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| 2. |
- Sundblad, K., et al.
(författare)
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Sphalerite geobarometry and arsenopyrite geothermometry applied to metamorphosed sulfide ores in the Swedish Caledonides
- 1984
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Ingår i: Economic geology and the bulletin of the Society of Economic Geologists. - : Society of Economic Geologists. - 0361-0128 .- 1554-0774. ; 79:7, s. 1660-1668
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Tidskriftsartikel (refereegranskat)abstract
- Metamorphosed massive sulfide deposits in the Swedish Caledonides were investigated using sphalerite geobarometry and arsenopyrite geothermometry. The sphalerite investigations yield pressure estimates of 3 to 5 kb for six deposits from host rocks of greenschist-lower amphibolite facies. A bimodal FeS distribution is apparent for the chlorite-grade deposits whereas the FeS distribution in biotite-grade deposits is unimodal. The arsenopyrite geothermometry is apparently sensitive to high contents (>0.2 wt %) of either of the trace elements Co and Ni, and possibly also of Sb. Temperature estimates for six deposits from the chlorite zone of greenschist facies yield 371 degrees + or - 45 degrees C, whereas one deposit from the biotite zone gives a temperature of 422 degrees + or - 25 degrees C. The pressure and temperature data obtained for the deposits correspond excellently with the metamorphic grade of the host rocks. Thus, sphalerite geobarometry and arsenopyrite geothermometry can be applied successfully to metamorphosed sulfide orebodies if attention is paid to textural relationships and minor element distribution in the minerals investigated
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| 5. |
- Berglund, S., et al.
(författare)
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Arsenopyrite and sphalerite as T-P indicators in sulfide ores from northern Sweden
- 1980
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Ingår i: Mineralium Deposita. - 0026-4598 .- 1432-1866. ; 15:2, s. 175-187
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Tidskriftsartikel (refereegranskat)abstract
- The compositions of arsenopyrite and sphalerite from five Swedish metamorphosed Cu, Zn-sulfide deposits are related to T and P, according to the methods described by Kretschmar and Scott (1976) and Scott (1973). The As/S ratio of arsenopyrite indicates an equilibrium temperature around 400°C for all the deposits studied, whereas the sphalerite barometer shows pressures between 5 and 7 kb. The mineral assemblages of the bedrocks indicate a similar temperature but a lower pressure. A constant fs2 is probably only effective over distances of millimetres or a few centimetres in the samples studied. The fs2 has always been lower in the surrounding rocks than in the ores as indicated by a higher As/S in arsenopyrite, more FeS in sphalerites and the absence of pyrite.
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| 6. |
- Hartel, R.W., et al.
(författare)
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Crystallization kinetics for the sucrose-water system
- 1980
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Ingår i: Design, control and analysis of crystallization processes. - : American Institute of Chemical Engineers. ; , s. 65-72
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Konferensbidrag (refereegranskat)abstract
- Crystallization kinetics for the sucrose-water system were studied in a continuous MSMPR cooling crystallizer. Growth and nucleation rates were derived from the measured size distributions using the population balance equation. In the region of higher supersaturation, where secondary nucleation occurs, it appeared that growth was a linear function of supersaturation; whereas, nucleation was approximately 1. 5 order in supersaturation. Growth rates were lower for crystals smaller than about 60 mu m, although these too increased with supersaturation. The latter trends were observed in both the higher (nucleating) and lower (non-nucleating) supersaturation regions. Preliminary batch studies indicated that the rate of secondary nucleation was also a function of both the method of contact and the impact energy.
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