Arctic 21: Understanding the history of the Greenland Ice Sheet

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  • เผยแพร่เมื่อ 25 พ.ย. 2024

ความคิดเห็น • 8

  • @compostjohn
    @compostjohn 2 หลายเดือนก่อน +2

    Fascinating, thank you.

  • @bradriney919
    @bradriney919 2 หลายเดือนก่อน

    Thank you for a wonderful talk on the paleo climate of Greenland. You might be interested in in the MIS 5e exposures produced by heavy equipment on large construction sites in the coastal river valleys in north western San Diego County that record a very rapid sea level rise between 130,000 to 120,000 years before present. One particular site, the "Wanis View Estates" project, records 20 meters or 60' of sea level rise in a tributary canyon of the main San Luis Rey river valley or "SLRV" Here, mass grading produced 3 main exposures totaling around 1000 meters laterally north south. As sea level rose, the main SLRV drainage filled with over a hundred feet of fluvial deposits in response to the rise in world wide sea levels, damming a tributary canyon with ever thickening deposits, producing a lake that simply migrated up stream in response to the thickening of the sediment package due to sea level rise. Sand deltas with 2 meter high fore sets entered the lake from the south, marching north across the lacustrine mud, each stopping a short distance into the lake. This produce a stacked sequence of sand deltas in response to sea level rise. As the SLRV sediment dam thickened to the south, a new sand delta would overshoot the older one never able to fill the lake indicating a sea level rise faster than the rate of sedimentation. The lake would simply shift higher in elevation and further up stream with each sand delta. Once sea level rise slowed, sedimentation would finally fill in the lake with flood plain overbank fine grained deposits. Today the southernmost basal contact of the lowest sand delta today is 46' MSL in elevation while the highest basal contact is at an elevation 108' MSL at the northern most exposure. Coastal San Diego preserves many transgressive estuarine valley fills covering a large portion of the Pleistocene. We have 21' to go to beat this old MIS 5e record plus an added anthropogenic cause to make things even more interesting!

  • @robertforsythe3280
    @robertforsythe3280 2 หลายเดือนก่อน +3

    Loss of Greenland ice will match while the ice loss in the Antarctic will be ten fold. A very dynamic overturn of waterfront property. Here today and gone tomorrow.

  • @andymccracken4046
    @andymccracken4046 2 หลายเดือนก่อน

    Thanks, very interesting lecture.

  • @al2207
    @al2207 2 หลายเดือนก่อน

    sea rise by 7 meters

  • @TheShootist
    @TheShootist 2 หลายเดือนก่อน +2

    Greenland was ice free in the last interglacial.
    carry on.

    • @Jc-ms5vv
      @Jc-ms5vv 2 หลายเดือนก่อน

      😂😂😂 mass extinctions have happened in the past, nothing to worry anout

  • @andywomack3414
    @andywomack3414 2 หลายเดือนก่อน

    My picture of a map of Greenland 400k years ago would have an inland sea with rocky perimeter islands.
    How fast isostatic rebound? Could that lift the center of Greenland above sea-level when the ice was gone?
    Any plans for more ice-cores?
    The first Sumerian cities began to develop about the same time sea-level rise slowed enough for stable coastlines to develop.
    Stable coastlines are an essential need for our civilization.