The Impact of Erosion on Exhumation and Structural Configuration in Mountain Belts: Insights from Image Velocimetry Analysis of Coulomb Wedge Models

Phiala Jane Thouvenin, Purdue University

Abstract

Erosion, in its many forms, is thought to have a measurable impact on the development and evolution of mountain belts. In this work, we examine the response of physical scaled (analog) Coulomb wedges to different erosional styles. Data is collected in the form of velocimetry data within images of these models, using particle image velocimetry (PIV) and particle tracking velocimetry (PTV), with each dataset rendering whole wedge slip magnitude fields and material pathways, respectively. Results for channelized glacial erosion models demonstrate a significant focusing of faulting below the glacial channel itself, as well as a shift of the locus of greatest exhumation to within the channel. This shift in the locus of exhumation also allows for deep material to make it to the model surface, with models featuring a strong basal décollement having higher amounts of exhumation than those with weaker basal décollements. This same pattern is seen with regards to fault slip and shortening, with stronger décollement allowing for greater slip and more shortening. Increases in erosion magnitude are also seen as increasing total fault slip as well. With regards to thermal conditions and surface heat flow, we highlight that increasing erosion increases heat flow and temperatures within the wedge. Using Pressure-Temperature-time (P-T-t) pathways, we also see that the inclusion of weak material stratigraphy allows for duplexing and subsequent exhumation of deep-seated material, leading to complex thermal histories. Overall, we see erosion localization and magnitude being proportional to the magnitude of fault activity, and that this increased fault activity allows for deep-seated material to be exhumed from the system.

Degree

Ph.D.

Advisors

Haq, Purdue University.

Subject Area

Mathematics|Mechanics

COinS