Ore formation

Jurassic—Cretaceous Besshi-type and Mn-Fe strata-bound deposits are present in Hidaka, Hokkaido (Fig. 1.2). Geochemical data and geological evidence all point to a midoceanic ridge environment of ore formation. values of Shimokawa Besshi-type... 

Two hypotheses of seafloor depth at the time of mineralization have been proposed based on foraminiferal data, ca. 3500 m (Guber and Ohmoto, 1978 Guber and Merrill, 1983) and 1500 m (Kitazato, 1979). Considering seafloor depth of present-day ore formation at back-arc basins and fluid inclusion data mentioned above, shallow seafloor depth hypothesis (Kitazato, 1979) seems more likely. If the pressm e-temperature condition of Kuroko ore fluids was close to the boiling curve, the depth could be estimated to be 1,000-1,500 m, which is similar to that for present-day back-arc mineralization such as Okinawa Trough. 

Horikoshi, E. (1977) Tectonics of ore formation. In Tatsumi, T. (ed.). Fundamental Aspects of Modem Economic Geology. U. Tokyo Press, pp. 32-43 (in Japane.se). 

Takahashi, H. (1988) Wall-rock alteration and ore-formation model of Hosokura Pb-Zn ore deposits, Japan. Mining Geology, 38, 335-346 (in Japanese). 

As considered by White (1981), the depth of ore formation relates to the type of ore deposits. Although the estimate of depth of formation for Japanese epithermal... 

To model the process of ore formation in the district, we first consider the effects of simply cooling the ore fluid. We begin by developing a model of the... 

Let us now consider the effects of chemical complexity on the predominance limits of solutes at environmental P and T conditions. The elements in question are emblematic for their particular importance in ore formation. 

The aim of this work is to further characterize the different generations of uranium oxide from three basement-hosted deposits the Miiiennium, Eagie Point, and P-Patch with muitipie micro-scaie anaiysis techniques. The resuits wiii be compared to those previousiy obtained on uranium oxides from deposits iocated in the vicinity of the unconformity to evaiuate the previousiy proposed ore formation modeis. 

The ore formation itself is connected with the oxidation state of ore-bearing fluids for which reducing mediums are... 

Zotov, I.A. 1989. Transmagmatic fluids In magmatism and ore formation. Moscow. Nauka publishing house, 215 p.(ln Russian)... 

This group of deposits is closely associated in space and time with magmatic intrusions that were emplaced at relatively shallow depths. They have been developed in hydrothermal systems driven by the cooling of magma (e.g., porphyry-type deposits and skams). From 8D- and 8 0-measurements, it has been concluded that porphyry copper deposits show the clearest affinity of a magmatic water imprint (Taylor 1974) with variable involvement of meteoric water generally at late stages of ore formation. 

The Cigar Lake uranium deposit is located in northern Saskatchewan in the eastern part of the Athabasca basin (Fouques et al. 1986 Bruneton 1987, 1993 Cramer Smellie 1994). Similar to the Gabon ore deposits, the primary mineralization is hosted by a hydrothermally altered sandstone (Athabasca formation), above the contact with an Archean metamorphic basement at a depth of about 430 m (Fig. 2). The ore formation occurred 1360 Ma to 1550 Ma... 

The Possible Involvement of Organic Coordination Compounds in Ore Formation 868... 

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