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Christopher Smith PhD thesis

Integrated study of a major biological crisis: how to characterize paleoenvironmental fluctuations during the Smithian‐Spathian transition (Early Triassic)?

Started in november 2019

Funding: doctoral grant

Supervisors: Arnaud Brayard & Emmanuel Fara

 

Abstract

Since the appearance of life, Earth has gone through several major crises grandly modifying the surface environments and deeply influencing the biosphere and biogeochemical cycles. Among these crises, the Permian/Triassic (PT) boundary mass extinction was the most severe. It also marks one of the most important transitions in the history of life: the shift from the Paleozoic evolutionary fauna to the modern evolutionary fauna.

Following the PT crisis, during the early Triassic, the environment was very unstable leading to multiple small scale biotic crises in particular around the Smithian/Spathian boundary (SSB). This event appears to be closely linked to significant changes in various parameters, such as oceanic oxygen concentration, temperature or primary productivity. The processes underlying these environmental fluctuations and observed biotic changes however, remain unclear.

Based on various unexpectedly rich fossil assemblages from the western USA basin, I develop an innovative and integrated approach in order to better understand environmental and biotic changes around the SSB. The aim is to provide precise constraints on the evolution of: (i) the paleoenvironments and communities encountered within this basin, (ii) the different biogeochemical cycles, as well as oxygen concentration in the ocean and in the sediments, and (iii) the richness and complexity of biological communities by correcting the observed signals using innovative imagery methods to reveal potentially “hidden” biodiversity in the fossil record.

The overall objective is to specify the spatiotemporal constraints acting on the intricate responses of biotic changes and environmental fluctuations around the SSB.

 

Keywords

Paleontology, Paleoecology, Evolution, Taxonomy, innovative imagery, Early Triassic

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Integrated study of a major biological crisis: how to characterize paleoenvironmental fluctuations during the Smithian‐Spathian transition (Early Triassic)?

Started in november 2019

Funding: doctoral grant

Supervisors: Arnaud Brayard & Emmanuel Fara

 

Abstract

Since the appearance of life, Earth has gone through several major crises grandly modifying the surface environments and deeply influencing the biosphere and biogeochemical cycles. Among these crises, the Permian/Triassic (PT) boundary mass extinction was the most severe. It also marks one of the most important transitions in the history of life: the shift from the Paleozoic evolutionary fauna to the modern evolutionary fauna.

Following the PT crisis, during the early Triassic, the environment was very unstable leading to multiple small scale biotic crises in particular around the Smithian/Spathian boundary (SSB). This event appears to be closely linked to significant changes in various parameters, such as oceanic oxygen concentration, temperature or primary productivity. The processes underlying these environmental fluctuations and observed biotic changes however, remain unclear.

Based on various unexpectedly rich fossil assemblages from the western USA basin, I develop an innovative and integrated approach in order to better understand environmental and biotic changes around the SSB. The aim is to provide precise constraints on the evolution of: (i) the paleoenvironments and communities encountered within this basin, (ii) the different biogeochemical cycles, as well as oxygen concentration in the ocean and in the sediments, and (iii) the richness and complexity of biological communities by correcting the observed signals using innovative imagery methods to reveal potentially "hidden" biodiversity in the fossil record.

The overall objective is to specify the spatiotemporal constraints acting on the intricate responses of biotic changes and environmental fluctuations around the SSB.

 

Keywords

Paleontology, Paleoecology, Evolution, Taxonomy, innovative imagery, Early Triassic

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