Current Research (interested in working on one of these projects? contact me!)

Students sampling in the freezing rain - and loving it! 

Exploring the Kern Arch

 

Testing links between crustal deformation and episodic magmatism in the Coast Mountains, British Columbia


Large Cordilleran arcs undoubtedly form in response to subduction of oceanic lithosphere at ocean–continent convergent margins, yet even when subduction is continuous, arc magmatism appears to be episodic. In this project, my colleagues and I are seeking to better understand what is controlling flare-ups (short-lived, well-defined periods of high-volume magma genesis) in the Coast Mountain batholith, and in cordilleran arcs in general.



Subduction initiation along the southwestern Laurentian margin in Permian time


Subduction of oceanic lithosphere at convergent margins is a fundamental plate tectonic process, yet it’s not well understood how subduction zones initiate or how a continental margin evolves as a result of a major change in plate margin dynamics. My colleagues and I are investigating unique Permian metasedimentary and associated igneous arc rocks in southern California and northern Mexico that may record the initiation of subduction along the southwestern Laurentian margin.


Petro-tectonic development of the Sierra Nevada batholith


I have a long-standing interest in better understanding the petrology and tectonic development of the Sierra Nevada batholith, and large continental arcs in general. Central research questions include: When and why do magmatic flare-ups occur? How do magma sources evolve over time? What role does delamination play in modifying arc crust? How are batholiths exhumed? What is the relationship between lithospheric-scale batholith processes and deformation and/or vertical transients at the surface?


Recent Research



Tectonics and dynamic topography of the southern Sierra Nevada and San Joaquin Basin


This work is aimed at constraining the timing and magnitude of a Neogene cryptic subsidence and exhumation event in the southern San Joaquin basin and adjacent Sierra Nevada. Read more here. See a recent abstract about this work here.


Evolving O and Hf isotopes in the Bass Lake tonalite, Sierra Nevada


This is a collaborative project with Jade Star Lackey (Pomona College), focusing on the development of magmatism in the young (mid-Cretaceous) Sierran arc. See more here.



“Arclogite” in the northern Sierra Nevada batholith?


The development and removal of “arclogite”, an eclogite-like dense residue formed in continental magmatic arc systems, from beneath the southern Sierra Nevada has been called upon to explain a myriad of geologic observations there.  Because the northern part of the Sierra Nevada is different from the main body of the batholith in several important ways, it is not known whether or not a similar arclogite was generated and / or subsequently delaminated there. New geochronology, whole rock geochemistry, and Sr-Nd isotopes from plutons in the northern Sierra Nevada,  are used to constrain the petrogenesis of the northern batholith and to address the question of arclogite formation in the north. See more here.


Exhumation and topographic development of the northern Sierra Nevada


The Sierra Nevada is one of the greatest topographic features in North America, yet its post-magmatic uplift history and geomorphic development is not well understood. The Sierra is high and rugged and commonly considered a text book example of a tectonically youthful range, yet some evidence suggests it has not experienced recent tectonic uplift. Much of my research to date has focused on unraveling the timing of uplift and evolution of topography in the central and northern parts of the range. Read more here.


Petrogenesis and crustal architecture of the Coast Mountain Batholith, British Columbia


This work is an offshoot of a larger, collaborative continental dynamics project (BATHOLITHS).  All analyses were performed at the University of Arizona’s LaserChron center using the Nu (new!) MC-ICP-MS. This was part of a postdoc that I did with George Gehrels, aimed at the development and application of U-Pb-Hf analysis. See more here.


K-Ca (thermo-?) geochronology


Part of my Phd work focused on the development and application of the K-Ca decay system to the dating of authigenic, K-rich sediments. Read more here.


Timing of deformation and stratigraphic affinity of the Mount Morrison block, Sierra Nevada


This is part of an ongoing group project with a UA regional tectonics class.  We used: 1) U-Pb geochronology of dikes cross-cutting metamorphic fabrics in the pendant rocks to constrain timing of deformation; and 2) U-Pb detrital zircon geochronology of Pz sandstones in the pendant to constrain it’s tectonic affinity.