Abstract
The global expansion of C4 grasslands in the late Miocene has been attributed to a large-scale decrease in atmospheric carbon dioxide (CO2) concentrations. This triggering mechanism is controversial, in part because of a lack of direct evidence for change in the partial pressure of CO2 (pCO2) and because other factors are also important determinants in controlling plant-type distributions. Alkenone-based pCO2 estimates for the late Miocene indicate that pCO2 increased from 14 to 9 million years ago and stabilized at preindustrial values by 9 million years ago. The estimates presented here provide no evidence for major changes in pCO2 during the late Miocene. Thus, C4 plant expansion was likely driven by additional factors, possibly a tectonically related episode of enhanced low-latitude aridity or changes in seasonal precipitation patterns on a global scale (or both).
Original language | English (US) |
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Pages (from-to) | 876-879 |
Number of pages | 4 |
Journal | Science |
Volume | 285 |
Issue number | 5429 |
DOIs | |
State | Published - Aug 6 1999 |
All Science Journal Classification (ASJC) codes
- General