchers have proposed various scenarios for the evolution of the EARS, but the impact of continent-scale rotational rifting, linked to the rotation of the Somalian Plate, has received only limited attention. In this study we apply analogue models to explore the dynamic evolution of the EARS within its broader rotational-rifting framework. Our models show that rotational rifting leads to the lateral propagation of deformation towards the rotation axis, which reflects the general southward propagation of the EARS. However, we must distinguish between the propagation of distributed deformation, which can move very rapidly, and localized deformation, which can significantly lag behind the former. The various structural-weakness arrangements in our models (simulating the pre-existing lithospheric heterogeneities that localize rifting along the EARS) lead to a variety of structures. Laterally overlapping weaknesses are required for localizing parallel rift basins to create rift pass structures, leading to the rotation and segregation of microplates such as the Victoria Plate in the EARS, as well as to the simultaneous north- and southward propagation of the adjacent Western Rift. Additional model observations concern the development of early pairs of rift-bounding faults flanking the rift basins, followed by the localization of deformation along the axes of the most developed rift basins. Furthermore, the orientation of rift segments with respect to the regional (rotational) plate divergence affects deformation along these segments: oblique rift segments are less wide due to a strike-slip deformation component. Overall, our model results generally fit the large-scale present-day features of the EARS, with implications for general rift development and for the segregation and rotation of the Victoria Plate.

Like any science marked by high uncertainty, climate science is characterized by a widespread use of expert judgment. In this paper, we first show that, in climate science, expert judgment is used to overcome uncertainty, thus playing a crucial role in the domain and even at times supplanting models. One is left to wonder to what extent it is legitimate to assign expert judgment such a status as an epistemic superiority in the climate context, especially as the production of expert judgment is particularly opaque. To begin answering this question, we highlight the key components of expert judgment. We then argue that the justification for the status and use of expert judgment depends on the competence and the individual subjective features of the expert producing the judgment since expert judgment involves not only the expert's theoretical knowledge and tacit knowledge, but also their intuition and values. This goes against the objective ideal in science and the criteria from social epistemology which largely attempt to remove subjectivity from expertise.

This paper presents the results of the provenience analysis of siliceous artefacts from Neolithic lakeshore settlements studied in the scope of the SNSF-project MET (“Mobilities, entanglements and transformations in Neolithic societies on the Swiss Plateau (3900-3500 BCE) supported by the Swiss National Science Foundation (Project No 100011 156205). The aim of this paper is to compare the cultural entanglements as defined by the pottery studies with the regions of origins of the knappable siliceous sedimentary rocks (KSSR) raw materials. The analysed siliceous artefacts were found in cultural layers of wetland settlements in the Northern Alpine Foreland, most of which are dated dendrochronologically with extreme precision. The sources of the raw materials were determined by the identification of the sedimentary microfacies of the siliceous artefacts, which allows the accurate location of the exploited outcrops without destroying the artefacts. This enabled detailed insights into complex entanglements, ties and mobility patterns in the raw material procurement between settlement communities on the Swiss Plateau, southern Germany and eastern France. Furthermore, these results were compared visually with stylistic entanglements in the pottery of the 4th millennium BCE. As a first attempt in this direction, this paper shows the potential of studies on mobility patterns when different find categories are studied in combination regarding their raw materials but also their typology.

Explosive volcanism is a key contributor to climate variability on interannual to centennial timescales1. Understanding the far-field societal impacts of eruption-forced climatic changes requires firm event chronologies and reliable estimates of both the burden and altitude (that is, tropospheric versus stratospheric) of volcanic sulfate aerosol2, 3. However, despite progress in ice-core dating, uncertainties remain in these key factors4. This particularly hinders investigation of the role of large, temporally clustered eruptions during the High Medieval Period (HMP, 1100–1300 ce), which have been implicated in the transition from the warm Medieval Climate Anomaly to the Little Ice Age5. Here we shed new light on explosive volcanism during the HMP, drawing on analysis of contemporary reports of total lunar eclipses, from which we derive a time series of stratospheric turbidity. By combining this new record with aerosol model simulations and tree-ring-based climate proxies, we refine the estimated dates of five notable eruptions and associate each with stratospheric aerosol veils. Five further eruptions, including one responsible for high sulfur deposition over Greenland circa 1182 ce, affected only the troposphere and had muted climatic consequences. Our findings offer support for further investigation of the decadal-scale to centennial-scale climate response to volcanic eruptions. Acknowledgements: S.G., C.C., M.K. and M. Stoffel were supported by the Swiss National Science Foundation Sinergia Project CALDERA (CRSII5_183571). S.G. acknowledges A. Harrak (Department of Near and Middle Eastern Civilizations, University of Toronto), F. Espenak (NASA Goddard Space Flight Center), F. Hierink (Institute for Environmental Sciences, University of Geneva) and P. Souyri (Department of East Asian Studies, University of Geneva) for providing advice on the manuscript. F. Lavigne was supported by Institut Universitaire de France (IUF, Academic Institute of France). M.K. received funding from the EUR IPSL – Climate Graduate School project, managed by the ANR within the “Investissements d’avenir” programme under reference ANR-11-IDEX-0004-17-EURE-0006. F. Ludlow received funding from an Irish Research Council Starting Laureate Award (CLICAB project, IRCLA/2017/303). F. Ludlow and Z.Y. also received funding from a European Research Council (ERC) Synergy Grant (4-OCEANS; grant agreement no. 951649) under the European Union’s Horizon 2020 research and innovation programme. M. Sigl received funding from the ERC under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 820047). This paper is a product of the Volcanic Impacts on Climate and Society (VICS) working group.