Climatic and Tectonic Evolution of the Northern Patagonian Andes
Funded by the NSF EAR Postdoctoral Fellowship program
Paso del Sapo Basin
The Paso del Sapo basin in the Chubut Province of Argentina records both climatic change and tectonic growth of the Andes during the middle Miocene. The basin hosts a stack of alluvial - lacustrine sediments that are ideal for testing hypotheses about the coevolution of climate and tectonics in a terrestrial setting.
Collaborating with faculty from Universidad Nacional de La Plata
I'm collaborating with Dr. Joaquín Bucher and Dra. Micaela García, who both are jointly apointed by CONICET and Universidad Nacional de La Plata. Dr. Bucher is a sedimentologist/stratigrapher who carefully described the basin for his PhD. Dra. García in an expert in the structural evolution of the region. I'm so excited to be working with them!
Integrating thermochronology and stable isotope geochemistry
(U-Th)/He thermochronology is used to constrain the exhumation history of the upper crust, which can be driven both tectonically and climatically, and stable isotope geochemistry is used to infer
information about local climate which can be influenced by both paleotopography and paleoclimate. Over the last 20 years, these techniques have most commonly been used separately. By combining both techniques, I can more directly understand the overlapping and competing effects of changing climate and tectonic setting.
Coming soon: using landscape evolution models to quantitatively test the (co)evolution of climate and tectonics
I will use landscape evolution models to create an interpretative framework that can tie the exhumation recorded by thermochronology with the surface uplift preserved in the stable isotope archives. These models will use a proxy system model framework to test the degree to which different tectonic and climatic scenarios control the observed proxy data.
Soil Water Isotope Storage System
Soil water isotopes are wildly helpful for tracking all sorts of ecosystem processes like soil water infiltration, evaporation, plant-root water uptake, and the mixing of multiple sources. But, soil water isotope records have historically been challenging to create because they require an arduous, labor intensive sampling process.
In recent years, researchers have started to use a vapor permeable tubing that makes the reliable sampling of soil water much easier! Using dry air as a carrier gas, it’s possible to entrain water vapor from the soil and carry that to either a storage device or a cavity ring down spectrometer. Once installed in a soil, this vapor permeable tubing can sample soil water from the same location for over 2 years. We developed a way to store water vapor collected using this vapor permeable tubing, so that one could take a time-series of samples in the field, and then return to the lab to measure those samples.
We have a paper out now of a paper published in HESS that describes our successes and failures of building and testing six(!) SWISS units. You can find that publication here.
Easily replicable
The soil water isotope storage system uses commercially available parts, and is relatively easy to construct. The full parts list is included as a supplement our paper, now out in preprint. If you're thinking of building one - get in touch!! I have lots of pro-tips
Automation that can be adjusted to fit your needs
We automated the SWISS using simple microcontrollers (similar to Arduinos or Raspberry Pis). Like the SWISS itself, our automation system uses commercially available microcontroller parts. Our automation scripts can be easily programmed to fit a users desired sampling frequency.
Pedogenic Carbonate formation in fine grained soils
Stable isotope values of pedogenic carbonate are important archives of paleoenvironmental information because they reflect a wide range of environmental parameters. To better understand how the stable isotope composition of pedogenic carbonate reflects the environments of the past, we need to understand what drives the timing and style of carbonate precipitation in modern soils.
To address this question, I studied three Holocene, fine-grained, clay-bearing soils. I compared environmental parameters like air and soil temperature with geochemical parameters like the clumped isotope temperatures of pedogenic carbonate. An important and unique contribution of this study was the addition of soil water isotope datasets for each site. These data will help shed light on what the oxygen isotope values of pedogenic carbonates reflect, and improve paleoclimate interpretations.
This work was funded by NSF EAR 2023385, which was co-written by myself and my advisor Dr. Katie Snell.
Brigsdale, Colorado
Fine-medium grained mollisol
Seibert, CO
Fine grained alfisol
Oglala National Grassland
Fine grained, clay rich aridisol
Terrestrial climate change during the PETM
Bighorn Basin, WY
The Paleocene-Eocene Thermal Maximum (PETM) is an ancient example of relatively rapid climate change that has been widely studied as a potential analogue for modern climate change. To understand how terrestrial environments respond to rapid warming, researchers have turned to a thick stack of paleosols that record the PETM preserved in the Bighorn Basin, WY. The fine-grained, clay-rich paleosols of the Bighorn Basin preserve a rich floral and faunal fossil record, and a variety of geochemical proxy records have created environmental context. But, we still lack an understanding of how absolute temperature evolved through the PETM. To fill this gap, we created a pedogenic carbonate clumped isotope record through PETM.
Testing exhumation histories of the Colorado Front Range
I received an MSc in Geological Sciences from University of Colorado Boulder in 2017. In my thesis I used three vertical profiles of zircon (U-Th)/He thermochronology to better understand the time-temperature history of the Colorado Front Range and to explore what constraints are needed to make robust deep-time low-temperature thermochronology interpretations. See the publication here.
