A train of kink folds in the surficial salt of Qom Kuh, Central Iran

• The many subaerial extrusions of salt current in Iran are smaller and   faster versions of steady state extrusions of metamorphic rocks from   crustal channels in mountain chains. The extruded salt develops a   variety of internal folds as the salt accumulates ductile displacements   that can reach metres a year. Weather-induced elastic strains de-stress   the outer layers of salt extrusions to a brittle carapace of broken   dilated salt. Qom Kuh, situated in Central Iran, is a comparatively   small and slow example of a viscous salt fountain and, as a result, its   brittle elastic carapace may be thicker than most This may account for   Qom Kuh being the only salt fountain known to have a train of 10 m   scale kink folds in its surficial salt. We attribute these folds to   lateral shortening and back-shear of a surface-parallel planar   mechanical anisotropy in the surficial salt induced by gravitationally   driven ductile flow of the underlying salt. When it is dry, the elastic   carapace is relatively strong and acts as a stiff corset impeding   gravity spreading of the underlying confined salt. However, the   carapace weakens and kinks on wetting, allowing the underlying salt to   gravity spread. These folds illustrate how the weather can affect   gravity spreading of surficial salt masses and how complex the   interplay of tectonic and climatic signals can be in "steady state"   mountains.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Nyckelord

Salt extrusion

Iran

Dilated carapace

Mechanical anisotropy

Kink folds

Chevron folds

Earth sciences

Geovetenskap

Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics

Geovetenskap med inriktning mot mineralogi, petrologi och tektonik

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)