Here's a breakdown:

* Crustal fragments: These are pieces of Earth's crust, often in the form of volcanic arcs, oceanic plateaus, or smaller continental fragments.

* Continent: A large landmass made up of continental crust.

* Collision: As the crustal fragments move towards the continent, they collide with it, often causing mountain building (orogenesis) as the plates buckle and fold.

* Joining: Over time, the fragments are welded onto the continent, adding to its size and complexity.

Here are some key points about accretion:

* It's a slow process: Accretion happens over millions of years, gradually adding to a continent's size.

* It shapes continents: Accretion is a major force in continental growth and shaping.

* It's a complex process: Accretion involves multiple geological processes, including subduction, volcanism, and plate tectonics.

Examples of accretion:

* The western coast of North America: The accretion of terranes (crustal fragments) has contributed significantly to the growth of the North American continent.

* The Himalayas: The collision of the Indian subcontinent with Asia is a prime example of accretion, leading to the formation of the Himalayas.

Let me know if you have any other questions about accretion or the Earth's geological processes!