A divergent plate boundary.
A transform fault boundary is a conservative plate boundary. This is what gets rid of lithosphere.
The plate you are describing is the Nazca Plate. It features a large central core of continental lithosphere, primarily consisting of the continent of South America, while being surrounded by oceanic lithosphere on the west, south, and southeast. The northern boundary of the Nazca Plate is characterized by a converging boundary with the South American Plate, which is responsible for significant geological activity, including the Andes mountain range formation.
At a convergent boundary, typically an oceanic lithosphere collides with either another oceanic lithosphere or continental lithosphere. When an oceanic plate meets a continental plate, the denser oceanic plate subducts beneath the continental plate, leading to the formation of deep ocean trenches and volcanic arcs. If two oceanic plates collide, one may subduct beneath the other, resulting in the creation of island arcs.
As the lithosphere moves away from a divergent plate boundary, its thickness generally increases. This occurs because new oceanic crust is formed at the boundary through volcanic activity and then cools and solidifies as it moves away from the heat source. As it ages, the lithosphere becomes denser and thicker due to cooling and the accumulation of sediments. This process leads to a gradual thickening of the lithosphere away from the divergent boundary.
The lithosphere sinking into the mantle occurs at a convergent plate boundary, specifically in subduction zones. In these regions, one tectonic plate is forced beneath another, typically an oceanic plate descending beneath a continental plate or another oceanic plate. This process leads to the formation of deep ocean trenches and volcanic arcs. The subduction of the lithosphere is a key driver of tectonic activity and geological phenomena associated with plate interactions.
The boundary separating the African Plate from the Arabian Plate is a divergent boundary. This type of boundary occurs where tectonic plates move away from each other, leading to the formation of new crust. Specifically, this divergence is associated with the East African Rift system, which is characterized by rifting and volcanic activity as the plates move apart.
The Andes Mountains are an example of mountain building activity at a convergent plate boundary, where the South American plate is colliding with the Nazca plate. This collision has led to the uplift and formation of the Andes mountain range.
Subduction
Oceanic lithosphere plunges beneath an overriding continental plate at a convergent boundary, specifically at a subduction zone. The denser oceanic plate is forced beneath the less dense continental plate due to tectonic forces, leading to the formation of deep oceanic trenches and volcanic arcs on the overriding plate.
Rift are formed between divergent boundaries, as the plates break apart from each other, a rift is formed between them. Also as they split apart the void between them forms a rift valley. Like the great rift valley in Africa.
Subduction
transform fault boundary