SGER: Intensive Collection of Paleocene-Eocene Mammal Fossils and Development of a Stratigraphic Section in the Trans-Saharan Seaway (Mali)

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SGER: Intensive Collection of Paleocene-Eocene Mammal Fossils and Development of a Stratigraphic Section in the Trans-Saharan Seaway (Mali)Maureen O?LearyThis project is jointly funded by EAR (SGP), Environmental Biology, and the Office of International Science and Engineering. 40-80 mya shallow seas inundated the region now occupied by the Sahara Desert, and supported an extraordinary diversity of marine and nearshore species. This time interval is significant because it also included some of the hottest recorded climates of the last 100 Ma of Earth history. Few well-understood stratigraphic sections in this interval, however, are known from the African tropics, and even fewer that also yield extensive vertebrate fossils. Northern Mali has extensive, relatively unexplored sedimentary deposits from this time. Our preliminary work there (1999, 2003) indicates excellent potential for developing terrestrial-near shore stratigraphic sections spanning the Paleocene-Eocene (P/E) boundary, with vertebrate, micro-, and macroinvertebrate fossils. Study of the stratigraphy and systematic paleontology of this area could catalyze regional examination of the P/E boundary in the African tropics. Here we propose a Small Grant for Exploratory Research during which we would take a 5 week expedition (Jan. '09) to these known fossiliferous rocks of Mali with two major goals: (1) to target collection of complete and associated mammal and other vertebrate fossils, and (2) to establish a robust stratigraphic framework for these vertebrate discoveries using a combination of magnetostratigraphy, chemostratigraphy, sequence stratigraphy and biostratigraphy. The urgency of our application stems from our recent award of a National Geographic grant for $26,664 towards these goals. The budget of that grant does not, however, cover the cost of an expedition with students as well as the PI and co-PIs. With combined SGER funding, however, we would be capable of mounting a full-sized expedition that would train Malian and American graduate students, and bring new expertise to a region of the world that could yield discoveries transforming our knowledge of the early evolution of mammals in Africa. The expedition will include a non-Malian team: O'Leary (mammal systematics), Roberts (sequence stratigraphy, sedimentology), Tapanila (biostratigraphy, ichnology), Goodwin (chemostratigraphy), Muttoni (magnetostratigraphy), and McCartney (Ph.D. student, paleontology), and a Malian team Sissoko (mammal evolution), Bouare (sedimentology), Cisse (Ph.D. student, sedimentology). We have a proven ability to work together having collaborated on two expeditions and published eight joint papers.Intellectual Merit.- Our pilot research indicates that Malian deposits of the Trans-Saharan Seaway contain the most continuous record of Cretaceous-Neogene sedimentation in tropical Africa. Pilot work has resulted in several well-defined P/E sections that include the P/E boundary constrained to within several meters. Development of these sections would lay the groundwork for transformative research by establishing an African comparison for the well-studied Early Tertiary basins of North America and Asia. P/E mammal-bearing sections south of the Sahara Desert are also very rare, yet molecular phylogenetics research on mammals predicts that Africa had a rich mammal fauna at this time that remains to be discovered. Multiple stratigraphic sections will be mapped and measured at the sub-meter scale, and detailed fossil sampling undertaken. Identification of facies along with key surfaces will help correlate sections within a sequence stratigraphic framework. Provenance, geochemical, and chemostratigraphic analysis will aid in correlations. Oriented hand samples for magnetic polarity stratigraphy will be collected at high-resolution (m-scale) and tied to measured sections, with emphasis on intervals of section that display potential for recovery of a continuous polarity record.Broader Impacts - This project involves seven diverse scientists from American, European and African institutions. Two students - one Malian and one American will participate in the expedition and will publish on the discoveries.