Updated Map Of Earth’s Tectonic Plates

In Context

• Recently researchers from the University of Adelaide, Australia, have carried out a new study that includes an updated map of the earth’s tectonic plates.
  • The paper “New maps of global geological provinces and tectonic plates” is published in the journal Earth-Science Reviews.

About

• The new model for tectonic plates better explains the spatial distribution of 90 percent of earthquakes and 80 percent of volcanoes from the past two million years.
  • Existing models only capture 65 percent of earthquakes.
• The map includes several new microplates to the existing tectonic plate model like the 
  • Macquarie microplate which sits south of Tasmania and 
  • The Capricorn microplate which separates the Indian and Australian plates.
• Researchers found that plate boundary zones account for nearly 16% of the Earth’s crust and an even higher proportion, 27%, of continents.
• The new model now includes all the deformation zones north of India as the plate bulldozes its way into Eurasia.

Significance

• The map will help in forming a better understanding of natural hazards like earthquakes and volcanoes.
• The province model can be used for further exploration of minerals and the orogeny model.
• The orogeny model helps to understand the evolution of geodynamic systems 
• It will help in better understanding of the evolution of the earth.

Plate Tectonic Theory/Plate Tectonic

• This concept was formulated in the 1960s by Alfred Wegener. 
• According to the theory, Earth has a rigid outer layer, known as the lithosphere, which is typically about 100 km (60 miles) thick and overlies a plastic (moldable, partially molten) layer called the asthenosphere. 
• The lithosphere is broken up into:
  • seven very large continental- and ocean-sized plates,
  • six or seven medium-sized regional plates, and 
  • several small plates. 
• These plates move relative to each other.
  • They typically move at rates of 5 to 10 cm (2 to 4 inches) per year, and interact along their boundaries.
  • They converge, diverge, or slip past one another. 
  • Mountain formation:
    • Plate motions cause mountains to rise where plates push together or converge. 
  • Ocean formation:
    • Continents fracture and oceans are formed where plates pull apart or diverge.
• The continents are embedded in the plates and drift passively with them, which over millions of years results in significant changes in Earth’s geography.
• Such interactions are thought to be responsible for most of Earth’s seismic and volcanic activity, although earthquakes and volcanoes can occur in plate interiors.

Evidence of Plate Tectonic Theory

• Continent Puzzle:
  • The continents fit together almost like puzzle pieces forming Pangaea (one super-continent).
• Fossil evidence:
  • Fossils on different continents are similar to fossils on continents that were once connected.  
  • When the continents split, different life forms developed.
• Distributions of rocks:
  • Most distributions of rocks within Earth’s crust, including minerals, fossil fuels, and energy resources, are a direct result of the history of plate motions and collisions and the corresponding changes in the configurations of the continents and ocean basins.
• Sea floor spreading:
  • Seafloor spreading theory validated the Plate Tectonics Theory.
  • As per the theory, the ocean floor is always moving from the mid-oceanic ridge towards the trenches.
  • Hot basaltic magma rises and erupts at the ridge. It cools down to become a new seafloor at this juncture.
  • The newly formed seafloor at the ocean crust then gradually moves away from the ridge and its place is taken by a newer seafloor and the cycle repeats.
  • In the process the older rocks move farther away from the spreading zone while younger rocks will be found nearer to the spreading zone.
  • The entire process looks like a conveyor belt.

Source: DTE