The effects of radiation damage and annealing on the diffusion of helium from zircon ...

• Main Authors: Goldsmith, Adam S., 0000-0003-0894-0227
• Format: Thesis
• Language: English
• Published: The University of Texas at Austin 2018
• Subjects: Zircon; Helium; Thermochronology; U-Th/He; Radiation damage; Annealing; Recrystallization; Hall Peninsula; Sinai Peninsula; Gulf of Suez; Grasberg Igneous Complex
• Online Access: https://dx.doi.org/10.26153/tsw/2075; https://repositories.lib.utexas.edu/handle/2152/74963

The relationship between radiogenic ⁴He in zircon, and its associated radiation damage to the crystal lattice, have been of scientific interest since the earliest attempts at geochronology, and remain an active topic of research today in the pursuit of understanding the timing of low-temperature geological processes. Recently, the complex interrelationships between ⁴He diffusion kinetics, time, temperature, and radiation damage were quantified into a complete model for the zircon (U-Th)/He (ZHe) thermochronometric system: the Zircon Radiation Damage Accumulation and Annealing Model (ZRDAAM). Many researchers have taken issue with the predictions of this model, however, particularly at moderate to high radiation doses (~3 × 10¹⁷ – 2 × 10¹⁹ α/g). In this submission, the relationship between radiation damage and ⁴He diffusion kinetics are examined in greater detail to identify sources of discrepancy between observations and model predictions. Using zircons from three geologically distinct localities, this work ...