Heavy minerals distribution

This paper documents a soil and till survey of the Shiko Lake porphyry copper-gold mineral occurrence near Quesnel Lake, British Columbia, and the comparison of Cu, Au, and other elements by partial extraction geochemical analysis with the distribution of gold and other heavy mineral grains (Lett Doyle 2009). 

Dreimanis, A., Knox, K.S., Moretti, F.J., Reavely, G.H. 1957. Heavy mineral studies in tills of Ontario and adjacent areas. Journal of Sedimentary Petrology, 27, 148-161. Dreimanis, A. Vagners, U.J. 1971. Bimodal distribution of rock and mineral fragments in basal tills. In Goldthwait, R.P. (ed) Till, A... 

The distribution of Jarosite in till samples is even more compelling than that for gold. Except for three samples with trace amounts, the most abundant Jarosite (from 1 to 25% of the grains in the heavy mineral fraction) occurs in samples adjacent to and within 7 km down-ice from the deposit (Fig. 4). Most Jarosite grains have a detrital morphology (variably... 

Rare-earth minerals exist in many parts of the world the overall potential supply is essentially unlimited. As a group, these elements rank fifteenth in abundance, somewhat more plentiful than zinc. Rare-earth minerals generally are classified as sources for light (La through Gd) or heavy (Y plus Tb through Lu). Typical mineral distributions are given in Table 3. 

Fig. 3. Mean mineral density profiles of two artificial caries lesions. Mineralisation, as a percentage of sound enamel, assumed to be 87% mineral by volume, is expressed as a function of depth into the lesion. The two mineral distributions are clearly different but the amount of mineral loss is almost identical in each case. In the text, the terms shallow and deep refer to lesion depth, whereas the terms small lesion and Targe lesion refer to amount of mineral loss, regardless of depth. The heavy line represents a lesion with a high R parameter and the lighter line, a lesion with a lower R parameter (see 4.6).

Rubey, W.W. (1933). The size distribution of heavy minerals within a water-laid sandstone. 

For full details on the occurrence of minerals in rocks, the reader should consult textbooks on petrology or mineralogy, but for the present purpose, a brief discussion of the geological distribution of heavy minerals can be made by grouping rocks into seven broad categories. 

Adams, J. E., and R. P. Matelski, 1955. Distribution of heavy minerals and soil development in Scott silt loams. Soil Sci. 79 59. 

Barium [7440-39-3] Ba, is a member of Group 2 (IIA) of the periodic table where it Hes between strontium and radium. Along with calcium and strontium, barium is classed as an alkaline earth metal, and is the densest of the three. Barium metal does not occur free in nature however, its compounds occur in small but widely distributed amounts in the earth s cmst, especially in igneous rocks, sandstone, and shale. The principal barium minerals are barytes [13462-86-7] (barium sulfate) and witherite [14941-39-0] (barium carbonate) which is also known as heavy spar. The latter mineral can be readily decomposed via calcination to form barium oxide [1304-28-5] BaO, which is the ore used commercially for the preparation of barium metal. 

Fig.1. Eh-pH diagram for the system Fe-U-S-C-H2O at 25 °C showing the mobility of uranium under oxidizing conditions, the relative stability of iron minerals, and the distribution of aqueous sulfur species. Heavy line represents the boundary between soluble uranium (above), and insoluble conditions (below), assuming 1 ppm uranium in solution.

Barium sulfate is widely distributed in nature and occurs as the mineral barite (also known as barytes or heavy spar). It often is associated with other metallic ores, such as fluorspar. Barites containing over 94% BaS04 can be processed economically. 

---