World Mineral Deposits

Generalized Geology of the World: Age Domains (GSC:WORLD_AgeDomains)

This data set is a choropleth or patchwork map depicting generalized bedrock domains for era-level age ranges and predominant rock types. This theme was derived by sequentially querying the Generalized Geology of the World (GGW) rock unit database that houses 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), predominant rock type(s), and combined era range and predominant rock type(s). The level of spatial generalization is geared to global visualization on a wall map or over the web. This data set is spatially inaccurate. The accuracy of some of the original map data sources may be poor, and therefore intricate detail from relatively accurate sources was deliberately generalized for the sake of consistency. The attributes extracted from the full GGW dataset rely on the legends of source maps and accessibilty of appropriate details in literature sources.

Generalized Geology of the World: Mafic and/or Ultramafic Magmatic Domains Subdivided by Age (GSC:WORLD_MaficDomains)

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.

Generalized Geology of the World: Major Fault Zones (GSC:WORLD_FaultZones)

This theme depicts the generalized traces of major fault zones of the world, classified where possible into five displacement categories, and further classified into age ranges for each displacement if the information was readily available. The theme was derived from a more complex geospatial arc data set associated with a database that can store more than one displacement class and age range for each fault (all major fault zones have complex displacement histories). Default record sets are tagged for quick plots, and these were subjected to a sequential series of age and fault type queries. The geospatial data set was copied and simple attribute fields were attached and classified using the query results. The attribute fields are age at the eon level, age range at the era level, displacement type, combined age range and displacement type, and name. Many of the fault zones are still unclassified pending availability of source information. The downloadable data summary has been extracted from a database compiled for the World Minerals Geoscience Database Project (1998-2003). Data sources for the fault zones are mainly 1-10 million scale maps and synthesis literature. The traces presented here are generalized and acknowledged to be inaccurate. They are simply presented for global scale visualization. Many source maps do not commit to the depiction of displacement classes because multiple histories and variations in interpretation may make such classification controversial.

World Distribution of Porphyry, Porphyry-Related Skarn, and Bulk-mineable Epithermal Deposits (GSC:WORLD_PorphyryDeposits)

The global distribution of a broad class of large, low- to medium-grade mineral deposits in which primary ore minerals are mainly structurally controlled, and which are spatially and genetically related to felsic to intermediate porphyritic intrusions, is represented in this data set. Variations of this class include large mineralized stockwork and veins directly connected to the intrusions (porphyry), replacement deposits in a predominantly calc-silicate (formerly carbonate-rich sedimentary rock) host (porphyry-associated skarn), and large precious metal (+/- base metal) deposits that are distal but related to porphyry deposits (epithermal deposits). Porphyry and porphyry-associated deposits are the world's most important source of copper, molybdenum, and rhenium, and are major sources of gold, silver, and tin. Other by-product metals include tungsten, indium, platinum, palladium, and selenium. The downloadable data summary is periodically extracted from a database compiled between 1982 and 2004, in part for the World Map Project (1995-1997) and updated for the World Minerals Geoscience Database Project (1998-2003). The full database can be viewed and queried over the Internet.

World Distribution of Sediment-hosted, Stratiform Copper Deposits and Occurrences (GSC:WORLD_SedCuDeposits)

This data set depicts the spatial distribution and most significant geological attributes of the world's most important sediment-hosted, stratiform copper mineral deposits. These deposits form the world's second most important source of copper, and are found in chemically reduced zones, commonly associated with evaporite and red (oxidized) sandstones, in continental marginal, lacustrine, or continental settings. This data set has been extracted from a database compiled between 1982 and 1995 (Kirkham, Carrière, Garson, and Laramée; 1995), and updated for the World Minerals Geoscience Database Project (1998-2003). The downloadable data summary is periodically extracted from a database published in 1995, and updated for the World Map Project (1995-1997) and the World Minerals Geoscience Database Project (1998-2003). The full database can be viewed and queried over the Internet.

World Distribution of Sedimentary Exhalative (Sedex) Pb-Zn Deposits (GSC:WORLD_SedexDeposits)

The spatial distribution and most significant geological attributes of the world's largest sedimentary exhalative (Sedex) lead-zinc metallic mineral deposits and mineral districts are depicted in this data set. These deposits are hosted by marine sedimentary rocks, such as shale, greywacke, and carbonate, and are thought to have originated because of the submarine venting of hydrothermal fluid rich in zinc and lead. The downloadable data summary has been extracted from a database prepared for the World Minerals Geoscience Database Project (1998-2003). The full database can be viewed and queried over the Internet.