The ecosystem of Mexico’s Yucatan Peninsula is the result of a combination of geologic events, climatic change and the impact of a large asteroid millions of years ago. While scientists have been able to gather a sizable amount of data on its formation, the geologic history of the Yucatan Platform is difficult to establish due to the lack of investigatory geologic excavations, the little amount of exposed rock strata, and the relative inaccessibility of the inland terrain due to the thick and vast jungles.
So What Do We Know?
In a quest for potential oil reserves in the early 1970's, PEMEX (Petroleos Mexicanos) drilled 10 exploratory wells in the Yucatan Peninsula. Most of these wells were drilled in the state of Yucatan and were often in excess of 2000 meters (1.2 miles). The data collected from these drill sites indicated that the Yucatan Peninsula is in fact a great limestone platform that gently slants into the sea. As you travel south on the Peninsula you will encounter low, sloping hills and you must travel far offshore before you reach deep water.
As the Yucatan Peninsula is made up primarily of limestone (which is soluble in water), the underground bedrock is honeycombed with multitudes of caves and sinkholes (which we know
as cenotes).
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Because the limestone has so many holes in it, there are no major above-ground rivers throughout the entire Yucatan Peninsula; all of the water runs underground! In many places in the Yucatan you don’t have to dig very far to hit groundwater, 30-50 feet, and in some areas closer to the coast, you only have to go down about 5 feet!
Glaciers and the Yucatan Peninsula
The last Ice Age had an important impact on the Yucatan Peninsula; mainly due to the extreme drop in sea levels at the time. During the last Ice Age, water levels of the world's oceans were on average 100 meters or 328 feet lower than their present day levels; this would mean that all of the underground caves and cenotes that are presently filled with water would have been bone dry. When the Ice Age came to a close some 10,000 to 12,000 years ago, the climate of the planet warmed up, the glaciers receded and the caves flooded. This flooding created a myriad of different underground rivers. Scientists have varying views on how fast the water levels rose back up, but most agree that it reached its current level around 1,000 years ago. Carbon dating of artifacts found in some area caves shows them to be 7,000 years old.
Andrew Synsyhyn
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