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Revealing the secrets of Norway’s seafloor – geological mapping within the MAREANO programme and in coastal areas

Reidulv Bøe*, Lilja Rún Bjarnadóttir, Sigrid Elvenes, Margaret Dolan, Valérie Bellec, Terje Thorsnes, Aave Lepland and Oddvar Longva Geological Survey of Norway (NGU), Postal Box 6315 Torgarden, 7491 Trondheim, Norway SE, 0000-0002-3343-613X; TT, 0000-0002-4040-2122; AL, 0000-0002-8713-7469 *Correspondence: [email protected]

Abstract: Results from geological mapping within the MAREANO (Marine Areal Database for Norwegian Coasts and Sea Areas) programme and mapping projects in the coastal zone reveal a rich and diverse seafloor in Norwegian territories. The geomorphology and sediment distribution patterns reflect a complex geological history, as well as various modern-day hydrodynamic processes. By early 2019, MAREANO has mapped more than 200 000 km2 (c. 10%) of Norwegian offshore areas, spanning environmental gradients from shallow water to more than 3000 m depth, with ocean currents in places exceeding 1 m s−1 and water temperatures below −1°C. Inshore, along the 100 000 km-long Norwegian coastline, the Geological Survey of Norway (NGU) has conducted a series of seabed mapping projects in collaboration with local communities, industry and other stakeholders, resulting in detailed seabed and thematic maps of seabed properties covering c. 10 000 km2 (11% of the areas). Bathymetric and geological maps produced by MAREANO and coastal mapping projects provide the foundation for benthic habitat mapping when combined with biological and oceanographic data. Results from the mapping conducted over the past decade have significantly increased our understanding of Norway’s seabed and contributed to the knowledge base for sustainable management. Here we summarize the main results of these mapping efforts.

The multidisciplinary Norwegian seabed mapping water depth) and cross-shelf troughs (200–500 m programme MAREANO (Thorsnes et al. 2008; water depth) occur over wide areas, and a rich faunal MAREANO 2019) is a collaboration between the diversity has been observed (e.g. Bellec et al. 2008, Geological Survey of Norway (NGU), the Institute 2009, 2010, 2016, 2017a, b, 2019; Chand et al. of Marine Research (IMR) and the Norwegian Map- 2008, 2009, 2012; Thorsnes et al. 2008, 2009, ping Authority (Norwegian Hydrographic Service 2016a, b, 2017; Bøe et al. 2009, 2012, 2015, 2016; (NHS)). The programme is financed by the Ministry Buhl-Mortensen et al. 2009a, b, 2012, 2015; Dolan of Trade, Industry and Fisheries, and the Ministry of et al. 2009, 2012b; Elvenes et al. 2012, 2013, Climate and Environment. These ministries, along 2016; Rise et al. 2013, 2015, 2016a, b; Elvenes with the ministries of Petroleum and Energy, Local 2014; King et al. 2014; Bjarnadóttir et al. 2016, Government and Modernisation, and Transport and 2017; Diesing and Thorsnes 2018). Communications, form the MAREANO Steering Results from MAREANO (MAREANO 2019) Board. have contributed significantly to the revision of Nor- Between 2006 and early 2019, more than way’s management plan for the Barents Sea–Lofoten 200 000 km2 of seabed have been mapped (Fig. 1), areas, as well as the management plan for the Norwe- corresponding to around 10% of the Norwegian off- gian Sea (Fig. 2). These plans are used by Norwegian shore area. The areas mapped span broad environ- authorities in their management of the northern seas, mental gradients with water depths extending to particularly in relation to fisheries and petroleum more than 3000 m, ocean currents exceeding activities. 1ms−1 and seawater temperatures below −1°C. Spatial management of the Norwegian nearshore Dramatic landscapes (Fig. 2) have been observed, areas is the responsibility of coastal municipalities. with canyons up to 1 km deep formed by fluid-flow Municipal jurisdiction extends to 1 nautical mile off- processes and sliding, and locally almost subvertical shore of a baseline joining the outermost islets and margins. Continental slopes vary in width from skerries. Coastal marine areas cover c. 90 000 km2, 30 km to more than 100 km, with gradients locally comprising a wide range of environments from reaching 60°. Shelf plains and banks (30–300 m rocky, exposed shallows to fjords up to 1300 m

From: Asch, K., Kitazato, H. and Vallius, H. (eds) From Continental Shelf to Slope: Mapping the Oceanic Realm. Geological Society, London, Special Publications, 505, https://doi.org/10.1144/SP505-2019-82 © 2020 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/). Published by The Geological Society of London. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021

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Fig. 1. Areal coverage of seabed sediments (grain size) maps at scale 1:1 000 000–1:4 000 000 by April 2019. Areas mapped in higher detail in Norwegian areas are shown with black (MAREANO and previous projects in the North Sea) and red outlines (coastal mapping projects). L, Lofoten. Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021

Revealing the secrets of Norway’s seafloor

Fig. 2. Example of nearshore–offshore seabed morphology mapped by MAREANO, Lofoten–Vesterålen, north Norway. V, Vesterålsgrunnen. See Figure 1 for the location of Lofoten. deep. Through a series of mapping projects in coop- Methods eration with local authorities and other stakeholders, NGU has published geology-focused seabed maps MAREANO and derived thematic maps (‘marine base maps’: Elvenes et al. 2019; NGU 2019a) covering c. 10 Mapping of a new area commences with multibeam 000 km2 of the coastal areas (Fig. 1; see below). echo-sounder surveys by NHS or external contrac- These offer invaluable knowledge to marine spatial tors according to defined standards (NHS 2018). planners and the many users of the Norwegian Other bathymetry data may be available from the coastal zone. petroleum industry, research institutions or the In this paper, we describe the mapping process Olex database (mainly single-beam echo-sounder and the geological maps produced by NGU. The data) (e.g. Elvenes et al. 2012). geological maps (e.g. Fig. 3), along with bathymetry, Multibeam echo sounders are used for detailed biological data and oceanographic modelling results, mapping of the bathymetry. Furthermore, co-regis- form the basis for further mapping and modelling of tered backscatter data provide additional information benthic habitats (including biotopes, nature types, on the composition and structure of the seafloor vulnerable habitats, etc.) both offshore and in the through the amplitude of the returned signal from coastal zone (e.g. Buhl-Mortensen et al. 2009a, b, the seafloor (e.g. Lurton and Lamarche 2015). 2012, 2015; Dolan et al. 2009, 2012a; Bekkby Bathymetry data are processed by NHS and subcon- et al. 2012; Elvenes et al. 2013; Gonzalez-Mirelis tractors (data correction and cleaning), and, after and Buhl-Mortensen 2015). Mapping of the environ- quality control, NHS produces terrain models at hor- mental chemistry of the seabed sediments (e.g. Pb izontal resolutions appropriate to the sounding den- and PAH) is included in the MAREANO programme sity (in the range 2–50 m). Backscatter datasets are and in multiple coastal mapping projects (e.g. processed from raw data by NGU using Elvenes et al. 2018; Jensen et al. 2018; Knies and industry-standard software to produce mosaics with Elvenes 2018). a pixel resolution of 1–50 m, depending on the All maps from MAREANO and NGU’s coastal data density and quality. Since 2010, water column mapping projects are published online and are freely data have also been acquired as part of the MAR- available for viewing, downloading and WMS use EANO multibeam echo-sounder surveys. Subcon- (MAREANO 2019; NGU 2019a). Additionally, tractors acquire sub-bottom profiler data (only a a series of composite, printable PDF MAREANO few surveys prior to 2018), yielding additional infor- maps is published online (e.g. Bjarnadóttir et al. mation about the structure and composition of the 2017; NGU 2019a). uppermost c. 100 m of the seafloor. Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021

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Fig. 3. Landscapes and landforms in an area mapped by the MAREANO programme outside north Norway. The map is made for viewing at a scale of 1:100 000. S, Sveinsgrunnen; M, Malangsdjupet. See Figure 2 for the location of Andøya.

IMR and NGU plan and arrange common sam- per 1000 km2) are so-called full stations where a pling cruises. Given MAREANO’s wide mapping range of sampling gear (see below) is used in support focus, the station planning must take broad-scale of multidisciplinary mapping (geology, biology, environmental variability into consideration, includ- chemistry). These general averages in terms of sta- ing both geological and biological diversity, as well tion density have been adapted from area to area in as identifying suitable locations for retrieving sam- recent years, depending on the complexity of the ples for chemical analysis. High-resolution bathyme- seabed and/or the length of the video lines. In try and backscatter data, supplemented with 2018, the sampling density for video and geological available oceanographic model data, are fundamen- grab samples was increased to 20 stations per tal to this station planning process. 1000 km2, in connection with a reduction in the While early MAREANO station planning was length of video lines from 700 to 200 m. This change essentially expert driven (but guided by a simple allows more locations to be documented which gen- unsupervised classification of the physical environ- erally increases the environmental space observed ment), MAREANO has now phased in more objec- within a similar timeframe. tive and automated methods (Thorsnes et al. 2015). MAREANO employs the towed video platforms The sampling effort is matched as far as possible to Campod and Chimaera for seabed video surveying the scale of the map product(s) and available bud- deployed from relatively large, stable research ves- gets. Approximately 10 stations per 1000 km2 have sels with dynamic positioning (e.g. R/V G.O. been visited for the collection of video data, allowing Sars). These platforms are equipped with a low-light visual observation of seabed sediments and mega- charge-coupled device (CCD) (forward-looking) and fauna. A proportion of these stations (generally two high-definition (HD) video cameras, in addition to Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021

Revealing the secrets of Norway’s seafloor lights, scale indicator and a geopositioning transpon- In the coastal zone, where surveys are generally der accurate to c. 2% of the water depth. The HD conducted from NGU’s 17 m-long research vessel camera has a manual zoom and focus, and is R/V Seisma, video data are recorded by means of mounted on a pan-and-tilt device. The video plat- a towed platform equipped with one low-light forms are used both temporarily parked on the CCD camera and one HD camera, as well as lights, seabed for detailed studies and in a transect mode scale indicator and geopositioning transponder. towed by the ship along a predefined survey line. Camera settings are locked during operation, and The height above the seabed is maintained by a the platform is kept at 0.5–1 m above the seabed winch operator using visual observations from the while the ship is moving at low speed. Video lines forward-looking camera. are generally 50–300 m long. Their final lengths A variety of other physical sampling gear is used are adapted en route depending on the heterogeneity by MAREANO at full stations including grab, box of the observed seabed. The main sampling gears corer, multicorer and gravity corer, all providing consist of grab and multicorer or Niemistö-corer. material and information from the seafloor and Sub-bottom profiler (TOPAS) data are also uppermost metres of the seafloor for geological and acquired on coastal mapping cruises on R/V Seisma ecological (infauna and epifauna) studies. The multi- during transits between stations, as well as along corer is used for environmental sampling of undis- selected transects, and data are used to support the torted core material. Epibenthic sledge and beam geological interpretations. trawl are employed to sample fauna on and above the seabed. Oceanographic properties are measured with CTD, ADCP and rosette sampler. Results During MAREANO sampling cruises, sub- bottom profiler data (e.g. TOPAS topographical In MAREANO, geological seabed maps based on parametric sonar) are acquired during transit high-quality multibeam echo-sounder data (5 m between all stations and along selected transects cov- grids) and seabed ground-truth data include seabed ering features of special interest (e.g. sand waves or sediments (grain size), seabed sediments (genesis), pockmarks observed in multibeam bathymetry). sedimentary environment, and landscapes and land- Sub-bottom penetration depends on grain size and forms. These are all mapped for use at the scale compaction of the seabed, and may be up to 100 m 1:100 000 (digitizing scale c. 1:50 000) (Table 1) with a vertical resolution of 0.5–1minfine-grained and coarser. Marine base maps for the coastal zone sediments. These data support the geological inter- are generally made for use at the scale 1:20 000 (dig- pretation and are particularly useful for the produc- itizing scale c. 1:10 000). In both cases, map scales tion of NGU’s sediment genesis map (see below). may vary depending on the purpose, multibeam Sub-bottom profiler data are now also regularly data quality and available ground-truth data. acquired during the MAREANO multibeam mapping cruises. Landscapes and landforms

Coastal mapping The marine landscape mapping performed by MAR- EANO delimits broad-scale morphological elements Coastal mapping projects have so far been limited to (Thorsnes et al. 2009). Landscape classification is areas with existing multibeam data available from based on the national nature description and typifica- NHS or other sources (e.g. the Norwegian Defence tion system NiN (Nature types in Norway: Artsdata- Research Establishment (FFI)). Additional multi- banken 2019). NiN defines landscapes as large beam data are occasionally acquired during NGU geographical areas with a visually homogeneous cruises. Pre-cruise station planning for video survey- character. Through a semi-automated GIS method ing and physical sampling in the coastal zone is (Elvenes 2014), bathymetry data and derived terrain expert-driven, based on multibeam bathymetry and attributes (e.g. slope. curvature, relative relief, rela- backscatter, and the number and distribution of sta- tive vertical position) are used to categorize all tions vary depending on seabed complexity and the areas of the seabed as one of the following classes: availability of existing observations. Commonly, strandflat; smooth continental slope; marine canyon; 100–200 stations are visited per 1000 km2. Auto- marine valley; shallow-marine valley; fjord; deep sea mated methods for station planning, like those now plain; continental slope plain; continental shelf plain; adopted by MAREANO, need to be improved before and hilly/mountainous marine landscape (Fig. 3). they integrate the complexities of the coastal envi- Strandflat is the crystalline platform which char- ronment and the geologist’s need for ground truth- acterizes large parts of the Norwegian coast and in ing, particularly when multibeam backscatter many areas contrasts sharply with the sedimentary datasets from multiple sources are applied, as these rocks of the continental shelf. Fjords and marine val- can be challenging to harmonize. leys are the results of concentrated glacial erosion Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021

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Table 1. Map products and mapping scales – MAREANO and coastal mapping projects

MAREANO Coastal mapping projects

Map products: Included: Map scale/raster Included: Map scale/raster resolution: resolution: Seabed sediments (grain Yes 1:100 000–1:3 000 000 Yes 1:10 000–1:50 000 size) Seabed sediments Yes 1:100 000 No (genesis) Sedimentary environment Yes 1:100 000 No Accumulation areas No Yes 1:10 000–1:50 000 Anchoring conditions No Yes 1:10 000–1:50 000 Digability No Yes 1:10 000–1:50 000 Slope .30° No Yes 1:10 000–1:50 000 Slope (raster) No Where 1–5m permitted Seabed terrain (raster) Yes 2–25 m Where 1–5m permitted Backscatter (raster) Yes 1–10 m Where 1–5m permitted Landforms Yes 1:100 000 No Marine landscapes Yes 1:100 000–1:1 000 000 No Mapping strategy Large and coordinated mapping Smaller projects in cooperation with local efforts, long-term planning authorities and stakeholders Video transects Length Standardized: 700 m pre-2018, Adjusted to local conditions, often 200– 200 m from 2018 300 m Number Standardized but varying from area Adjusted to local conditions, often c. 100 to area, typically 5–20 transects transects per 1000 km2 per 1000 km2 Video platform Towed and stationary on seabed Towed Samples Sediment grab and other sampling Mainly sediment grab; number of samples equipment, standardized number adjusted to local conditions of samples during repeated glaciations, with fjords incising the depending on the type of landform and size. Exam- mainland. Continental shelf plain is the residual low- ples of landforms mapped are drumlin, moraine, relief landscape between marine valleys on the esker, meltwater channel, crevasse-fill ridge, glacial continental shelf. lineation, glaciotectonic hole, glaciotectonic hill, For areas with multibeam data coverage, MAR- sediment wave field, channel, canyon, slide scarp, EANO’s marine landscape maps are based on bathy- slide front, slide fan, submarine slide and pockmark metry data with a horizontal resolution of 50 m and area. A collaboration has been developed between are at a scale of 1:100 000. In other areas, maps are MAREANO, the British MAREMAP programme based on best available resolution data such as and the Irish INFOMAR programme to develop a Olex or IBCAO bathymetry, which are generally common framework for morphological and geomor- of lower quality (larger uncertainty) than multibeam phological mapping (Dove et al. 2016). data. Landscape delineation in areas without multi- Thousands of cold-water coral reefs occur on the beam data coverage is, therefore, conducted at Norwegian continental shelf and in the coastal zone coarser map scales – typically 1:500 000–1:1 000 (e.g. Mortensen et al. 2001; Bøe et al. 2016; 000. Marine landscape maps do not form part of Thorsnes et al. 2016a, 2017; Jarna et al. 2017). the coastal marine base maps, although some From 2018, offshore coral carbonate mounds are mapped areas are covered by the MAREANO mapped by a methodology that combines image seg- classification. mentation and spatial prediction based on multibeam Marine landforms (Figs 3 & 4) are mapped in bathymetry. The results of Diesing and Thorsnes MAREANO based on detailed bathymetry and sub- (2018) show that, for a limited study area, the image- bottom profiler data, supported by video observa- object mean planar curvature is the most important tions of the seabed. Landforms are interpreted and predictor, and their approach allows the presence digitized manually in GIS as polygons or lines, and absence of carbonate mounds to be mapped Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021

Revealing the secrets of Norway’s seafloor

Fig. 4. Landscapes and landforms mapped by MAREANO. (a) Continental shelf and slope with canyons and slides outside Vesterålen, north Norway. In this area, water depths increase from around 50 m on the Sveinsgrunnen Bank to 200 m in the Malangsdjupet Trough and to more than 2000 m in the Lofoten Basin. See Figure 3 for the location of Sveinsgrunnen and Malangsdjupet. (b) Sand waves (up to 5 m high) and coral reefs (up to 17 m high) in the Hola Trough outside Vesterålen, north Norway. Water depths are 70–90 m on the Vesterålsgrunnen Bank and 200–270 m in the Hola Trough. See Figure 2 for the locations of Hola and Vesterålsgrunnen. (c) Iceberg plough marks and pockmarks in the Barents Sea. In this area, with water depths of around 270 m, pockmarks are 20–50 m across and 2–5 m deep, while plough marks are 60–70 m wide and 6–7 m deep. See Figure 1 for the location. Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021

R. Bøe et al. with high accuracy. This method is currently being For expert-driven interpretation and compilation scaled up for application to wider areas. Prior to of the grain-size map, all available data (i.e. multi- the development of Diesing and Thorsnes’ (2018) beam bathymetry and backscatter, videos, seabed method in 2018, coral reefs and associated sediments samples taken with grab, box corer, and multicorer, were manually digitized and classified as ‘bioclastic as well as sub-bottom profiler data) are used by the sediments’ (Bellec et al. 2014). In the seabed sedi- geologist, and published literature is consulted ments (grain size) map (see the following subsec- where available. The classification of sediment tion), coral carbonate mounds are indicated as type is determined by the final scale of the map ‘mud, sand and gravel of biological origin’, while, and the degree of detail in the data used for interpre- in the seabed sediments (genesis) map, they are clas- tation and map compilation. sified as ‘bioclastic sediment’. Seabed sediments (genesis) Seabed sediments (grain size) The seabed sediments (genesis)/Quaternary geology The seabed sediments (grain size) map (Fig. 5) map reveals processes on the seafloor during and reflects the sediment or bottom type in the uppermost after the last ice age. The map describes deposits c. 10 cm of the seabed, categorized as one of 35 and bottom types in the upper 1–2 m of the seafloor defined classes (NGU 2019b). Most of the classes (i.e. not only the surface deposits influenced by the comprise a mixture of grain sizes (e.g. ‘gravelly most recent processes). sand’ or ‘mud and sand with gravel, cobbles and For mapping of seabed sediments (genesis), the boulders’), which is a signature of predominantly geologist chooses from amongst 32 sediment/bot- glacially influenced environments. tom type classes (NGU 2019c). Examples include

Fig. 5. Seabed sediments (grain size) in an area mapped by the MAREANO programme outside north Norway. The map is made for viewing at a scale of 1:100 000. Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021

Revealing the secrets of Norway’s seafloor suspension deposit, glaciomarine deposit, bedload Deposition of fine-grained sediments (mud and (traction) deposit, contourite, glaciofluvial deposit, sandy mud) primarily occurs in deep or sheltered till, mass-movement deposit, debris-flow deposit waters. Erosion may remove fines and deposit sand and exposed bedrock. Vast areas, especially on the where bottom currents become weaker or where continental shelf, are dominated by sediments depos- sand is transported back and forth by tidal currents. ited in glacial environments. The shallowest areas are often dominated by erosion, The map is based on the seabed sediments (grain although fine-grained sediments may accumulate in size), as well as the landscapes and landforms maps, local, topographical depressions. A lag deposit of in addition to further interpretation of multibeam sandy gravel, cobbles and boulders is often formed bathymetry, and sub-bottom profiler and seismic where bottom currents (wave, tidal or oceanographic data. The classification of sediment type is deter- currents) are strong. Grain size generally indicates mined by the final scale of the map and the degree the strength of the bottom currents; mud suggests of detail in the data used for interpretation and map weak bottom currents, while coarser sediments or compilation. So far, seabed sediments (genesis) erosion suggest stronger currents. maps have only been compiled within MAREANO for the offshore areas. Marine base maps in the coastal zone

Sedimentary environment The marine base maps published by NGU since 2003 (Sandberg et al. 2005; Longva et al. 2008; The sedimentary environment map is based on the Thorsnes et al. 2013; Elvenes et al. 2019) present seabed sediments (grain size) map and the datasets geological information relevant to end users out- used for producing that map. A predefined number side the geological community in a format that is of classes is used for compilation (NGU 2019d). comprehensible to geologists and non-geologists The main purpose of the map is to visualize areas alike. As described above, sediment type mapping of erosion and deposition of sediments, and how bot- in Norwegian nearshore areas is based on pre- tom currents influence the seabed. existing multibeam echo-sounder data ground-

Fig. 6. Example of high-resolution multibeam bathymetry and backscatter data used for compilation of the seabed sediments (grain size) map at a scale of 1:20 000 from a Norwegian fjord. Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021

R. Bøe et al. truthed by video observation and physical samples. Harmonized maps for EMODnet Geology Figure 6 shows an example of shaded bathymetry, backscatter and interpreted sediment types from a The EMODnet (European Marine Observation and Norwegian fjord. Data Network) Geology portal (EMODnet Geology Since grain size can be difficult for the non- 2019) aims to provide harmonized information on specialist to interpret with respect to everyday marine geology in Europe. NGU has delivered applications, the detailed, full-coverage maps of harmonized datasets at different scales (both MAR- seabed sediment types (grain size) are supple- EANO and coastal data) on landscapes and land- mented with thematic maps based on expert knowl- forms, seabed substrates (seabed sediments (grain edge of sediment properties and on high-resolution size)), the Quaternary (seabed sediments (genesis)), multibeam data. A full stack of marine base maps the pre-Quaternary, mineral occurrences, sediment will contain shaded relief bathymetry and slope accumulation rates, geological events and probabili- data of the highest permitted resolution (given mil- ties, and coastal behaviour. itary restrictions), seabed sediments (grain size), anchoring conditions, digability and accumulation basins (examples shown in Fig. 7). Most marine Summary base maps published since 2015 have a scale of 1:20 000. This suite of applied marine base maps Results from MAREANO and coastal mapp- conveys useful information on the coastal marine ing projects show that Norway has a rich and environment to managers, industry, fishermen, diverse seafloor. The geomorphology and sedi- recreational users, marine scientists, etc., even in ment-distribution patterns reflect a long geological areas where access to high-resolution multibeam history and complex modern-day hydrodynamic pro- bathymetry is restricted by the Norwegian defence cesses. By 2019, approximately 10% of the Norwe- authorities. gian seafloor had been mapped: c. 200 000 km2

Fig. 7. Marine base maps. Example of use of the seabed sediments (grain size) map (in addition to detailed bathymetry) for compilation of the derived thematic maps for anchoring conditions, digability and accumulation basins. See Figures 5 and 6 for the legends to the seabed sediments (grain size) map. In the thematic maps, the most favourable conditions for anchoring are shown in green; for digging, in light grey; and for soft-sediment accumulation, in blue. Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021

Revealing the secrets of Norway’s seafloor offshore and 10 000 km2 in the coastal zone. Geo- References logical maps by MAREANO include seabed sedi- Artsdatabanken. 2019. Natur i Norge. Artsdatabanken, ments (grain size), seabed sediments (genesis), // sedimentary environment, and landscapes and land- Trondheim, Norway, https: www.artsdatabanken. no/NiN [accessed 30 January 2019]. forms. These are made for use at a scale of c. Bekkby, T., Moy, F.E. et al. 2012. The Norwegian program 1:100 000. Marine base maps for the coastal zone for mapping of marine habitats – providing knowledge include seabed sediments (grain size) and the derived and Maps for ICZMP. In: Moksness, E., Dahl, E. and maps – anchoring conditions, digability and accumu- Støttrup, J. (eds) Global Challenges in Integrated lation basins – made for use at a scale of c. 1:20 000. Coastal Zone Management. Wiley-Blackwell, Chiches- Bathymetric and geological maps produced by ter, UK, 21–30. MAREANO and coastal mapping projects, along Bellec, V., Wilson, M., Bøe, R., Rise, L., Thorsnes, T., with biological and oceanographic data, have Buhl-Mortensen, L. and Buhl-Mortensen, P. 2008. Bot- been found to form an invaluable basis for further tom currents interpreted from iceberg ploughmarks revealed by multibeam data at Tromsøflaket, Barents mapping and modelling of benthic habitats, with Sea. Marine Geology, 249, 257–270, https://doi.org/ grain-size and landscape maps often serving as 10.1016/j.margeo.2007.11.009 important predictor variables. In addition, mapping Bellec,V.K., Dolan, M.F.J., Bøe, R., Thorsnes, T., Rise, L., of seabed chemistry (including pollution) is included Buhl-Mortensen, L. and Buhl-Mortensen, P. 2009. in the working programmes of both MAREANO and Sediment distribution and seabed processes in the the coastal mapping projects. Troms II area – offshore North Norway. Norwegian Journal of Geology, 89,29–40. Bellec, V.K., Bøe, R., Rise, L., Slagstad, D., Longva, O. and Dolan, M.F.J. 2010. Rippled scour depressions Acknowledgements We would like to thank all par- on continental shelf bank slopes off Nordland and ticipants of the MAREANO programme and the coastal Troms, North Norway. Continental Shelf Research, mapping projects, onshore and offshore, for their invaluable 30, 1056–1069, https://doi.org/10.1016/j.csr.2010. cooperation. Matthias Forwick and an anonymous reviewer 02.006 are thanked for constructive comments to a previous ver- Bellec, V., Thorsnes, T. and Bøe, R. 2014. Mapping of Bio- sion of the manuscript. clastic Sediments – Data, Methods and Confidence. NGU Report 2015.043, https://www.ngu.no/upload/ Publikasjoner/Rapporter/2015/2015_043.pdf Funding This research received no specific grant from Bellec, V., Rise, L., Bøe, R. and Dowdeswell, J. 2016. Gla- any funding agency in the public, commercial, or cially related gullies on the upper continental slope, SW not-for-profit sectors. Barents Sea margin. Geological Society, London, Mem- oirs, 46, 381–382, https://doi.org/10.1144/M46.31 Bellec, V.K., Bøe, R., Rise, L., Lepland, A. and Thorsnes, T. 2017a. Seabed Sedimentary Environments and Sed- Author contributions RB: conceptualization iments (Genesis) in the Nordland VI Area off Northern (equal), data curation (equal), formal analysis (equal), fund- Norway. NGU Report 2017.046, https://www.ngu.no/ ing acquisition (equal), investigation (equal), methodology upload/Publikasjoner/Rapporter/2017/2017_046.pdf (equal), project administration (equal), resources (equal), Bellec, V.K., Bøe, R., Rise, L., Lepland, A., Thorsnes, T. supervision (equal), validation (equal), visualization and Bjarnadóttir, L.R. 2017b. Seabed sediments – – (equal), writing original draft (lead), writing review & (grain size) of Nordland VI, offshore north Norway. editing (lead); LRB: funding acquisition (equal), methodol- Journal of Maps, 13, 608–620, https://doi.org/10. ogy (equal), project administration (equal), resources 1080/17445647.2017.1348307 – (equal), writing review & editing (supporting); SE: for- Bellec, V.K., Bøe, R. et al. 2019. Sandbanks, sandwaves mal analysis (equal), investigation (equal), project adminis- and megaripples on Spitsbergenbanken, Barents Sea. – tration (equal), visualization (equal), writing review & Marine Geology, 416, https://doi.org/10.1016/j.mar editing (supporting); MD: conceptualization (supporting), geo.2019.105998 – methodology (equal), writing review & editing (support- Bjarnadóttir, L.R., Ottesen, D., Dowdeswell, J.A. and ing); VB: formal analysis (equal), investigation (equal), Bugge, T. 2016. Unusual iceberg ploughmarks on visualization (equal); TT: conceptualization (equal), fund- the Norwegian continental shelf. Geological Society, ing acquisition (equal), methodology (equal), project London, Memoirs, 46, 283–284, https://doi.org/10. administration (equal), resources (equal); AL: data curation 1144/M46.126 (lead), validation (equal), visualization (equal); OL: con- Bjarnadóttir, L.R., Ottesen, D. et al. 2017. Geologisk hav- ceptualization (equal), funding acquisition (equal), method- bunnskart, Kart 65000900, Mai 2017. M 1:100 000. ology (equal). Norges geologiske undersøkelse, Trondheim, Norway, https://www.ngu.no/upload/Kart%20og%20data/ Maringeologiske%20kart/GEOLOGISK_HAVBUNN Data availability statement The datasets gener- SKART_65000900.pdf ated during and/or analysed during the current study are Bøe, R., Bellec, V.K., Dolan, M.F.J., Buhl-Mortensen, available in the NGU repository, www.mareano.no and P.B., Buhl-Mortensen, L. and Rise, L. 2009. 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