14 DAY TRIAL // This new NASA image is centered on a series of roughly parallel lakes in upstate New York, called the Finger Lakes. This natural-color view was collected by the Moderate-resolution Imaging Spectroradiometer (MODIS) instrument on the Terra satellite earlier this year, on May 6.
NASA scientists say that the water itself is color-coded dark blue, while the orchards and farms on the north banks of the lakes appear in beige. The forests scattered around this location appear in brown, since the image was taken before full forest foliage could develop. The green in this photo codes grass and low-lying types of vegetation.
Geologists say that these lakes started out as streams that used to flow north. Their paths took them through a series of deep, V-shaped valleys, which were relatively steep until 2 million years ago. At that time, the Pleistocene glaciation began, and started covering the streams up with glaciers. As the ice flowed, it carved smoother, wider valleys, via a process called glacial scouring.
Some 10,000 years ago, when the ices retreated for good, they left behind recessional moraines, which are piles of various types of debris. These materials blocked the path of the streams, and forced water into the newly formed, deep U-shaped valleys, forming the Finger Lakes.