66
C. Variations of Stable Isotope Ratios in Nature
derived from associated sediments, but sulfur and some water and metals
may be volcanic.
4) Red Sea geothermal system: seawater dominant in the ore fluid,
with dissolved salts and metals from associated evaporites and clastic
sediments.
5) Nonesuch Shale, Michigan: connate water and copper probably
introduced diagenetically soon after the shale was deposited."
1. Sulfur Isotope Ratios of Ore Deposits
A great deal of literature on sulfur isotope ratios concerns the origin
of sulfide ores. It becomes increasingly difficult to give a survey of the
sulfur isotope work done on ore deposits. The following is a list of only
some of the numerous papers:
ANGER et al. (1966), AULT and KULP (1959, 1960), BOTH et al. (1969),
BROWN (1967), BUSCHENDORF et al. (1963), DECHOW (1960), DECHOW
and JENSEN (1965), FRIEDRICH et al. (1964), GAVELIN et al. (1960), von
GEHLEN et al. (1962), von GEHLEN (1965), GROSS and THODE (1965),
HOEFS and GRAESER (1968), JENSEN (1957, 1958, 1959, 1967), KAJIWARA
(1971), KULP et al. (1956), LUSK and CROCKET (1969), NIELSEN (1968a),
PINCKNEY and RAFTER (1972), ROBERTSON and CUMMING (1968),
RYZNAR et al. (1967), SANGSTER (1968), SASAKI and KROUSE (1969),
STANTON and RAFTER (1966), TATSUMI (1965), TUPPER (1960), WANLESS
et al. (1960), VINOGRADOV et al. (1956), WHITE (1968).
Many of these investigations have been undertaken to discover systematic isotopic variations between ores of various types.
The goal of many determinations was to use 34S/32S ratios in distinguishing between high temperature magmatic or magmatic hydrothermal and low temperature biogenic deposits. Another aim was the use of
sulfur isotopes to demonstrate the syngenetic or epigenetic origin of
certain ore deposits. Some investigators have tried to find criteria for
equilibrium, temperature of formation, and other related problems. On
the whole there seems to be too much overlap between the different
classes of ore body for sulfur isotope ratios to be regarded as unambiguous indications of origin, though they may limit the range of possibilities.
On the basis of 34S/32S determinations some vague generalizations
can be stated:
1) Sulfides of biogenic (sedimentary) origin exhibit two differences
from the "magmatic" hydrothermal deposits, a much greater spread in
<5 34 S-values, and a preferential enrichment in the lighter isotope (there
are, however, "heavy" sedimentary sulfides too).
C. Variations of Stable Isotope Ratios in Nature
derived from associated sediments, but sulfur and some water and metals
may be volcanic.
4) Red Sea geothermal system: seawater dominant in the ore fluid,
with dissolved salts and metals from associated evaporites and clastic
sediments.
5) Nonesuch Shale, Michigan: connate water and copper probably
introduced diagenetically soon after the shale was deposited."
1. Sulfur Isotope Ratios of Ore Deposits
A great deal of literature on sulfur isotope ratios concerns the origin
of sulfide ores. It becomes increasingly difficult to give a survey of the
sulfur isotope work done on ore deposits. The following is a list of only
some of the numerous papers:
ANGER et al. (1966), AULT and KULP (1959, 1960), BOTH et al. (1969),
BROWN (1967), BUSCHENDORF et al. (1963), DECHOW (1960), DECHOW
and JENSEN (1965), FRIEDRICH et al. (1964), GAVELIN et al. (1960), von
GEHLEN et al. (1962), von GEHLEN (1965), GROSS and THODE (1965),
HOEFS and GRAESER (1968), JENSEN (1957, 1958, 1959, 1967), KAJIWARA
(1971), KULP et al. (1956), LUSK and CROCKET (1969), NIELSEN (1968a),
PINCKNEY and RAFTER (1972), ROBERTSON and CUMMING (1968),
RYZNAR et al. (1967), SANGSTER (1968), SASAKI and KROUSE (1969),
STANTON and RAFTER (1966), TATSUMI (1965), TUPPER (1960), WANLESS
et al. (1960), VINOGRADOV et al. (1956), WHITE (1968).
Many of these investigations have been undertaken to discover systematic isotopic variations between ores of various types.
The goal of many determinations was to use 34S/32S ratios in distinguishing between high temperature magmatic or magmatic hydrothermal and low temperature biogenic deposits. Another aim was the use of
sulfur isotopes to demonstrate the syngenetic or epigenetic origin of
certain ore deposits. Some investigators have tried to find criteria for
equilibrium, temperature of formation, and other related problems. On
the whole there seems to be too much overlap between the different
classes of ore body for sulfur isotope ratios to be regarded as unambiguous indications of origin, though they may limit the range of possibilities.
On the basis of 34S/32S determinations some vague generalizations
can be stated:
1) Sulfides of biogenic (sedimentary) origin exhibit two differences
from the "magmatic" hydrothermal deposits, a much greater spread in
<5 34 S-values, and a preferential enrichment in the lighter isotope (there
are, however, "heavy" sedimentary sulfides too).