No abstract

This report provides palynological data and age interpretations for six outcrop areas (Ivishak River, Echooka River, Shaviovik anticline, Toolik River-White Hills, Marsh Creek anticline, and Jago River) and parts of four well sections (the Arco Ugnu SWPT-1 well, the Arco West Sak River #23 well, the Mobil West Staines State #1 well, and the Mobil et al. West Kadleroshilik Unit #1 well) on the North Slope of Alaska. The described pollen assemblages are Maastrichtian to Eocene in age. A new, latest Maastrichtian pollen subzone is proposed based on samples from the Ugnu SWPT-1 core. The Cretaceous-Tertiary (K-T) boundary in the core, and in cuttings from the Arco West Sak River #23 well, can easily be picked using the abrupt Terminal Cretaceous Extinction Event. If an unconformity is present at the K-T boundary in the Ugnu SWPT-1 well core, it is probably a minor one at least with regard to the loss of Cretaceous strata. Cretaceous samples collected near the K-T boundary along the Ivishak River, the Echooka River, and in the Shaviovik anticline area were found to be late but not necessarily latest Maastrichtian in age. At least in some places on the North Slope, it appears that lowermost Paleocene strata are present, but such a determination is difficult or impossible to make using ditch (cuttings) samples. A range chart is compiled for pollen distributions from the middle Paleocene to the lower Eocene in the Canadian Arctic based on published sources, and, using this chart, two samples from the Toolik River-White Hills were found to be probably late Paleocene and probably middle Paleocene, respectively. Ditch samples were analyzed from the Mobil West Staines State #1 well, just west of the Arctic National Wildlife Refuge, and it is shown that upper Paleocene strata are present in the well section. Ditch samples were analyzed from the Mobil et al. West Kadleroshilik Unit #1 well, a short distance east of Franklin Bluffs on the Sagavanirktok River. The presence of middle and upper Paleocene strata could not be demonstrated in this well section; thus, it is possible but not provable that Eocene rocks rest directly on lower Paleocene rocks in this area. It has been found that the practice of consulting palynologists, studying palynomorphs in ditch samples, who pick the top of the Paleocene at the uppermost occurrence or uppermost consistent occurrence of Paraalnipollenites alterniporus, produces only an approximately dated correlation marker because the actual range top of the species is in the lower Eocene. Samples from the Marsh Creek anticline and the Jago River are shown to contain pollen assemblages similar to those of early to middle(?) Eocene age in the Franklin Bluffs on the Sagavanirktok River. angiosperm pollen. However, counts to determine relative frequencies of palynomorph groups were only made using >7 pm residues. All residues were mounted in glycerine jelly.

No abstract

Turon (1984) presented raw counts for 45 coretop samples from the northwestern Atlantic Ocean. Raw counts were converted to percentage values based on the total number of dinocysts present. The samples in the Turon (1984) dataset are, for the most part, from open ocean sediments, east of the Mid-Atlantic Ridge, from near Norway to the north to just south of the Azores (latitudes range from 34-66°N and longitudes 36°W to 11°E). Reported depths range from 410-4787 m (average 2875 m). Winter and summer sea-surface temperatures were taken from the February and August isotherms on Turon's (1984) figure 49, interpolated to the nearest 0.5°C. Winter sea surface temperatures range from 3-17°C and summer sea surface temperatures range from 8-24°C. Average winter-summer temperature difference is 5.8°C. Only a few samples have winter sea surface temperatures above 11°C. According to Turon (1984), his processing steps consisted of: removal of carbonates using cold hydrochloric acid in progressively stronger concentrations (10-25%), removal of silicates using cold hydrofluoric acid (40%) for 24 hours, treatment in cold hydrochloric acid (10%), heavy liquid treatment (cadmium and potassium iodide solution with a specific gravity of 2), filtration, final wash and centrifugation in distilled water. He processed 5-15 g of sediment for each sample. The total number of dinocysts counted per sample ranges from 16 to 848 with an average value of 195 and a median value of 171. Fourteen samples had less than 100 specimens counted; seven had greater than 300. TAXONOMIC NOTE Because the relationships between cyst and parent theca are often unknown or uncertain, a dual nomenclature has evolved for dinoflagellates. Both names are given in the key to the data tables. More documentation of the taxonomy can be found in Lentin and Williams (1989). KEY TO ABBREVIATIONS Snum Sample number or code as given by the originial author(s). Auth Author(s). Wall=Wall and others (1977); Turon=Turon (1984). Lat Latitude, in decimal degrees. North latitude is positive. Long Longitude, in decimal degrees. East longitude is positive. Depth Water depth (m) at sample location, as given by the original author(s). Wsst Winter sea-surface temperature (°C), average monthly temperature for the coldest month of the year, as interpolated from source given in column "tsource." Ssst Summer sea-surface temperature (°C), average monthly temperature for the warmest month of the year, as interpolated from source given in column "tsource." tsource Reference used to obtain winter and summer sea-surface temperatures. NOO67=U.S. Naval Oceanographic Office (1967), NOC81=U.S. Naval Oceanographic Command (1981), Turon=Turon's (1984) figure 49. sum Total number of dinocysts counted.