Other
Scientific paper
Jul 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008e%26psl.272..148s&link_type=abstract
Earth and Planetary Science Letters, Volume 272, Issue 1-2, p. 148-157.
Other
4
Scientific paper
The density distribution of the lithosphere is non-linear and discontinuous due to complex mineralogy and, most importantly, phase transitions. We evaluate the influence of changes in mantle composition on lithospheric density and its evolution during horizontal stretching, using thermodynamic calculations of the density as a function of pressure, temperature and composition. We also develop a simple parameterization based on end-member mineral reactions and geometric relationships between the geotherm and the phase boundary for comparison. The garnet spinel peridotite transition leads to a moderate decrease in density of the mantle part of the lithospheric column at the initial stages of stretching. When the crust is sufficiently thinned and temperature is relatively high, plagioclase peridotite becomes stable in the upper part of the mantle. The density reduction due to the plagioclase-in reaction is controlled by bulk Al2O3 in the mantle and by the depth of the plagioclase-in reaction, which is mainly governed by the Na2O/Al2O3 ratio. Since Na2O and Al2O3 increase with the fertility of the mantle the phase transition effect is most pronounced for relatively fertile mantle (and strong extension) and can lead to 2.3% density reduction. This is equivalent to heating the entire lithosphere by 700 °C if only the effect of thermal expansion on density is taken into account. The formation of plagioclase peridotite can explain syn-rift uplift in sedimentary basins that experienced large mantle stretching without invoking an unrealistically strong increase in temperature. It might also be responsible for the break-up unconformity observed at continental margins.
Podladchikov Yuri Yu.
Simon Nina S. C.
No associations
LandOfFree
The effect of mantle composition on density in the extending lithosphere does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The effect of mantle composition on density in the extending lithosphere, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The effect of mantle composition on density in the extending lithosphere will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1831868