Mantle plume

Fig. 4.10. Atmo.spheric CO2 variation estimated by modified BLAG model including CO2 flux related to mantle plume activity (Ishikawa, 1996). t c02 = 202/ 002 - prescut-day PcOi)-...

Camp, V.E. (1995) Mid-Miocene propagation of the Yellowstone mantle plume head beneath the Columbia River basalt source region. Geology, 23, 435-438. 

The mantle viscosity which controls much of the dynamics of mantle plumes is not well known (Watson and Mackenzie 1991 Hauri et al. 1994). There are also additional effects such as when the mantle contains even small amounts of volatiles, as these volatiles will significantly lower the viscosity of the mantle (Hirth and Kolhstedt 1996). Once the volatiles are extracted, the increased viscosity will slow down the upwelling mantle (Ito et al. 1999). 

For the range of buoyancy fluxes found in mantle plumes (0.5-11 M g s ), the mantle upwelling velocities should vary by a factor of 3-4. This was shown by Bourdon et al. (1998) to be consistent with the range in °Th- U and disequilibrium found... 

Bercovici D, Lin J (1996) A gravity current model of cooling mantle plume heads with temperature dependent buoyancy and viscosity. J Geophys Res 101 3291-3309 Blundy J, Wood B (1994) Prediction of crystal-melt partition coefficients from elastic moduh. Nature 372 452-454... 

Hauri EH, Whitehead JA, Hart SR, (1994) Fluid dynamic and geochemical aspects of entrainment in mantle plumes. J Geophys Res 99 24275-24300... 

Loper DE, Stacey FD (1983) The dynamical and thermal structure of deep mantle plume. Phys Earth Planet Int 33 304-317... 

Ribe NM Smooke MD (1987) A stagnation point flow model for melt extraction from a mantle plume. J Geophys Res 92 6437-6443... 

Schilling JG (1991) Fluxes and excess temperatures of mantle plumes inferred from their interaction with migrating mid-ocean ridges. Nature 352 397-403... 

Wendt Jl, Regelous M, Collerson KD, Ewart A (1997) Evidence for a contribution from two mantle plumes to island arc lavas from northern Tonga. Geology 25 611-614 Williams RW, Gill JB (1989) Effects of partial melting on the uranium decay series. Geochim Cosmochim Acta 53 1607-1619... 

Hofmann AW, White WM (1982) Mantle plumes from oceanic crust. Earth Planet Sci Lett 57 421-436 Hoering TC, Parker PL (1961) The geochemistry of the stable isotopes of chlorine. Geochim Cosmochim Acta 23 186-199... 

Mulch A, Chamberlain CP (2007) Stable isotope paleoaltimetry in orogenic belts — the silicate record in surface and crustal geological archives. Rev Mineral Geochem 66 89-118 Parsons T, Thompson GA, Sleep NH (1994) Mantle plume influence on the Neogene uplift and extension of the U.S. western Cordillera Geology 22 83-86... 

Saltus RW, Thompson GA (1995) Why is it downhill from Tonopah to Las Vegas A case for mantle plume support of the high northern Basin and Range. Tectonics 14(6) 1235-1244 Schott B, Schmeling H (1998) Delamination and detachment of a lithospheric root. Tectonophysics 296(3-... 

The timing and extent of the Colorado Plateau uplift bears on the possible mechanisms that caused it. Various hypotheses have been suggested including influence of a mantle plume (Parsons et al. 1994), lithospheric thinning and/or delamination (Spencer 1996 Lastowka et al. 2001), and subduction of the Farallon plate margin (East Pacific Rise) (Dickinson and Snyder 1979). With a definitive uplift history, it will be possible to place constraints on the mechanisms of uplift and thereby shed light on mantle processes and lithospheric evolution. 

Parsons T, Thompson G, Sleep N (1994) Mantle plume influence on the Neogene uplift and extension of the United States Western Cordillera. Geology 22 83-86... 

The variable isotopic compositions (especially for Pb) reveal geochemi-cally heterogeneous sources. The origin of this heterogeneity is debated and may derive either from shallow mantle processes, such as variable me-tasomatic modifications of the lithosphere by asthenospheric melts, or from mixing between a deep-mantle plume and asthenosphere-lithosphere material. Etna and Ustica show some trace element and isotopic characteristics (e.g. Rb/Nb, Ce/Pb, and boron isotopes), indicative of a contribution from subduction-derived components. 

Upwelling of deep-rooted mantle plumes that impinge upon the lithosphere, cause opening of the Tyrrhenian basins and trigger magmatism ... 

Smooth trends of Sr-Nd-Pb-Hf-He isotopes connecting different mantle compositions (Fig. 10.4). These are suggested to derive from mixing among different mantle end-members (HIMU or FOZO, EMI and EM2), which occur worldwide and are believed to represent deep mantle plumes by several authors (e.g. Hofmann 1997) ... 

The predominance in central Italy of ultrapotassic rocks, possibly associated with carbonatites, and the absence of calc-alkaline activity. A similar association occurs in the Toro-Ankole igneous province (western branch of the East Africa Rift Bailey and Collier 2000), classically believed to have developed above mantle plumes. 

Other geochemical characteristics of Italian volcanism are also not easily explained by the plume hypotheses. For example, deep mantle plumes are commonly associated with high 3He/4He ratios (e.g. Farley and Neroda 1998). However, measurements carried out on fluid inclusions in olivine phenocrysts from mafic Italian rocks have yielded low He isotopic ratios with R/Ra < 7.5 (e.g. Sano et al. 1989 Graham et al. 1993 Marti et al. 1994 Di Liberto 2003 Martelli et al. 2004), which are much lower than compositions found for plume-related magmas. 

Finally, the Tyrrhenian Sea (i.e. the focus of the mantle plume ascent) has a considerable depth (3700 m) and magmatism is not particularly voluminous. These characteristics do not fit a plume hypothesis. The suggestion that lack of magmatism is related to the great depth of the plume head is reasonable. However, the idea that such a deep body would be able to induce basin opening of the order of several hundred km, and to generate a collisional chain, is difficult to accept and needs much further refinement to avoid scepticism. 

Bell K, Castorina F, Lavecchia G, Rosatelli G, Stoppa F (2004) Is there a mantle plume below Italy EOS 85 541-547... 

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