The determination of gold in geologic materials by neutron-activation analysis using fire assay for the radiochemical separations

Rowe, J. J.; Simon, F.O.

doi:10.3133/cir599

Cited by 10 publications

(7 citation statements)

References 9 publications

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“…(1967). For example, in contrast to our method (see Rowe and Simon, 1968), the method of Mantel and Brownlow did not involve radiochemical separation after irradiation and the use of a standard with each sample. Nevertheless, examination of Table 1 reveals several noteworthy points: 1) For gold abundance of whole-rock samples, the two sets of data compare favorably, even though the reproducibility for some individual samples we analyzed (e.g., nos.…”

Section: Montanamentioning

confidence: 85%

“…The USGS gold analyses discussed in this report were obtained by a combined neutron-activation and fire assay method, the precision and accuracy of which have been given in detail elsewhere (Rowe and Simon, 1968;Gottfried et al, 1972). The reproducibility for our data is -+10 percent for concentrations above 1 ppb and -+30 percent for concentrations below 1 ppb; Figure 1 Even though the range of gold content in plutonic rocks is small, mean (arithmetic) gold content tends to decrease from mafic to felsic calc-alkalic rocks (Fig.…”

Section: Gold Abundance In Igneous Rocksmentioning

confidence: 99%

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Gold Abundance in Igneous Rocks; bearing on Gold Mineralization

Tilling¹,

Gottfried²,

Rowe³

1973

Economic Geology

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HydrothermM deposits of gold and other metals are commonly associated with igneous rocks that are thought by many to be the source of the ore metals. However, hypotheses linking gold mineralization and gold abundance in the associated igneous rock have been ambiguous and nonspecific. For example, abundance levels higher as well as lower than those considered as background or normal have been invoked as evidence to support theories that the gold was derived from the igneous rock.A review of the quantitative data now available indicates that unaltered igneous rocks have a rather restricted range in gold content, rarely exceeding 10 ppb (parts per billion) and generally well below 5 ppb. Mafic rocks tend to have more gold than felsic and intermediate rocks in both plutonic and volcanic suites. Furthermore, gold also tends to be higher in the early crystallizing minerals (mafic silicates, Fe-Ti-oxides, etc.) than in the later crystallizing quartz and feldspar. These observations suggest that gold becomes depleted in the residual silicate melt in differentiating calc-alkalic magmas.Comparison of fresh and altered rocks from the Butte and Marysville districts, Montana, shows that higher than background gold values invariably can be ascribed to secondary introduction rather than to initial high abundances in the magma. Evaluation of available abundance data for greenstone-granite gold belts demonstrates no appreciable differences in gold content between the granitic rocks and the metavolcanic country rock;hence, the gold data neither support or refute the currently popular hypothesis that the gold in the deposits had its ultimate source in the country rock.Geochemical abundance data do not provide reliable guides to areas favorable (or unfavorable) for gold mineralization, nor do they help to identify source rocks or to clarify processes that bring about economic concentration of gold. Precipitation of oregrade concentrations of gold by thermal waters that are extremely low in gold (0.05 ppb or less) and that have circulated through rock also low in gold (1 ppb or less) shows convincingly that low concentration of gold in a sufficiently long-lived hydrothermal system poses no deterrent to gold mineralization (e.g., as in the Yellowstone area and the Taupo Volcanic Zone, New Zealand). Whether or not gold mineralization occurs is largely determined by geologic, geochemical, and geophysical factors other than the concentration of gold available at various places in the mineralizing system. Available data suggest that regions of gold mineralization do not necessarily coincide with segments of the Earth's crust intrinsically higher (or lower) in gold abundance.

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Section: Montanamentioning

confidence: 85%

Section: Gold Abundance In Igneous Rocksmentioning

confidence: 99%

Gold Abundance in Igneous Rocks; bearing on Gold Mineralization

Tilling¹,

Gottfried²,

Rowe³

1973

Economic Geology

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“…Fire assay has a long history as a technique for the extraction of precious metals from ores by fusion with a collector metal. This method has been used for the radiochemical separation of gold by Rowe and Simon (1968), Pd, Pt, Au, Ru, Os, and Ir by Millard and Bartel (1971), and Cu, As, Sb, Re, Pt, Au, W, and Mo by Rammensee and Palme (1982).…”

Section: Radiochemical Separationsmentioning

confidence: 99%

Methods for geochemical analysis

Baedecker¹

1987

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“…In contrast, 13 samples of cement copper col-lected from seven leach operations in Arizona were analyzed by F. 0. Simon, using activation analyses (Rowe and Simon, 1968), and were found to contain from 0.007 to 0.066 ppm Au. These data show that the increasing use of present leaching processes can result in the loss of many thousands of ounces of gold.…”

Section: -----------------------------mentioning

confidence: 99%