The upper Paleocene-lower Eocene stratigraphic record is currently one of the best suited for deciphering synsedimentary tectonic control on the architecture of stratigraphic sequences. In an effort to understand the drastic evolutionary, paleoceanographic and climatic events that occurred during Magnetochron C24r (from ~ 56 to ~ 53.5 Ma) a fine chronologic framework based on magnetic, paleontologic, isotopic and volcanic events has been constructed through the detailed analysis of numerous deep sea, epicontinental and terrestrial sections. This chronologic framework in turn has allowed the temporal interpretation of the sections, upon which truly temporal correlations have been established. This means that it has been possible to assess the temporal completeness of sections, particularly in the deep sea, to date precisely the surfaces associated with sequence boundaries in marginal settings, and with stratigraphic gaps in the deep sea, and to determine the corresponding hiatuses (in m.y.).

Two major changes in sedimentation occurred in NW Europe during the late Paleocene-early Eocene interval. They are described here based on stratigraphic sequences in the London-Hampshire basin(s). The oldest is the interruption of marine sandy deposition of the Thanet Beds (Thanetian) during Chron C26r . The youngest is the resumption of marine deposition associated with the widespread early Eocene (Ypresian) transgression which corresponds, in turn, to the London Clay transgression. Between the two events, brackish to lacustrine deposition of the Lambeth Group occurred. Major hiatuses separate the Thanet deposits from the Lambeth Group and the Lambeth Group from the London Clay. It is clear through correlation with DSDP Site 550 that the London clay transgression correlated with the cessation of explosive volcanism in the British Tertiary Volcanic Province. Although the evidence is less clear, it is likely that the termination of Thanetian deposition correlated with the onset of major volcanism in the province.

A major change in sedimentary regime occurred between the Paleocene and Eocene on the New Jersey Margin, as reflected by the unconformable contact between the Vincentown (upper Paleocene) and Manasquan (lower Eocene) Formations, Two onshore New Jersey coreholes (Island Beach and Bass River) have recently recovered this sequence boundary. The upper surface of the sequence boundary in the Island Beach Corehole is of the same age (± 50.000 yrs) as the lower bounding surface of the London Clay (54.37 Ma; time-scale of Berggren et al., 1995). The lower surface is younger than the upper bounding surface of the Thanet Sands, and older than the lower bounding surface of the Lambeth Group. The upper surface of the sequence boundary in the Bass River Corehole is much younger (~ 200,000 yrs) than that in the Island Beach Corehole. On the other hand the lower surface in the Bass River Corehole is much younger (~ 700,000 yrs) than in the Island Beach Corehole (<200 km distant, along strike) and correspond to an as yet undetermined level within the Lambeth Group.

The lack of similarity in the stratigraphic record across the Paleocene/Eocene boundary preserved on the eastern and western margins of the Atlantic Ocean is striking and reminiscent of similar findings regarding the stratigraphic record on these margin around the lower/middle Eocene boundary. The similarity in age of the bases of the Manasquan Formation in the Island Beach Corehole and the London Clay Formation (London-Hampshire Basin) strongly suggests that the early Eocene transgression on both margins was related to the end of regional compressive tectonism in the North Atlantic. However, the difference in age of the two surfaces of the Vincentown/Manasquan sequence boundary in two, closely located coreholes on the New Jersey margin suggests that local tectonism is also a significant component of the architecture of the stratigraphic record.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah