Earth’s crust is divided into different plates and the continents reside on these plates. Continuous movement of these plates brings all the continents to one place as a Supercontinent. Collision of these continents creates folded mountains in the interior of the Supercontinent. As the mountains grow bigger, the weight of these mountains acts as a break to the movement of the plates as the undelivered load at the end of the conveyor belt accumulates and finally stops the movement of the belt. When the weight of the folded mountains grows sufficient enough to stop the movement of the plates, magma within the ridges seals all the plates creating a single plate covering all the surface of the Earth causing a “Tectonic Pause”. This loss of heat source in the oceans cools the ocean waters and triggers a global ice age. If the ice covers all the surface of the Earth it is a snowball Earth event.
This removal of water from the oceans and depositing on the continental crust as the ice sheets drastically reduces the sea level and exposes the continental shelves. Frozen ocean and the exposed continental shelves causes a major mass extinction of the marine life. Hot Spots are the only vent for the dissipation of heat within the mantle and will be continuously active in the Supercontinental period. Hot spots on the oceanic crust emerges onto the surface on the lowered sea level. Hot spots on the continental and the oceanic crust harbor the life in the Supercontinental period. Pre Supercontinental period will face a major mass extinction in the global ice age and the post Supercontinental period will have an explosion in the evolution of the surviving species.
After a brief period, the stationary and heavier Supercontinent breaks up by creating new ridges. Oceanic crust at the continental shelves breaks to form the trenches. These newly created ridges and trenches, reverses the movement of the plates. The open ridges on the continent spews the green house gases and ejects the magma onto the ice sheets, melting them rapidly in a severe global warming. With the raising sea level, water seeps into the open ridges further heating and circulating the oceanic waters. Accumulation of green house gases and the heat from the new ridges melts the ice exiting the global ice age.
Ridges are the major source of heat supply into the oceans. Speed of the Tectonic plates dynamically changes as they grow or shrink in size. Total heat supply or the total magma outflow into the ocean depends upon the combined length of the ridges and the speed of the plates. Increase in the speed of the plates or formation of a new ridge adds more magma into the ocean waters and causes a global warming. Hot ocean currents melts the ice caps at the poles and increases the sea level. Steady subduction of the oceanic plate maintains a constant temperature on the planet. Continental collision reduces the speed of the subducting plate and releases less magma into the oceans, cooling the ocean waters. Cold ocean water starts to freeze from the poles and reduces the sea level in an ice age. Subsequent global warming and ice age together forms a distinct sedimentary layer on the continental crust.
This theory explains the formation of the first Supercontinent and the beginning of the plate tectonics on the Earth. This theory also resolves the two known snowball Earth events and predicts three more to be in between these known events with the Supercontinental formations. Ice age on the Gondwana land around 200 million years ago was the recent Supercontinental global ice age. In this period, the frozen ocean and the exposed continental shelves with the global ice age caused the Permian mass extinction. Breakup of the Pangaea thawed the environment with a global warming and started the Mesozoic era. Extinction of the dinosaurs around 65 million years ago coincides with the formation of a new ridge when the Indian plate was separated from the Gondwana. Subsequent global warming increased the sea level and flooded the continents starting the Tertiary sedimentary layer. Collision of the Indian plate with Asia reduced the rate of subduction and released less magma into the oceans and caused the recent ice age. Decreased sea level solidified the sedimentary layer and created a new boundary for the new deposits. In between the breakup and collision of the Indian plate, there was a steady phase or constant rate of sea floor spreading for about 60 million years in the whole Tertiary period while the oceanic crust was steadily subducted under the Asia.
This theory not only proposes a Supercontinental “Tectonic pause” with a global ice age but also combines the ice ages, global warming, sea level changes and formation of sedimentary layers with the Plate Tectonics and creates a unified view of this dynamic Earth. This proves that all the phenomena on the Earth works as a system not as independent entities. Plate tectonics not only effects the climate in a broader level but also changes the climate even at a small scale. Earthquakes are the sudden movement of the plates and sometimes may release excess amount of magma at the ridges. This causes the ocean to over heat at a particular point and may effect the local climate. In future weather forecasting, we may have to include another column for the rate of sea floor spreading. Present thawing may be the result of increase in subduction rate at any of the existing trenches or formation of any new ridge in recent times.
Complete theory is available at: http://www.geocities.com/karunakarm/TectonicPause.html
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