Understanding the dynamics of submarine density flows through direct observations from modern systems
- Resource Type
- Electronic Thesis or Dissertation
- Authors
- Azpiroz, Maria
- Source
- Subject
- 551.46
- Language
- English
Submarine density flows are the volumetrically most important process for transporting sediment across our planet and form the largest sediment accumulations on Earth. Current models for turbidity currents are largely based on experimental and numerical models, and inferences from deposits in the geological record. This thesis provides a new understanding of the structure of submarine density flows through the analysis of direct measurements of submarine density currents near the seafloor. This is achieved by the analysis of datasets of density flows collected in two submarine channel systems: Congo Submarine Canyon and a channel on the Black Sea Shelf. The analysis of new measurements of submarine density flows suggests a new structure for submarine density flows that contrasts with previous models. The new structure shows that the flow front is the fastest part of the flow that outruns the rest of the flow. The difference in velocities between the front and end of the flow results in a flow stretching. This model contrasts with previous field observations of submarine flows collected in coarser sediment submarine channel systems. This thesis also analyses the cross-stream evolution of submarine density flows through meandering submarine channel systems. This new model studies the evolution of the flow processes around meanders, and suggests different scenarios of the flow structure based on the dominant process. This document links the evolving structure of the flow around bends with the sediment distribution of the submarine channel systems, and reconciles discrepancies among earlier models. This thesis provides a better understanding of the complexity of the system formed by submarine density flows and the interaction of these flows with seafloor sediment and channel morphology.