U.S DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY DISTRIBUTION AND TAXONOMY OF LATE QUATERNARY DIATOMS FROM GRAVITY CORES L13-81-G117, L13-81-G138, L13-81-G145, AND TT197-G330, NORTHERN CALIFORNIA CONTINENTAL SLOPE by Eileen Hemphill-Haley 1 OPEN-FILE REPORT 93-340 This report is preliminary and has not been reviewed for conformity with 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. 1) Menlo Park, CA 94025 INTRODUCTION.................................................................................1 DEFINITIONS.....................................................................................1 METHODS.........................................................................................2 SUMMARY OF CORE LITHOLOGIES AND DIATOM DISTRIBUTIONS...............^ L13-81-G138................................................................................2 L13-81-G117................................................................................3 L13-81-G145................................................................................4 TT197-G330................................................................................5 LATE QUATERNARY PALEOCLIMATOLOGY BASED ON DIATOMS.................5 EVIDENCE FOR THE PLEISTOCENE TO HOLOCENE TRANSITION .................6 DIATOM DISTRIBUTIONS IN LAMINATED VERSUS BIOTURBATED UPPER- SLOPE DEPOSITS..............................................................................7 DIATOM EVIDENCE FOR RESTRICTED PELAGIC SEDIMENTATION AND WINNOWING..................................................................................8 CONCLUSIONS..................................................................................^ ACKNOWLEDGMENTS.........................................................................10 FLORAL LIST.....................................................................................11 MARINE PLANKTONIC AND MEROPLANKTONIC DIATOMS................11 Actinocyclus curvatulus Janisch in Schmidt, 1878..........................11 Actinocyclus ochotensis Jous6, 1961...........................................11 Actinocyclus spp.................................................................11 Azpeitia tabularis (Grunow) Fryxell and Sims in Fryxell et al., 1986.............................................................................. 12 Coscinodiscus marginal us Ehrenberg, 1843 .................................12 Coscinodiscus oculus-iridis Ehrenberg, 1841................................12 Coscinodiscus radiatus Ehrenberg, 1841......................................13 Coscinodiscus spp................................................................13 Delphineis karstenii (Boden) Fryxell in Fryxell and Miller, 1978....... 14 Delphineis surirella (Ehrenberg) G.W. Andrews, 1981....................14 Denticulopsis seminae (Simonsen et Kanaya) Simonsen, 1979........... 14 Hemidiscus cuneiformis Wallich, 1860......................................15 Nitzschia spp.....................................................................15 Pseudopodosira elegans Sheshukova-Poretzkaya, 1964 ....................16 Pseudoeunotia doliolus (Wallich) Grunow in Van Heurck, 1880 .........16 Rhizosolenia hebetata form hiemalis (Bailey) Gran, 1904.................16 Rhizosolenia hebetata form semispina (Hensen) Gran, 1904..............17 Rhizosolenia styliformis Brightwell, 1858................................... 17 Roperia tesselata (Roper) Grunow in Van Heurck, 1883.................... 17 Skeletonemacostatum (Greville) Cleve, 1878................................18 Stellarima stellaris (Roper) Hasle and Sims, 1986..........................18 Stephanopyxis dimorpha Schrader, 1973......................................19 Stephanopyxis kulmii Schrader, 1973 ........................................19 Stephanopyxis turris (Greville and Arnott) Ralfs, 1861.....................19 Thalassiosira decipiens (Grunow ex Van Heurck) Jorgensen, 1905......20 Thalassiosira eccentrica (Ehrenberg) Cleve, 1904..........................20 Thalassiosira ferelineata Hasle and Fryxell, 1977 ........................21 Thalassiosira gravida Cleve, 1896............................................21 Thalassiosira hendeyi Hasle and Fryxell, 1977.............................21 Thalassiosira leptopus (Grunow) Hasle and Fryxell, 1977.................22 Thalassiosira nordenskoldii Cleve, 1873 ....................................22 Thalassiosira oestrupii var. venrickae Fryxell and Hasle, 1980.........22 Thalassiosira pacifica Gran and Angst, 1931...............................23 Thalassiosira punctigera (Castracane) Hasle, 1983........................23 Thalassiosira tenera Proschkina-Lavrenko, 1961..........................23 Thalassiosira trifulta Fryxell, 1979...........................................23 Thalassiosira cf. lineata .......................................................24 Thalassiosira sp. 1..............................................................24 Thalassiosira sp. E..............................................................24 Thalassiosira spp................................................................ 24 Thalassionema nitzschioides (Grunow) H. and M. Pergallo, 1901 ......24 Thalassiosira nitzschioides var. parva Heiden and Kolbe, 1928..........25 Thalassiothrix longissima Cleve and Grunow, 1880 .......................25 FRESHWATER, BENTHIC AND TYCHOPELAGIC DIATOMS.................26 Actinocyclus normanii (Gregory) Hustedt, 1957 ............................26 Actinoptychus senarius (Ehrenberg) Ehrenberg, 1838......................26 Actinoptychus splendens (Shadbolt) Ralfs, 1861.............................26 Actinoptychus vulgaris Schumann, 1867.....................................27 Aulacoseira granulata (Ehrenberg) Sim on sen, 1979 .......................27 Aulacoseira islandica (0. Miiller) Simonsen, 1979.........................27 Aulacoseira italica (Ehrenberg) Simonsen, 1979............................27 Aulacoseira spp..................................................................28 Cocconeis spp.....................................................................28 Cyclotella spp.....................................................................28 Endictya sp. 1....................................................................28 Odontella aurita (Lyngbye) Argardh, 1830...................................28 Odontella (Biddulphia) longicruris Greville, 1859..........................29 Odontella spp.....................................................................30 Paralia sulcata (Ehrenberg) Cleve, 1873......................................30 Raphoneis amphiceros (Ehrenberg) Ehrenberg, 1844.......................30 Raphoneis margaritalimbata Mertz, 1966....................................30 Raphoneis psammicola Rizynk, 1973.........................................30 Stephanodiscus spp..............................................................31 Thalassiosira lacustris (Grunow) Hasle and Fryxell, 1977 ...............31 REFERENCES....................................................................................^ Table 1. Core locations. ..........................................................................45 Table 2. Conventional and Acclerator Mass Spectrometer 14C Ages.......................46 Table 3. Abbreviations for diatom species listed in Tables 4-7..............................47 Table 4. Diatom counts for L13-81-G138........................................................48 Table5. Diatom counts for L13-81-G117........................................................67 Table 6. Diatom counts for gravity core L13-81-G145.........................................74 Table 7. Diatom counts for gravity core TT197-G330.........................................81 Figure 1.............................................................................................95 Figure 2.............................................................................................96 Figure 3.............................................................................................97 Figure 4.............................................................................................98 Figure 5.............................................................................................99 Figure 6............................................................................................. 100 Figure 7.............................................................................................101 Figure 8.............................................................................................102 Figure 9.............................................................................................103 Figure 10............................................................................................104 Figure 11............................................................................................105 Figure 12............................................................................................106 Figure 13............................................................................................107 Figure 14............................................................................................108 ii INTRODUCTION The purpose of this report is to document the distribution of late Quaternary diatoms on the northern California continental slope. Analyses were generated as part of a multi- disciplinary study