Study area.-All the study streams are on the northern quarter of Prince of Wales Island (Figure 1) and traverse a mixture of karst and nonkarst geology. Some streams are fed directly by resurgence from limestone caves, whereas others are fed by overland flow. Hecata Limestone and Bay of Pillars are the major karst formations (Wissmar et al. 1997). Many of the streams flow along contact zones be...

Siderite (FeCO3) is an important reduced phase iron mineral and end product of bacteria anaerobic respiration. This study addresses its dissolution behavior in the presence of the oxidant chromate, which is a common environmental contaminant. Macroscopic dissolution experiments combined with microscopic observations by atomic force microscopy show that at pH < 4.5 the dissolution rate with chro...

Gypsum karst problems in the Permian and Triassic sequences of England have caused difficult conditions for bridge and road construction. In Northern England, the Ripon Bypass crosses Permian strata affected by active gypsum karst and severe subsidence problems. Here, the initial borehole site investigation for the road was supplemented by resistivity tomography studies. The roadway was reinfor...

At oxic/anoxic transition zones, manganese release from (hydr)oxide minerals into aqueous solution is a dynamic balance between mineral dissolution and Mn2+(aq) oxidation and precipitation, which are processes respectively promoted by organic reductants and molecular oxygen. We employ a flow-through atomic force microscope reactor (AFM-R) to investigate the reductive dissolution of the [010] su...

In this paper we employ homogenization techniques to provide a rigorous derivation of the Darcy scale model for precipitation and dissolution in porous media proposed in [19]. The starting point is the pore scale model in [12], which is a coupled system of evolution equations, involving a parabolic equation and an ordinary differential equation. The former models ion transport and is defined in...