Merlin Energy Resources is pleased to be hosting a new product; an extensive biostratigraphy database compiled by expert palynologist, Dr. Jonathan Bujak. The database comprises detailed biostratigraphic data for over 1000 wells in the North Sea and West of Shetland areas.
Dr. Bujak writes:
Paleogene rocks of the northeast Atlantic and adjacent basins were deposited during massive changes in the region’s oceanography, basin configuration, chemistry and a climate that shifted from greenhouse to icehouse. These affected the entire region and its individual basins, including the North Sea, Norwegian-Greenland Sea, and Faroe-Shetland, Porcupine, Rockall and Hampshire basins (Figure 1).
Mantle Plume Uplift
The Early Paleocene was a period of warm-water conditions with open-marine connections across the entire North Atlantic region. This benign environment and its marine biotas and sediments underwent extensive changes during the Late Paleocene when uplift and igneous extrusion from the Greenland-Iceland mantle plume enclosed the North Sea-Norwegian-Greenland Sea System, severely restricting basin circulation and marine biotas.
This was overprinted by a succession of hyperthermal events which resulted in warm-water taxa, including the dinoflagellate Apectodinium, migrating into the North Sea during the Paleocene Eocene Thermal Maximum (PETM) (Figure 2). The combination of high water-temperature, basin enclosure and bottom-water anoxia also resulted in the deposition of oil-prone sapropel from the remains of plankton blooms fed by abundant nutrients transported from newly emergent sediments.
Following collapse of the mantle plume and regional transgression, some basins were partially reconnected, but the North Atlantic region was still separated into three oceanographic systems: (1) the ‘North Atlantic System’ including the Scotian Shelf, Grand Banks, NE Newfoundland, Rockall and Hampshire basins, (2) the ‘North Sea – Norwegian-Greenland Sea System’ including the Faroe-Shetland Basin, and (3) the ‘Labrador Sea – Baffin Bay System’ (Figure 3).
Separation of the three oceanographic systems had a major effect on their sedimentation and biotas during the subsequent change from a greenhouse climate towards today’s icehouse with its glacial-interglacial cycles.
The Greenhouse-to-Icehouse Shift
The North Atlantic System was connected to tropical waters and had sea-surface temperatures (SST) that were warmer than those of the other two systems. These changes became more pronounced following the Arctic Azolla Event, as atmospheric carbon dioxide and global temperatures fell.
The decreased temperatures had a greater impact on the North Sea – Norwegian-Greenland Sea System and Labrador Sea – Baffin Bay System, which were not connected oceanographically to warmer waters of the North Atlantic System. As a result, a succession of warmer-water, temperature-sensitive species, including dinoflagellates and planktonic foraminifera, died out in the North Sea – Norwegian-Greenland Sea System, but persisted in the North Atlantic System. This resulted in diachronism of many last occurrence events and potential miscorrelations of some sections including wells drilled in the different basins, and latitudinally within the North Sea – Norwegian-Greenland Sea System (Figure 4).
Biostratigraphic correlation of the region’s offshore Paleogene sections, therefore, presents both a challenge and an opportunity because the constraints described above can be used to gain a broader and more detailed perspective of events occurring during the Paleogene and their effect on petroleum generation, migration and preservation.
This needs a regional perspective as well as detailed analysis of sections within each basin.
The Bujak North Sea – West of Shetland database
The database is based on more than 50 years’ work by Dr. Jonathan Bujak on both sides of the Atlantic, including his role as a Senior Research Scientist with the Geological Survey of Canada and Nova Scotia’s Bedford Institute of Oceanography. Dr. Bujak has contributed to over 100 scientific publications, including definitive biostratigraphic and sequence stratigraphic schemes for the North Sea, Faroe-Shetland Basin, offshore eastern Canadian and Hampshire Basin type sections.
The database includes 1155 North Sea and West of Shetland wells based on detailed interpretations undertaken by Dr. Bujak and compiled in Stratabugs 3.0 in 2022.
This database is now for sale via the Merlin website, where you can also find out more about the products on offer. Alternatively you can email info@merlinenergy.co.uk or jonathanbujak@outlook.com for further information.
A PowerPoint of one of Dr. Bujak’s Keynote presentations is provided here.
Selected References
BUJAK, J.P. & MUDGE, D.C. (1994). A high-resolution North Sea Palaeocene – Eocene dinocyst zonation. Journal of the Geological Society of London, vol. 151, pp. 449-462.
MUDGE, D.C. & BUJAK, J.P. (1994). Eocene stratigraphy of the North Sea Basin. Marine and Petroleum Geology, vol. 11, no. 2, pp. 166-181.
MUDGE, D.C. & BUJAK, J.P. (1996). An integrated stratigraphy for the Paleocene and Eocene of the North Sea. In: Correlation of the Early Paleogene in Northwest Europe (Eds Knox, R.W.O’B. et al.), Geological Society Special Publication No. 101, pp. 91-113.
MUDGE, D.C. & BUJAK, J.P. (1996). Palaeocene biostratigraphy and sequence stratigraphy of the UK central North Sea. Marine and Petroleum Geology, vol. 13, pp. 195-312.
