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To ensure harmonised seabed mapping over large areas and to facilitate the exchange of information, a common geological knowledge base is being developed for the southern part of the North Sea. Data, sustaining this marine geological database, originate from a variety of sources, including the industry. Related to the seabed and its subsurface, two main databases are being compiled: one comprising all available lithological descriptions and one with all numerical grain-size information. To enable standardisation of the data and make them easily queryable, non-numerical descriptions are being coded to an international standard (EU FP7 Geo-Seas), of which the Udden-Wentworth scale is the main classifier. Several other parameters were derived, such as percentages mud, sand, gravel, shells and organic material. For the second database, cumulative grain-size distribution curves were compiled, enabling calculations of any desired granulometry parameter, such as percentages of the grain-size fractions (fine, medium, coarse sand) and percentiles that are relevant in seabed-habitat mapping or sediment-transport modelling (D35, D50, D84). To quantify data uncertainty in the derived data products, metadata on sampling and coring techniques, analytical methods, horizontal and vertical positioning accuracy and the exact timing of data acquisition were included. These metadata fields are also crucial in the quantification of habitat changes, a key issue in the assessment of good environmental status within Europe’s Marine Strategy Framework Directive. The newly developed database and its associated data products contribute to the objectives of the projects TILES (Belspo Brain-be), EMODnet-Geology (EU DG MARE), and ZAGRI (private revenues from the marine-aggregate industry).

Extreme-wave events (tsunamis, storm surge and waves) pose significant hazards to coastal communities worldwide. Onshore deposits from these events significantly enhance our understanding of their long-term frequency-magnitude patterns, which are usually not covered by historical and instrumental documentation. Such perspectives are crucial for successful coastal hazard assessments and consequential efforts to mitigate against the loss of life and assets. Methods enabling reliable and consistent differentiation between the sedimentary evidence for tsunamis and storms remain elusive as deposits from both processes share a number of sedimentary criteria. Microfossil approaches (foraminifera, ostracods, diatoms) have yielded promising progress towards conclusive identification (PILARCZYK et al., 2014), however dissolution and bacterial degradation of carbonate tests often prevent microfossil identification. To address this issue in a pioneering project kicked-off in late 2017, we aim at using high-throughput, metagenomic sequencing techniques to identify marine organisms in onshore sand layers from their DNA remains and to unravel cryptic diversities. We focus on foraminifera, single-celled protists, which show depth-related zonation in subtidal environments and have already been traced successfully in palaeo-tsunami deposits by their ancient DNA (SZCZUCIŃSKI et al., 2016), and compare classic and molecular methods for their identification. Three objectives will be followed to reach this goal: 1. Quantify the relationship between water depth and the distribution of different species of foraminifera using both classic assemblage methods and metagenomic approaches. 2. Assess the potential for identifying key indicator species in extreme-wave deposits in different climate settings based on both assemblage approaches and metagenomic high-throughput sequencing techniques; 3. Establish how metagenomic approaches contribute to consistent and reliable differentiation between the sedimentary evidence for storms and tsunamis in coastal settings. The three key field areas, which share an abundance of published, well-dated evidence for both storms and tsunamis, comprise the Shetland Islands, south central Japan, and southern Chile. The Shetland Islands have a temperate oceanic climate, and near-shore lakes and coastal peat lowlands feature sand sheets deposited by the submarine Storegga landslide around 8 ka years ago and a younger tsunami dated to 1.5 ka (e.g. BONDEVIK et al., 2005). Extreme-wave deposits from south central Japan, underlying a subtropical climate, are available through the ongoing BELSPO BRAIN-be-funded QuakeRecNankai project, focusing on records of past earthquakes and tsunamis along the Nankai Trough (GARRETT et al., 2016). At temperate-humid Chaihuin, southern Chile, deposits of the 1960 Chile tsunami and several older events have been documented (HOCKING & GARRETT, 2016) and sampled for identification of foraminiferal assemblages based on DNA remains. REFERENCES BONDEVIK, S., MANGERUD, J., DAWSON, S., DAWSON, A. & LOHNE, Ø. 2005. Evidence for three North Sea tsunamis at the Shetland Islands between 8000 and 1500 years ago. — Quaternary Science Reviews, 24: 1757–1775. GARRETT, E., FUJIWARA, O., GARRETT, P., HEYVAERT, V.M.A., SHISHIKURA, M., YOKOYAMA, Y., HUBERT-FERRARI, A., BRÜCKNER, H., NAKAMURA, A., DE BATIST, M. & THE QUAKERECNANKAI TEAM. 2016. A systematic review of geological evidence for Holocene earthquakes and tsunamis along the Nankai-Suruga Trough, Japan. — Earth-Science Reviews, 159: 337–357. HOCKING, E. & GARRETT, E. 2016. Geological records of recent and historical ruptures of the Chilean subduction zone: a latitudinal transect of earthquake deformation and tsunami inundation. — Geophysical Research Abstracts, 18: EGU2016-938. PILARCZYK, J.E., DURA, T., HORTON, B.P., ENGELHART, S.E., KEMP, A.C. & SAWAI, Y. 2016. Microfossils from coastal environments as indicators of paleo-earthquakes, tsunamis and storms. — Palaeogeography, Palaeoclimatology, Palaeoecology, 413: 144–157. SZCZUCIŃSKI, W., PAWŁOWSKA, J., LEJZEROWICZ, F., NISHIMURA, Y., KOKOCIŃSKI, M., MAJEWSKI, W., NAKAMURA, Y. & PAWLOWSKI, J. 2016. Ancient sedimentary DNA reveals past tsunami deposits. — Marine Geology, 381: 29–33.

Nous présentons les résultats de l'analyse de l'ADN ancien provenant d'un pion d'échecs en ivoire découvert dans une occupation médiévale lors de fouilles archéologiques au pied de l'Enjambée, à Jambes (Namur). Le léger endommagement de la pièce lors des fouilles nous a permis de prélever quelques fragments d'ivoire ne pouvant pas être recollés lors de la restauration. Les analyses ADN nous ont permis de vérifier qu'il s'agit bien d'ivoire d'éléphant et plus précisément, d'un éléphant provenant vraisemblablement de l'est ou du sud de l'Afrique. Nous reconstituons également le trajet le plus probable de l'ivoire en territoire africain.