Lithospheric mantle thickness

Pearson D. G., Shirey S. B., Carlson R. W., Boyd F. R., Pokhilenko N. P., and Shimizu N. (1995a) Re-Os, Sm-Nd and Rb-Sr isotope evidence for thick Archaean lithospheric mantle beneath the Siberia craton modified by multi-stage metasomatism. Geochim. Cosmochim. Acta 59, 959-977. 

To extract the refractory constituents to form a thick, uniform layer of refractory components like the subcontinental lithospheric mantle requires an efficient sorting process. To emphasize the problem we need only to consider that if high-temperature residue constitutes 20% of the total residue of melting, to accumulate a 200 km thick layer of Kaapvaal-type lithosphere requires the elimination of five times the volume (the equivalent of a 1000 km thick layer) of less depleted material. 

Pearson DG, Shirey SB, Carlson RW, Boyd FR, Pokhilenko NP, Shimizu N (1995) Re-Os, Sm-Nd, and Rb-Sr isotope evidence for thick Archaean lithospheric mantle beneath the Siberian craton modified by multistage metasomatism. Geochim Cosmochim Acta 59 959-977 Polyak BG, Tolstikhin IN, Kamensky IL, Yakolev LE, Marty B, Cheshko AL (2000) Helium isotopes, tectonics and heat flow in the Northern Caucasus. Geochim Cosmochim Acta 64 1925-1944... 

Fig. 15.11 This cross-section of the crust of West and East Antarctica was drawn along line A-B in Fig. 15.10 using the contours of crustal thickness of a diagram by Bentley (1983). The profile of crustal thickness indicates the depth to the Mohorovicic Discontinuity (Moho) which separates the continental crust of Antarctica from the lithospheric mantle below. This cross-section demonstrates that the crust of West Antarctica is thinner than the crust of East Antarctica and that the transition is abrupt which suggests the presence of a fault zone or suture. The vertical exaggeration is 40x. The crustal thicknesses were derived from gravity anomalies by Groushinsky and Sazhina (1982)...

The outer shell of the earth, consisting of the upper mantle and the crust (Figure I4. lO), is formed of a number of rigid plates. These plates are 20 in number and are shown in Figure 14.1 I. Of these, six or seven are major plates, as can be seen in the map. The edges of these plates define their boundaries and the arrows indicate the direction of their movement. These plates contain the continents, oceans and mountains. They almost float on the partially molten rock and metal of the mantle. The outer shell, known as the lithosphere, is about 70 to 1,50 km thick. It has already moved great distances below the etirth s surface, ever since the earth was formed and is believed to be in slow and continuous motion all the time. The plates slide on the molten mantle and move about lO to 100 mm a year in the direction shown by the arrows. The movement of plates is believed to be the cause of continental drifts, the formation of ocean basins and mountains and also the consequent earthquakes and volcanic eruptions. 

Lithosphere The outermost, rigid layer of the Earth, which includes the crust and upper mantle. The thickness of the lithosphere usually ranges from about 50 km in ocean basins to 100 km in the high mountainous areas of the continents. 

Figure 6 P-T arrays compiled for garnet peridotite xenoliths from several suites using two-pyroxene thermometry and Al-in-orthopyroxene barometry (Tbkn and Rbkn methods, Table 5). Data sources given in Rudnick and Nyblade with additional data here for Vitim (Ionov et al., 1993a) and Canada (MacKenzie and Canil, 1999 Schmidberger and Francis, 1999). The best-fit line for the Kaapvaal data is plotted in each figure for reference. Intersection of P-T array with mantle adiabats (shaded field) represents an estimate of the thickness of lithosphere at the time of sampling.

Rudnick R. L. and Nyblade A. A. (1999) The thickness and heat production of Archean lithosphere constraints from xenolith thermobarometry and surface heat flow. In Mantle Petrology Field Observations and High Pressure Experimentation A Tribute to Francis R. (Joe) Boyd, The Geochemical Society Special Publication (eds. Y. Fei, C. M. Bertka, and B. O. Mysen). The Geochemical Society, Houston, Texas, vol. 6, pp. 3-12. 

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