|Title||Generalized Geology of the World: Mafic and/or Ultramafic Magmatic Domains Subdivided by Age|
|Abstract||This theme depicts the generalized global distribution of mafic and/or ultramafic intrusive and volcanic bedrock domains subdivided by age range at the era level, against a backdrop of unclassified eon-level age domains (Precambrian and Phanerozoic). Magmas of this composition generally originate at very high temperatures in the earth's upper mantle or deep crust. Primitive oceanic crust (ophiolite) generated by seafloor spreading at oceanic ridges are predominantly of this composition, and are often subsequently thrust onto continental margins during the plate tectonic closure of ocean basins. Volcanism along island arcs that develop above subducting oceanic crustal slabs, a plate-tectonic process counterpart to oceanic spreading, may produce substantial mafic igneous rock, particularly during the early stages of arc development. Extensive flood basalts and radiating swarms of mafic dykes result from mantle plumes, or 'hot spots' in areas of previously thickened continental crust. These rocks tend to carry with them enrichments of the metals copper, platinum group elements, nickel, titanium, chromite, and gold, which may be precipitated as magmatic or hydrothermal minerals. |
This theme was derived by sequentially querying the Generalized Geology of the World (GGW) rock unit database housing age and rock type information in the detail reflective of the small scale (approximately1:5 million scale) data source map legends. Simplified attributes were attached to a copy of the GGW vector data and classified based on the query results, and boundaries for adjacent source domains that were classified to identical values were removed. The resulting spatially simplified data set includes four descriptive attributes: eon range (very general age), era range (age) for classified rock types, classified mafic and/or ultramafic rock type or the term 'unclassified', and combined era range and classified rock type or a combination of eon and the term 'unclassified rocks'.
The level of spatial generalization is geared to global visualization and therefore this data set is geospatially inaccurate. Mafic and/or ultramafic igneous, and particularly intrusive, domains may be exaggerated in size to be distinguishable on a global scale.
|Keywords||GeoscientificInformation, Geological and geophysical, age, era, eon, rock type, generalized, intrusive, volcanic, igneous, mafic, ultramafic, Precambrian, Paleozoic, Mesozoic, Cenozoic|
|Distance unit of measure||degrees|
|Title||World Mineral Deposits|
|Abstract||Mineral deposits are natural accumulations of one or more useful minerals that may provide society with metallic or non-metallic raw materials. The Geological Survey of Canada has been compiling databases for major metallic mineral deposits on Canada-wide and world-wide scale over a three decade period. The most recent compilation was enabled by industry-sponsored World Map and World Minerals Geoscience Database Projects. Global databases for seven important metallic deposit types: lode gold, porphyry-related, nickel-platinum group-chromite, sedimentary exhalative lead-zinc, Mississippi Valley-type zinc-lead, iron oxide-copper-gold (IOCG), and sediment-hosted copper deposits are now available On-Line. Five easy-to-use thematic world geology datasets provide generalized geological context for the global databases.|
|Creator||Lesley B. Chorlton|
|Publisher||Mineral Resources Division, Geological Survey of Canada|
|Contributor||Lesley B. Chorlton|
|Organization||Lesley B. Chorlton|
|Distance unit of measure||degrees|
|Service type version||1.1.1|
|Operations||GetCapabilities, GetMap, GetFeatureInfo, DescribeLayer, GetLegendGraphic|
|Operates on||GSC:WORLD_MineralDeposits, GSC:WORLD_SedCuDeposits, GSC:WORLD_MaficDomains, GSC:WORLD_AgeDomains, GSC:WORLD_FeOxDeposits, GSC:WORLD_MVTDeposits, GSC:WORLD_NiPGECrDeposits, GSC:WORLD_PrecambrianDomains, GSC:WORLD_FelsicDomains, GSC:WORLD_AgeRockDomain, GSC:WORLD_PorphyryDeposits, GSC:WORLD_SedexDeposits, GSC:WORLD_AuDeposits, GSC:WORLD_FaultZones|