A Geosystems Approach to Paleobotany, Isotope Geochemistry, and Paleoecology of the Late Oligocene Chilga Deposits, Northwest Ethiopian Plateau

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A Geosystems Approach to Paleobotany, Isotope Geochemistry, and Paleoecology of the Late Oligocene Chilga Deposits, Northwest Ethiopian PlateauBonnie Jacobs and Neil TaborSouthern Methodists UniversityEAR-0617306This award is co-funded by NSF's Office of International Science and Engineering.ABSTRACTAncient biotic response to geographic and climatic events has implications for predicting the effects of current global change on modern ecosystems. The tropical regions are of special concern because that is where Earth's greatest percentage of biodiversity resides. Fossils hold the key to past community ecology, and can be used to document past climates.This project will greatly improve documentation of paleoecology, paleoclimate, and floral communities in eastern Africa between 28 and 27 million years ago. To do this, PIs plan to focus on a wealth of plant fossils in an area near Chilga, in northwestern Ethiopia, by involving students and specialists in paleobotany, paleosols (fossil soils), isotopes, dating, and the rock record. This collaboration will allow them to obtain independent estimates of landscape characteristics, ecology, and climate from paleosols and isotopes that can be compared and integrated with information from plant and vertebrate fossils. Fossil leaves provide estimates of precipitation and vegetation on the landscape. Paleosols and isotopes provide estimates of climate and the physical landscape. Plant fossils will help document aspects of floristics and evolution not currently available for tropical Africa. The plant fossils occur as leaf litter assemblages with cellular detail, wood, and flowers, fruit and seed casts co-occurring with vertebrate fossils; and silicified (petrified) wood assemblages representing standing forests. PIs will test three hypotheses: 1. Fossil floras and the geochemistry of paleosols from Chilga provide data that yield quantitatively consistent records of climate. 2. Contemporaneous, but separate, leaf assemblages from the same depositional settings provide estimates of precipitation that are within a standard error of each other. 3. Taxa found separately today in the forests of West and East Africa (and excluding NW Ethiopia), were present at Chilga 28 million years ago.Ethiopian students will participate in a field school learning from paleontologists, geologists, and graduate students beginning in year one. This will advance plans for a paleotoursim heritage site. Collectively, PIs efforts will improve infrastructure and positively impact the local economy. Project members have participated in 3 Ethiopian conferences about Ethiopian paleontology, paleotourism, and tropical African botany. The geological map created by this project will be available for publication by the Ethiopian Mapping Authority. All new geochronologic, stratigraphic and paleontological data will be entered into the Paleostrat and Paleobiology databases. PIs will send daily reports from the field to an SMU web site publicized through the Texas Earth Science Teachers Association and other associates. This award was co-funded by the Office of International Science and Engineering.