A prehistoric jade axe from Galicia (Northwestern Iberia): Researching its origin

The Vilapedre axe (Lugo, Northwest Iberia) has been traditionally considered by archaeologists as evidence of prehistoric long-distance contacts along the Atlantic Coast of France and Spain. This artefact - as other “Tumiac type” axes (long polished blades, generally butt-perforated) - would have been produced in Brittany during the Neolithic (5th millennium BCE) using jadeitite as raw material, a green-coloured rock for which there are sources in the western Italian Alps. In this paper, we have traced the possible archaeological origin of this artefact back by examining the personal files of one of its first owners, Santiago de la Iglesia. Furthermore, we have conducted a mineralogical (X-Ray Diffraction, XRD) and an elemental analysis (Scanning Electron Microscopy with Energy Dispersive X-ray Detection, SEM-EDX) of both the Vilapedre axe and geological samples from several places at the Alps where prehistoric quarrying of greenstones has been reported. The aims were physicochemically characterizing the axe to provide information about its possible geological source. During our analyses, we have found significant compositional similarities between the Vilapedre axe and one of the geological samples coming from the Alps (Alp06). The results are therefore consistent with the alleged Alpine origin of this artefact. The presence of this axe in Northwest Spain, together with other evidence, such as the presence of objects of Iberian origin in Breton monuments, strongly suggests the existence of contacts between both regions of the Atlantic façade during the Neolithic onwards in which seafaring would undoubtedly have played an important role.

Artefact Categories, Artefact Assemblages and Ontological Alterity

Joan Gero argued that archaeological interpretation is not the accumulation of truth but rather an ideological construct. Post-colonial studies building on Gero's work critique notions of universal value, that aspects of human cultural heritage hold value for all peoples. However, these studies are not specific about what a post-colonial analysis of the archaeological record might look like, particularly involving material culture categories. What appear as fundamental artefact classes remain and so appeal to a form of universal value. Here we employ a novel application of the ontological turn, specifically Holbraad's method of ontography, to break away from conventional approaches to stone artefact categorization and interpretation. We use Lucas’ discussion of materialization to develop an alternative approach to artefact categories considering two assemblages of artefacts from the North Island of Aotearoa. Both feature large numbers of obsidian artefacts. The obsidian provides the means to investigate levels of historical use, since the material is identifiable to geological source, analysable technologically and retains traces of use. Using the results of obsidian analyses, we investigate the concepts on which archaeologists have based assessments of the relationships among material culture items, suggesting ways in which archaeologists might consider creating space for post-colonial ontologies.

Effects of rotational submarine slump dynamics on tsunami genesis: new insight from idealized models and the 1929 Grand Banks event

Sediment slumps are known to have generated important tsunamis such as the 1998 Papua New Guinea (PNG) and the 1929 Grand Banks events. Tsunami modellers commonly use solid blocks with short run-out distances to simulate these slumps. While such methods have the obvious advantage of being simple to use, they offer little or no insight into physical processes that drive the events. The importance of rotational slump motion to tsunamigenic potential is demonstrated in this study by employing a viscoplastic landslide model with Herschel–Bulkley rheology. A large number of simulations for different material properties and landslide configurations are carried out to link the slump's deformation, rheology, its translational and rotational kinematics, to its tsunami genesis. The yield strength of the slump is shown to be the primary material property that determines the tsunami genesis. This viscoplastic model is further employed to simulate the 1929 Grand Banks tsunami using updated geological source information. The results of this case study suggest that the viscoplastic model can be used to simulate complex slump-induced tsunami. The simulations of the 1929 Grand Banks event also indicate that a pure slump mechanism is more tsunamigenic than a corresponding translational landslide mechanism.

Geological Sources of Obsidian on Lipari and Artifact Production and Distribution in the Neolithic and Bronze Age Central Mediterranean

The Aeolian island of Lipari, just north of eastern Sicily, was a major geological source of high quality obsidian that was volcanically formed in the Late Mesolithic, followed by another major production in the 1st millennium AD. A much earlier volcanic event on Lipari also produced some obsidian, but not of sufficient quality for tool production. A detailed geological survey of the Lipari obsidian source areas, including assessments of quantity, quality, accessibility, and visual variation was performed, followed by elemental analyses using INAA, LA-ICP-MS, ED-XRF, and pXRF which show that many different groups may be distinguished from each other. Geochemical analyses of several thousand obsidian artifacts from sites in Sicily and southern Italy reveal that two early Holocene subsources, Gabellotto Gorge and Canneto Dentro, were used during the Neolithic and Bronze Ages.

Reanalysis of the 1761 transatlantic tsunami

The segment of the Africa–Eurasia plate boundary between the Gloria Fault and the Strait of Gibraltar has been the setting of significant tsunamigenic earthquakes. However, their precise location and rupture mechanism remain poorly understood. The investigation of each event contributes to a better understanding of the structure of this diffuse plate boundary and ultimately leads to a better evaluation of the seismic and tsunami hazard. The 31 March 1761 event is one of the few known transatlantic tsunamis. Macroseismic data and tsunami travel times were used in previous studies to assess its source area. However, no one discussed the geological source of this event. In this study, we present a reappraisal of tsunami data to show that the observations data set is compatible with a geological source close to Coral Patch and Ampere seamounts. We constrain the rupture mechanism with plate kinematics and the tectonic setting of the area. This study favours the hypothesis that the 1761 event occurred in the southwest of the likely location of the 1 November 1755 earthquake in a slow deforming compressive regime driven by the dextral transpressive collision between Africa and Eurasia.

Late Palaeolithic and Mesolithic Treatment and Use of Non-flint Stone Raw Materials: Material Collection From Site 17 at Nowogród, Golub-Dobrzyń District, Poland

The aim of the article is to present the results of a multifaceted analysis of a collection of non-flint stone artefacts obtained during excavations of the complex of Late Palaeolithic camps at site 17 in Nowogród, Golub-Dobrzyń district. It included an obsidian artefact and objects made of crystalline rocks (quartzite, quartzite sandstone, quartz, coarse sandstone and diorite), which were created as a result of knapping the raw material using techniques similar or identical to those used during the processing of flint. The results of petrographic analysis confirmed that these raw materials had come from natural resources located near the site. Most of the analysed artefacts are represented by large flakes. In addition, one chip and two tools, a multiple burin and a pebble tool, were distinguished. Use-wear analysis showed signs of use on two artefacts, including the pebble tool. The obsidian artefact is currently the northernmost Late Palaeolithic find of this type. In order to determine the geological source of the raw material, the artefact was subjected to PGAA and XRF analysis. PGAA analysis confirmed that the obsidian originated from a source in northern Slovakia (Carpathian 1 type), probably from the Cejkov or Kašov deposits, Trebišov district. The article also describes a rock crystal and a probable concretion of quartz of this type originating from site 6 in Ludowice, Wąbrzeźno district