Cape Cod, the one of a kind landmass deposited by a giant, continental glacier named the Laurentide Ice Sheet, is being rapidly destroyed by the winds, waves, and currents of its own world famous beaches. Cape Cod's beaches are diminishing in size do to these three main forces of erosion. It is very possible that in a few hundreds of thousands of years, to a couple of millions of years, that Cape Cod will simply be a giant mass of submerged sediments. Humans will slowly be able to observe these small changes to the Cape over hundreds and maybe even thousands of years. Eventually we will notice gargantuan changes in Cape Cod's size and shape.
Cape Cod was created by the Laurentide Ice Sheet, which was created during the end of the Pleistocene Epoch, otherwise know as the “Ice Age”. Although the “Ice Age” began about two million years ago, the Laurentide Ice Sheet began its creation about ninety-five thousand years ago, and finished its creation as a glacier about twenty-five thousand years ago. It started to scrape across Cape Cod, Martha's Vineyard, and Nantucket about twenty-three thousand years ago. As it was fluctuating in its path of coming and going, it deposited gravel on the continental shelf, and created the moraines and outwash plains on the Cape and Islands. As it starts to retreat, it is defined into three distinct lobes. These three lobes are the single most determining factor in the formation of Cape Cod. By eighteen thousand years ago, the Laurentide Ice Sheet had retreated to the Gulf of Maine. By fifteen thousand years ago, the Laurentide Ice Sheet retreats out of all of New England.
The three ice lobes responsible for the creation of Cape Cod is the Buzzards Bay Lobe (western lobe), Cape Cod Bay Lobe (northern lobe), and South Channel Lobe (eastern lobe). The arm shape that we associate with Cape Cod was created by these ice lobes depositing sediment, glacial till, into this particular shape. As these three lobes melted away and receded, Martha's Vineyard and Nantucket were first exposed, and followed by the exposure of Cape Cod. The melting away of these lobes made the water level in Nantucket Sound rise severely, first isolating Martha's Vineyard and Nantucket, and then Cape Cod. The ice lobes left behind chunks of ice which later formed into kettle ponds and kettle holes. They also left behind extremely sandy soil, which erodes very easily. These three ice lobes are also the reason for the moraines and outwash plain that Cape Cod is now riddled with due to the back and for movement of them.
Glacial till is any deposit of the rock fragments brought by ice and later exposed by the melting of that ice. There are two kinds, basal till, till that is rich in clay and densely compact, and residual till, till that is soft, sandy, and riddled with boulders. Cape cod is almost entirely made up of residual till. None of the sediment found on Cape Cod is native, it all came from a different location where it was picked up by the glacier and then deposited where it is today. Because of Cape Cod's sandy soil, there are not any flood problems. Any heavy rainfall would just run straight though the sand into the groundwater.
The sandwich moraine was created by these ice lobes as well. It passes through Sandwich, Barnstable, Dennis-Yarmouth, and Brewster. It extends as far north as the shore of the Cape Cod Bay. I have bike up and down this moraine many time, it is quite fun on the ride down, but it is an extremely tough ride back up. I live on this moraine, so I do not pay much attention to it. It actually used to extend much further east, but the erosion from wind, waves, and currents weathered much of it away. It is by far the largest moraine on Cape Cod.
In addition to the moraines that the three ice lobes created, there were outwash plains created as well. They are almost right next to a moraine, as they are on Cape Cod. There is the giant outwash plain right next to the Sandwich moraine. I have biked there as well, and it is a much easier, flat ride. They often contain kettle pond and kettle holes. Because they are so flat, they are an ideal place to build homes, complexes, sporting fields, farms, and roads.
Kettle pond are created by blocks of ice that have fallen from the large glacial body, buried under sand, and slowly melted into a large body of water. Because cape cod has such sandy soil, the water usually distributed equally, and made circular ponds. In addition to this, they almost always have perfectly clear water, unless of course they have been polluted. The reason for this is because they are isolated from any other water supplies other than rain. Rivers and streams carry dirty water into ponds, but because there are not rivers and streams flowing into the kettle ponds on cape Cod, the water stays perfectly clear. Some of these kettle ponds that I like to fish in are Peter's Pond, Waikbe Pond, snake Pond, and Long Pond.
