3-D assessment of peak-metamorphic conditions by Raman spectroscopy of carbonaceous material: an example from the margin of the Lepontine dome (Swiss Central Alps) |
| |
| Authors: | Michael Wiederkehr Romain Bousquet Martin A Ziemann Alfons Berger Stefan M Schmid |
| |
| Institution: | 1.Geologisch-Pal?ontologisches Institut,Universit?t Basel,Basel,Switzerland;2.Institut für Erd- und Umweltwissenschaften,Universit?t Potsdam,Potsdam/Golm,Germany;3.Institut for Geografi og Geologi,K?benhavns Universitet,K?benhavn K,Denmark;4.Institut für Geologische Wissenschaften,Freie Universit?t Berlin,Berlin,Germany;5.Geotechnisches Institut AG,Basel,Switzerland |
| |
| Abstract: | This study monitors regional changes in the crystallinity of carbonaceous matter (CM) by applying Micro-Raman spectroscopy
to a total of 214 metasediment samples (largely so-called Bündnerschiefer) dominantly metamorphosed under blueschist- to amphibolite-facies
conditions. They were collected within the northeastern margin of the Lepontine dome and easterly adjacent areas of the Swiss
Central Alps. Three-dimensional mapping of isotemperature contours in map and profile views shows that the isotemperature
contours associated with the Miocene Barrow-type Lepontine metamorphic event cut across refolded nappe contacts, both along
and across strike within the northeastern margin of the Lepontine dome and adjacent areas. Further to the northeast, the isotemperature
contours reflect temperatures reached during the Late Eocene subduction-related blueschist-facies event and/or during subsequent
near-isothermal decompression; these contours appear folded by younger, large-scale post-nappe-stacking folds. A substantial
jump in the recorded maximum temperatures across the tectonic contact between the frontal Adula nappe complex and surrounding
metasediments indicates that this contact accommodated differential tectonic movement of the Adula nappe with respect to the
enveloping Bündnerschiefer after maximum temperatures were reached within the northern Adula nappe, i.e. after Late Eocene
time. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
