Question

In the oceanic-oceanic convergence, on the left, we would expect what type of rocks to be found in the island arc marked by the red star?

a) Igneous
b) Sedimentary
c) Metamorphic
d) Fossiliferous

Answer 1

option a

Step-by-step explanation:

There are three kinds of plate tectonic boundaries: divergent, convergent, and transform plate boundaries. This image shows the three main types of plate boundaries: divergent, convergent, and transform. Image courtesy of the U.S. Geological Survey.

Answer 2

At an island arc formed by oceanic-oceanic convergence, we would expect to find igneous rocks, specifically mafic rocks like basalt or gabbro, as a direct result of the volcanic activity associated with the subduction of one oceanic plate beneath another.The correct answer is option a.

Step-by-step explanation:

In oceanic-oceanic convergence, where two oceanic plates collide and one is subducted beneath the other, the intense heat and pressure create conditions for the melting of subducted oceanic crust, leading to the formation of magma. This magma is less dense than the surrounding rocks, causing it to rise through the overlying plate and potentially lead to volcanic activity. The associated igneous rocks can be both extrusive and intrusive, depending on whether they solidify at the surface or beneath it.

Igneous rocks, particularly mafic ones like basalt if extrusive, or gabbro if intrusive, are typically the primary types of rocks found in island arcs formed by oceanic-oceanic convergence. These rocks originate from the partial melting of the subducted oceanic plate. While sedimentary rocks can also be present due to subsequent deposition of erosion materials, and metamorphic rocks can emerge from the alteration of existing rocks under high pressure and temperature, the predominant rock type associated with the initial island arc formation is igneous.

Therefore, in an island arc marked by the red star, resulting from oceanic-oceanic convergence, you would most expect to find igneous rocks (a).