PALEOCLIMATE CONTROL ON SEQUENCE STRATIGRAPHIC PATTERNS IN THE LATE JURASSIC TO MIDCRETACEOUS, WITH A CASE-STUDY FROM EASTERN ENGLAND

Sediment supply is a fundamental control on the architecture of sedimentary sequences. In clastic depositional environments, the volume of sediment being transported into the basin of deposition is strongly dependent on both the nature of the weathering regime in the hinterlands, and on runoff. During arid, low sea-level phases in the late Jurassic and early-mid-Cretaceous, clastic supply was reduced and long hiatuses became common at sequence boundaries or during maximum flooding. These hiatuses amalgamated where sediment starvation produced strongly condensed (''super-condensed'') sections. In intervening humid, higher sea-level phases, clastic supply was more abundant: hence thick sediment packages separate sequence boundaries, downlapping surfaces should be apparent on seismic sections, and condensed sections become rare. Where carbonate deposition dominates over clastic, sediment formation is largely intrabasinal and the effects of palaeoclimate on sequence stratigraphy are less obvious. Knowledge of palaeoclimates may lead us to search for certain sequence stratigraphic patterns connected to changes in sediment supply.