Weathering processes during

Note that this estimate of the annual O2 loss to weathering processes is approximately equal to the estimated annual production of oxygen estimated above. Hence, the weathering of rocks and burial of organic carbon in sediments during their formation are important processes for the oxygen content of the atmosphere. 

Figure 13. Schematic of the degradation processes during the weathering of binders pigmented with TiO, (2)...

The text deals with the microbial and chemical process engineering of sewer networks. It emphasizes dry-weather processes and not the wet-weather impacts that are primarily controlled by physical processes. Under such conditions, the physical in-sewer processes in terms of, for example, hydraulics, sediment and biofilm erosion and solids transport are important. A quite different approach must be applied when wet-weather conditions in sewers dominate. However, wet-weather performance of sewers also requires that sediment deposition be dealt with during dry-weather periods. 

Wet-weather processes have, in general, been excluded in the text, because they are based on a different concept and perform differently. Microbial and physicochemical processes are contrary to the physical processes dominating in sewers during dry-weather transport of the wastewater. When dealing with combined sewer networks in terms of pollutant loads during overflow events, dry-weather solids deposition and erosion and solids transport during high-flow events are, in addition to the rainfall/runoff hydraulic and sewer solids characteristics, the central physical in-sewer processes. Quite different process approaches are, therefore, required to describe dry-weather and wet-weather sewer performance. 

Pistiner J, Henderson GM (2003) Lithium isotope fractionation during continental weathering processes. Earth Planet Sci Lett 214 327-339... 

For various reasons, gibbsite and kaolinite are really the only minerals of the "neutral lattice" type which occur with any frequency in non-metamorphic rocks. These minerals are formed in soils, most noticeably from granitic rocks but are also commonly found forming from basic rocks during the weathering process (Millot, 1964 Tardy, 1969). The... 

Tomita, et al., 1970 Meilhac and Tardy, 1970.) The prevalence of montmorillonites, in river sediments and those studied as deep-sea cores in the numerous JOIDES reports leads one to believe that montmorillonite is a very common weathering product. Certainly a portion of it is derived from degraded micas but if one considers that the next most common sedimentary mineral is illite, one is forced to conclude that either continental rocks are for the major part made of micas or that many other minerals are transformed into montmorillonite during the weathering process. 

---