Context: Scientists examining rocks older than 3 billion years discovered that the Earth's tectonic plates move around today much as they did between 2 and 4 billion years ago. The findings suggest that the continents settled into place and sustained life much earlier than previously thought, and give insights into plate tectonics on other planets.

Background

• An enduring question in geology is when Earth's tectonic plates began pushing and pulling in a process that helped the planet evolve and shaped its continents into the ones that exist today.
• Some researchers theorize it happened around four billion years ago, while others think it was closer to one billion.

Key Findings 

• A research team led by Harvard researchers looked for clues in ancient rocks (older than 3 billion years) from Australia and South Africa, and found that these plates were moving at least 3.2 billion years ago on the early Earth. 
• In a portion of the Pilbra Craton in Western Australia, one of the oldest pieces of the Earth's crust, scientists found a latitudinal drift of about 2.5 centimeters a year, and dated the motion to 3.2 billion years ago.
• The researchers believe this shift is the earliest proof that modern-like plate motion happened between two to four billion years ago. It adds to growing research that tectonic movement occurred on the early Earth.
• "Basically, this is one piece of geological evidence to extend the record of plate tectonics on Earth farther back in Earth history. Based on the evidence we found, it looks like plate tectonics is a much more likely process to have occurred on the early Earth and that argues for an Earth that looks a lot more similar to today's than a lot of people think."
• Plate tectonics is key to the evolution of life and the development of the planet. Today, the Earth's outer shell consists of about 15 rigid blocks of crust. 
• On them sit the planet's continents and oceans. The movement of these plates shaped the location of the continents. It helped form new ones and it created unique landforms like mountain ranges.
• It also exposed new rocks to the atmosphere, which led to chemical reactions that stabilized Earth's surface temperature over billions of years.
• A stable climate is crucial to the evolution of life. When the first shifts occurred has long been an issue of considerable debate in geology. Any information that sheds light on it is valuable. The study helps fill in some of the gaps. 
• The researchers point out they weren't able to rule out a phenomenon called "true polar wander." It can also cause the Earth's surface to shift. Their results lean more towards plate tectonic motion because of the time interval of this geological movement.

About Plate tectonics

• Plate tectonics is the theory that Earth’s outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core. The plates act like a hard and rigid shell compared to Earth’s mantle. This strong outer layer is called the lithosphere.
• The earth’s lithosphere is composed of seven or eight major plates and many minor plates. The lithosphere is a rigid outermost shell of earth and is broken up into tectonic plates. When these plates meet, their relative motion determines the type of boundary like convergent, divergent or transform.
• Volcanic activity, earthquakes, mountain-building and oceanic trench formation occur along these plate boundaries. The relative movement of the plates typically ranges from zero to 100 mm annually.

Causes of Plate Tectonics:

• It causes earthquakes
• It causes volcanism
• It induces recycling of elements within the biosphere and between the geosphere and biosphere
• It causes mountain-building

Types of plate boundaries:

Plate Boundaries mainly consists of three types (fourth is a mixed type), formed in the manner the plates shift in relative to each other. These are collectively referred to surface phenomena’s of different types. Plate boundaries are of different types, namely:

• Transform boundaries: These boundaries happen where two lithospheric plates move apart, or maybe further precisely, collide away from one other despite the transform faults, where plates are neither created nor destroyed.
• Divergent boundaries: These boundaries happen when both plates move apart from one other.
• Convergent boundaries: These boundaries happen where both plates move towards one other to form a zone of subduction or a continental collision.
• Transform boundaries: These boundaries happen when natural or human-made structures that cross a transform boundary are offset—split into pieces and carried in opposite directions.
• Plate boundary zones: These boundaries happen where the effects of the interactions are unclear, and the boundaries, usually occurring along a broad belt.