An oxygen-rich atmosphere is essential for complex animals. The early Earth had an anoxic
atmosphere, and understanding the rise and maintenance of high O2 levels is critical for …

The distribution of sulfur isotopes in geological materials reveals information about Earth
history and biogeochemical processes. Research during the last several decades has used …

Oxygen is essential for animal life, and while geochemical proxies have been instrumental
in determining the broad evolutionary history of oxygen on Earth, much of our insight into …

The composition of sulfur isotopes in sedimentary sulfides and sulfates traces the sulfur
cycle throughout Earth's history. In particular, depletions of sulfur-34 (34S) in sulfide relative …

Mapping the history of atmospheric O2 during the late Precambrian is vital for evaluating
potential links to animal evolution. Ancient O2 levels are often inferred from geochemical …

Climate change can affect organisms both directly via physiological stress and indirectly via
changing relationships among species. However, we do not fully understand how changing …

The observed stability of Earth's climate over millions of years is thought to depend on the
rate of carbon dioxide (CO2) release from the solid Earth being balanced by the rate of CO2 …

Phanerozoic levels of atmospheric oxygen relate to the burial histories of organic carbon
and pyrite sulfur. The sulfur cycle remains poorly constrained, however, leading to …

Long-term secular variation in seawater sulfate concentrations ([SO 4 2−] SW) is of interest
owing to its relationship to the oxygenation history of Earth's surface environment. In this …

Abstract The Proterozoic Eon spans Earth's middle age during which many important
transitions occurred. These transitions include the oxygenation of the atmosphere …