Dologrus: The impact of meteoric-water-controlled diagenesis following early-marine dolomitization

Abstract

Carbonate rocks that have suffered early near-surface dolomitization followed by extended meteoric exposure commonly undergo partial delithification, a process that results in the formation of dolomitic silts and sands, herein termed dologrus. Dologrus is interpreted to form as a result of diffuse dissolution in porous and permeable dolostones prior to burial and compaction. Such dissolution occurs at the crystal–pore-water interface, causing individual crystals to corrode along interfacial boundaries, eventually leading to delithification and the formation of sediment composed of corroded crystals. The resulting sediment grain size is likely controlled in part by the crystal size of the precursor dolostone. Loss of rock competency through the process of dologrus formation in the shallow subsurface can lead to collapse of overlying bedrock and the formation of dolines common to karstic carbonate landscapes.