Sulfur isotope abundances in basic sills, differentiated granites, and meteorites

Abstract

Studies have been made of the S32/S34 ratios in four large basic sills presumably of deep‐seated origin. The average ratio for these sills was determined by weighting each sample according to sulfur content and in accordance with the thickness of rock represented by each sample. These average ratios were within 1.0 per mil of the value for meteoritic sulfur. This is comparable with a spread of about 12.0 per mil for igneous rocks and an over‐all spread of about 120.0 per mil for terrestrial samples. In the study of igneous rocks, both intrusive and extrusive, a number of granitic intrusives were found to have S32/S34 ratios completely outside the range of values for all other igneous rocks. The results suggest that these intruded granites are regenerated sediments rather than acidic differentiates that have risen from the subcrust or mantle.

Sulfur Isotope Ratios of Leg 126 Igneous Rocks

“…However, the average δ 34 S of total sulfur in submarine basalts varies from +0.3 o/ oo to +0.7 o/ oo . The good agreement between all these closely related studies and with continental tholeiites (with δ 34 S = -0.03 o/oo, Harmon et al, 1987; between 0 o/oo and +1.0 o/ oo , Smitheringale and Jensen, 1963;Shima et al, 1963) suggests that the depleted mantle is homogeneous in its sulfur isotope composition. However, ion microprobe measurements of sulfide inclusions in diamonds have a large range in δ 34 S, which suggests that the mantle is heterogeneous in its sulfur isotope composition (Chaussidon et al, 1987).…”

Mineralogy and Isotopic Composition of Sulfur in Layer 3 Gabbros from the Indian Ocean, Hole 735B

“…Mafic intrusions exhibit similar variation in the isotopic composition of sulfide, with δ 34 S mostly ranging from -1.5 to around +5% 0 ( Fig. 7; Thode et al, 1962;Shima et al, 1963;Sasaki, 1969aSasaki, , 1969b. In some cases, δ 34 S of sulfide increases with differentiation in mafic intrusions, whereas in others no clear trend is evident, or δ 34 S may decrease in more differentiated rocks (Thode et al, 1962;Shima et al, 1963;Sasaki, 1969aSasaki, , 1969b.…”

“…In some cases, δ 34 S of sulfide increases with differentiation in mafic intrusions, whereas in others no clear trend is evident, or δ 34 S may decrease in more differentiated rocks (Thode et al, 1962;Shima et al, 1963;Sasaki, 1969aSasaki, , 1969b. Slight variations in oxygen and sulfur fugacities implied by the presence or absence of igneous troilite in Hole 735B rocks could affect the speciation of sulfur in the melt (Katsura and Nagashima, 1974;Ueda and Sakai, 1984), consequently resulting in slight vari- Thode et al, 1962;Shima et al, 1963;Sasaki, 1969aSasaki, , 1969bSasaki and Ishihara, 1977). For Japan data, I = ilmenite series; M = magnetite series.…”

Simultaneous determinations of the concentration and isotope ratio of sulfate- and sulfide-sulfur and carbonate-carbon in geological samples.

“…SHIMA et al (1963) and SMITHERINGALE and JENSEN (1963) measured the sulfur isotope ratios of sulfide minerals separat ed from rocks. These techniques, chemical and isotopic, require a large quantity of rock sam pies.…”