Meltwater Infiltration in Greenland FirnI am currently working with Dr. Joel Harper to better understand the impact of meltwater infiltration on Greenland firn density records through quantitive alignment with dynamic time warping. We find that mass redistribution through meltwater infiltration substantially impacts these records, hindering confident correlation between proximal records. A manuscript detailing out work was published in Annals of Glaciology (Hagen and Harper, 2023).
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New R package for Dynamic Time WarpingI translated the Hay et al. (2019) DTW algorithm from MATLAB into R to make it free and open source. This code is the basis of an upcoming graphical user interface (GUI) for the DTW algorithm, aimed at making this objective, reproducible technique for time-series stratigraphic correlation more accessible – Stay tuned! If you are interested in the R package, containing the underlying DTW algorithm, please check it out here!
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Chemostratigraphic
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I worked with Dr. Jessica Creveling to adapt a cellular automata model of carbonate system development (CarboCAT; Burgess, 2013) to be isotope-enabled. By modifying the CarboCAT model, we forward modeled different carbonate systems and projected δ13Ccarb signals across space and time. We interrogated the influence of various physical processes on the 'preserved' δ13Ccarb signal, and investigated ramifications for intra- and interbasinal correlations.
2019 GSA Annual Meeting abstract:
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Paleosecular Variation (PSV) Stratigraphy |
I worked with Drs. Brendan Reilly, Joe Stoner, and Jessica Creveling to adapt the dynamic time warping alignment algorithm (Hay et al., 2019) to handle paleosecular variation data. Our new formulation of the algorithm allows for the simultaneous alignment of inclination and declination archives. Like with chemostratigraphic records (see below), this technique can be used to export the chronology of one locality to another. In doing so, we assembled a library of potential alignments between the target and candidate datasets, allowing for a more objective correlation. We leverage radiometric constraints to test the validity of the resulting correlations. A manuscript detailing out work was published in Geophysical Journal International (Hagen et al., 2020). Check it out here!
2019 AGU Annual Meeting abstract:
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Deep Time PaleoceanographyI worked with Drs. Jessica Creveling and Alan Mix to better understand Neoproterozoic ocean chemistry. This period of Earth history is marked by anomalously large carbon isotope excursions (e.g., the Shuram-Wonoka excursion, the Bitter Springs Stage excursion) that are not well understood. The mechanism for these excursions is still widely debated. I worked to develop a new hypothesis and accompanying simplified carbon cycle model for the Neoproterozoic. A manuscript detailing our work is currently in preparation (Hagen et al., in preparation).
I presented our results at the 2018 GSA Annual Meeting:
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Computational ChemostratigraphyAs part of my dissertation research, I worked to employ a statistical fitting routine (Hay et al., 2019) for chemostratigraphic datasets. This algorithm allows for the chronology of one locality to be exported to another. I focused my efforts on the Ediacaran–Cambrian interval to elucidate the rates and timing of biological and chemical evolution events (multiple papers in preparation). This tool can be readily applied to a variety of geochemical datasets across Earth history.
See the conference abstracts below for more detail:
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Geochronology & TaphonomyLotosaurus adentus is an enigmatic archosaur known from a sole locality in Hunan, China. The locality hosts a sizable bonebed comprised almost exclusively of L. adentus. For my undergraduate senior honors thesis, I began conducting research with Dr. Eric M. Roberts (James Cook University) and Dr. Raymond Rogers (Macalester College) on this bonebed in order to revise the archosaurian phylogeny and better understand the tectonic assembly of China during this time interval (Anisian). We employed detrital zircon geochronology, C/O isotope analyses, and more to better understand the taphonomy and paleoenvironment of the locality. We also apply novel fractal analyses on the bonebed in order to better understand bone distribution and sorting. Additionally, we are working on a similar project for an embryonic dinosaur bonebed from Yunnan, China (Roberts et al., in prep.).
A manuscript detailing our results was published in Palaios (Hagen, C.J., E.M. Roberts, C. Sullivan, J. Liu, Y. Wang, P.O. Agyemang, and X. Xu, 2018. Taphonomy, Geological age and paleobiogeography of Lotosaurus Adentus (Archosauria: Poposauroidea) from the Middle Upper Triassic Badong Formation, Hunan, China, PALAIOS 33, 3. doi: 10.2110/palo.2017.084) |
Stellar ActivityOur team, including Drs. Brendan Miller (College of St. Scholastica), Elena Gallo (U. Michigan), and Jason Wright (Penn State), has worked to combine archival datasets, as well as newly collected X-ray activity data from the SWIFT observatory, in order to better understand stellar activity in sun-like stars. We found that many stars do behave cyclicly in chromospheric output, and that these sun-like stars have cyclic periods similar to that of the solar cycle. We attempted to tie coronal activity to chromospheric activity in a small pilot study. Our initial findings show that these sun-like stars exhibit more X-ray variability than expected, with flaring occurring both more regularly and on shorter time scales than previous thought. We are currently investigating X-ray flaring in M dwarf stars, with hopes to better constrain the impact of flaring on exoplanet habitability.
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(Dwarf) Galaxy EvolutionI studied surface brightness profiles of the SHIELD (nearby, irregular dwarf) galaxies via Hubble Space Telescope imaging with Dr. John Cannon. In order to do this I designed an automated program to manipulate images and extract surface brightness profiles (CleanGalaxy; Hagen et al., 2014). Ultimately, we found that these surface brightness profiles drop off at a much faster rate than expected, manifesting as 'sharp edges of brightness' around the galaxies. This work has also lead to a better understanding of the galaxies themselves, such as their gas kinematics and star formation rates: see McNichols et al. (2016) and Teich et al. (2016).
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