HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation
Journal articles

Worldwide distribution of ages of the continental lithosphere derived from a global seismic tomographic model

Abstract : It has long been known that continental regions of different age have different seismic properties: the older the lithosphere, the greater the velocity. Here we ask whether we can obtain a more formal relationship between seismological observations and the age of continents. The deep structure of continents has been seismically mapped for the entire Earth. S-vertical travel time delay maps were computed from velocity maps. S-delay maps (using [Shapiro, N.M., Ritzwoller, M.H., 2002. Monte-Carlo inversion of broad-band surface wave dispersion for a global shear wave velocity model of the crust and upper mantle. Geophys. J. Int. 151, 88-105]) correlate with maps show a broad correlation with the ages of surface rocks but when studied in detail, the correlation is not good. The histogram of the S delays for continents is not Gaussian but contains two maxima. From a study in North American stations, Romanowicz and Cara [Romanowicz, B.A., Cara, M., 1980. Reconsideration of the relationship between S and P station anomalies in North America. Geophys. Res. Lett. 7, 417-420] found that the ratio of S- to P-delay does not fit a linear relationship: different intercept times have to be used for positive and for negative S to P ratios. They explained this by the presence of low-velocity mantle beneath tectonically active regions but not beneath stable cratons. By imposing that the negative peak of the S-delay histogram corresponds to a major period of continent growth, a relationship between S delay and age is obtained. Using this relationship, a “seismic continental growth curve” is derived. This growth curve is similar to curves published by geochronologists in that it shows strong growth between 3 and 1 Ga. Many uncertainties remain, particularly on the exact meaning of the age of a continental region.
Document type :
Journal articles
Complete list of metadata

https://hal-insu.archives-ouvertes.fr/insu-00447662
Contributor : Pascale Talour Connect in order to contact the contributor
Submitted on : Friday, January 15, 2010 - 3:15:48 PM
Last modification on : Tuesday, November 16, 2021 - 4:54:35 AM

Identifiers

Citation

G. Poupinet, N.M. Shapiro. Worldwide distribution of ages of the continental lithosphere derived from a global seismic tomographic model. Lithos, Elsevier, 2009, 109 (1-2), pp.125-130. ⟨10.1016/j.lithos.2008.10.023⟩. ⟨insu-00447662⟩

Share

Metrics

Record views

40