Reconstructing the Earth's Climate using the Sulfur Cycle
The sulfur cycle is a key biogeochemical cycle which influences climate, ocean chemistry, and biology. The sulfur cycle is affected by most significant biological and climatic events, such as mass extinctions, the evolution of oxygen in the Earth's atmosphere, and the development of early life. Our ability to reconstruct these events depends critically on measurements of ancient sulfur in rocks. This provides a powerful tool to understand climatic responses, but our interpretations are limited to the preservation of these rocks-which have often undergone severe environmental variations. The discovery of sulfate in carbonate and its subsequent extraction has provided us with the potential to reconstruct the ancient sulfur cycle at higher temporal and spatial resolution, with reliable preservation over time, however the extent to which carbonate-associated sulfate provides a reliable record of ancient sulfur is not yet well constrained. We present new high resolution records of carbonate-associated sulfate, which both lend confidence to this method, and have important implications for the behaviour of other proxies for the sulfur cycle.