U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY PLANKTIC FORAMINIFER CENSUS DATA FROM NORTHWIND RIDGE CORE 5, ARCTIC OCEAN Open-File Report 91-346 By Kevin M. Foley and Richard Z. Poore This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards (or with the North American Stratigraphic Code). Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Kevin M. Foley Mail Stop 906, National Center U.S. Geological Survey Reston, VA 22092 Tel: (703) 648-5285 FAX: (703) 648-5420 email: kfoley@usgs.gov Richard Z. Poore Mail Stop 906, National Center U.S. Geological Survey Reston, VA 22092 FAX: (703) 648-6647 email: rpoore@usgs.gov INTRODUCTION The U.S. Geological Survey recovered 9 piston cores from the Northwind Ridge in the Canada Basin of the Arctic Ocean from the USCGC Polar Star during 1988 and 1989. Preliminary analysis of the cores suggests sediments deposited on Northwind Ridge preserve a detailed record of glacial and interglacial cycles for the last few hundred thousand to million years. This report includes quantitative data on planktic foraminifers and selected sediment size-fraction data in 130 samples from the Northwind Ridge Core 5. These foraminifer data will be the basis for future interpretive studies. METHODS Samples numbered 1 through 88 are 10cc samples obtained for lithostatigraphy and biostratigraphy. Samples numbered 89 through 131 are cuttings obtained when paleomagnetics samples were taken and are approximately 10cc. The samples were washed in distilled water, wet sieved to three size fractions; <62um, 62um - 2mm, and >2mm. The size fractions were dried and weighed. The 62um - 2mm and the >2mm fractions were combined after weighing. The >62um fraction was sieved at 150um and counting splits of 300 - 350 planktic foraminifers were obtained from the >150um fraction using a Carpco sample splitter. Planktic foraminifers were identified, sorted and glued to standard 60 square micropaleontological slides. Benthic foraminifers were also counted. All planktic foraminifers were removed from samples containing insufficient specimens for a counting split. Northwind Ridge Core 5 is located at 74.622 degrees north latitude, 157.884 degrees west longitude, where the depth to the sea floor is 1089 meters. [Editor's note: From subsequent work (USGS OFR 93-218) the proper identifier for this core is "PI-88-AR P5".] COUNTING CATEGORIES Taxa included in the counting categories are summarized below. In general, our taxonomic concepts follow Parker (1967, 1962). Explanation of column headings in file Core/raw/nwr5.txt. depth1 Depth in cm of the top of the sampled interval. For samples 89 through 131 this value indicates instead the midpoint of the sampled interval. depth2 Depth in cm of the bottom of the sampled interval. For samples 89 through 131 this value is meaningless. wt<62um Weight in grams of that part of the sample passing through the 62um sieve. wt%<62um Percentage of the total sample weight represented by the material passing through the 62um sieve. wt62um-2mm Weight in grams of that part of the sample passing through the 2mm sieve but retained on the 62um sieve. wt%62um-2mm Percentage of the total sample weight represented by the material passing through the 2mm sieve but retained on the 62um sieve. wt>2mm Weight in grams of that part of the sample retained on the 2mm sieve. wt%>2mm Percentage of the total sample weight represented by the material retained on the 2mm sieve. total wt Total weight of the sample. 1/split Proportion of the sample from which specimens were counted; a value of 1 indicates all of the sample was used to derive the counts, a value of 2 indicates half of the sample was used, and so on. spach Neogloboquadrina pachyderma (Ehrenberg) left coiling. dpach Neogloboquadrina pachyderma (Ehrenberg) right- coiling. This category is restricted to specimens with 4 chambers in the ultimate whorl. Right- coiling specimens that have more than 4 chambers in the ultimate whorl are tabulated as "dupac". dupac This category is used for specimens of right- coiling Neogloboquadrina with more than 4 chambers in the ultimate whorl. other Deformed planktic specimens and specimens resembling Turborotalita quinqueloba. total plank Total number of planktic foraminifers in the counting split. total benth Total number of benthic foraminifers in the counting split. plank/sample>150um The number of planktic foraminifers >150um found in the counting split divided by the fraction of the sample that the counting split represents. plank/gram>150um The total number of planktic foraminifers >150um in the sample divided by the weight of the sample in grams. %dextral The percentage of right-coiling Neogloboquadrina pachyderma. ACKNOWLEDGEMENTS We thank Larry Phillips for providing the washed residues and sedimentological data from the core 5 samples. REFERENCES Parker, F.L., 1962, Planktonic foraminiferal species in Pacific sediments, Micropaleontology, v. 8, p. 219-254. Parker, F.L., 1967, Late Tertiary biostratigraphy (Planktonic Foraminifera) of tropical Indo-Pacific deep-sea cores: Bulletins of American Paleontology, v. 52, p.115-208. (end)