• Landscape/ecosystem resilience to climate and land-use change
• Tropical biogeography and paleoenvironments
• Past and future of biodiversity hotspots
• Vegetation controls on weathering and landscape evolution
• Reconstructing the environmental context of hominin evolution

For more info: https://sarahivorypollen.wordpress.com/

I combine field geology, petrography, and stable isotope geochemistry to improve the use of chemical sediments in tectonic and paleoenvironmental reconstructions. I am particularly interested in how terrestrial environments, like those in which humans live, responded to globally warm periods in Earth history to better understand how our habitats will adapt (or not) to future warming. To understand the feedbacks of tectonic uplift, weathering, and marine and atmospheric carbon, I measure carbon, oxygen, and clumped isotopes in carbonate rocks to reconstruct uplift of high-altitude terranes and alkalinity of ancient oceans. In addition, I am interested in reconstructing the phosphate levels of Precambrian environments to better understand the how phosphate accumulated for prebiotic phosphorylation and the role phosphate played in biological processes on early Earth.

Current projects:

• What were the alkalinity and phosphate levels of carbonate-forming environments on Precambrian Earth and Mars? How did these chemical conditions impact or facilitate the evolution of early life?  
• What is the fate of wastewater in the Florida Keys, and what novel techniques could be used to remove nutrients from the subsurface karst? (collaboration with Lee Kump)
• What processes facilitate late-stage, shallow carbonate diagenesis, and how can we detect cryptic carbonate alteration on the micron to nanometer scale to improve tectonic reconstructions?
• Who are the metabolic players in organic and inorganic carbon cycling in alkaline lakes, and how do they impact geochemical and isotopic signals recorded in microbial carbonate facies?  (collaboration with CU-Boulder and Weber State University)
• How did Earth’s terrestrial environments respond to globally warm periods and tectonics?

My research is motivated by fundamental questions of whole Earth evolution. A key geodynamic question is how large-scale mass transfer occurs between deep and shallow regions of the mantle. This question is important because the phenomena of mantle plume activity, continental rifting and plate convergence are intimately linked to the thermo-chemical structure of the deep Earth. Related questions are the extent to which the mantle preserves geochemically discrete reservoirs, and how chemical heterogeneities from the mantle are manifest in the compositions of mafic lavas. Research in East Africa, Turkey and Saudi Arabia explores the geochemical consequences of large- and small-scale lithospheric delamination associated with slab rollback and/or breakoff and lithospheric drip magmatism. Research throughout the East African Rift System evaluates models of continental break-up and the initiation of oceanic rift segmentation using structural and geochemical evidence. My work also includes study of the dynamics of volcanism and lithospheric modification in subduction environments. These volcanoes have the capacity for explosive activity that could prove fatal to millions of people, so characterizing magmatic processes and eruptive behavior is critical. My approach to these questions combines field work, geochemical analysis and microanalysis of mineral textures and compositions to determine thermal, chemical and physical properties of eruptive systems. My ultimate goal is to develop a robust model of lithospheric behavior that compares and contrasts the geochemical effects of disturbance in extensional and compressional tectonic environments.

Current research projects include:

• Origin of the Tungnáhraun in SE Iceland: Earth’s largest basalt lava flows
• Deciphering the lithospheric metasomatic history beneath the African Western Rift
• Genesis of Eocene Turkish lamprophyres associated with orogenic collapse
• Evolution of heterogeneous mantle source domains beneath Anatolia
• Geodynamics of NW Saudi Arabia: diffuse Red Sea rifting, Dead Sea Fault evolution, plume material transport and mafic volcanism in young Harrat basalts
• Understanding controls on U isotopes in reducing environments
• Determining the silicate weathering feedback strength during critical Earth history events
• Reconstructing the marine redox state and Earth system feedbacks around the Ediacaran-Cambrian Transition