"There's a lot more litter fall in an environment with a lot of plants, and that produces a lot of organic material in the soil, creating CO2. So we see more soil-produced CO2, displacing the atmospheric CO2. These are established relationships," Myers said.
"Our method can be used to infer relative levels of richness for areas where soils have been preserved, but where fossils are lacking because conditions were unsuitable for their preservation," he said.
The research demonstrates creative use of existing geological data, said co-author Tabor, an expert in ancient soil.
"Vertebrate paleontologists have been accumulating information about vertebrate fossils in the Jurassic for well over 100 years. In addition, geochemists have been systematically sampling the composition of ancient soils for several decades," Tabor said. "In these respects, the data that are the foundation of this study are not extraordinary. What is remarkable, though, is combining the paleontology and geochemistry data to answer large-scale questions that extend beyond the data points specifically, to answer questions about ancient ecosystems."
Data from Morrison Formation, Central Africa and Portugal
Myers tested Upper Jurassic soil nodules collected from the Morrison Formation in the western United States. The formation extends from Montana to New Mexico and has been the source of many dinosaur fossil discoveries.
He also analyzed Upper Jurassic soil nodules from Portugal, another location well-sampled for dinosaur fossils. The region's paleoclimate was broadly similar to that of the Morrison Formation.
In addition, Myers tested a small Upper Jurassic core sample from Central Africa, where there's no evidence of any major terrestrial life. Unique minerals in the rocks indicate that the region had an arid environment during the
|Contact: Margaret Allen|
Southern Methodist University