Abstract

Syn-Upper Cretaceous tectonic movements are recognized along tectonic axes including the Portsdown-South Downs axis, Sandown pericline, Kingston anticline, the Fécamp-St Valery fault blocks and at the Bresle Valley axis. A spatial relationship is described between surface structures, chalk sedimentation and deeper level fault systems identified on seismic sections. The Ouse valley between Lewes and Newhaven, Sussex, provides the strongest evidence for this relationship in the Chalk of the Anglo-Paris Basin.. The sedimentary features that can be related to tectonic lines are local thickness changes, anomalous sequences including scour surfaces such as Strahan's Hardground, Rowe's Flintless Belt (Isle of Wight), the Downend slump sequence (Portsdown). These discordant surfaces and slumps relate to particular tectonic 'hinge lines' whilst other sedimentary features such as the Tilleul Hardgrounds appear to have formed flat-ramps over blocks. These two types of tectono-sedimentary feature are used to delineate horst-like structures from tilted surfaces or half grabens which underlie the surface periclinal fold-belts. Rejuvenation movements along tectonic axes during the Cenomanian to Campanian are discussed in relation to the currently recognized sequence stratigraphy and sea-level curves for the period.

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