Solute transport shales

The processes can be considered as three initially independent processes. These include the undrained load-deformaiion-failure process and the fluid and heat flow processes. The fluid flow process may include solute transport. Other mechanisms include swelling of shale caused by change in water potential resulting from the other processes. The main coupling parameters are stress, pore pressure and temperature. 

Thus, there are difficulties in the acquisition of porewater hydrochemical data that can be interpreted meaningfully in terms of solute transport. Direct porewater sampling or pH or redox potential Eh) measurement cannot be carried out in situ in the Tournemire shales. The total moisture content is too low for a direct application of the squeezing technique (Entwisle Reeder 1993). Instead porewater data is acquired using the leaching/cation exchange method (Baeyens Bradbury 1994). The method has been employed using anoxic laboratory conditions to avoid pyrite oxidation which would otherwise disturb the porewater s chemical composition. 

REE patterns in The aqueous geochemistry of the REE is a function of the type of complexes that sea and river the REE may form, the length of time the REE remain in solution in the oceans water (their residence time), and to a lesser extent the oxidizing potential of the water. The topic is well reviewed by Brookins (1989). The REE contents of rivers and seawater are extremely low (Table 4.6), for they are chiefly transported as particulate material. When normalized to a shale composite (Section 4.3.2), REE concentrations in seawater are between six and seven orders of magnitude smaller that the shale value. River wafers are about an order of magnitude higher. 

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