Low long-term erosion rates and extreme continental stability documented by ancient (U-Th)/He dates

R. M. Flowers, S. A. Bowring, P. W. Reiners

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

Zircon and apatite crystal the western Canadian shield yield (U-Th)/He dates that are the oldest yet reported for terrestrial rocks. Zircon dates from 1.73 to 1.58 Ga are consistent with independent geological and thermochronological constraints, and indicate that the rocks were at temperatures ≤180 °C and crustal depths ≤7-10 km since ca. 1.7 Ga. Apatite dates from 0.95 to 0.55 Ga suggest residence of rocks at temperatures ≤40-50 °C and crustal depths ≤1.5-2 km for ∼1.0-0.6 b.y., when interpreted using conventionally accepted apatite He diffusion kinetics and considering the proposed effect of radiation damage on apatite He retentivity. Our analysis implies long-term integrated unroofing rates of ≤2.5 μm/yr since ca. 1.7 Ga. These rates are significantly lower than the long-term rates suggested by previous thermochronological data sets in continental interiors, but are within the range of short-term erosional estimates. The results are consistent with the extreme stability of this region since the Proterozoic.

Original languageEnglish (US)
Pages (from-to)925-928
Number of pages4
JournalGeology
Volume34
Issue number11
DOIs
StatePublished - Nov 1 2006
Externally publishedYes

Keywords

  • (U-Th)/He
  • Continental stability
  • Craton
  • Low erosion rates

ASJC Scopus subject areas

  • Geology

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