Reconstructing Paleovegetation in mid-Miocene Tropical South America: An Analysis of Carbon and Oxygen Stable Isotopes
Abstract
The advance of the C4 photosynthetic pathway in the late Miocene (~7 Ma) has typically been associated with a global shift from cold, wet conditions to a warmer, dryer climatic regime (MacFadden, 1997; Cerling et al., 1997; Winslow et al., 2003; Balasse and Ambrose, 2005). Because C4 photosynthesis is energetically advantageous at low levels (<400 ppm) of CO2, a global decrease in atmospheric CO2 may have initiated this shift (Cerling et al., 1993). However, changes in precipitation, temperature, and humidity would also have affected the evolutionary growth of C4 plant biota (Winslow et al., 2003). Reconstructing vegetation and temperature records just prior to the global radiation of C4 plants may therefore provide valuable insight into the exact cause and timing of this shift. Here we present new data obtained from ungulate tooth enamel from the Villavieja Formation (mid-Miocene) in central Colombia (5° North). An analysis of the carbon and oxygen isotopic signals embedded in fossilized toxodontid tooth enamel reveals a reconstruction of vegetation and temperature in central Colombia during the mid-Miocene. By correlating the presence of C3 versus C4 plant biota with paleotemperature, we attempt to analyze the biogeography and paleoclimatic implications of these plant types during the Miocene and further constrain the parameters that drive biotic change.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFMPP23D1804J
- Keywords:
-
- 1041 Stable isotope geochemistry (0454;
- 4870);
- 1605 Abrupt/rapid climate change (4901;
- 8408);
- 1630 Impacts of global change (1225);
- 9360 South America;
- 9605 Neogene