Title

Sandbox Experiments as Analogues for Continental Rifts: Investigation of the Impact of Rock Strength in Extensional Stress Regimes

Presenter Information

Cassandra Browne

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

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Apr 8th, 9:00 AM Apr 8th, 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.