How Sediment Layers Reveal Earth’s Ancient Climate Cycles

Ribbons of blue — the modern Raritan and Neshanic rivers — slice across a landscape that’s key to understanding Earth’s deep-time climate cycles. This colorized elevation map captures a 40-square-mile chunk of an ancient lakebed in central New Jersey. The purple and gray stripes represent layers of sediment that were deposited horizontally in a huge lake, then tilted and beveled off by erosion so the layers could be seen in cross section from above.