UNIGE document Scientific Article
previous document  unige:28478  next document
add to browser collection
Title

The transition from rifting to sea-floor spreading within a magma-poor rifted margin: field and isotopic constraints

Authors
Desmurs, Laurent
Manatschal, Gianreto
Müntener, Othmar
Meier, Martin
Frank, Martin
Bernoulli, Daniel
Published in Terra Nova. 2002, vol. 14, no. 3, p. 156-162
Abstract We provide new geological and isotope geochemical constraints on the evolution from continental rifting to sea-floor spreading along a segment of the Jurassic Tethyan margin exposed in the Platta and Err nappes (eastern Central Alps). Field observations show that the ocean-continent transition zone is characterized by oceanward-dipping detachment faults leading to the exhumation of subcontinental mantle rocks subsequently intruded by gabbro bodies and dolerite dikes, and covered by pillow basalts and radiolarites. Zircons extracted from gabbros and albitite yield concordant U-Pb ages of 161 ± 1 Ma; their initial ɛHf (+ 14.4 to + 14.9) as well as bulk rock ɛNd values of from gabbros and basalts (+ 7.3 to + 9.5) point to a MORB-type depleted mantle source. These data suggest that the onset of magmatic activity coincides with the latest phase of mantle exhumation along low-angle detachment faults and may be controlled by upwelling asthenosphere beneath a zone of exhumed continental mantle.
Identifiers
Full text
Structures
Research group Isotope Geochemistry, Geochronology and Thermochronology
Citation
(ISO format)
SCHALTEGGER, Urs et al. The transition from rifting to sea-floor spreading within a magma-poor rifted margin: field and isotopic constraints. In: Terra Nova, 2002, vol. 14, n° 3, p. 156-162. https://archive-ouverte.unige.ch/unige:28478

211 hits

0 download

Update

Deposited on : 2013-06-10

Export document
Format :
Citation style :