An appraisal of the early Palaeogene deposits of north Kent

After an introduction and a brief outline of the main sources of geological information on the area, this report describes the early Palaeogene deposits of North Kent (the area between the River Medway and the River Great Stour). These are the Thanet Formation, the Upnor Formation, the Woolwich Formation and the Harwich Formation. The main types of overlying superficial deposits are also described briefly. Although these Palaeogene formations are predominantly silty, sandy or pebbly, clay-rich facies also occur, notably in the lower part of the Thanet Formation. This suggests that there is potential for an aquifer within the early Palaeogene sequence to be hydraulically separated from the Chalk aquifer in at least part of the area. It is probable that the delineation of certain Palaeogene formation boundaries could be significantly improved by a new, detailed, geological survey. It seems unlikely that the individual formations could be subdivided in any significant or useful way by new geological surveys. Even if such improvements in the geological information were achieved, there is no guarantee that they would significantly advance the hydrogeological understanding of the North Kent marshes. Acquisition and interpretation of natural gamma logs from currently available boreholes is most likely to produce useful new information about lithological variation in the Palaeogene sequence, relatively quickly and cheaply, if further opportunities for this exist. This report is part of a wider project co-funded by the Environment Agency to investigate the geology of the North Downs aquifer.