Why is there no evidence of a global flood in Ice Core series?

Ice cores from Greenland have been dated back more than 40,000 years by counting annual layers. A worldwide flood would be expected to leave a layer of sediments, noticeable changes in salinity and oxygen isotope ratios, fractures from buoyancy and thermal stresses, a hiatus in trapped air bubbles, and probably other evidence. Why doesn't such evidence show up?