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She received geology degrees from Carleton College (B.A., 1996) and Stanford University (Ph.D., 2002), where she also completed postdoctoral research on sequence stratigraphy of the San Joaquin basin. Her dissertation focused on the sedimentary record of Late Mezosoic extension in the China-Mongolia border region. She continues to conduct research in basin analysis, sedimentation and tectonics, and petroleum geology in east-central Asia and western North America.

Recent molecular phylogenetic and molecular clock data both suggest a pre-Mesozoic age for the divergence of the angiosperm lineage from other seed plants, greatly predating the confirmed fossil record of the angiosperm crown group. In addition, molecular phylogenetic stud ies have not supported the morphologically based conclusion that gnetophytes are the extant sister group to angiosperms. We examine these relationships and divergence ages by using a novel ap proach of examining the presence of oleanane. This includes the development of methods using zeolites to preferentially reduce hopanes that can co-elute with oleanane. The presence of this mo lecular fossil strongly correlates with angiosperm diversification; in its functionalized form, along with its triterpenoid precursors, it is found in many living angiosperms. Our data show that among non-angiosperm seed plants examined thus far, oleanane is found only in fossil Cretaceous Bennettitales and Permian Gigantopteridales, both of which share characteristics with angiosperms. Previous morphological phylogenetic results indicate Bennettitales could be a sister group to or member of the angiosperm stem lineage, and results of our preliminary phylogenetic analysis in cluding the Gigantopteridales suggests the same. Our data, based on a new pyrolysis method to treat living species, support previous research indicating that oleanane and its precursors are ab sent in living gnetophytes. If oleanane originated once in seed plants then the angiosperm stem lineage would have diverged from other seed plant lineages by the late Paleozoic.

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