Duration
The length of time taken for the extinction to occur is a controversial issue, because some theories about the extinction's causes require a rapid extinction over a relatively short period (from a few years to a few thousand years) while others require longer periods. The issue is difficult to resolve because of the Signor–Lipps effect; that is, the fossil record is so incomplete that most extinct species probably died out long after the most recent fossil that has been found. Scientists have also found very few continuous beds of fossil-bearing rock which cover a time range from several million years before the K–Pg extinction to a few million years after it.
Read more about this topic: Cretaceous–Paleogene Extinction Event
Famous quotes containing the word duration:
“What matters it that man should have a little more knowledge of the universe? If he has it, he gets little higher. Is he not always infinitely removed from the end, and is not the duration of our life equally removed from eternity, even if it lasts ten years longer?”
—Blaise Pascal (1623–1662)
“Higher than the question of our duration is the question of our deserving. Immortality will come to such as are fit for it, and he would be a great soul in future must be a great soul now.”
—Ralph Waldo Emerson (1803–1882)
“This pond never breaks up so soon as the others in this neighborhood, on account both of its greater depth and its having no stream passing through it to melt or wear away the ice.... It indicates better than any water hereabouts the absolute progress of the season, being least affected by transient changes of temperature. A severe cold of a few days’ duration in March may very much retard the opening of the former ponds, while the temperature of Walden increases almost uninterruptedly.”
—Henry David Thoreau (1817–1862)