The Onset of Recrystallization in Polar Firn, Summit, Greenland, June 2017

Constraining the onset of dynamic recrystallization (DRX) and its effects on the mechanical properties of firn is crucial for firn densification modeling. To that end, samples from a depth of 13m in a Summit, Greenland (7235'N, 3825'W) firn core were subjected to creep tests at -14ºC and...

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Bibliographic Details
Main Authors: Ayobami Ogunmolasuyi, Andrii Murdza, Ian Baker
Format: Dataset
Language:unknown
Published: Arctic Data Center 2023
Subjects:
Firn
Densification
Recrystallization
Microstructural Evolution
Rheology
Greenland
Online Access:https://search.dataone.org/view/urn:uuid:f7060358-6d82-4727-a831-007f5cd62bc7
Description
Summary:Constraining the onset of dynamic recrystallization (DRX) and its effects on the mechanical properties of firn is crucial for firn densification modeling. To that end, samples from a depth of 13m in a Summit, Greenland (7235'N, 3825'W) firn core were subjected to creep tests at -14ºC and 0.21MPa compressive stress to strains of 7, 12, 18, and 29%. Microstructural analyses using thin-section imaging and microcomputed x-ray tomography (micro-CT) revealed smaller grain sizes, reduced specific surface area and connectivity, and increased density in relation to reduced porosity as the strain increases. These results show that DRX occurs in firn under creep, with strain-induced boundary migration (SIBM) and nucleation and growth starting at ~7%. DRX leads to elongated grains, reduced grain size, and the development of a preferred crystallographic orientation, indicating that DRX occurs by both SIBM and nucleation and growth.

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