Niklas Hausmann

Mapping, modelling and predicting prehistoric coastal archaeology in the southern Red Sea using new applications of digital-imaging techniques

Abstract Over 3,000 shell-midden sites have been located in the southern Red Sea using digital-imaging techniques, in a combination of palaeo-landscape reconstruction and remote survey. The primary methods include digital-imaging techniques – high-resolution satellite images, false colour images and radar data. Surveying and recording these sites during excavation has also been enhanced using digital photogrammetry – allowing high-resolution site-level data to be incorporated into wider landscape reconstructions. The resulting data are combined to construct site location models that have been proved and tested in other areas of the southern Red Sea. We also show how satellite imagery can be modified and exploited for seabed mapping and the search for underwater sites.

Seasonal Patterns of Coastal Exploitation on the Farasan Islands, Saudi Arabia

ABSTRACT Here we present the results of the analysis of coastal exploitation patterns in the southern Red Sea during the Middle Holocene. We focus on the shell midden cluster of the Farasan Islands, Saudi Arabia, which comprises over 3,000 shell midden sites. These sites date from 6,500 to 4,500 cal BP and are part of an arid landscape. We focus on one site, JW1727, which provides a snapshot of marine exploitation and will help to understand the use of food resources within the region. Stable isotope values (δ18O) were collected from the marine gastropod Conomurex fasciatus (Born 1778), which represents 72% of shell weight of JW1727, in order to reconstruct the season of capture. Results demonstrate that 1) every season is represented within the dataset; and 2) there is increased C. fasciatus deposition during the summer and autumn months. This indicates a diet consisting of C. fasciatus throughout the year in combination with other food sources and an increase of the C. fasciatus component during the arid seasons, possibly linked to the unavailability of vegetation. Additionally, size measurements of C. fasciatus were carried out to examine changes in size distribution throughout the occupation of the site that could be related to overexploitation of C. fasciatus. However, no significant trends could be observed. In sum, the results suggest a sustainable and constant habitation of the Farasan Islands despite the highly arid conditions.

Elemental mapping of Mg/Ca intensity ratios in marine mollusc shells using laser-induced breakdown spectroscopy

Records of past environmental conditions in shell carbonate are usually derived from compositional analysis (i.e. trace elements, stable oxygen, carbon, and nitrogen isotopes) performed along the direction of the shells growth and thus through time. However, compositional variations within isochronous parts of the shell can distort the environmental record and are difficult to assess without extensively mapping the whole shell. Here we apply Laser Induced Breakdown Spectroscopy (LIBS) to efficiently map the elemental change throughout the growth increments of three mollusc shells (Conomurex fasciatus, Ostrea edulis, Anomalocardia flexuosa). We employ an automated LIBS setup to map the Mg/Ca composition of whole shell sections with over 2000 data points per hour. By assessing the spatial variability of Mg/Ca intensity ratios this method has the potential to mitigate distorted results while increasing the resolution of derived palaeoenvironmental information.