78
C. Variations of Stable Isotope Ratios in Nature
Zechstein
.. Late"
Zechstein
Maim
(Upper Jurassic)
i
i
ndITT'
I
i
i
K,ehe' kQIk ~~:" Boo',,1
25 d"S%.
Fig. 30. b 34 S histograms of evaporite formations in central Europe. The Zechstein
histogram is strongly reduced in its vertical scale. The shaded histogram refers to
sulfates occurring in the K-Mg facies of the Zechstein evaporation cycles. (After
NIELSEN, 1968c)
and ocean water. However, if isotopic equilibrium between water and
sulfate controlled the isotopic composition of sulfate, the latter should
have either a b-value of + 24%0 deduced from theoretical calculations
(UREY, 1947) or a b-value of + 38%0 deduced from experimental determinations (LLOYD, 1967). LLOYD (1967, 1968) proposed a model in which
the bacterial turnover of sulfate in the sulfur cycle plays a decisive role in
oxygen isotope composition of sulfate. ROSLER et al. (1968) and PILOT et
C. Variations of Stable Isotope Ratios in Nature
Zechstein
.. Late"
Zechstein
Maim
(Upper Jurassic)
i
i
ndITT'
I
i
i
K,ehe' kQIk ~~:" Boo',,1
25 d"S%.
Fig. 30. b 34 S histograms of evaporite formations in central Europe. The Zechstein
histogram is strongly reduced in its vertical scale. The shaded histogram refers to
sulfates occurring in the K-Mg facies of the Zechstein evaporation cycles. (After
NIELSEN, 1968c)
and ocean water. However, if isotopic equilibrium between water and
sulfate controlled the isotopic composition of sulfate, the latter should
have either a b-value of + 24%0 deduced from theoretical calculations
(UREY, 1947) or a b-value of + 38%0 deduced from experimental determinations (LLOYD, 1967). LLOYD (1967, 1968) proposed a model in which
the bacterial turnover of sulfate in the sulfur cycle plays a decisive role in
oxygen isotope composition of sulfate. ROSLER et al. (1968) and PILOT et