Chalk : its stratigraphy, structure and engineering geology in east London and the Thames Gateway

The geology of the Chalk beneath east London and the Thames Gateway is reviewed and key features affecting engineering geology are summarized. In particular, the variable stratigraphy preserved beneath the sub-Palaeogene erosion surface, the evidence for syndepositional tectonics in the Chalk, and the recognition of tectonic fractures and strata-bound fracture systems are emphasized. The contrasting physical properties of chalk and flint are discussed and the depth of weathering in the subcrop and outcrop are compared and contrasted. The information gained from separate ground investigations is combined to suggest that there are regions in east London where better quality chalk and less permeable ground are present between regions of poorer quality chalk with higher permeability, closely related to zones of faulting.