Resúmenes sobre el VIII Simposio MIA15, Málaga del 21 al 23 de Septiembre de 2015
Primer catálogo de mineralizaciones submarinas en España: Proyecto EMODnet-Geology First catalogue of submarine mineral deposits from Spain: EMODnet-Geology Project F.J. González T. Medialdea, G. Gómez-Ramos, L. Somoza, E. Marino y R. León Servicio de Recursos Geológicos Marinos. Instituto Geológico y Minero de España. C/ Ríos Rosas 23, 28003 Madrid, Spain,
[email protected]
Abstract: This study presents the first catalogue of marine mineral deposits and energy resources along the continental margin of Spain. The catalogue, implemented in a geographic information system (GIS), is conceived as a first national database within the European network, which is being built as part of the EMODnet-Geology project. It comprises 8 types of mineral and energy resources: aggregates, hydrocarbons, evaporites, placer deposits, phosphorites, polymetallic sulfides, polymetallic nodules and cobalt-rich ferromanganese crusts. The catalogue stores a total of 409 marine mineral deposits and compiles information such as name, deposit type, main morphology, main minerals, setting or area extent for each mineral deposit. By number of deposits compiled, the aggregates are the most abundant (286) followed by hydrocarbons (62), cobalt-rich ferromanganese crusts (32), evaporites (9), placer deposits (8), phosphorites (5), polymetallic nodules (4) and 2 polymetallic sulphide deposits (3). Considering the total extension, hydrocarbons (32,386 km ) and 2 cobalt-rich ferromanganese crusts (24,951 km ) represent the biggest areas. This study presents a first approximation to the potential areas for marine minerals investigation, exploration and exploitation. Key words: GIS Catalogue, marine minerals, energy resources, Spanish Continental Shelf, Iberian continental margin
1. INTRODUCTION Marine mineral deposits are metal-rich chemical and detrital sediments that are potential mineral resources. Several main mineral deposits are typically found on the coastal zones: aggregates and placer deposits, or the deep seafloor: Fe-Mn crusts and nodules, phosphorites, and massive sulphides (e.g. Rona, 2008; Hein et al., 2013). The supply of rare/critical elements used in technology is a necessary issue for economic development of society. E-tech elements such as cobalt, tellurium and rare earths are essential for developing environmental technologies and occur in high concentrations in ferromanganese deposits found in the deep ocean. Other metals such as copper, zinc or gold appear in high contents in hydrothermal sulfides, distributed along spreading ridges and hot-spot volcanoes. In addition, hydrocarbons, abundant in the continental margins, are essential for industry, electricity and heating worldwide. The International Seabed Authority (ISA) regulates the mining activity beyond the national water
jurisdictions, entering into 15-year contracts for exploration for polymetallic nodules (14 contracts), polymetallic sulphides (5 contracts) and cobalt-rich ferromanganese crusts (3 contracts) in the deep seabed with twenty two contractors. The contracts cover areas from the Pacific, Indian and Atlantic oceans (ISA, 2015). The European economies are highly dependent on imports of many of these strategic metals from political and/or economical unstable countries. For these reasons the European Commission considers a priority the investigation of strategic mineral resources in the European Territory (EC, 2015), including the seabed and contracts with ISA (H2020, EIP Raw Materials). This paper is the first GIS catalogue of marine mineral deposits and energy resources built on the continental margin of Spain. The database is referred to marine mineral deposits on or under the seabed and has been ellaborated as part of the the EMODnet-Geology project (EMODnet, 2015). This GIS catalogue of marine minerals shows the potential in the different continental margin areas. It is a first step
for economic and environmental management in a sustainable manner for future generations.
2. GEOLOGICAL SETTING The study area covers the continental margins of Spain from the coastal areas to the deep-sea abyssal plains: Galicia, Bay of Biscay, Gulf of Cadiz, Mediterranean and Canary Islands margins (Fig. 1). The Galician and Bay of Biscay margins were formed after the oceanic spreading of the northern Atlantic and the opening of the Bay of Biscay. The Bay of Biscay is characterized by narrow shelf incised by deep submarine canyons and associated deep-sea turbiditic systems and banks as Le Danois Bank. The Galicia margin is hyper-extended, morphologically characterized by a wide shelf, with submarine canyons that feed deep-water valleys intercalated between shallow banks and seamounts as the Galicia Bank. The Gulf of Cádiz margin is located along the African– Eurasian plate boundary. It is characterized by the emplacement of a huge wedge on the continental slope. Fluid escape structures (mud-gas volcanoes, pockmarks, diapirs, methane-derived carbonates) are very common at this area. A huge net of current channels associated with the Mediterranean Outflow Water crosscut the seafloor sediments. The Spanish Mediterranean margin is characterized by a wide variety of geological contexts for mineral deposits: from a delta system at the Ebro River mouth to volcanic edifices and hydrothermal systems at the Alboran Sea and Cabo de Gata area. The Canary Islands margin is located in an intraplate hot-spot volcanic province where stand out the abundance of seamounts and volcanic edifices with associated hydrothermal, hydrogenetic and diagenetic processes and huge submarine landslides.
(MAGRAMA, 2015) and the National Inventory of Hydrocarbons (MINETUR, 2015). Other supplementary sources of data are the ISA and Interridge mineral databases (ISA, 2015; INTERRIDGE, 2015), published papers and PhD theses. 3.2 Minerals mapping Mapping of spatial extent of minerals have been defined using a common data standard (within the INSPIRE theme on “Geology and Mineral Resources”) and a common scale for all the European countries. Mineral deposits are naturally occurring materials of economic interest. The EMODnet-Geology minerals GIS layer includes data for 9 typologies: aggregates, hydrocarbons, gas hydrates, marine placers, phosphorites, evaporites, polymetallic sulphides, polymetallic nodules and cobalt-rich ferromanganese crusts. The attribute tables include: name, location, deposit type, main morphology, main minerals/ commodities, setting, status, operator, exploitation type, area extent, depth to seabed/deposit, data provider and references. Shape area has been calculated by the system and a GIS operator with expert criteria has measured extent directly over the map. The quality and quantity of information for each of the mineral deposits depends on the available information. Legend for minerals represented in the Figures 1-3 is available at the EMODnet-Geology web site.
4. MARINE MINERALS: GIS CATALOGUE OF SPAIN A total of 409 mineral deposits have been stored in the continental margin of Spain (Figs. 1 and 2): 286 aggregates, 62 hydrocarbons, 32 cobalt-rich ferromanganese crusts, 9 evaporites, 8 placer deposits, 5 phosphorites, 4 polymetallic nodules and 3 polymetallic sulphides.
3. DATA AND METHODS 3.1 GIS catalogue The GIS catalogue of Spanish marine minerals (EMODnet-Geology, 2015) has been implemented with ArcGIS ESRI®. The GIS catalogue covers the seafloor of the whole Spanish Continental Shelf, including the Iberian continental margins and the entire Canary Islands. The mineral deposits have been compiled from geo-referenced papers and digital maps using a Geographic coordinate system (WGS84). Attributes for each mineral deposit are sourced from published data. The main sources of cartographic information of the catalogue are the projects from IGME, some of them mapped under the National Marine Mapping FOMAR Programme at 1:200,000 scales, the Inventory of Aggregates
Figure 1. Marine mineral deposits GIS catalogue (inventory map) along the Iberian margin.
8º Simposio sobre el Margen Ibérico Atlántico MIA15
The Galicia margin (Figs. 1 and 3) shows the most abundant and vast deposits of phosphorites, in the Galicia Bank region and the edge of the continental shelf. Polymetallic nodules and cobalt-rich crusts cover the seafloor in areas from the Cantabria knoll and Galicia Bank. Rare earth placer deposits are located in coastal areas from Pontevedra. In the Bay of Biscay, highlight the importance of Le Danois Bank whit phosphorite and ferromanganese crusts deposits, and hydrocarbons on the continental shelf from the Bask Country (Fig. 3). In the Gulf of Cádiz, stands out the importance of gas hydrocarbons linked to Miocene-Mesozoic sediments from the Gulf of Cádiz wedge. In addition, ferromanganese deposits of nodules and crusts cover the seafloor of current channels and banks. Titanium placer deposits are present in coastal areas from Huelva and Cádiz (Fig. 1).
Málaga, del 21 al 23 de septiembre de 2015
Pt. All the crust deposits are unexploited at the present time. Evaporites form diapiric bodies of gypsum, halite or anhydrite from Triassic and Miocene age. The diapirs are located at variable depths below the seafloor (from 490 to 2450 m). They are located at the Mediterranean Sea, the Bay of Biscay and the Gulf of Cádiz. Placer deposits cover a total seafloor area of about 2 1,815 km at shallow water depths (
