Multiple episodes of regional exhumation and inversion identified in the UK Southern North Sea based on integration of palaeothermal and palaeoburial indicators

Abstract

AbstractWe present a consistent synthesis of palaeothermal (apatite fission track analysis (AFTA) and vitrinite reflectance) data from UK Southern North Sea wells with the regional pattern of exhumation defined from sonic velocity data. Cenozoic exhumation across most of the region began in the Paleocene between 63 and 59 Ma. Amounts of removed section are around 1 km across the offshore platform, increasing to 2 km or more on the Sole Pit axis. Neogene exhumation within this area began between 22 and 15 Ma, and led to removal of up to 1 km of section. Along the eastern flank of the Sole Pit axis, sonic data define a pre-Chalk event, and AFTA data from these wells show that exhumation began between 120 and 93 Ma. This timing correlates with events defined from AFTA data in the Sorgenfrei–Tornquist Zone, further east, presumably reflecting a response to regional tectonic stresses. East of the Sole Pit axis, AFTA and sonic velocities suggest that Neogene exhumation dominates, while further east towards the central parts of the North Sea Mesozoic sediments appear to be at maximum burial today except for local effects related to salt movement. The multiple episodes of exhumation and burial defined here have important implications for exploration.