Upper mantle cooling

Miintener O., Hermann J., and Trommsdorff V. (2000) Cooling history and exhumation of lower-crustal granulite and upper mantle (Malenco, eastern Central Alps). J. Petrol. 41, 175-200. 

Earth is made up of several layers. The outermost layer is called Earth s crust. The thickness of Earth s crust varies. Under the oceans the crust is only about 3-5 mi (5-10 km) thick. Under the continents, however, the crust thickens to about 22 mi (35 km) and reaches depths of up to 37 mi (60 km) under some mountain ranges. Beneath the crust is a layer of rock material that is also solid, rigid, and relatively cool, but is believed to be made up of denser material. This layer is called the upper part of the upper mantle, and varies in depth from about 31 mi (50 km) to 62 mi (100 km) below Earth s surface. The combination of the crust and this upper part of the upper mantle, which are both comprised of relatively cool and rigid rock material, is called the lithosphere. 

Assume a planet in which the upper mantle has about 0.2% water, and the composition is broadly peridotitic, with heat production as on Earth. The geotherm depends on the vertical distribution of the heat production in the interior and on the surface temperature, and on the heat transfer controls. The surface temperature is maintained by the radiative balance of the atmosphere and any greenhouse increment, and is only indirectly dependent on interior processes. If the state of the atmosphere means that the surface is cold, say — 100°C to —200°C, then the lithosphere will be thick. The top of the mantle adiabat will be forced to cool. The deeper mantle will thus store heat until melting extracts it as... 

Zipfel J. and Wdrner G. (1992) Thermobarometry on four- and five-phase periodotites from a continental rift system evidence for upper mantle uplift and cooling at the Ross Sea margin (Antartica). Contrib. Mineral. Petrol. Ill, 24-36. 

FIGURE 3.25 The secular cooling curve for the potential temperature of the Earth s mantle (from Richter, 1988) and calculated upper mantle potential temperatures based on basalt chemistry (Abbott et al., 1994 - shaded field). Also shown are the potential temperatures for komatiites from Barberton Greenstone Belt (Barb) and the Belingwe Greenstone Belt (Bel), estimated komatiite temperatures from Grove and Parman (2004) and the calculated temperature of the subcontinental lithosphere from beneath the Kaapvaal Craton (Richardson et al., 1984). 

Flumetralin was extracted from tobacco using Soxhlet extraction. A 5-g amount of Florisil (5% deactivated) was transferred directly on to the filter disk of a Soxhlet extractor followed by another 5 g of Florisil mixed with 5 g of ground tobacco sample as an upper layer. A 60-mL volume of hexane and 3mL of a 4 agmL internal standard solution were placed in a 250-mL round-bottom flask prior to attaching the Soxhlet extractor. The unit was placed on a heating mantle and the hexane was refluxed through the extractor at the rate of about 250 mLh for 4.5 h. After cooling, 0.5 pL of the extract was injected directly into a GC/FCD or GC/MS system. 

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