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Walter Dean , USGS, Denver, Colorado, USA

History of sedimentation in Bear Lake, Utah and Idaho, USA, over the last 240,000 years: links to Pacific climate. Walter Dean , USGS, Denver, Colorado, USA. Elev. = 1845 m. Elev.= 1800 m. GLACIAL THROUGH HOLOCENE CHANGES IN CARBONATE DEPOSITION. 1996 Kullenberg Piston Cores.

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Walter Dean , USGS, Denver, Colorado, USA

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  1. History of sedimentation in Bear Lake, Utah and Idaho, USA, over the last 240,000 years: links to Pacific climate Walter Dean, USGS, Denver, Colorado, USA

  2. Elev. = 1845 m Elev.= 1800 m

  3. GLACIAL THROUGH HOLOCENE CHANGES IN CARBONATE DEPOSITION 1996 Kullenberg Piston Cores

  4. O, C, and Sr isotopes in BL96-2 aragonite qtz. Glacial-age red, calcareous clay Average Bear River sediment 80% quartz, 6% dolomite

  5. In the US aragonite usually occurs in saline prairie lakes Aragonite does not form in large, cold, deep, oligotrophic, high altitude, north temperate lakes fed by snowmelt!

  6. CARBONATE DEPOSITION DURING THE LAST TWO GLACIAL-INTERGLACIAL CYCES The 2000 GLAD800 cores

  7. GLAD800 (aka R/V Kerry Kelts) Bear Lake, Utah

  8. Warm/dry evaporation BL00-1

  9. Santa Barbara Basin

  10. D/O 14 (Dean et al., 2006)

  11. Greenland Ice

  12. Depth (m)

  13. Low product. High product. high runoff

  14. El Nino

  15. ENSO

  16. Hadley Circulation

  17. CONCLUSIONS From the sediment record in Bear Lake it appears that the high-carbonate, aragonitic interglacial intervals in BL00-1 coincide with warm, dry continental climates, warm Pacific SSTs, and increased coastal upwelling recorded in cores from the OMZ off California and Mexico. This implies that the Subtropical High that drives the California Current Upwelling system today during the summer was a more permanent feature of the North Pacific during interglacials. During the LGI and other glacials the Aleutian Low, presently dominant during the winter, was a more permanent feature of the North Pacific, producing storms and precipitation that increased the levels of Lakes Lahontan and Bonneville, and increased the flow of the Bear River.

  18. IMPLICATIONS It is likely that the Atlantic and Pacific were linked through the atmosphere. Warmer interstadials would have strengthened Hadley and Walker circulations, which, in turn would have strengthened the subtropical high-pressure systems in both the North Pacific and North Atlantic, producing increased upwelling along the western margin of North America and increased precipitation over the Cariaco Basin. Increased Hadley and Walker circulations would have increased the amount of water vapor in the atmosphere, which potentially could have had a large effect on the global climate system.

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