9. Initial pipe development within epikarst microfractures
Published:January 01, 2016
Maria Inés Dragila, Katrina M. Hay, Stephen W. Wheatcraft, 2016. "9. Initial pipe development within epikarst microfractures", Caves and Karst Across Time, Joshua M. Feinberg, Yongli Gao, E. Calvin Alexander, Jr.
Download citation file:
Karst systems continually evolve in response to complex hydrological and geochemical processes. A factor not previously considered is the role played by wavy free-surface fluid films in the geochemical erosion of microfractures. Films seeping down nearly vertical walls naturally evolve into wavy films, with some waves growing into solitons. Solitons that continue to grow eventually contact the opposite fracture wall, developing into capillary droplets that persist. The combination of capillary droplets surrounded by free-surface films creates a dissolve-and-sweep mechanism for soluble rocks such as limestone, dolomite, and gypsum. While films participate in calcite transfer from the matrix by diffusive processes, the pressure gradient imposed by a capillary droplet can extract pore solution from within the matrix, chemically leaching the matrix to a deeper depth than film flow. This chapter presents experimental evidence of the formation of droplets and provides a first-order analysis of their solute transfer and transport potential.