Extension usage examples:
Here's how our browser extension sees the article:
Article summary:
1. This article presents a high-resolution record of δ34S (sulfate and pyrite) and δ13Ccarbonate from the Middle–Upper Cambrian Port au Port Group in western Newfoundland, Canada.
2. The results indicate that Middle to Late Cambrian sulfate concentrations were low and that the sulfate reservoir was more sensitive to change than it was in either terminal Neoproterozoic or Cenozoic oceans.
3. The conclusion is that later Cambrian oceans featured both low sulfate levels and widespread subsurface anoxia, which may have been linked to the delayed recovery of skeletal animals and metazoan reefs from late Early Cambrian extinction.
Article analysis:
This article provides a detailed analysis of the relationship between the carbon and sulfur cycles in the later Cambrian ocean, using data from the Port au Port Group in western Newfoundland, Canada. The authors present a high-resolution record of δ34S (sulfate and pyrite) and δ13Ccarbonate, which illustrate systematic δ34Ssulfate shifts of > 15‰ over relatively short stratigraphic intervals (10 m). They also present a simple carbon (C) and sulfur (S) isotope box model of the Late Cambrian ocean, which suggests that low sulfate concentrations alone cannot account for these large shifts. This leads them to conclude that later Cambrian oceans featured both low sulfate levels and widespread subsurface anoxia.
The article is generally well written and provides a thorough analysis of its subject matter. It is based on reliable data collected from the Port au Port Group, which has been extensively studied by geologists in recent years. The authors provide clear evidence for their conclusions, including a detailed description of their data as well as a simple box model illustrating how large shifts can be generated if fluctuating oceanic redox is invoked.
However, there are some potential biases in this article that should be noted. For example, while the authors do mention possible links between marine redox conditions and delayed recovery of skeletal animals/metazoan reefs from late Early Cambrian extinction, they do not explore any other potential causes or implications for this phenomenon. Additionally, they do not discuss any possible risks associated with their conclusions or provide any counterarguments to their claims. Finally, they do not provide any evidence for their assertion that “the sulfate reservoir was more sensitive to change than it was in either terminal Neoproterozoic or Cenozoic oceans”; this statement should be supported with additional evidence before being accepted as fact.