Lithospheric Geodynamics of the Arabian Margin
Open Access
- Author:
- Alotaibi, Thamer
- Graduate Program:
- Geosciences
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- October 18, 2019
- Committee Members:
- Kevin Patrick Furlong, Dissertation Advisor/Co-Advisor
Kevin Patrick Furlong, Committee Chair/Co-Chair
Charles James Ammon, Committee Member
Tanya Furman, Committee Member
Francesco Costanzo, Outside Member
Andrew Arnold Nyblade, Committee Member
Rocco Malservisi, Special Member
Mark E Patzkowsky, Program Head/Chair - Keywords:
- Lithospheric geodyanmics
Arabian Margin deformation
Red Sea rifting evolution - Abstract:
- The Arabian Margin experienced intense volcanism over the last 10 Ma, including volcanic eruptions as recent as 600 years ago. What is more, two earthquakes with magnitude > 5 have been recently reported with normal faulting along the Arabian Margin, suggesting that the Arabian Margin is undergoing active deformation. Due to the limited number of GPS stations within the Arabian plate, investigating the intraplate deformation was challenging. A new set of GPS data with 87 stations is used in this thesis to investigate the Arabian margin rigidity and intraplate deformation. This new GPS velocities show higher residuals along the Arabian margin that produces dilatational and shear strain rate patterns within the Arabian margin, in the vicinity of the Makkah-Madinah Transtensional zone. Both anomalies can be correlated with the recent earthquake and volcanic activities that occurred along preexisting structures attributed to the northern Red Sea diffuse extension. The causes of these GPS residuals along the Arabian Margin are unknown. In this thesis, we use the finite element modeling approach (GTECTON platform) to highlight the mechanical deformation processes along the Arabian margin and test their driving forces. These candidate forces are related either to the edge forces, the Arabian Margin interior forces as introduced by calculating the Gravitational Potential Energy, or the basal tractions as driven by sub-lithospheric topography and mantle flow. Our results indicate that the GPS residuals are not likely linked with the Gravitational Potential Energy forces. Instead, the basal tractions along an asthenospheric channel is the potential driving force for the observed deformation along the Arabian margin. Although the asthenospheric channels and northern Red Sea diffuse extension appear to play an important role in accommodating the basal tractions and recent deformation, their origin is unknown. To address this problem, we adopt a comprehensive approach that combines the structural changes along the Red Sea with the regional tectonic forces evolution of the Afro-Arabian plate boundaries. To demonstrate, we test the effect of the Mediterranean tectonic evolution (the northern boundary of the Afro-Arabian plate) and the nature of rifting along the southern Red Sea and Sirhan rifts on the northern Red Sea rifting and the Arabian margin evolution. Our numerical results indicate that the African slab roll-back in the Mediterranean, as developed the Aegean extension, caused Africa to slow down with respect to Eurasia, allows the extensional processes along the southern Red Sea to transfer to the Sirhan rift through the Makkah Madinah transtensional zone. This motion transfer appears to play a significant role in initiating a relict boundary between Arabia and Africa at ~ 27 Ma that inhabited afterwards by what is known as the Makkah Madinah volcanic line. Accelerating the eastern Mediterranean while keeping the Aegean block fixed could provide the required boundary conditions to initiate northern Red Sea diffuse extension at 25 Ma. The region of diffuse extension is bounded by the volcanic provinces in NE Egypt to the west and Sirhan rift to the east, Makkah Madinah transtensional zone to the southeast and the Mediterranean to the north. Last, our results indicate that the northward propagation of the dike intrusions along the Red Sea can localize the rifting along the northern Red Sea at ~ 21 Ma.