Initial Core Descriptions
- 1. On the Cutting Edge-Teaching Climate Change: Lessons from the Past Initial Core Descriptions Introduction to making physical observations and documenting a stratigraphic sequence Julie Brigham-Grette UMass- Amherst June 20, 2012 AMQUA http://lrc.geo.umn.edu/laccore/assets/pdf/sops/icd.pdf
- 2. Why study lakes • Lakes found in a variety of environments • Dynamic environmental systems • Integrate environmental and climatic change on a variety of time scales • They collect sediments, organic matter in response to their surroundings • Sediments produce a continuous archive of change; layer upon layer, they record of Earth’s natural experiments in change.
- 3. Earth Scientists – Time lords! Sediment cores allow one to understand past change and system dynamics and to use this information to improve predictions about the future! If men could learn from history, what lessons it might teach us! But passion and party blind our eyes, and the light which experience gives is a lantern on the stern, which shines only on the www.bbc.co.uk/doctorwho waves behind us! Samuel Taylor Coleridge, 1831
- 4. Today Geochronology years • Age/Time Length of core • Resolution decades centuries Back in Time Millennia
- 5. Learning Goals • Concepts of the recent geologic record – causality at a distance, cyclic causality, environmental time delays • How to describe sediments – standardized approach to physical descriptions – Photographic and written documentation – Making observations and documenting those observations in meaningful way – Concept of particle size and sedimentary structures for understanding depositional environments – Facies model development • Develop stratigraphic column, (Psicat) • Quantitative image analysis (Image J)
- 6. Science Goals Difference between weather and climate (ave of > 3 decades) Regional climate change vs global climate change
- 7. The approach – lake sediments (Lake E example)
- 8. Proxies of climate Modeling and prediction of future change today Back in time
- 9. Science questions should drive analysis (ask students to develop their own) • Sedimentation rates and the geochronology of the core are fundamental to understanding all of the physical properties and quantifying the climate/environmental history. How can studies of the sedimentology and sediment flux rates be used with other proxies to best constrain the chronology? • What are the hydrological, biological, and geochemical controls on changes in sediment texture as they relate to changes in climate? • What are the lake processes and climatic conditions that produce laminated, non-laminated and weakly laminated
- 10. ADD YOUR OWN QUESTIONS: • How can the core stratigraphy be characterized into recognizable facies assemblages related to changes in climate? • What fundamental changes can we observe in the lake sedimentology . • What processes cause these changes as they relate to climate history and landscape change? • Is there a fundamental change in the sediment properties and biogenic sedimentation (or organic matter) with changes in land use, or external and internal forcing over time? • Characterization of primary controls on sediment character, flux rates and the proportions of clastic vs. biogenic deposition • Quantification of the relationship between sedimentology and climate change (hydrology, lake ice cover history, terrestrial vs aquatic inputs etc.) • Paleoclimate proxy development by comparisons between physical properties, sedimentology, and scanned data sets.
- 11. Terms - learning the lingo • Age resolution – years/cm • Lithostratigraphy – layering based on physical, lithic properties and petrology • Particle size/grain size • Facies – Sediments deposited in particular environment or process ; a vertical succession of facies suggest lateral migration of the depositional environment • Laminae/varves – Thin layers, if annual = varves Kurupa Lake core. Photo: Darrell Kaufman • Lets add more……..
- 12. Initial core splitting www.geotek.co.uk Emi Ito photo
- 13. Initial core splitting Blades cut only the core liner on either side. Sediment is cut with SS wire. Split cores
- 14. Cheap and easy too – skill saw? Using a Dremel Tool
- 15. Lake Sediment Core Processing Scheme Example from ICDP Lake El‘gygytgyn Project whole-core surface magn. suscept. cleaning (on site) line scan pictures with MSCL susceptibility and color spectra with SCLP3 core archiving core description manual LacCore Repository Duluth, U.S.A. 1. line scan picture & surface relief 2. XRF light elements with ITRAX core scanner p-wave velocity 3. X-radiography Gamma-ray density core subsampling 4. XRF heavy elements magn. susceptibility with ITRAX core scanner with MSCL
- 16. Initial core scanning • Magnetic susceptibility • Line scan (continuous photography) – Good digital camera can do! • Gamma density Geotek.co.uk • Color Spectrometer – L*a*b* parameters – http://www.hunterlab.com/appnotes/an07_96a.pdf • X-rays (use your univ clinic?) • XRF scanning for major elements (ITRAX)
- 17. Filling out the Barrel sheet – what to look for, what to describe Texture (grain size) Color (munsell scheme) Unit thicknesses nature of contacts clast lithology Compaction (stiffness) sedimentary structures organic content fossils http://lrc.geo.umn.edu/laccor Defining Facies e/assets/pdf/sops/sedclass_ba sics.pdf Making Smear slides
- 18. Sediment classification • Macroscopic structure of the sediment – – structures and textures (bedding features, texture, color) • ID of major and minor components – Eg. Clay, carbonate, peat, mud….) 1. Color + 2. Bedding + 3. Major Modifier + 4. Principal Name + 5. Minor Constituents e.g Dark reddish brown, massive, feldspathic clay with carbonaceous debris and trace gastropod fragments Schnurrenberger et al, 2003 at http://lrc.geo.umn.edu/laccore/assets/pdf/sops/sedclass.pdf
- 19. Classroom applications • Grain size charts http://www.concrete- catalog.com/soil_compaction.html
- 20. Classroom applications Munsell Color Book http://en.wikipedia.org/wiki/Munsell_color_system
- 21. Smear Slides Means of preparing a very thin layer of unconsolidated material Vascular (terrestrial or aquatic) organic matter embedded on a glass slide to examine mineralogy, provenance, grain shape, and identification of microfossils, even tephras. Quartz and/or feldspar, pitted and stained with . . . something There is even a video tutorial !! AMY ROCKS!https://tmi.laccore.umn.edu/tutorial/preparati on http://lrc.geo.umn.edu/laccore/assets/pdf/sops/smearslides.pdf http://lrc.geo.umn.edu/laccore/assets/pdf/sops/smear_slide_basics.pdf
- 22. Objective is to define sediment facies Lake El’gygytgyn Facies – related to ice cover duration Among other changes in lake system Melles et al. 2010 Melles et al. 2012 Brigham-Grette, in prep Glacial/cold warm Super warm
- 23. Core Lithology-PG1351 Lake El’gygytgyn Lithology Olive-Grey Laminae Massive Grey Silty ClayBrownish-Grey Silty Clay Unit Olive- Grey Silty Clay Depth (cm) Unit Unit Deposited under anoxic Massive conditions Interglacial-type Sandy Layer i.e. Glacial-type sediments climate Silty-Clastic Layer Paleolim 591L Depth: 385 cm
- 24. Transgressive – Regressive facies With Lake level changes. http://www.geol.umd.edu/~jmerck/geol342/lectures/16.html
- 25. Should develop a common language and facies description
- 26. From mud to seeing fine laminae Gravity Core GC-K05-03 Svalbard REU
- 28. Lake E Pliocene and xrays L Poppick, Bates Xrays done at Umass Health Center 1 yr?
- 29. PSICAT – simple software for constructing stratigraphic columns http://portal.chronos.org/psicat-site/ PSICAT, CHRONOS's Paleontological Stratigraphic Interval Construction and Analysis Tool, is a stand-alone Java based graphical editing tool for creating and viewing stratigraphic column diagrams from drill cores and outcrops. It is customized to the task of working with stratigraphic columns and captures data digitally as you draw and edit the diagram. Initial developed by Josh Reed for ANDRILL Project.
- 30. PSICAT Stratigraphic Log Summary 1pm Awesome WOW! 2PM, better than 1PM 3 PM 4pm classy group `
- 31. File Export Summary Spreadsheet
- 32. Image J – simple analysis software http://rsbweb.nih.gov/ij/ • Allows simple or complex analysis of textures, layering, color • Runs on any platform, public Use your own domain core images or have students • Allows statistics, histograms examine cores and surface profiles to transfer accessible at to excel. CoreRef.org
- 33. 10 cm 289.00 m comp depth
- 34. Image J analysis of Lake El’gygytgyn thin section without any enhancements to default settings.
- 35. Detailed Sedimentology via Image Analysis (Francus and Asikainen) http://www.geo.umass.edu/climate/francus/ss1_slide_show.htm Main Facies • Interglacial – Non-laminated – Lower TOC – High Magnetic susceptibility (MS) – Median Grain-size = 3.5 µm • Glacial – Finely Laminated – “Bleb” Structures – Higher TOC, low MS – Authigenic minerals – Median Grain-size = 3.5 µm
- 36. SEM view
- 37. SEM view
- 38. On-line Data Archiving and Global Access
Editor's Notes
- #2: From Mud to wiggles!
- #4: Samuel Taylor Coleridge was an English poet, critic, and philosopher who was, along with his friend William Wordsworth, one of the founders of the Romantic Movement in England and one of the Lake Poets. He is probably best known for his poems The Rime of the Ancient Mariner and Kubla Khan, as well as his major prose work BiographiaLiteraria.
- #5: Most people do not understand geologic time.
- #6: Grotzer, T., and Bell, B., 2004, How does grasping the underlying casual structures of ecosystems impact students' understanding? J. Bio. Educ., 38, 16-29.
- #17: Add definitions of color