skip to main content
Idioma:

Rapid erosion of the central Transantarctic Mountains at the Eocene-Oligocene transition: Evidence from skewed (U-Th)/He date distributions near Beardmore Glacier

He, John ; Thomson, Stuart N. ; Reiners, Peter W. ; Hemming, Sidney R. ; Licht, Kathy J.

Earth and planetary science letters, 2021-08, Vol.567, p.117009, Article 117009 [Periódico revisado por pares]

Elsevier B.V

Texto completo disponível

Citações Citado por
  • Título:
    Rapid erosion of the central Transantarctic Mountains at the Eocene-Oligocene transition: Evidence from skewed (U-Th)/He date distributions near Beardmore Glacier
  • Autor: He, John ; Thomson, Stuart N. ; Reiners, Peter W. ; Hemming, Sidney R. ; Licht, Kathy J.
  • Assuntos: apatite helium thermochronology ; East Antarctic ice sheet ; glacial erosion ; overdispersion ; subglacial landscape
  • É parte de: Earth and planetary science letters, 2021-08, Vol.567, p.117009, Article 117009
  • Descrição: •Probability distributions allow interpretation of overdispersed apatite helium data.•First quartile/minimum dates of apatite He data best represent skewed distributions.•Rapid exhumation near Beardmore Glacier started around Eocene-Oligocene transition.•Threshold benthic oxygen isotope value may correlate with enhanced glacial erosion. Apatite (U-Th)/He thermochronology has the potential to reconstruct records of erosional exhumation that are critical to understanding interactions between climate, tectonics, and the cryosphere at high latitudes on million-year timescales. However this approach is often hindered by the problem of intrasample single-grain date dispersion. Here we present an extensive new apatite (U-Th)/He dataset (n = 361) from the central Transantarctic Mountains of East Antarctica between 160°E to 170°W and 84 to 86°S, and show that apparently uninterpretable data in most samples are a reflection of inadequate sampling of skewed date distributions. We outline a workflow for interpreting such dispersed data and demonstrate that geologically meaningful age interpretations are possible in the case of rapidly cooled samples, despite the wide array of potential causes for date dispersion. We show that for samples and compilations with a large number of single-grain analyses (n > ∼25), the youngest probability distribution peak represents the most likely time of fast cooling through the apatite (U-Th)/He closure temperature. When fewer grains are analyzed, the youngest peak is represented best by the minimum date or first quartile date, depending on sample size. Using this workflow, we show that since the latest Eocene, up to 8.8 km of exhumation occurred to incise the deepest point of the Beardmore Glacier trough. Rapid incision began at c. 37-34 Ma (at the latest by 34±3 Ma), coinciding with or slightly preceding the initiation of Antarctic glaciation at the Eocene-Oligocene transition, and contributed to at least 2.6 km of exhumation within the first 3-6 million years, at an apparent exhumation rate of no less than 0.4 mm/a.
  • Editor: Elsevier B.V
  • Idioma: Inglês
Voltar para lista de resultados

  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

Buscando em bases de dados remotas. Favor aguardar.