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Evolution of Texas climate

Evolution of Texas climate. Richard Casteel Jackson School of Geosciences 11-24-09. Outline. Modern day Texas climate Climate change - varying resolutions Geologic indicators Soil indicators Fossils and isotopes Tree ring data Current research. Modern Texas climate. Hot, dry summers

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Evolution of Texas climate

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  1. Evolution of Texas climate Richard Casteel Jackson School of Geosciences 11-24-09

  2. Outline • Modern day Texas climate • Climate change - varying resolutions • Geologic indicators • Soil indicators • Fossils and isotopes • Tree ring data • Current research

  3. Modern Texas climate • Hot, dry summers • Mild, dry winters • Wet springs/falls • High rate of PET • Hot spot for climate change?

  4. Geologic map of Texas

  5. Geologic Map of Texas

  6. Soil map of Texas • Dominated by: • Thin, rocky soils • Thicker in past • Upland soils • Cave deposits

  7. Soil degradation - Sr isotopes • Carbon dated soil deposits Hall’s Cave • Gopher/vole tooth enamel • Diet • Hackberry seed fossils • Root position (Cooke et al, 2003)

  8. Paleoclimate inferred from fossils and isotopes Last glacial maximum

  9. 24-14 ka. • Cooler and wetter • Faunal evidence • Pollen data • Alluvium δ13C values of -21‰ • C3 plant abundance 62 - 72 73 - 78 79 - 82 83 - 86 87 - 94

  10. 6-2 ka. Warm/ dry period

  11. 6-2 ka. • δ13C values • Snail shells (Goodfriend and Ellis, 2000) • Alluvium and soil (Nordt et al, 1994) • More positive values = higher abundance C4 plants

  12. 1698-1980 • Post oak chronology • Annual resolution • Calibrated with modern record (Stahle and Cleaveland, 1998)

  13. June PDSI derived from tree rings

  14. Drought of the 1950s http://www.ncdc.noaa.gov/paleo/pdsidata.html

  15. Drought of the late 1850s-1860s http://www.ncdc.noaa.gov/paleo/pdsidata.html

  16. Drought of the 1770s http://www.ncdc.noaa.gov/paleo/pdsidata.html

  17. Current research • Extend the high resolution climate record • Past drought for water planning • Bald cypress trees • Preliminary results http://www.news8austin.com/content/your_news/default.asp?ArID=255153

  18. QUESTIONS?

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