纤细
发表于 2025-3-23 11:32:31
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Pathogen
发表于 2025-3-23 17:33:53
,Zur Auswertung der fraktionierten Fällung,t least partly syngenetic. Shale-hosted orebodies can be exceptionally large, and are perhaps the most popular exploration targets among sedimentary ores at the present time. A transitional form between these two, one that is accordingly given considerable attention, is syngenetic ore in carbonate rocks, such as at Tynagh, in Ireland.
伤心
发表于 2025-3-23 20:47:23
Introduction,o cover the subject matter of economic geology satisfactorily in one book or in one course. In practice, some sort of restriction is made. For North American geologists, there has been a tendency, now fading, to regard economic geology as synonymous with the study of hydrothermal deposits. At one ti
Epithelium
发表于 2025-3-23 23:34:09
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AGGER
发表于 2025-3-24 04:34:33
Copper and Silver,unt, however, comes from one district, the Central African Copperbelt. Silver is almost always associated with the copper in these ores, and so will also be considered in this chapter. Also discussed are supergene deposits of copper and silver. Although of diminished economic importance today, they
laxative
发表于 2025-3-24 07:29:12
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和平
发表于 2025-3-24 12:49:52
Manganese,eposits, particularly Nikopol in the Ukraine, which contains some 75 percent of the world’s reserves (Table 5-1). Also, note another large group of deposits in the Proterozoic, that occur at the same time as the largest iron ore accumulation. Geochemically, manganese behavior is controlled by the ox
反对
发表于 2025-3-24 16:32:28
Uranium, more exploration-intensive metal than the others described in this book. We have seen that deposits of Fe and Mn are vast, with reserves in single deposits as high as 10. tons of metal. For U, the largest deposits have 2 × 10. tons; the largest U.S. deposit (at Grants, New Mexico) has only 45,000 t
CHYME
发表于 2025-3-24 19:39:04
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ANNUL
发表于 2025-3-24 23:18:54
Volcanic-Sedimentary Ores, contemporaneous with deposition of the enclosing sediment. Thus, these ores are partly syngenetic, but would not be classed as sedimentary by most geologists. Such deposits easily warrant a separate book; in this chapter I will restrict the discussion mostly to the sedimentary portions of the depos