Date of Award

5-2026

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

College/School

College of Science and Mathematics

Department/Program

Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Ying Cui

Committee Member

Huan Feng

Committee Member

Sandra Passchier

Committee Member

Andy Ridgwell

Abstract

Emplacement of large igneous provinces (LIPs) are among the most consequential drivers of rapid carbon-cycle perturbation in Earth history, yet why some LIP-associated events are expressed primarily as hyperthermal events whereas others coincide with mass extinction events remains unresolved. This dissertation addresses that problem through a comparative investigation of the Paleocene–Eocene Thermal Maximum (PETM), the end-Permian mass extinction (EPME), and the end-Triassic mass extinction (ETME). Chapter 1 frames this comparison with the aim of distinguishing recurring Earth-system responses to rapid carbon release from responses that are strongly conditioned by depositional and climatic boundary conditions. Chapters 2–4 test LIP-related carbon-cycle perturbations from local, regional, and global perspectives. In Chapter 2, high-resolution major-element, trace-element, rare-earth-element, and clay-mineral records from the Kuzigongsu section in the Tarim Basin are used to reconstruct environmental change during the PETM in the eastern Tethys. The results suggest enhanced terrestrial input, intensified chemical weathering and physical erosion, increased nutrient delivery, elevated productivity, and episodic bottom-water deoxygenation in a shallow, semi-restricted marine setting. In Chapter 3, major- and trace-element geochemistry, lithium concentrations, organic carbon isotopes, and astronomical analysis from the Finnmark and Trøndelag Platforms are used to investigate the Permian–Triassic transition in the northern Panthalassa. These records indicate intensified chemical weathering across the interval, but they also show that productivity and redox signals were regionally heterogeneous and strongly influenced by depositional configuration, phosphogenesis, and sediment redeposition. In Chapter 4, a global compilation of terrestrial organic and marine carbonate carbon-isotope records is integrated with Earth system modeling to reconstruct atmospheric pCO₂ and the isotopic composition of emitted carbon across the Triassic–Jurassic transition. The reconstruction reveals a stepwise rise in atmospheric pCO₂ from ~500 ppm to ~1,500 ppm, followed by a second peak of ~1,800 ppm, and indicates an evolving carbon source from early thermogenic-dominated inputs to mixed volcanic and organic-carbon sources, followed by a later shift toward more ¹³C-depleted emissions. Chapter 5 synthesizes these case studies by comparing measurable indicators of carbon-cycle forcing and environmental response, including carbon-isotope excursions, reconstructed pCO₂, modeled emission pattern and δ¹³Csource, weathering proxies, productivity- and redox-sensitive geochemical signals. Taken together, these results show that enhanced weathering and terrestrial influx are among the most recurrent responses to rapid LIP-driven carbon release, whereas productivity and redox signals are more context-dependent and vary strongly with basin geometry, sedimentary dynamics, and background Earth-system state. More broadly, this dissertation argues that the severity of LIP-linked crises is governed not by magma volume alone, but by the interaction among carbon-source and isotopic compositions, emission tempo, and environmental susceptibility, including depositional environment and ocean buffering capacity. This comparative framework helps explain why some LIP-triggered perturbations remained primarily hyperthermal events, whereas others crossed ecological thresholds associated with mass extinction events.

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