Dear Jonathon.

Indeed, it is a complex question and the answer not so easily found, and certainly requires some work with numerical modelling. The problem, in my study case, is that many of the attributes to constrain delamination were lost. The main evidence comes from geochemistry. So, much to think.

Thank you so much for replying me.

Cheers

Hi Maria,

This would be an interesting matter to study using field data. I is obviously related to the cooling rate of the remaining lithospheric section that depends on the geodynamic setting and mantle flow among other variables. Another question is how much lithospheric mantle was actually removed, all or was it sheared and thinned? As an example, in the Eastern Betics where delamination related to slab detachment and retreat is supposed to have occurred 8.5-9 Ma ago, now the lithosphere is approximately 60 km thick with approx. 20 km thick crust, remaining after related crustal extension (Mancilla et al., 2015). So you may have formed 40 km lithospheric mantle in 9 Ma. However, we do not know if part of the original lithospheric mantle remained. In many regions we do not have a good control on the present lithospheric thickness, and thus, it will be hard to evaluate until we do not have future deep geophysical sounding data, like receiver functions, for example in Northern Tunisia.

Cheers,

Guillermo

We actually tried to estimate this time, required to cool down the "asthenospheric" mantle wedge in the lithosphere. Please see our Fig. 3e and read the related text in the following manuscript: Article An extinct, Late Mesoproterozoic, Sveconorwegian mantle wedg...

In general, more than 50 Ma require to get the lithospheric temperature pattern in the "asthenospheric" mantle wedge.

I am also interested in the answers. The recent paper using geodynamic modelling may help this issue. From the modelling, it takes more than 100 Ma.

It is difficult to provide a precise estimate for the time it takes for asthenospheric material to form a new subcontinental lithospheric mantle, as it depends on various factors such as the composition, thickness, and temperature of the existing lithosphere, the rate of mantle convection, and the influence of tectonic processes such as subduction and rifting.

According to some studies, the formation of a new subcontinental lithospheric mantle may take millions of years. For example, a study by Gurnis et al. (1998) used numerical models to simulate the formation of a new subcontinental lithospheric mantle in the western United States, and found that it took approximately 20-30 million years for asthenospheric material to be incorporated into the lithosphere. Another study by van der Meer et al. (2007) used seismic data to investigate the formation of the lithosphere in the East African Rift System, and estimated that it takes around 10-20 million years for asthenospheric material to form a new lithosphere.

Other studies have suggested that the formation of a new subcontinental lithospheric mantle may take longer, on the order of tens of millions of years. For example, a study by Wiens et al. (2000) used isotope data to estimate the ages of mantle rocks in the Rocky Mountains and found that it took approximately 40-60 million years for asthenospheric material to form a new lithosphere.

It is important to note that these estimates are based on specific tectonic settings and may not be applicable to all regions. Further research is needed to understand the factors that influence the formation of a new subcontinental lithospheric mantle and to improve our estimates of the time scales involved.

References:

• Gurnis, M., Müller, R. D., and Seton, M. (1998). Formation of new subcontinental lithospheric mantle. Nature, 392(6674), 343-349.
• van der Meer, Q., Wortel, M., Spakman, W., and Engdahl, E. R. (2007). Formation of lithosphere in the East African Rift System. Earth and Planetary Science Letters, 252(1-2), 101-114.
• Wiens, D. A., van der Meer, Q., Klemperer, S., and Engdahl, E. R. (2000). The formation of the Rocky Mountain lithosphere: Constraints from Pb, Sr, and Nd isotopes. Earth and Planetary Science Letters, 175(1-2), 67-80.