Description
- Abstract:
- The lithosphere preserves a record of tectonic evolution in its seismic velocity structure, reflecting variations in temperature, composition, and physical state. However, individual seismic observations are inherently non-unique for constraining lithospheric properties, limiting our ability to robustly resolve the characteristics of lithosphere and its evolution. This thesis addresses this challenge by integrating complementary seismic datasets to construct better-constrained models of lithospheric structure, with an emphasis on cratonic regions and their thermal, compositional, and structural characteristics. Chapter Two develops a new approach to jointly invert Rayleigh wave phase velocity and local amplification to constrain crustal Vp/Vs and Vsv in the crust and uppermost mantle, exploiting the sensitivity of amplification to shallow Vp structure. Applying this new method to the western US yields a new crustal Vp/Vs map that reveals compositional variations reflecting crustal evolution. Chapter Three investigates the lithospheric structure of the Fennoscandian Shield through joint inversion of Rayleigh wave phase velocity and S-to-P receiver functions. Compared to typical inversions of phase velocity alone, incorporating scattered body waves illuminates layering within the cratonic lithosphere and shifts the fastest shear velocities to greater depths. Modeling that incorporates the thermodynamics and elasticity of mantle minerals reveals (i) colder temperatures than suggested by uncorrected xenolith thermobarometry, (ii) only a moderate amount of high-velocity diamond at lithospheric depths, and (iii) widespread carbonate or hydrous minerals introduced through metasomatism at depths shallower than ~150 km. Chapter Four extends this framework to southern Africa cratons and compare them with Fennoscandia. While both regions exhibit similar shallow lithospheric structures above ~150 km, southern Africa cratons are characterized by a pronounced low-velocity zone between ~150–200 km, interpreted as a thermal perturbation that may contribute to elevated topography. Comparison with global Archean cratons highlights the broader role of lithospheric thermal state in governing craton evolution and surface uplift. Together, these studies advance a framework that integrates multiple seismic constraints to illuminate the formation, evolution, and characteristics of continental lithosphere.
- Notes:
- Thesis (Ph. D.)--Brown University, 2026
Citation
Huang, Yiran,
"Joint Seismic Constraints on the Structure and Evolution of the Continental Lithosphere"
(2026).
Earth, Environmental and Planetary Sciences Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://repository.library.brown.edu/studio/item/bdr:jbeafb8x/
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Earth, Environmental and Planetary Sciences Theses and Dissertations
Theses and Dissertations for the Earth, Environmental and Planetary Sciences department....