Source of Meltwater Pulse 1A
Hello! For this post, I’m going to be talking about a glacial period, known as Pulse-1a. This was a period in geologic history that occurred around 21,000-14,600 years ago. This time period was originally discovered through coral records back in 1989 on the island of Barbados in the Caribbean.
This time period is so unique because in a very short frame of time, sea levels rose about 120 meters, about 4 meters per century, which is a very rare occurrence. Since then, many scientists have debated how global sea level could have risen to such lengths.
The main theory is that this meltwater came from retreating ice sheets. During this time, temperatures were rising. Prior to, a portion of the world had been covered by ice sheets, a well known ice sheet being the Laurentide ice sheet, which covered Canada completely and parts of America. Global temperatures were rising, particularly around 14,700 years ago, known as the Bolling-Allerod period, a time of abrupt warming. Not too long before, a Heinrick event occurred, 16,000-17,000 years ago, which also caused global temperatures to spike. This caused ice sheets to melt, particularly the Laurentide ice sheet, which is what caused such a great rise in sea levels.
However, there are some problems with this theory. The Bolling-Allerod period was more at the end of 1A, so it may not account for the time before when global sea levels were still rising. The same goes for the Heinrich event. There are a few other prominent theories, with some scientists believing that the source could have come from the Southern Hemisphere, instead of just the Northern Hemisphere, from the Laurentide ice sheet. Some also believe that the meltwater may have come from the Antarctic region, using glacial isostatic adjustment. However, there is still not enough evidence to fully prove any theory. Due to constraints with geologic time frames, no method currently has been enough to fully support these theories.
Various methods have been used to find the source of the meltwater. Geologists have derived mathematical equations to find relative sea levels to find the source. Many have also used geophysical modeling to reconstruct past sea levels of 1a. However, more research is needed to conclude what the true source is. However, there is still not enough evidence to fully prove any theory. Due to how limited the scientific methods are, there's still research being done on this event today, and many geologists are still trying to figure out the source of meltwater. Only time will tell what the true cause is.
