Thursday, June 01, 2006

Fossil Frogs Predict Rain

New method to estimate paleoprecipitation using fossil amphibians and reptiles and the middle and late Miocene precipitation gradients in Europe. 2006. M. Böhme, and L. Maximilians. Geology 34: 425-428.


Precipitation is an important geodynamic control factor coupled to tectonics, erosion, continental run-off, weathering, and oceanic circulation. But in practice this climate parameter is difficult to estimate.

Existing methods for determining paleo-precipitation are either subject to large errors (± 350–400 mm or more using mammalian proxies) or restricted to wet climate systems due to their strong facies dependence (paleobotanical proxies). Böhme et al. describe a new tool to estimate paleo-precipitation based on an indexing of the frequency of eco-physiologic groups within fossil amphibian and reptile communities.

In recent communities, these indices show a highly significant correlation to annual precipitation (r2 = 0.88) and will yield paleo-precipitation estimates with average errors of ± 250–280 mm. Knowledge about fossil amphibians and reptiles has increased dramatically over the last decade, and large distribution databases also exist. Therefore, the new method will widely extend the applicability of precipitation estimates in the geological past.