- A nearly complete lowermost Albian (uppermost Aptian?) to
lowermost Oligocene sedimentary sequence of mudrock, shale, and interbedded turbidite sandstone and other gravity flow deposits was recovered at ODP Site 1276 in the deep Newfoundland Basin. Calcareous nannofossils provide the most complete biostratigraphic age control for Site 1276. Planktonic foraminifers provide sporadic but complementary age control and are best represented in turbidite sandstones. Palynomorphs are particularly abundant and useful for biostratigraphy in organic-rich Paleogene and mid-Cretaceous sediments.
- Site 1276 has been at abyssal depths (>2000 m) near or below the CCD since earliest Albian time (~112 Ma). Calcareous microfossils are not abundant, except in some turbidites. In situ mudrock and shale are characterized by abyssal agglutinated foraminifers and varying quantities of radiolarians, phosphatic fish debris, sponge spicules, and plant debris. Calcareous nannofossils are generally present in many samples owing to their transport to the deep sea in fecal pellets or distal turbidites.
- The Albian part of the succession accumulated very rapidly in response to erosion on the Grand Banks associated with the Avalon uplift, increased sedimentation associated with relatively low sea level, and/or increased accommodation space associated with subsidence of the young Newfoundland continental margin.
- Two mid-Cretaceous OAEs are well developed at Site 1276. Basal Albian OAE1b occurs in Cores 210-1276A-95R and 94R, and Cenomanian/Turonian boundary OAE2 occurs in Sections 210-1276A-31R-2 and 3. Both OAEs lack benthic biota in the laminated black shale, suggesting that anoxia may have existed through much of the basal water column, thereby contrasting the expanded oxygen minimum zone model for OAE development.
- Calcareous nannofossil assemblages suggest surface water cooling in the vicinity of Site 1276 following OAE2 in the early Turonian. This may be a widespread if not global phenomenon related to the excess burial of carbon during OAE2.
- Much of the Upper Cretaceous (Turonian–Maastrichtian) is represented by a relatively condensed sequence of oxidized sediments due to the combined influences of high global sea level, elevated CCD, and invigorated deepwater circulation during the Late Cretaceous.
- A biostratigraphically complete Cretaceous/Paleogene boundary was recovered in Section 210-1276A-21R-4. This represents one of the deepest water K/P boundary sections known.
- The discovery of redeposited large-size benthic foraminifers with Caribbean affinities in Cores 210-1276A-15R through 7R demonstrate that a shallow-water carbonate platform(s) existed nearby on the southeastern Grand Banks, Newfoundland Seamounts, or southern Flemish Cap during the Campanian–Maastrichtian and again during the latest Paleocene and early Eocene. Both time intervals correspond with high sea level and global warmth. These findings suggest that paleobiogeographic boundaries shifted much further north and that a proto-Gulf Stream probably crossed the offshore Newfoundland region at these times.
- A probable hiatus and condensed interval spanning ~4.8 m.y. in the early middle Eocene (~48.5–43.7 Ma) suggest that invigorated bottom water flow and a change in global eustatic sea level accompanied the onset of global cooling, or opening of the Arctic Basin, following the
early Eocene Climatic Optimum (EECO).