Investigating the Shallow to Mid-Depth (> 100-300 degrees C) Continental Crust Evolution with (U-Th)/He Thermochronology: A Review

Author(s)

Gautheron, Cecile ; Hueck, Mathias ; Ternois, Sebastien ; Heller, Beatrix ; Schwartz, Stephane ; Sarda, Philippe ; Tassan-Got, Laurent

• Document type: Journal article
• Source: MINERALS; v. 12, n. 5, p. 24-pg., 2022-05-01.

Abstract

Quantifying geological processes has greatly benefited from the development and use of thermochronometric methods over the last fifty years. Among them is the (U-Th)/He dating method, which is based on the production and retention, within a crystal structure, of radiogenic He-4 atoms associated with the alpha decay of U, Th and Sm nuclei. While apatite has been the main target of (U-Th)/He studies focusing on exhumation and burial processes in the upper levels of the continental crust (similar to 50-120 degrees C), the development of (U-Th)/He methods for typical phases of igneous and metamorphic rocks (e.g., zircon and titanite) or mafic and ultramafic rocks (e.g., magnetite) over the last two decades has opened up a myriad of geological applications at higher temperatures (>100-300 degrees C). Thanks to the understanding of the role of radiation damage in He diffusion and retention for U-Th-poor and rich mineral phases, the application of (U-Th)/He thermochronometry to exhumation processes and continental evolution through deep time is now mainstream. This contribution reviews the (U-Th)/He thermochronometer principle and the influence of radiation damage in modifying the diffusion behavior. It presents applications of (U-Th)/He dating to problems in tectonic and surface processes at shallow to middle crustal depths (>100-300 degrees C). New and promising applications using a combination of methods will stimulate a research avenue in the future. (AU)

• FAPESP's process: 19/06838-2 - Pan-African shear zones in the Kaoko Belt (Namibia) and links across Southwestern Gondwana: Neoproterozoic evolution and Phanerozoic reactivation
• Grantee: Mathias Hueck
• Support Opportunities: Scholarships in Brazil - Post-Doctoral