Event Title

The Heart Mountain Detachment, Wyoming: Processes Involved in a Mega-Block Slide

Location

CSU Ballroom

Start Date

21-4-2014 10:00 AM

End Date

21-4-2014 11:30 AM

Student's Major

Chemistry and Geology

Student's College

Science, Engineering and Technology

Mentor's Name

Steven Losh

Mentor's Email Address

steven.losh@mnsu.edu

Mentor's Department

Chemistry and Geology

Mentor's College

Science, Engineering and Technology

Description

The Heart Mountain detachment is an enigmatic geological feature in northwestern Wyoming which exhibits unique faulting. These faults underlie a slide block, which was over a kilometer thick, has a 3000 km2 area, and which moved tens of kilometers on a nearly level plane approximately 50 million years ago. Although the processes of this displacement have been debated for decades, this once wanderlust allochthon gives no transparent solution. The greatest mystery of Heart Mountain is the mechanics of faulting. Typically, the more movement there is on a fault, the thicker the zone of broken rock inside that fault. However, the Heart Mountain detachment faulting is commonly very narrow. It is evident that the slide block essentially glided on a very thin, frictionless surface, perhaps lubricated by a process called calcining, which releases carbon dioxide (CO2) from carbonate rocks in the fault at high temperatures (800˚C - 1000˚C). This process can cause fluidization of the carbonates, which produced clastic dikes located above the fault zones. If calcining was involved in the movement of Heart Mountain, where did all of the CO2 go? To solve this mystery, we have conducted field work and sample collection and examined thin sections of faulted rocks by use of petrographic microscopy, cathodoluminescence (CL), and scanning electron microscopy (SEM). SEM, CL and other petrographic data will be presented to evaluate the processes that occurred during the faulting event.

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Apr 21st, 10:00 AM Apr 21st, 11:30 AM

The Heart Mountain Detachment, Wyoming: Processes Involved in a Mega-Block Slide

CSU Ballroom

The Heart Mountain detachment is an enigmatic geological feature in northwestern Wyoming which exhibits unique faulting. These faults underlie a slide block, which was over a kilometer thick, has a 3000 km2 area, and which moved tens of kilometers on a nearly level plane approximately 50 million years ago. Although the processes of this displacement have been debated for decades, this once wanderlust allochthon gives no transparent solution. The greatest mystery of Heart Mountain is the mechanics of faulting. Typically, the more movement there is on a fault, the thicker the zone of broken rock inside that fault. However, the Heart Mountain detachment faulting is commonly very narrow. It is evident that the slide block essentially glided on a very thin, frictionless surface, perhaps lubricated by a process called calcining, which releases carbon dioxide (CO2) from carbonate rocks in the fault at high temperatures (800˚C - 1000˚C). This process can cause fluidization of the carbonates, which produced clastic dikes located above the fault zones. If calcining was involved in the movement of Heart Mountain, where did all of the CO2 go? To solve this mystery, we have conducted field work and sample collection and examined thin sections of faulted rocks by use of petrographic microscopy, cathodoluminescence (CL), and scanning electron microscopy (SEM). SEM, CL and other petrographic data will be presented to evaluate the processes that occurred during the faulting event.

Recommended Citation

Jaros, Matthew. "The Heart Mountain Detachment, Wyoming: Processes Involved in a Mega-Block Slide." Undergraduate Research Symposium, Mankato, MN, April 21, 2014.
http://cornerstone.lib.mnsu.edu/urs/2014/poster_session_A/48