Sandbox Experiments as Analogues for Continental Rifts: Investigation of the Impact of Rock Strength in Extensional Stress Regimes
Department
Geosciences and Geological and Petroleum Engineering
Major
Geology and Geophysics
Research Advisor
Hogan, John Patrick
Advisor's Department
Geosciences and Geological and Petroleum Engineering
Funding Source
Geological Sciences and Engineering
Abstract
Experimental sandbox analogs are an effective method for researching incremental strain at the scale of the continental crust. We investigate the role of rock strength on the nascent stages of continental rifts, such as the East African Rift. The 1st experiment, using only sand, developed horst and grabens as a result of normal faulting. The 2nd experiment included a strong stiff layer and strain was localized along steeply dipping normal faults and by block rotation. The 3rd experiment included a weak layer that progressively thinned (ductile faulting). The 4th experiment modeled a stiffer upper crust overlying a deeper ductile layer. Deformation in the upper crust occurred through a combination of fracturing, faulting, and block rotation. These faults merged into the thinning ductile layer. The results demonstrate that rock strength variation within the crust impacts both the mechanisms and distribution of strain throughout continental crust undergoing extension.
Biography
Cassandra Browne is an undergraduate student in the department of Geology.
Research Category
Sciences
Presentation Type
Poster Presentation
Document Type
Poster
Award
Sciences poster session, First place
Location
Upper Atrium/Hallway
Presentation Date
08 Apr 2009, 9:00 am - 11:45 am
Sandbox Experiments as Analogues for Continental Rifts: Investigation of the Impact of Rock Strength in Extensional Stress Regimes
Upper Atrium/Hallway
Experimental sandbox analogs are an effective method for researching incremental strain at the scale of the continental crust. We investigate the role of rock strength on the nascent stages of continental rifts, such as the East African Rift. The 1st experiment, using only sand, developed horst and grabens as a result of normal faulting. The 2nd experiment included a strong stiff layer and strain was localized along steeply dipping normal faults and by block rotation. The 3rd experiment included a weak layer that progressively thinned (ductile faulting). The 4th experiment modeled a stiffer upper crust overlying a deeper ductile layer. Deformation in the upper crust occurred through a combination of fracturing, faulting, and block rotation. These faults merged into the thinning ductile layer. The results demonstrate that rock strength variation within the crust impacts both the mechanisms and distribution of strain throughout continental crust undergoing extension.
