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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The structural and chemical evolution of phyllic alteration at North Silver Bell, Pima County, Arizona

Piekenbrock, Joseph Robert January 1983 (has links)
No description available.
2

The role of silicate mineral alteration in the supergene enrichment process

Marozas, Dianne Catherine January 1983 (has links)
No description available.
3

A determination of the sulfur isotopic signature of an ore-forming fluid from the Sierrita porphyry copper deposit Pima County, Arizona

Turner, Kent January 1983 (has links)
No description available.
4

Physiochemical characteristics during potassic alteration of the porphyry copper deposit at Ajo, Arizona

UyTana, Veronica Feliciano January 1983 (has links)
Potassium metasomatism is a widespread alteration type in porphyry copper deposits and is often spatially associated with hypogene sulfide ore formation. At Ajo, potassic alteration composes the dominant alteration type and is spatially, and to some extent, temporally, associated with chalcopyrite and bornite mineralization. Physiochemical conditions prevailing during potassic alteration thus describe a significant portion of the hydrothermal ore-forming process. Studies of fractures, fluid inclusions in quartz, and structural and compositional characteristics of K-feldspar, all in the potassic alteration zone at Ajo, indicate that: fracturing was strongest during potassic alteration and sulfide deposition, pressure were at approximately 650 bars, temperatures started a a minimum of 580°C, continued through 470°C, log aK+/aH+ changed from 2.6 at 580°C to 3.2 at 470°C, log aNa/aH+ changed from 2.7 at 580°C to 3.8 at 470°C, and the ratio aK+/aNa+ radically decreased from 0.8 to 0.3 in this temperature range.

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