Age of the lithosphere

Changes in ocean-floor depth, sediment thickness, and hydrothermai circuiation with increasing age of the lithosphere, (a) Heat loss is by advection, (b) heat loss is by advection and conduction, and (c) heat loss is by conduction alone. Source From Sclater, J. G. (2003). Nature 421, 590-591. 

Haase K. M. (1996) The relationship between the age of the lithosphere and the composition of oceanic magmas constraints on partial melting, mantle sources and the thermal structure of the plates. Earth Planet. Sci. Lett. 144(1-2), 75-92. 

Burton K. W., Schiano P., Birck J.-L., Allegre C. J., Rehkamper M., Halliday A. N., and Dawson J. B. (2000) The distribution and behaviour of rhenium and osmium amongst mantle minerals and the age of the lithospheric mantle beneath Tanzania. Earth Planet. Sci. Lett. 183, 93-106. 

Irvine G. J., Carlson R. W., Kopylova M. G., Pearson D. G., Shirey S. B., and Kjarsgaard B. A. (1999) Age of the lithospheric mantle beneath and around the Slave craton a rhenium-osmium isotopic study of peridotite xenoliths from the Jericho and Somerset Island kimberlites. In Abst. Ninth Annual V. M. Goldschmidt Conference LPI contribution no. 971. Lunar and Planetary Institute, Houston, pp. 134-135. 

Few systematic Sr-Nd isotope studies have been performed on ocean island xenolith suites. Ducea et al. (2002) analyzed clinopyroxenes from plagioclase-spinel and spinel peridotites from Pali, (Oahu, Hawaii) and found relatively depleted strontium and neodymium isotope systematics that they interpret as representing their evolution as residues from the extraction of Pacific Ocean crust. Consistent with this is a 61 20Ma errorchron defined by the pyroxene separates that is within error of the 80-85 Ma age of Pacific lithosphere beneath Hawaii. 

As discussed previously, numerous Premier peri-dotites give ages close to 2.0 Ga (Pearson et al. 1995a Carlson et al. 1999). The Premier kimberlite erupted near the 2.05 Ga Bushveld intrusion and the Palaeoproterozoic model ages probably reflect substantial modification of the lithosphere beneath this region at c. 2Ga plus possibly some new lithospheric material (Carlson et al. 1999). 

Abbott, D. H. Hoffman, S. E. 1984. Archean plate tectonics revisited 1, Heat flow, spreading rate and the age of subducting lithosphere and their effects on the origin and evolution of continents. Tectonics, 3, 429-448. 

Richardson and colleagues working at MIT in the 1980s showed that diamond inclusions in mantle xenoliths from beneath the >3.0 Ga Kaapvaal Craton in South Africa were extremely ancient. This discovery demonstrated for the first time a link between the age of the continental crust and its underlying lithospheric mantle (Richardson et al., 1984, 1985). 

Clearly these two events may be widely separated in time which is why it is difficult to measure the true age of the subcontinental lithosphere (Fig. 3.11). 

The size, composition, and age of the continental lithosphere have been the subject of numerous investigations. Following are some general considerations aimed at providing a context for viewing noble gas data. More detailed discussions are provided in the subsequent evaluations of specific noble gas studies. 

---