When Glaciers Ruled the World! Formation of the Boston Harbor Islands

Millions and millions of years ago glaciers ruled the world. Glaciers are ginormous blocks of ice that are always moving. In fact, glaciers formed one of my favorite places in the world, Boston, along with many of the Boston harbor islands! It all started on a cold winter day…

Alfonso, the largest glacier of them all, was on a stroll in the mountains. Alfonso was a bit of a bully to the smaller rocks because after all, he was over a mile tall. As he slid over rocks the impact was so great that he would form scratches in the rocks called abrasion. As the rocks cried in pain Alfonso dropped pebbles, sand and dirt on them called till. Till which is also called deposition started to form beaches.

The rocks on a beach aren’t perfect due to erosion by wind, which can make small sand particles blow around ( loess ), erosion by water which can form crevices and when water fills them (* rills ) and erosion by waves which, like any other type of erosion, causes the rocks to crack and fall apart. *When rills merge they form larger rills known as gullies. The rocks on a beach aren’t perfect due to erosion by wind, which can make small sand particles blow around ( loess ), erosion by water which can form crevices and when water fills them (* rills ) and erosion by waves which, like any other type of erosion, causes the rocks to crack and fall apart. *When rills merge they form larger rills known as gullies.

All of these rocks can form spits and longshore drifts which are small pieces of land attached to a larger piece of land. An example of this is cape cod.

Even though Alfonso wasn’t the fastest glacier he was always moving. He would push against dirt and then when he got tired he would retreat. The dirt that was pushed would cause moraines to form.

Another one of Alfonso’s hobbies was forming kettle ponds. When pieces of ice would break of him they would form pits in the ground. When the ice melted it would leave water in its place. These were known as kettle ponds.

 Then, after a long day of picking up rocks, pebbles and boulders, Alfonso came to a stop when he saw this huge rock ( erratic ) right in the middle of his path! Alfonso wondered who ever could have deposited this boulder so he looked around only to find the prettiest glacier he had ever seen...Gertrude!

 Alfonso approached Gertrude, tapped her on the shoulder and asked if it was her who had deposited that erratic. She looked up at him mesmerized by his glory. She nodded her head slowly and also admitted to being the one who put the sand particles in the streams ( runoff ). Gertrude apologized and Alfonso, being the kind and noble gentlemen that he is, accepted her apology.

10  Together they formed drumlins which are pretty much just huge piles of till. When these drumlins got surrounded by water they were known as drowned drumlins which are what many of the Boston Harbor Islands are including...Georges Island! Gertrude and Alfonso lived happily ever after and as for there baby’s (the boston harbor islands) well, lets just say they are grown up.