The influence of Tethyan evolution on changes of the Earth’s past environment

Abstract

Understanding changes in Earth’s past can provide valuable insights into prediction of its future. An example is the interactions between the internal and external spheres of Earth. The cyclical northward breakup-drift of Gondwana, driven by the opening and closure of Proto-, Paleo-, and Neo-Tethyan oceans, facilitated the transfer of landmasses from the southern to the northern hemisphere, traversing the tropic region. We have observed a compelling correlation between episodic increases in landmass area within the tropic regions (those lying at less than 20° latitude) and a subsequent temperature decrease during the three major glacial periods in the last 500 million years. This phenomenon can be attributed to low latitude regions receiving more solar energy influx on Earth’s surface than high latitude areas. In addition, an increase of landmass in tropic regions (low latitude) attenuates the net energy absorption by the Earth’s surface, consequently impeding the conduction and convection of absorbed energy toward the poles. The result is a decrease in global surface temperature. The tropic regions, benefiting from abundant sunlight, create an ideal environment for the proliferation of marine plankton species. These species are important in the generation of organic-rich sediment. Massive biological debris is therefore deposited on continental margins when a continent drifts across the tropic region. This creates favorable conditions for future hydrocarbon and reservoir formation. Northward subduction of organic-rich sediments during the closure of the Tethyan oceans results in the generation of mafic arc magmas with low oxygen fugacity. This chemical environment helps the mineralization of reduced-type ore deposits such as tungsten, tin, and lithium. Subducted-driven plate tectonics in the Tethys realm changes the distribution of oceans and landmass, subsequently affecting the balance and distribution of solar energy across Earth’s surface. These changes trigger consequential environmental shifts which in turn, impact the composition of rock and mineral along the Eurasian margin due to subduction. Consequently, the Tethyan realm and its history is an ideal natural laboratory for comprehending the processes and changes of the entire Earth’s system.