Nature Versus Nurture: Preservation and Destruction of Archean Cratons

Abstract

Initially studied from the surface of the Earth, cratons are large regions of stable continental crust that have undergone minimal deformation since Precambrian time. Whereas cratons were originally believed to be enduring features of the lithosphere, recent studies have revealed that some Archean cratons are susceptible to the tectonic forces that shape the planet and have been modified by subsequent events (e.g.,

Defining Continental Lithosphere as a Layer With Abundant Frozen‐In Structures That Scatter Seismic Waves

“…Beneath the Archean‐aged Superior Province we detect discontinuities down to ∼170 km while the estimate of lithospheric thickness is at least 50 km larger. This apparent seismic transparency of the lowermost part of cratonic lithosphere is consistent with petrological, heat flow, gravity and seismic characterizations (Bedle et al., 2021; Forte & Claire Perry, 2000; Jordan, 1978; Lee et al., 2011) suggesting that cratons are systematically different from continental regions formed in more recent times.…”

“…Continental lithosphere hosts rocks as old as 4.03 Ga (Bowring & Williams, 1999) and minerals dating to as early as 4.4 Ga (Valley et al., 2014). While the ability of the continents' Archean cores to resist destruction by tectonic and convective forces makes them an invaluable repository of planetary history, their origins and mechanisms of longevity are yet to be fully understood (Bedle et al., 2021; Jordan, 1978; Lee et al., 2011).…”

Strong Physical Contrasts Across Two Mid‐Lithosphere Discontinuities Beneath the Northwestern United States: Evidence for Cratonic Mantle Metasomatism

“…MLDs caused by volatile‐bearing phases and melts may facilitate the modification of the cratonic lithosphere in two ways. First, the presence of significant volumes of hydrous minerals and trace amounts of melts can rheologically weaken the mantle lithosphere and thus facilitate its modification by mantle convection (L. Liu et al., 2018; Bedle et al., 2021; Wang et al., 2023). We note that a recent petrological study found that whereas volatile‐rich melts significantly weaken the upper mantle, the presence of hydrous minerals up to 25 vol.% does not (Tommasi et al., 2017).…”

Convective Self‐Compression of Cratons and the Stabilization of Old Lithosphere

“…Understanding cratonic survival has remained a long-standing problem in the geoscience community. Bedle et al (2021) noted three significant geodynamical properties of a stable craton: (a) thick and buoyant cratonic roots, (b) highly viscous roots, and (c) integrated high yield strength that minimizes deformation. However, depending on their evolution, cratons can become unstable or partially destroyed (Bedle et al, 2021;Lee et al, 2011).…”

“…Bedle et al (2021) noted three significant geodynamical properties of a stable craton: (a) thick and buoyant cratonic roots, (b) highly viscous roots, and (c) integrated high yield strength that minimizes deformation. However, depending on their evolution, cratons can become unstable or partially destroyed (Bedle et al, 2021;Lee et al, 2011). For example, rapidly thickened lithosphere (e.g., Beall et al, 2018) can be subjected to basal erosion, subsequently leading to destabilization (Lenardic & Moresi, 1999).…”