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Lid Tectonics

Lid tectonics, commonly thought of as stagnant lid tectonics, is the type of tectonics that is believed to exist on several planets and moons in the Solar System and possibly on Earth, during the early part of its history. The lid is the equivalent of the lithosphere in plate tectonics, formed of solid silicate minerals (or solid ice in the case of icy planets and moons). The relative stability and immobility of the strong cooler lids leads to stagnant lid tectonics, which has greatly reduced amounts of horizontal tectonics compared with plate tectonics (which can also be described as "mobile lid tectonics"). The presence of a stagnant lid above a convecting mantle was recognized as a possible stable regime for convection on Earth, although active plate tectonics shows that this is not the current situation.

Formation

A lid tectonic regime arises because the cold upper lithosphere is too viscous to participate in the underlying flow of the mantle. The lids yield strength is high enough where the lid cannot brittley fail. This relationship relies heavily on the ratio of lithospheric strength to natural convective stresses. Hence, if lithospheric strength is greater than convective stresses then you will have stagnant lid tectonics.

Factors Contributing to Stagnant Lid Tectonics

There are many characteristics of a planetary body that influence the presence and degree of lid tectonics. The temperature of a bodies core–mantle boundary, and the presence of water strongly effect the rheological, composition, and thermal diagnostics of lid tectonics.

The lid will not participate in the underlying convection of the mantle. At the base of the lithosphere, where the lid is in contact with less viscous material, melts will form at the thermal boundary layer and cause drips, believed to be of peridotite composition.

Other Planetary Bodies

Stagnant lid regime is the most common type of plate tectonic style that exists in the solar system. Mercury and the Moon are both believed to have been dominated by lid tectonics for their entire history. Here, heat is mainly lost by conduction across the lid leading to low heat flows. A stagnant lid regime will not effectively mix a mantle.

Martian meteorite studies have shown that the Martian mantle is much more heterogeneous than Earth's mantle. This indicates the Martian mantle is not well mixed. A possible explanation for this is that Mars was in a stagnant lid tectonics for most of its history that resulted in a poorly mixed mantle.

Too be added:

Less vigorous convection and a thick elastic lithosphere.

To come out of stagnant lid you must (recycle lithosphere) break it with either high stress, thicken the base (with convection), hot interior,