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Nicole Flynn Senior Thesis: The Pennsylvania State University Advisor: Timothy Bralower

Use of Planktonic/Benthic Foraminiferal Ratios to Quantify Water Depth and Dissolution during the PETM from the Cambrian-Dorchester Core. Nicole Flynn Senior Thesis: The Pennsylvania State University Advisor: Timothy Bralower. Introduction: Paleocene Eocene Thermal Maximum (PETM).

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Nicole Flynn Senior Thesis: The Pennsylvania State University Advisor: Timothy Bralower

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  1. Use of Planktonic/Benthic Foraminiferal Ratios to Quantify Water Depth and Dissolution during the PETM from the Cambrian-Dorchester Core Nicole Flynn Senior Thesis: The Pennsylvania State University Advisor: Timothy Bralower

  2. Introduction: Paleocene Eocene Thermal Maximum (PETM) Massive input of isotopically depleted carbon • Methane clathrates in marine sediments on continental coasts (Dickens et al., 1995) • 3-4permil negative shift in carbon isotope values (Pagani et al., 2006; McInerney and Wing, 2011) Oceanic temperature increase • Bottom waters: 4-5°C (Kennett and Stott, 1991; Bralower et al., 1995) • Tropical surface waters: 5°C • High latitude surface waters: 9°C (see compilation of Dunkley Jones et al., 2013) http://www.dep.state.fl.us/geology/geologictopics/rocks/time_scale.htm

  3. Introduction: Paleocene Eocene Thermal Maximum Changes in carbon cycling, marine and terrestrial environments/ecosystems • Shoaling • (e. g., Colosimo et al., 2006, Petrizzo et l., 2007) • Lysocline • Depth where rate of calcite dissolution dramatically increases • Calcite Compensation Depth (CCD) • Depth where rate of calcite accumulation equals rate of calcite dissolution • Ocean acidification • (Doney, SC et at., 2009) • Decreased pH • Dissolution and reduced calcification of foraminifera

  4. Introduction: Sea Level Sea level rise documented during PETM (Zachos et al., 2005) (e.g., Sluijs et al., 2006, Sluijs et al., 2011) • Warming temperatures during PETM • Limited ice sheets • Minor rise due to melting of ice sheets • Thermal expansion • Increase in energy • Increase in bond length • Increase in volume

  5. Introduction: Foraminifera • Single-celled animals • Form test of CaCO3 • Carbon isotope excursion from composition • Approximately 270,000 species (Haynes, 1981) BenthicPlanktonic http://paleopolis.rediris.es/cg/CG2010_BOOK_02/index.html http://en.wikipedia.org/wiki/Foraminifera

  6. Introduction: Foraminifera Extinction Benthic Foraminifera • Largest extinction in last 90 million years • 50% species extinction (e.g. Scheibner, 2005; Alegret, 2009). Planktonic Foraminifera • Diversification (Kelly et al., 1996) http://www.ok4me2.net/page/11/?s=microscope http://pubs.usgs.gov/of/2000/of00-304/htmldocs/chap09/

  7. Introduction: Cambrian-Dorchester (Cam-Dor) • August 2009 • Dorchester County, Maryland Coordinates: 38°N, 70°W

  8. ~753-749 ft. ~749-732 ft. Heavily bioturbated, glauconitic sand Paleocene- Aquia Formation glauconitic quartz sand Eocene- Marlboro Clay Formation kaolinite rich clays

  9. ~732-725 ft. ~725-719 ft. Clay, very fine sand, quartz with minor glauconite

  10. ~712-695 ft. ~719-712 ft. Clay, faint bedding and bioturbation, sparse benthics

  11. ~679-669 ft. ~695-679 ft. Sandy clay, heavily bioturbated, echinoid spines, oyster shell bed

  12. Introduction: Cam-Dor Cont. Planktonic-Benthic ratios • Sea level Fragmentation • Dissolution and turbulence Quartz, pyrite, glauconite • Environmental changes http://health.wikinut.com/img/2d94qwjwf6qfq4xq/Clear-Quartz-Point http://www.fabreminerals.com/LargePhoto.php?FILE=specimens/s_imagesQ1/Pyrite-GB86Q1f.jpg&CODE=GB86Q1&NAME=Octahedral%20Pyrite&LANG=EN http://www.chinaneolithic.com/en/Mineral/Photos.asp?id=318

  13. Introduction: Hypotheses 1. There will be an increase in P/B ratio following the Paleocene-Eocene boundary after the onset of the PETM 2. a. Deep ocean acidification will lead to increased fragmentation in both benthic and planktonic foraminifera, with particularly more fragmentation in planktonics at the base b. Turbulent shelf environment will lead to increased fragmentation in both planktonic and benthic foraminifera at the top 3. Quartz and glauconite percentages will increase with decreasing core depth and pyrite percentages will decrease with decreasing depth due to falling sea levels

  14. Methods: Retrieval • 156 samples from Cam-Dor core • Distance between samples varied based on proximity to contact • Closer together if closer to contact • Stored in sealed plastic bags

  15. Methods: Washing Process • 75 washed purification • Sieved into 3 fractions: • 63-125 µm • 125-250 µm • >250 µm • 125-250 µm fraction analyzed

  16. Methods: Analysis and Identification • 100 counts • Planktonic • Fragmented planktonic • Benthic • Fragmented • benthic • Percentages of • Pyrite • Glauconite • Quartz

  17. Very little in five samples from: • 732.55-730.85 ft. • Small decrease in two samples: • 725.69 ft. • 725.2 ft.

  18. Missing from: • 732.55 to • 730.85 ft. • Increase from: • 730.35 to • 722.5 ft. • Average: 1.6 • Decrease from: • 719.5 to • 669.28 ft. • Average: 0.7

  19. Benthic: blue • 730.35 to 680.28 ft: 19.4% • 677.2 to 669.82 ft: 62% • Planktonics: red • Average: 30.3% • Comparison • Slightly more fragmented • planktonics than benthics • at base

  20. Quartz: blue • Decrease • Pyrite: red • Decrease • Glauconite: green • Increase

  21. Discussion: P/B Ratio Rise in P/B ratio • Increase in SL from 730.35-722.5 • Highest P/B ratio: 3.8 • 79% of foraminifera planktonic • Highest SL at 726.6 feet Decrease in P/B ratio • Drop in SL as ocean water temperature decrease after PETM from 719.5 to 669.82 • Increase in benthic activity • Dissolution zone missing planktonic and benthic foraminifera deep ocean acidification/rising CCD

  22. Discussion: Fragmentation Benthic Foraminifera Planktonic Foraminifera Increased fragmentation in planktonics at bottom due to dissolution Planktonics more susceptible than benthics Overall average: 30.3% • Bottom- Fragmentation due to dissolution • Top- Turbulence associated with decreasing sea levels

  23. Discussion: Quartz, pyrite, glauconite Pyrite Quartz Glauconite • Disagrees with hypothesis • Due to relative glauconite percentages • Agrees with hypothesis • Decreasing pyrite • Decreasing SL corresponds with decrease in pyrite • Pyrite indicates eutrophication during PETM • Agrees with hypothesis • Return to continental shelf marine depositional environment http://en.wikipedia.org/wiki/Quartz http://euromin.w3sites.net/mineraux/PYRITE.html http://www.chinaneolithic.net/en/Mineral/photos.asp?ID=318

  24. Conclusions Dissolution • Massive carbon input lead to ocean acidification or shoaling CCD • Dissolution zone from 732.55 to 730.85 feet Sea Level Fall • Fall in SL due to falling temperatures recovery • Fall in P/B ratio from 725.2 to 669.82 feet • Increased glauconite Sea Level Rise • Rise in SL following the Paleocene-Eocene contact • Rise in P/B ratio from 730.35 to 725.69 feet • Increased pyrite- eutrophication

  25. ? ? ? Questions? ? ?

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