14. Linking Core and Seismic Data without Logs: Core-Seismic Correlation at Site 12761

Donna J. Shillington,2 Brian E. Tucholke,3 Garry D. Karner,4, 5 Dale S. Sawyer,6 W. Steven Holbrook,7 and Heike Delius8


Forging a link between seismic data and the 936.9 m of core data at Ocean Drilling Program Site 1276 is essential to understand the tectonic and sedimentary history of the wider Newfoundland Basin. Logging data traditionally bridge the gap between core and seismic data by measuring in situ geophysical properties of borehole lithologies at a scale intermediate between seismic and core data. Unfortunately, such data could not be collected at Site 1276 because of unstable hole conditions. In lieu of logging data, we employed shipboard laboratory measurements of density and velocity to create synthetic seismograms in order to tie seismic data to core data at Site 1276. The upper 800 m of sediment at Site 1276 were not cored or logged. To establish a link between the top of the cored section and two-way traveltime, we determined velocities in the upper 800 m by analyzing multichannel seismic reflection data and refined the link by comparing the reflection characteristics of seismic data and synthetic seismograms beneath 800 meters below seafloor. We demonstrate that the prominent U reflection, which is observed throughout much of the Newfoundland Basin, is at least locally created by the shallower of two postrift igneous sills encountered at the base of Site 1276. A brighter reflection that lies beneath the U reflection is generated by the strong impedance contrast between very low-velocity, low-density sediments (interpreted as undercompacted) and the deeper postrift sill. Additionally, we describe linkages between other seismic stratigraphic horizons, such as Horizon AU, and the boundaries between primary lithologic units in Site 1276.

1Shillington, D.J., Tucholke, B.E., Karner, G.D., Sawyer, D.S., Holbrook, W.S., and Delius, H., 2007. Linking core and seismic data without logs: core-seismic correlation at Site 1276. In Tucholke, B.E., Sibuet, J.-C., and Klaus, A. (Eds.), Proc. ODP, Sci. Results, 210: College Station, TX (Ocean Drilling Program), 1–33. doi:10.2973/odp.proc.sr.210.110.2007

2National Oceanography Centre, Southampton, University of Southampton, School of Ocean and Earth Science, European Way, Southampton SO14 3ZH, United Kingdom. djshill@noc.soton.ac.uk

3Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole MA 02543-1541, USA.

4Lamont-Doherty Earth Observatory, 61 Route 9W, P.O. Box 1000, Palisades NY 10964, USA.

5Present address: ExxonMobil Upstream Research Company, New Play Concepts, 3120 Buffalo Speedway, P.O. Box 2189, Houston TX 77252-2189, USA.

6Department of Earth Science, Rice University, Keith-Wiess Geological Labs, 6100 Main Street, Houston TX 77005, USA.

7Department of Geology and Geophysics, University of Wyoming, 1000 E. University Way, Laramie WY 82071-3006, USA.

8Department of Geology, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.

Initial receipt: 20 January 2006
Acceptance: 13 April 2007
Web publication: 24 July 2007
Ms 210SR-110