Metallogenesis, through the mechanism of plate tectonics, has contributed to the formation of ore deposits in continental areas as well as within oceanic crust and the sea floor. Evidence for metallogenesis occurring on the sea floor includes the presence of copper in lava flows entering the sea off Hawaii; veins of ore found in deep-sea cores; high concentrations of ore in sediments near oceanic spreading centers and in deep-sea brines; and mineral concentrations in deep-sea manganese nodules. Because these minerals are found in abundance in oceanic trenches, and there is no evidence of extensive scraping off of sediments when an oceanic plate is subducted, the mineralized sediments appear to be subducted along with the crystalline rock section. Therefore, there is little reason to question that mineralized oceanic sediments, crust, and upper mantle material are being subducted beneath orogenic areas such as the Andes, and have contributed to the ore deposits now found in such areas.
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Energy Resources of the Pacific Region
The energy and mineral resources of the vast Pacific basin and its neighboring land areas play a vital role in meeting the ever-growing needs of society worldwide. Building on the foundation of a highly successful conference held in 1978, this volume contains 51 of the 135 papers presented there. Subjects included are general and specific in nature--oil, gas, and coal resources; geothermal fields, uranium; tin; evaporites, trace elements; water resources; magma energy and fuels from magma. Geological and geophysical techniques, and also the new tool of remote sending for petroleum and minerals exploration are represented. Tectonics, structure fundamentals, subsurface hazards, international treaties and the law of the deep sea are discussed. Seventeen countries and regions are represented in these papers: Thailand, Nicaragua, the United States, Japan, Peru, Antarctica, El Salvador, Australia, Mexico, Taiwan, New Zealand, China, Chile, Indonesia, Canada, and the Pacific Ocean.