CAS ES 351 Chapter Notes - Chapter 15: Laurentide Ice Sheet, Ice Rafting, Atlantic Ocean
26 Apr 2019
School
Department
Course
Professor
Document Summary
Greenland ice cores show two signals of interest: Local air temp is the primary control for the signals preserved in ice sheets. Dansgaard-oeschger oscillations: sawtoothed oscillations of fast warming and slow cooling during a cold interval every 1,000 to 9,000s years in length (greenland ice core) ~oscillations are between high and low dust and 18o concentrations. ~fluctuations toward more negative 18o values (glacial, in ice) is matched by an increase in dust. ~these changes happen more often in glacial periods. Heinrich events: episodes of unusually abundant ice rafting during short terms of 7,000 to. ~times of cold air (more negative 18o values in greenland ice) correlate with times of cold ocean temps (larger percentages of polar species in nearby ocean) ~happened during glacial events where icebergs break off from ice sheets and cause major ice-rafted debris to be added to seafloor. ~most of the ice rafted debris came from laurentide ice sheet.
