Fill and Wall Architecture of Clastic Dikes at Slim Buttes, South Dakota
Advisor Information
Dr. Harmon Maher
Location
MBSC 201
Presentation Type
Poster
Start Date
6-3-2020 9:00 AM
End Date
6-3-2020 10:15 AM
Abstract
Clastic dikes are common in the south part of Slim Buttes, in NW South Dakota, cutting through the Brule Formation, and truncated by the Arikaree Group sandstones above. A clastic dike is a tabular body of sedimentary material discordant to host sedimentary rock strata or other rock types. Clastic dikes are thought to form either by a) rapid fluidized injection of ‘quick’ sediment mobilized by pressurized pore fluids, or b) passively by surface sediment swept into fractures open to the surface. The clastic dikes at Slim Buttes are likely due to fluidizing injection aided by the process of diagenesis (specifically volume changes during burial, compaction and mineral transformation). Internally the dikes are highly structured with vertical internal layering of alternating sand and mud laminae (often only several mm thick). The layers in these dikes were both continuous in some, and discontinuous in others. These clastic dikes are not simple opening cracks, where the walls match. Instead walls can be rough or smooth and must have been modified by dike emplacement through scouring and other processes. These dikes also display complicated cross cutting relationships, containing various bends and offshoots. The dikes in Slim Buttes are complicated fractures with complex fill and wall architecture.
Fill and Wall Architecture of Clastic Dikes at Slim Buttes, South Dakota
MBSC 201
Clastic dikes are common in the south part of Slim Buttes, in NW South Dakota, cutting through the Brule Formation, and truncated by the Arikaree Group sandstones above. A clastic dike is a tabular body of sedimentary material discordant to host sedimentary rock strata or other rock types. Clastic dikes are thought to form either by a) rapid fluidized injection of ‘quick’ sediment mobilized by pressurized pore fluids, or b) passively by surface sediment swept into fractures open to the surface. The clastic dikes at Slim Buttes are likely due to fluidizing injection aided by the process of diagenesis (specifically volume changes during burial, compaction and mineral transformation). Internally the dikes are highly structured with vertical internal layering of alternating sand and mud laminae (often only several mm thick). The layers in these dikes were both continuous in some, and discontinuous in others. These clastic dikes are not simple opening cracks, where the walls match. Instead walls can be rough or smooth and must have been modified by dike emplacement through scouring and other processes. These dikes also display complicated cross cutting relationships, containing various bends and offshoots. The dikes in Slim Buttes are complicated fractures with complex fill and wall architecture.
Additional Information (Optional)
I have Class that Friday from 11:00am -11:50am and again from 1:00pm-3:50pm so I will be unable to present during those times.