My research on ancient sedimentary basins (from Western Europe to the east & midcontinent U.S.) illuminates aspects of the Earth’s climate system (e.g., long-term controls on carbon cycling) that have implications for understanding present and future climate solutions. What are the impacts of climatic extremes on environments and ecosystems? What is the origin (and transport history) of sediment and what does this tell us about paleogeography/climate? Can we discern climatic variability from the ancient record?
I explore these questions through field-based sedimentology and a broad range of analytical techniques (e.g., geochronology, particle-size analysis, sediment geochemistry, cyclostratigraphy, thermochronology) to understand the climatic and tectonic processes that prevailed hundreds of millions of years ago. Much of my work has been in the Late Paleozoic -- a dynamic and climatically unique period of Earth’s history (Pangean assembly, icehouse collapse) -- but I apply similar techniques to learn about the processes that influenced landscape evolution in many intervals of deep time!
[under construction]
Tropical ice? ...And a link to volcanism
Ice crystal traces (below; e.g., Pfeifer et al., 2021) and significant loess deposits (right) in lower Permian strata (France) record freezing temperatures and extreme atmospheric dustiness (respectively) in tropical Pangea during peak icehouse conditions. Our current (NSF P2C2-funded) research explores the relationship between high frequency, highly explosive volcanism at low-latitudes and the onset/preservation of global icehouse conditions in the late Paleozoic. This collaborative work will assess linkages between volcanism of this nature, atmospheric dustiness, and nutrient reactivity to better understand climate-system behavior (and the impact on Earth's carbon cycle).
Paleoclimatic signals in Permian loessite
Voluminous loess deposits (fine-grained Permian redbed strata) across low-latitude Pangea -- from the western U.S. (Colorado, Oklahoma; see Soreghan research group papers) to western Europe (e.g., Pfeifer et al., 2020a) -- record perhaps the dustiest atmosphere in Earth's history. Geochemical and provenance data suggest consistencies with silt generation by cold-weathering (glacial/periglacial) processes in the Central Pangean Mountains... which is controversial given their paleolatitude, at the equator. Rock magnetic cyclostratigraphy in such strata (e.g., Pfeifer et al., 2020b ) records astronomically-forced climate change in eastern equatorial Pangea.
Rapid Permian exhumation (recorded in unroofing sequence)
Provenance data shows the source of upper Paleozoic strata exposed in the Graissessac-Lodève basin is the Montagne Noire metamorphic core complex (a local Variscan paleohigh southwest of the basin). Detrital zircon geochronology and fission track thermochronology data reflect extremely rapid (1–17 mm/yr) exhumation of the core complex during late-stage orogenesis ca. 300–285 Ma, much earlier than previously thought (Pfeifer et al., 2018; Basin Research).
Mesoproterozoic orogenesis (The Picuris Orogeny)
Geochronological analysis of the metasedimentary Marqueñas Formation (Picuris Mountains, New Mexico) yields a youngest age population of 1471 Ma (detrital zircon) and 1444 Ma core & rim ages (metamorphic monazite). The documentation of sedimentation and regional metamorphism in northern New Mexico signals a Mesoproterozoic orogenic event that Daniel et al. (2013,GSA Bulletin) propose as the "Picuris orogeny".
