Initial core descript teachers
- 1. Initial Core Descriptions Introduction to making physical observations and documenting a stratigraphic sequence On the Cutting Edge-Teaching Climate Change: Lessons from the Past June 25, 2014 Lake E Teachers Workshop also at http://lrc.geo.umn.edu/laccore/assets/pdf/sops/icd.pdf Julie Brigham-Grette UMass- Amherst
- 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! www.bbc.co.uk/doctorwho Climate Today Climate of Past Climate Future
- 4. years decades centuries Millennia Today Back in Time Lengthofcore Geochronology • Age/Time • Resolution
- 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 Backintime
- 9. • 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 units throughout the core? Science questions should drive analysis (ask students to develop their own)
- 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 • Lets add more…….. Kurupa Lake core. Photo: Darrell Kaufman
- 12. Initial core splitting Emi Ito photo www.geotek.co.uk
- 13. Blades cut only the core liner on either side. Sediment is cut with SS wire. Split cores Initial core splitting
- 14. Cheap and easy too – skill saw? Using a Dremel Tool
- 15. Lake Sediment Core Processing Scheme Example from ICDP Lake El‘gygytgyn Project surface cleaning whole-core magn. suscept. (on site) line scan pictures with MSCL susceptibility and color spectra with SCLP3 1. line scan picture & surface relief 2. XRF light elements with ITRAX core scanner core description manual 3. X-radiography 4. XRF heavy elements with ITRAX core scanner p-wave velocity Gamma-ray density magn. susceptibility with MSCL core archiving LacCore Repository Duluth, U.S.A. core subsampling
- 16. Initial core scanning • Magnetic susceptibility • Line scan (continuous photography) – Good digital camera can do! • Gamma density • Color Spectrometer – L*a*b* parameters – http://www.hunterlab.com/appnotes/an07_96a.pdf • X-rays (use your local health clinic?) • XRF scanning for major elements (ITRAX) Geotek.co.uk
- 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 Defining Facies Making Smear slides http://lrc.geo.umn.edu/laccor e/assets/pdf/sops/sedclass_ba sics.pdf
- 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 Or Globe color book http://en.wikipedia.org/wiki/Munsell_color_system
- 21. Smear Slides Means of preparing a very thin layer of unconsolidated material embedded on a glass slide to examine mineralogy, provenance, grain shape, and identification of microfossils, even tephras. http://lrc.geo.umn.edu/laccore/assets/pdf/sops/smearslides.pdf http://lrc.geo.umn.edu/laccore/assets/pdf/sops/smear_slide_basics.pdf There is even a video tutorial !! AMY ROCKS!https://tmi.laccore.umn.edu/tutorial/preparati on Vascular (terrestrial or aquatic) organic matter Quartz and/or feldspar, pitted and stained with . . . something
- 22. 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 et al. 2013 Glacial/cold warm Super warm Objective is to define sediment facies
- 23. Paleolim 591L Core Lithology-PG1351 Lake El’gygytgyn Silty-Clastic Layer Massive Grey Silty Clay Brownish-Grey Silty ClayOlive-Grey Laminae Deposited under anoxic conditions i.e. Glacial-type climate Lithology Depth(cm) Unit Olive-Grey Silty Clay Massive Interglacial-type sediments UnitUnit Sandy Layer 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. 1 yr? L Poppick, Bates Xrays done at Umass Health Center Lake E Pliocene and xrays
- 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. ` 1pm Awesome WOW! 2PM, better than 1PM 3 PM 4pm classy group PSICAT Stratigraphic Log Summary
- 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 domain • Allows statistics, histograms and surface profiles to transfer to excel. Use your own core images or have students examine cores accessible at CoreRef.org
- 33. 289.00 m comp depth 10 cm
- 34. Image J analysis of Lake El’gygytgyn thin section without any enhancements to default settings.
- 35. 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 Detailed Sedimentology via Image Analysis (Francus and Asikainen) http://www.geo.umass.edu/climate/francus/ss1_slide_show.htm
- 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 Biographia Literaria.
- #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