Geothermal resources

Fig. 2. Types of geothermal resources. Only the geopressured resource is typically found in sedimentary rock.

Temperatures of hydrothermal reservoirs vary widely, from aquifers that are only slightly warmer than the ambient surface temperature to those that are 300°C and hotter. The lower temperature resources are much more common. The value of a resource for thermal appHcations increases directiy with its temperature, and in regions having hotter water more extensive use of geothermal resources has been implemented. Resources in remote areas often go unused unless hot enough to be employed in generating electricity. 

G. M. Reistad, paper presented at the Proceedings of the 2nd UN Symposium on the Development and Use of Geothermal Resources, Vol. 1, Lawrence Berkeley Laboratory, San Erancisco, 1975, pp. 2155—2164 "Analysis of the Economic Potential of Solar Thermal Energy to Provide Industrial Process Heat," U.S. ERDN Contract, EY-No-C-02-2829, Intertechnology Corp., 1977. 

C. Stone, ed.. Monograph on The Geyser s Geothermal Field, Geothermal Resources Council, Davis, Calif., 1992. 

The ocean is host to a variety and quantity of inorganic raw materials equal to or surpassiag the resources of these materials available on land. Inorganic raw materials are defined here as any mineral deposit found ia the marine environment. The mineral resources are classified generally as iadustrial minerals, mineral sands, phosphorites, metalliferous oxides, metalliferous sulfides, and dissolved minerals and iaclude geothermal resources, precious corals, and some algae. The resources are mosdy unconsoHdated, consoHdated, or fluid materials which are chemically enriched ia certain elements and are found ia or upon the seabeds of the continental shelves and ocean basias. These may be classified according to the environment and form ia which they occur (Table 1) and with few exceptions are similar to traditional mineral deposits on land. 

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