Figure 2

Fig. 2. ³³S versus ³⁴S versus plots of sulfides (black diamonds) and barite (red squares) analyzed in (4). All analyses were performed on drill core samples shown as "rock sequence" on right [see (4) for details]. Diagrams on the left-hand side show the effect of mixing small amounts of extremely fractionated (³³S +70) atmospheric sulfur with a large volume of sulfides derived from the reduction of oceanic sulfates. The highest amount of particulate atmospheric S⁰ aerosols will be stored in the sedimentary layers located on the sea floor. This in turn should result in increasing mechanically the ³³S scatter of the sedimentary sulfides (large dashed orange circle evolving toward the "S⁰ atmospheric pool") compared with the macroscopic and microscopic sulfides present in the underlying bedded barite. The range of measured ³³S versus ³⁴S values of North Pole sulfides are shown for comparison (black areas). Recognition that the sedimentary sulfides show systematic positive ³³S anomalies indicates that the source of sedimentary sulfur was indeed almost exclusively derived from atmospheric S⁰, which agrees with the sulfide source defined in (1). However, the limited range of 33S and ³⁴S values of sedimentary sulfides argue against their mixing scenario. [View Larger Version of this Image (109K JPEG file)]

 

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