Originally presented 17 Nov 2012)
Dr. Sidney Hemming uses the geochemistry of sediments and sedimentary rocks to unravel events in Earth’s past. She is a Professor in the Department of Earth and Environmental Sciences, and directs the Argon Geochronology Lab at Lamont.
In this E2C Workshop, Dr. Hemming shares some of the results from fieldwork in the Mono Basin of eastern California. This is one of the most dynamic Quaternary landscapes because it has been shaped by complex interactions of volcanic eruptions, glaciers, and climate changes. These have been recorded in the lake sediments with the valley high in the Sierra Nevadas.
This session will explain the techniques used to unravel events which have created some of the most beautiful parts of our country’s geology. Dr. Hemming has brought undergraduates to the region for some of their first geological field experiences as a spring break course.
Introduction to this Workshop
Introductory presentation
Cutting-Edge Research
Dr. Hemming’s slideshow is available at
https://www.dropbox.com/s/67ob9b5mny641ji/SRH%20for%20earth2class.pptx
One of the most dynamic Quaternary landscapes in the world, the Mono Basin is renowned for displaying conspicuous evidence of past fluctuations in lake level, of past glaciations, and of frequently-recurring volcanism. The record of these dynamic elements is expressed not only geomorphically, but also in stratigraphic sections exposed along the faces of wave-cut cliffs, and along the channel walls of deeply incised streams. Such exposures, up to several km in length, reveal as much as 75 vertical meters of alternating glacio-fluvial and glacio-lacustrine sediments intercalated with 19-plus locally erupted volcanic ashes. This sequence of glacially- and volcanically-derived sediments deposited in a high standing, though widely fluctuating, lake constitutes the Wilson Creek Formation. Its upper half is the regional lacustrine expression of Marine Oxygen Isotope Stage 2 (MIS-2), coeval with the Tioga stage of glaciation in the eastern Sierra Nevada.
The presence of these dynamic elements, all operating in close proximity to one another (the Tioga-age glaciers advanced to within one km of the lake’s highest MIS-2 level, and volcanoes that produced the Wilson Creek-age tephras erupted within a few km of, and in at least one case beneath, the lake) makes the Mono Basin an ideal setting for developing a precise lake-fluctuation history for deglacial time. Moreover, the Mono Basin is a compact (1800 km2), highly accessible watershed that is free of factors that confound hydroclimatic modeling: throughout Wilson Creek time the lake neither desiccated nor overflowed; it has not to any substantial degree been deprived of inflow due to stream piracy; and its primary influent streams do not pass through extensive, water-consumptive alluvial basins before reaching the lake. These factors make first-order paleo-hydroclimatic modeling of Mono Lake a relatively simple task.
We believe we are now in a position to make significant headway to overcome the dating problems which have previously stymied a full reconstruction, and to develop a deglacial lake-fluctuation/hydroclimatic chronology record which, when applied to a refined curve of lake transgressions and regressions, has the potential to serve as a standard for climate change in the western United States. This multi-chronometer-based record will enable us to make comparisons to index chronologies from regions far distant (e.g. the Greenland and Antarctic ice cores as well as from localities nearby (e.g. the fluctuation records from Lakes Lahontan, Bonneville, and Owens) and the recently generated suites of surface-exposure dates on terminal and recessional moraines from canyons in and immediately adjacent to the Mono Basin.
NEWS STORY: “CLIMATE CHANGE AND THE FUTURE OF MONO LAKE“ (12/12/13)
Classroom Resources
Earth and Environmental Sciences V1900y “Geological Excursion to the Eastern Sierra, California”
“Mark Twain’s Visit to Mono Lake: An Example of ‘Reading in the Science Classroom’ ” pdf ppt
Integrating Educational Technologies
General suggestions: Integrating Educational Technologies into Your Classrooms
Your assignment: Using Image Galleries
The Internet has created countless collections of images that can be used by teachers and students for educational projects. This assignment focuses on best practices for utilizing image galleries.
1) What characteristics make image galleries effective as a classroom teaching tool?
2) When should image galleries be used for full-class instruction, and when should they be used for small groups or individual projects?
3) Describe strategies to locate suitable image galleries for your classes.
and
4) Design a lesson plan that incorporates at least one image gallery.
E2C Follow-up:
You may send your model lesson and other responses to this “assignment” to michael@earth2class.org. If suitable, we will post your work in the E2C lesson plans and/or add them to this section of the Workshop website.
Multimedia
Teacher Tube: Mono Lake, an Amazing Place
NEWS STORY: “CLIMATE CHANGE AND THE FUTURE OF MONO LAKE“ (12/12/13)