HR: 17:25h
AN: U44A-05    [Abstracts]
TI: Growth rate of the lithospheric mantle: variations in time and space
AU: * Artemieva, I M
EM: irina@geol.ku.dk
AF: Geological Inst., Copenhagen Univ., Oester Voldgade 10, Copenhagen, 1350, Denmark
AB: Two global databases for the continents, (a) for tectono-thermal ages and (b) for lithospheric thermal thickness (Artemieva, Tectonophysics, 2006 and available for download at the web-site), are used to calculate (i) the volume of the preserved continental lithosphere of different ages within the individual cratons, (ii) the lithospheric growth rate for different continents over the past 3.6 Ga, (iii) a global model of lithosphere growth rate since the Archean. The submerged areas with continental crust are excluded from the analysis. On the scale of a craton, significant differences in the rates of lithosphere growth are observed between the individual cratons. These data are compared with independent estimates of growth rate of juvenile crust on different continents as constrained by sedimentary record, geological and isotope data. On the global scale, the results show a general agreement between the global cumulative growth rate of the continental lithosphere and juvenile crust (Condie, 1998). The most pronounced peak in lithosphere growth occurred at 2.1-1.7 Ga, when the volume of lithospheric mantle was increasing with the rate of ca. 10-20 (km3 per year). Contrary to growth models of juvenile crust, the peaks in growth rate of the lithospheric mantle at ca. 2.7- 2.6 Ga and 1.3-1.1 Ga are weak, ca. 5-8 (km3 per year). The differences between the growth rates of the lithosphere and juvenile crust are interpreted as indicator of the preservation rate of the cratonic lithosphere since the Archean.
UR: http:www.lithosphere.info
DE: 1038 Mantle processes (3621)
DE: 7218 Lithosphere (1236)
DE: 8103 Continental cratons
DE: 8125 Evolution of the Earth (0325)
DE: 8130 Heat generation and transport
SC: Union [U]
MN: 2007 Joint Assembly