Rheological Bridge Zone - The Initialization of Localization

by He Feng, Christopher Gerbi and Scott E. Johnson
Strain localization occurs under different geological scales and in both the brittle and viscous regimes, as the one of most significant processes of solid earth. The earliest stages of strain concentration essential to determining the cause(s) of localization. Bridge zone, or "interconnection of weak phases", occurs in less deformed, which reveals initialization of localization. These “bridge zones” comprise reduced grain sizes and an aggregation of relatively fine grains in a narrow band. Combined optical, electron beam petrography with cathodoluminescence (CL) and electron backscatter diffraction (EBSD) are used to characterize these “bridge zones”: 1. Bridge zones result from not only in-situ grain size reduction (such as recrystallization or cataclasis), but some chemical processes (not major elements) for phase mixing or element discharging on a short spatial scale; 2. The Bridge zone can be observed in wide range of P-T conditions; 3. Bridge zone is an aggregation of relatively fine grains in a narrow band and mechanically links rheologically weak phases or domains, which is weaker than the domains it replaced, and efficiently reduces the bulk strength of rock.

Cite as:

Feng, H., Gerbi, C., & E. Johnson, S.. (2020, July 20). HeFengCIGPoster.tif (Version 1). Tectonics Community Science Workshop 2020.

author = "He Feng, Christopher Gerbi and Scott E. Johnson",
title = "{HeFengCIGPoster.tif (Version 1)}",
year = "2020",
month = "7",
url = "",
doi =}



Posted by ljhwang on
Posted on behalf of Pamela Burnley
I really like your poster, it’s very interesting! In panel 2, for the simulations, I assume that the grey lines are grain boundaries. What are the black lines in the center? Also how do you simulate microcracking in TESA? You show a plot of stress vs steps in the simulation, what is changing for each step? I see that the stress spikes a lot, but if this is an elastic simulation what allows the stress to decay? Is PLC also included in the simulation? Sorry for asking a lot of questions, it looks like your modeling technique would be useful to me in several different areas, so I want to make sure I really understand it.
PS – as you can see from my poster I completely agree with you about the importance of local/grain scale fluctuations in stress and strain
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