Abstract The Upper Cretaceous (Senonian) Chalk in Kent, SE England, is considered with the aim of establishing the tectonic history of the basin in which it was deposited, based on the chronology of fractures and an understanding of the role of these fractures in controlling fluid movement in high-porosity-low-permeability sediments. The earliest brittle structures in the study area are NE-SW-striking, flint-filled shear fractures, with dips of c. 60°, which were formed when the maximum compression (σ 1 ) was vertical and were utilized as channels for fluid movement during flint filling. Flint also occurs along bedding planes, suggesting a diagenetic source. This phase was followed by the development of NW-SE-striking fracture swarms containing fractures ranging between vertical joints and steeply dipping hybrid fractures with acute dihedral angles of c. 40°. The absence of flint along these fractures indicates that they formed after diagenesis of the Chalk. NW-SE-striking, subvertical, regularly spaced, through-going joints then formed as a result of a NW-SE regional compression linked to the Alpine collision. The final stage in the basin history relates to the formation of bed-parallel and vertical (i.e. bed-normal), bed-restricted, systematic and unsystematic fractures associated with uplift and unloading. To model fluid flow through the fracture network present in the Chalk, a finite-element-finite-volume modelling was carried out. The fracture geometries mapped in the field were discretized using unstructured hybrid element meshes with discrete fracture representations. The permeability of fractures was calculated from the cubic law and the petrophysical properties of the rock matrix were taken from Chalk reservoirs in the North Sea. In the models, a constant pressure was applied at the top of the oil-saturated, fractured Chalk while water was injected at the base. In spite of greater density, the water preferentially displaced the oil from the fractures and migrated faster through the fracture swarms and joints than through bed-restricted fractures and the rock matrix. Almost 830f the total flow within the model occurred through the fractures. The results of the field study, combined with those of the numerical modelling, suggest that fracture swarms have a strong impact on the movement of fluids in fractured and faulted reservoirs.

Abstract Waterfalls have long attracted the attention of travellers, some of whom were writers and artists who have left us a cultural legacy of their observations and interpretations. Likewise, geologists have studied and recorded these landscape features since the infancy of their science. An examination of travellers’ experiences of waterfalls since the emergence of Romanticism in eighteenth-century Europe reveals a variety of responses, both utilitarian and aesthetic. Seen as valuable sources of renewable energy, impediments to navigation, beautiful, sublime or picturesque natural wonders and resources for tourism, waterfalls continue to appeal to the Romantic traveller and the pleasure-seeking tourist. Increasingly, waterfalls are being threatened by schemes to exploit them, especially for power generation or intensive tourism development. In many parts of the world, this presents a serious challenge to those responsible for the management of this often spectacular aspect of geodiversity. This paper explores these various themes which are contextualized within the historical and cultural framework of Romanticism.