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Dr. Randall Parkinson and Dr. John Meeder, researchers in the Sea Level Solutions Center and Southeast Environmental Research Center within the FIU Institute of Water and Environment, may have pinpointed the beginning of a new epoch in the Geologic Time Scale.

Scientists use the Geologic Time Scale to identify the time periods that have come and gone throughout Earth’s existence. Each event is defined by a change in rock or soil layers. Geologists call these layers “stratum” and the study of stratum and their relationship to the Geologic Time Scale is termed “stratigraphy”.

Today, according to the Geological Society of America, we live in the Holocene epoch, which began over eleven thousand years ago. However, some scientists disagree with this claim. Instead, they believe the Holocene has already given way to a new epoch, the Anthropocene (“anthro” meaning man and “cene” meaning new). They argue that mankind has already done so much to alter our earth and environment (through mass plant and animal extinctions, extensive environmental pollution, and changes in our atmosphere), and that this can be cause for a new epoch in the Geologic Time Scale. The argument continues however, because although humans have changed the earth on the outside, there needs to be clear evidence of change to the inside of the planet for a new epoch to be accepted.

Parkinson and Meeder’s study may have identified the changes in strata to support this move to the Anthropocene. They specify exactly when, from a geological standpoint, humans began leaving their mark on the inside of the planet.

Landscape change in SE Saline Everglades based upon analysis of 1938, 1952, 1968, and 2009 aerial photography.

Parkinson and Meeder studied the changes in rock and soil layers in the SE Saline Everglades due to historic sea level rise. The region’s low elevation makes for an ideal study site, as the effects of sea-level rise are more clearly detected. The team used sediment core samples and historic aerial photography to see how this area has adapted to sea level rise over a number of decades. What they found was that the physical and biological changes of the marshes and mangrove forests in the SE Saline Everglades reflect the effects of accelerating sea level rise. This means that when the rate of sea level rise was slower a few decades ago, coastal zones could still keep pace with them. Now that the rate of sea level rise is quicker, the capacity for coastal zones to keep pace have been surpassed, resulting in increased mangrove habitats (versus freshwater marshes) and increased flooding. Sedimentary changes in the area as a result of accelerating sea level rise (like the thinning of peat and marl deposits) contributed to this change in coastal ecosystems.

Parkinson and Meeder are suggesting to link these changes in strata in this area to the historic changing rates of sea level rise. These observed changes have been seen worldwide and should be considered in defining the lower boundary of the proposed Anthropocene epoch.

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