United States Geological Survey YearbookThe Survey, 1987 - Forest reserves |
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Page 23
... associated silica or carbonate alteration of wall rocks . In con- trast , the Red Dog deposit contains few sedimentary / clastic or exhalative type ores , and contains very common replace- ment and multistage ore textures , in which ...
... associated silica or carbonate alteration of wall rocks . In con- trast , the Red Dog deposit contains few sedimentary / clastic or exhalative type ores , and contains very common replace- ment and multistage ore textures , in which ...
Page 25
... associated base metals , principally copper . The rocks in these exposed seg- ments extend into the subsurface . Drilling also has shown that the basement contains several other Precambrian terranes that have potential for other kinds ...
... associated base metals , principally copper . The rocks in these exposed seg- ments extend into the subsurface . Drilling also has shown that the basement contains several other Precambrian terranes that have potential for other kinds ...
Page 26
... associated rocks ( age uncertain ) Granite ( 1.8 billion years old ) Wisconsin magmatic terrane of Penokean orogen ( 1.8-2.1 billion years old ) -Favorable for copper - zinc deposits ARCHEAN ( 2500 million years old and older ) ...
... associated rocks ( age uncertain ) Granite ( 1.8 billion years old ) Wisconsin magmatic terrane of Penokean orogen ( 1.8-2.1 billion years old ) -Favorable for copper - zinc deposits ARCHEAN ( 2500 million years old and older ) ...
Page 27
... associated with many of the early Mesozoic basins , are reported to have high silver contents . Fluid - inclusion , isotope , and other studies indicate that the veins are associated with the transport of moderate temperature ( 100-250 ...
... associated with many of the early Mesozoic basins , are reported to have high silver contents . Fluid - inclusion , isotope , and other studies indicate that the veins are associated with the transport of moderate temperature ( 100-250 ...
Page 29
... associated with fault motion might be expected to produce relatively higher geothermal levels than those measured from the rocks in the surrounding region . Generally referred to as the stress - heat- flow paradox , the measured levels ...
... associated with fault motion might be expected to produce relatively higher geothermal levels than those measured from the rocks in the surrounding region . Generally referred to as the stress - heat- flow paradox , the measured levels ...
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