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Discovering Europe's seabed geology: the EMODnet concept of uniform collection and harmonization of marine data
Abstract Maritime spatial planning, management of marine resources, environmental assessments and forecasting all require good seabed maps. Similarly there is a need to support the objectives to achieve Good Environmental Status in Europe's seas by 2020, set up by the European Commission's Marine Strategy Framework Directive. Hence the European Commission established the European Marine Observation and Data Network (EMODnet) programme in 2009, which is now in its fourth phase (2019–21). The programme is designed to assemble existing, but fragmented and partly inaccessible, marine data and to create contiguous and publicly available information layers which are interoperable and free of restrictions on use, and which encompass whole marine basins. The EMODnet Geology project is delivering integrated geological map products that include seabed substrates, sedimentation rates, seafloor geology, Quaternary geology, geomorphology, coastal behaviour, geological events such as submarine landslides and earthquakes, and marine mineral occurrences. Additionally, as a new product during the ongoing and preceding phase of the project, map products on submerged landscapes of the European continental shelf have been compiled at various time frames. All new map products have a resolution of 1:100 000, although finer resolution is presented where the underlying data permit. A multi-scale approach is adopted whenever possible. Numerous national seabed mapping programmes worldwide have demonstrated the necessity for proper knowledge of the seafloor. Acting on this, the European Commission established the European Marine Observation and Data Network (EMODnet) programme in 2009. The national geological survey organizations of Europe have a strong network of marine geological teams through the Marine Geology Expert Group of the association of European geological surveys (Eurogeosurveys). This network was the foundation of the EMODnet Geology consortium which today consists of the national geological surveys of Finland, the UK, Sweden, Norway, Denmark, Estonia, Latvia, Lithuania, Poland, The Netherlands, Belgium, France, Ireland, Spain, Italy, Slovenia, Croatia, Albania, Greece, Cyprus, Malta, Russia, Germany, Montenegro and Iceland, as well as marine teams of research organizations in Portugal (IPMA), Bulgaria (IO-BAS), Romania (GeoEcoMar), the UK (CEFAS), Greece (HCMR) and Ukraine (PSRGE, replaced in the fourth phase by Institute of Geological Sciences, NAS of Ukraine). The consortium is further strengthened with experts from six universities: Edge Hill University (UK), Sapienza University of Rome (Italy), University of Tartu (Estonia), University of Crete through FORTH-ICS, Institute of Marine Science and Technology of Dokuz Eylul University (Turkey), and EMCOL Research Centre of Istanbul Technical University – altogether, 30 partners and nine subcontractors. The EMODnet Geology programme is now in its fourth phase, which started in September 2019. In addition to geological information, the wider EMODnet programme aims to also bring together information from European seas on seabed habitats, physical properties, chemistry, biology, human activities and hydrography. This paper describes the EMODnet Geology project and the different end products which were delivered in the end of the third phase and will be further developed during the recent fourth phase of the project.
Abstract Analyses of high-resolution multibeam and sub-bottom profiling data, acquired during marine geological field cruises between 2017 and 2019 in the eastern Gulf of Finland (Baltic Sea), enabled the detailed mapping of Quaternary deposits, and revealed diverse submerged glacial and post-glacial landforms (e.g. streamlined moraine ridges, large retreat moraine ridges, De Geer moraines and kettle holes). The morphology of these glacial features provides evidence of the ice-sheet retreat direction and rate throughout the deglaciation of the region, which occurred between 13.8 and 13.3 ka BP (Pandivere–Neva Stage) and 12.25 ka BP (Salpausselkä I Stage). Analysis of sub-bottom profiling, supported by piston long-core sampling, indicates periods of bottom erosion/non-deposition during the Holocene caused by relative water-level regressions. Significant negative relief features are also observed in the area for the first time. These linear and curved V-shaped furrows are several kilometres long and 5 m deep, and are tentatively ascribed to bottom current and gas-seepage processes.
Abstract Through Ireland's national seabed mapping programme, Integrated Mapping for the Sustainable Development of Ireland's Marine Resource (INFOMAR), the collaboration between Geological Survey Ireland and the Marine Institute continues to comprehensively map Ireland's marine territory in high resolution. Through its work, the programme builds on earlier Irish seabed mapping efforts, including the Irish National Seabed Survey project in producing seabed mapping products that support Ireland's blue economy, European marine policy and international efforts to understand our global oceans. INFOMAR uses a variety of marine technologies to deliver accurate bathymetric maps and useful data products to end users through a free and open source licensing agreement. To reflect the diversity of applications these data products serve, a series of four case studies are presented here focusing on marine geophysical and geological data from locations within Ireland's marine territories. The case studies illustrate how data generated through seabed mapping may be interpreted to directly impact the generation of blue knowledge across a variety of marine environments ranging from shallow coastal and shelf waters to the deep oceanic depths of the continental slope of Ireland's marine area. The impact of Ireland's seabed mapping efforts is further considered in the context of national, European and international initiatives where Ireland's marine knowledge resource is leveraged to deliver positive benefit to the programme's stakeholders.
Abstract The European Marine Observation and Data Network (EMODnet) Project provides freely available data on European seas. The main purpose of EMODnet is to overcome the fragmentation and dishomogeneity of the available data, providing access to a harmonized and interoperable database. The EMODnet Geology Lot includes information at multiple scales on the seabed and its substrate ( http://www.emodnet-geology.eu/ ). The dataset on ‘Geological events and probabilities’ collects information on landslides, earthquakes, volcanic structures, active tectonics, tsunamis and fluid emissions. The Geological Survey of Italy, which coordinates the collation of ‘Geological events and probabilities’ data, provided guidelines to compile layers complemented by comprehensive and detailed patterns of attributes for each feature in order to characterize each type of geological event. Occurrences of events are often associated with each other, particularly in tectonically active areas. Geological events affect both submerged and coastal environments. Data gathered by EMODnet Geology provide a good basis for further studies, contributing to the outlining of different tectonic settings and providing support to the use of marine resources, as well as to the management of marine-coastal areas particularly regarding the identification and assessment of geological and environmental hazards.
EDWARD HITCHCOCK’S GEOLOGICAL SURVEY OF MASSACHUSETTS, 1830–1833
KEEPING THE BAY IN GLACIER BAY NATIONAL PARK: INTRODUCING GLACIER SCIENCE TO THE UNITED STATES SUPREME COURT
Abstract The current strong motivation to explore those traces of the archaeological and prehistoric human heritage that presently lie submerged on the continental shelf requires large-scale and precise underwater mapping. One Mediterranean sector deserving particular attention is the Sicily Channel, which is critical for a better understanding of the Africa–Europe migratory routes and early civilization patterns due to its large expanses of shallow seabed that were partially or totally exposed at times of lower relative sea levels. We have focused our attention on the submerged continental margin of the Maltese archipelago. A detailed bathymetric map is here presented, and is discussed in terms of features interpretable as former subaerial landforms and inundated by sea-level rise following the Last Glacial Maximum lowstand at approximately –130 m. Our datasets combine multibeam surveys, Light Detection And Ranging (LiDAR)-derived digital terrain models (DTMs), Chirp sub-bottom profiler records and bottom samples acquired between 2009 and 2012. The main features identified are former river incisions, alluvial plains, karst landscapes (sinkholes, limestone plateaus), slide deposits and palaeoshorelines. This study provides a detailed topographical reconstruction of the palaeolandscape of this key region that is relevant to any future archaeological exploration of the Maltese offshore area.
Abstract Recent underwater archaeological surveys recovered hundreds of flint artefacts between depths of 18 and 21 m at Cala Tramontana, a small bay located in the eastern part of Pantelleria Island. Most of the flint artefacts indicate debitage, and are characterized by cores and flakes without any specific morphology. Different lithic tools were also identified, such as fragments of blades, truncations, end-scrapers, points and crested blades. An initial hypothesis is that this lithic industry represents the oldest traces of human visitation to the island, possibly related to the exploitation of the nearby obsidian source, and favoured because of the sheltered coastal configuration of Cala Tramontana and Cala Levante with respect to the dominant winds and related storms. However, the present-day coastal setting in the bay is rather inhospitable, with high cliffs and difficult marine access. In contrast, palaeo-landscape reconstructions by means of high-resolution multibeam bathymetry reveal the possible presence of a small palaeo-beach in the inner part of the bay when the sea level was 15 m lower than at present. By comparing this palaeo-sea level with the eustatic curve (and by excluding possible vertical movements), we roughly estimate an age of the lithic industry of 9.6–7.7 cal ka BP.
Pleistocene submerged landscapes and Palaeolithic archaeology in the tectonically active Aegean region
Abstract In this paper we review the main, long- and short-term geological and geotectonic processes that have controlled the development of Pleistocene landscapes in the Aegean region above and below the fluctuating sea level. We discuss the potential for further research on reconstruction of submerged landscapes of the continental shelf and beyond with the aim of addressing questions concerning Palaeolithic settlement. The geological, tectonic, morphological and hydrogeological background provides information for the assessment of the natural resources available to hominins. Along with the palaeogeographical evolution of the shallow coastal and shelf areas, they are examined in parallel with the terrestrial archaeological record in order to open windows to future work in a region that has remained marginal to human origins research. On the basis of the multi-variable tectonic evolution and geomorphological configuration of the coastal and shelf areas, we propose to divide the Aegean region into nine geographical units, each with its own geotectonic and morphological history and traits. These units can be further grouped to provide larger neighbouring and culturally meaningful regions, suitable for archaeological analysis, or subdivided to provide smaller target areas in which to work.
Abstract Coastal geomorphic systems have been studied widely to understand the responses of shorelines to fluctuating sea levels. Submerged shorelines, remnant of Pleistocene sea-level lowstands, are well preserved on the South African continental shelf. This paper describes work undertaken to better understand offshore coastal environments now submerged by high sea levels off the South African south coast near Mossel Bay, offshore of the Pinnacle Point archaeological locality. Multibeam bathymetry and side-scan sonar reveal evidence of past sea-level fluctuations and submerged coastal landscape features on the seabed. These results form the basis of an ongoing palaeoenvironmental reconstruction for this part of the shelf. We describe seven significant geomorphic features that show a submerged environment that differs significantly to the immediate adjacent coastal plain. However, these features are comparable to other stretches of the present South African shoreline that serve as modern analogues. We propose that features on the continental shelf primarily reflect geological substrate, gradients and Pleistocene sea-level fluctuations. Early modern humans were likely to have had a different set of resources to use in this Pleistocene landscape compared to those available along the presently exposed coast.
Abstract This paper focuses on the continental shelf of NW Australia, and on models for change in littoral and offshore environments of relevance to human occupation over the last 50 kyr. Major island groups occur on the shelf including the Montebello and Barrow islands, and those of the Dampier Archipelago. At lowest sea level around 22 ka, these would have been uplands that then became progressively isolated by subsequent sea-level rise. By integrating archaeological and zooarchaeological records from excavations on these islands with the geology and geomorphology, we interpret palaeoeconomic resource potential in relation to changing sea level and coastline morphology. The preservation potential for submerged archaeological sites and features is also assessed. Current archaeological evidence from these offshore islands indicates that the submerged coastal landscape is likely to have been a potentially rich environment for resources and human occupation, even at times of lowest sea level and regional aridity. Should any exploration of submerged archaeology be carried out in this region, it is likely to be rewarding, offering unique insights into Late Pleistocene coastal occupation.
Potential submerged Aboriginal archaeological sites in South West Arm, Port Hacking, New South Wales, Australia
Abstract Sealed, submerged palaeoenvironmental deposits date the time range for lithic technologies and enable inferences about cultural change – potentially more accurately than radiometric methods. Sea-level rises triggered by global warming reduce available land, and change the availability of flora, fauna, geological resources, rivers and wetlands. Australian archaeological studies on human adaptation to climate change focus mainly on terrestrial sites, coastal intensification and the few archaeological sites that were not inundated. The South West Arm project at Port Hacking, south of Sydney, looks at the potential for rock shelters to survive inundation and expand the sites available for studying human adaption to climate change. Site prediction was based on recorded terrestrial rock-shelter landforms at South West Arm. Underwater surveys were conducted by divers who located, photographed and mapped similar formations. No excavation was conducted. The pre-disturbance survey examined approximately 1800 m of seabed, between water depths of 0 and 9 m, primarily along the eastern shoreline of South West Arm where the seabed emulates the steep slope, with sandstone rock outcrops that form terraces and rock overhangs above water. Twelve submerged rock overhangs were recorded and confirmed the potential for rock-shelter sites to survive the process of inundation.
Geology and archaeology: submerged landscapes of the continental shelf: an introduction
Anatomy of a submerged archipelago in the Sicilian Channel (central Mediterranean Sea)
The Waipounamu Erosion Surface: questioning the antiquity of the New Zealand land surface and terrestrial fauna and flora
Modern Vertical Deformation above the Sumatran Subduction Zone: Paleogeodetic Insights from Coral Microatolls
Patterns and Rates of Sediment Accumulation in the Chesapeake Bay During the Holocene Rise in Sea Level
Abstract Holocene sediment thicknesses measured from seismic-reflection profiles, together with long-term rates of sediment accumulation calculated from these thicknesses and the history of relative sea level, indicate that the Chesapeake Bay has filled rapidly with sediment during Holocene submergence of the bay. Sediment-accumulation patterns indicate that both the Susquehanna River system and the continental shelf are important sources of sediment; averaged over Holocene time, sediment transported from the continental shelf through the mouth of the bay may be volumetrically more important than sediment derived from rivers. Average Holocene rates of sediment accumulation show considerable spatial variability, presumably related to local variations in sediment sources, wave energy, and tidal currents. Nonetheless, these rates show several clear trends. Rates on the shallow marginal shelves of the bay tend to be low (0 to 2 mm/yr) and to increase only slightly toward the bay mouth. Rates in the deep channels are higher (1 to 5 mm/yr), have local maxima, and increase distinctly toward the bay mouth. At any given position in the bay, sediment-accumulation rates increase with depth to the base of the Holocene section. Our estimates of average Holocene rates of sediment accumulation are clearly higher in many places than previous estimates, but they are somewhat less than short-term rates previously measured by a variety of methods. Short-term rates may be affected by anthropogenic changes in the basin and by recent acceleration of relative sea-level rise. In addition, most short-term rates are site specific, biased in their distribution, and fail to account for the large spatial variability observed in long-term rates. Maximum long-term rates of sediment accumulation are limited by the rate of submergence; many existing short-term measurements clearly cannot be extrapolated back in time. Long-term rates of sediment accumulation confirm the ephemeral nature of estuaries and the close tie between sea level and estuarine history. These observations are important considerations for studies of the evolution of estuaries and the record of estuaries in the geologic record.
Holocene Tidal-Marsh Stratigraphy in South-Central Oregon-Evidence for Localized Sudden Submergence in the Cascadia Subduction Zone
Abstract Protected tidal inlets in four estuaries along 100 km of the south-central Oregon coast contain tidal-marsh stratigraphic sequences that suggest different styles of relative sea-level rise during the late Holocene. The south-central coast lies 70 to 90 km east of the leading edge of the overriding North America plate in the central part of the Cascadia subduction zone. Localized differences in the style of submergence along this actively deforming coast imply differences in the rate and extent of coastal subsidence or uplift during subduction of the Juan de Fuca plate beneath the North America plate. Thick tidal-marsh peat in the northern part of the study area records gradual submergence (1.0-1.6 mm/yr since 2.0-2.5 ka) that rules out large (>0.5 m), sudden changes in relative sea level, such as have occurred along other subduction-zone coasts during some historic great earthquakes (magnitude>8). In the south part of the study area, changes in intertidal lithofacies across abrupt transgressive and regressive overlap boundaries are consistent with localized coseismic subsidence and uplift of about 0.5 to 1.0 m above faults and folds in the accretionary wedge of the North America plate. Most coseismic deformation on these local structures probably coincides with great subduction earthquakes, but some localized deformation may reflect much smaller earthquakes that occur independently of plate-boundary events.