Stress-induced chemical waves in sediment burialdiagenesis

摘要

Lateral metre-scale periodic variations in porosity and composition are found in many dolomitestrata. such variations may embed important information about dolomite formation andtransformation. Here we show that these variations could be fossilized chemical waves emergingfrom stress-mediated mineral-water interaction during sediment burial diagenesis. under theoverlying loading, crystals in higher porosity domains are subjected to a higher effective stress,causing pressure solution. The dissolved species diffuse to and precipitate in neighbouringlower porosity domains, further reducing the porosity. This positive feedback leads to lateralporosity and compositional patterning in dolomite. The pattern geometry depends on fluid flowregimes. In a diffusion-dominated case, the low- and high-porosity domains alternate spatiallywith no directional preference, while, in the presence of an advective flow, this alternationoccurs only along the flow direction, propagating like a chemical wave. our work provides anew perspective for interpreting diagenetic signatures in sedimentary rocks.