Abstract
The factors that promote stability of Archean cratons are investigated
from a combined geodynamic, geological, and geophysical perspective in
order to evaluate the relative importance of nature—the initial
conditions of a craton—versus nurture—the subsequent tectonic
processes that may modify and destabilize cratonic lithosphere. We use
stability regime diagrams to understand the factors that contribute to
the intrinsic strength of a craton: buoyancy, viscosity, and relative
integrated yield strength. Cratons formed early in Earth history when
thermal conditions enhanced extraction of large melt fractions and early
cratonization (cessation of penetrative deformation, magmatism and
metamorphism) promote formation of stable Archean cratonic lithosphere.
Subsequent processes that may modify and weaken cratonic lithosphere
include subduction and slab rollback, rifting, and mantle plumes
–processes that introduce heat, fluids, and partial melts that warm and
metasomatize the lithosphere. We examine tomographic data from eight
cratons, including four that are thought to be stable and four that have
been proposed to be modified or destroyed. Our review suggests that
continental lithosphere formed and cratonized prior to the end of the
Archean has the potential to withstand subsequent deformation, heat, and
metasomatism. Survivability is enhanced when cratons avoid subsequent
tectonic processes, particularly subduction. It also depends on the
extent and geometry of modification. However, because craton stability
decreases as the Earth cools, marginally stable cratons that undergo
even modest modification may be set on a path to destruction. Therefore,
preservation of Archean cratons depends both on nature and nurture.