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Context:

The article examines the gradual sinking of Iraqi land, driven by natural and human-induced factors, and its far-reaching consequences.

Why is Iraqi territory sinking?

A research team has observed a sinking oceanic slab beneath the Earth’s surface that is responsible for gradually pulling this area downwards. This phenomenon is a result of complex tectonic processes occurring over millions of years.

About Plate tectonics and the Neotethys oceanic slab

• The outer most part of Earth's structure is known as the The lithosphere consists of the crust and a small portion of the upper mantle.
• The lithosphere is divided into a number of tectonic plates. Tectonic plates are gigantic pieces of the Earth's crust and uppermost mantle.
• They are made up of the oceanic crust and continental crust. These plates move and interact with one another, driven by conventional forces within the Earth.
• Plate tectonics is the scientific theory that explains the movement of the Earth’s lithosphere.
• The lithosphere is divided into several plates that float on the semi-fluid asthenosphere
• The interaction of these plates can lead to various geological phenomena, including
• earthquakes,
• volcanic activity,
• mountain formation.
• This phenomenon is happening mainly due to the dynamics between the Arabian and Eurasian continental plates.
• When the Arabian and Eurasian plates collide, a huge crack is formed, called the "Neotethys oceanic slab".
• This slab originated from the bottom of an ancient ocean that existed 66 million years ago.
• Now this slab is slowly sinking into the Earth's mantle (deep layer).
• This process is pulling Iraq's Zagros region down with it, causing this area of Iraq to slowly sink.
  

Structure and Types of Tectonic Plates

• The Earth has a total of seven major tectonic plates, some of which cover entire continents, while some only cover oceanic areas

Some important minor plates are

 (i) Cocos plate: Between Central America and the Pacific plate.

 (ii) Nazca plate: Between South America and the Pacific plate.

 (iii) Arabian plate: Mostly the Saudi Arabian landmass.

 (iv) Philippine plate: Between the Asiatic and Pacific plates.

 (v) Caroline plate: Between the Philippine and Indianplate

 (North of New Guinea).

 (vi) Fuji plate: North-east of Australia

Movement of Tectonic Plates

Convergent boundaries  

• In this kind of interaction, two lithospheric plates collide against each other.
• The zone of collision may undergo crumpling and folding, and fold mountains may emerge ( orogenic collision ). Himalayan Boundary Fault is one such example.
• When one of the plates is an oceanic plate, it gets embedded in the softer asthenosphere of the continental plate, and as a result, trenches are formed at the zone of subduction.
• Near the convergent edge a part of the crust is destroyed, hence the name Destructive Edge.
• The subducted material gets heated up and is thrown out, forming volcanic island arc and continental arc systems, and dynamic equilibrium is achieved
  

Diverging Boundaries 

• In this kind of interaction, the plates diverge (move away from each other).
  

• Mid-ocean ridges are formed due to this kind of interaction. The Mid-Atlantic Ridge is one such example.
  

• In the continent, the East African Rift Valley is the most important geomorphological feature formed due to the divergence of African and Somali plates.
  

• Divergent edges are sites of earth crust formation and hence the name constructive edge.
  

• Earthquakes (shallow focus) are common along divergent edges. Seafloor spreading occurs at divergent plate boundaries
  

Side-sliding boundaries 

• When two plates slide past each other, this process can cause earthquakes.

Example: The San Andreas Fault

Sources:

INDIAN EXPRESS