Roni Essex
Freediver, Spearo, Creator
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Roni Essex
Freediver, Spearo, Creator
Looking for a spearfishing trip to remember? The Gulf Of Mexico provides an abundance of fish for the traveling spearo. How much do you know about the Gulf though? Here are a few interesting facts about its birth.
Destination - the early Jurassic period! As we fly back in time 200 million years, the continents were changing shape and positions. As the tectonic plates that form the earth's surface are on the move, we will arrive just in time to witness the birth of the Gulf of Mexico. During that era, Africa was drifting eastward, saying goodbye to South America, which was moving towards the south. As the continents moved apart, the ocean water entered the space they had occupied and the Gulf of Mexico was born.
The newborn gulf was shallow and its waters were warm. Those conditions, along with changes in sea level over the next 70 million years resulted in extensive evaporation. The sun's warmth turned gulf waters into water vapor, leaving behind huge salt deposits that covered large areas of land, creating landscapes that would have looked something like today's Bonneville Salt Flats. During the Cretaceous period, higher seas covered the gulf region for the next 70 million years. As aquatic plants and marine creatures lived and died, their remains accumulated on the sea floor, and coral reefs grew and gradually compressed into dense layers of limestone, the Gulf continued to expand and its waters deepen. As this happened a different kind of limestone formed from the accumulation of microorganisms on the seafloor, a material widely used for sidewalk art and on school blackboards - chalk. After the cretaceous period, sea levels dropped and the Mississippi river began flowing toward the Gulf. On its downhill journey across the continent, the river picked up and carried massive amounts of sand, silt, and clay, to create a growing delta made of material from the far reaches of the north American continent.
Today tall buildings in New Orleans sit on top of this massive accumulation of Mississippi river sediment and far below them the layers of chalk limestone and salt. The many layers of sand silt and clay are as much as six miles deep and form a foundation for today's Mississippi river delta. Their unimaginable weight has produced some extraordinary effects. Under extreme pressure and with heat from the earth's core, long-dead sea creatures and aquatic plants were gradually transformed into oil and natural gas. The tremendous weight and pressure also affected the deeply buried salt layer which is less dense than the material above it. Behaving much like liquids do when placed under great pressure, in places salt would rise upward in formations called salt domes. As the domes made their way toward the surface, fault lines formed and oil and gas accumulated in pockets formed along the fault lines. These reservoirs of oil and gas are tapped today by wells located throughout the delta. Underground movements of salt still happen today. Sometimes they produce spectacular results like suddenly appearing sinkholes, big enough to swallow large trees. Many of the processes that gave birth to the Gulf and built the foundation for today's river delta are still at work.