Question

Select the correct answer. A 20-pound sedimentary rock formed on a mountain cliff near the sea. The rock was made up of grains of sand, pebbles, and exoskeletons of tiny insects. It was held together by calcite. One day, the rock fell into the ocean and over time was buried deep inside Earth. Once inside, the rock was no longer sedimentary but instead turned into a metamorphic rock. After many years, it returned to Earth’s surface. Why did the rock not become an igneous rock? A. It lay in a region that was close to the salt-filled ocean. B. It contained organic material from a number of insects. C. It did not experience high enough pressure for compaction. D. It had not experienced high enough temperatures to melt. E. It had a composition that was not homogenous.

Answer 1

The rock did not become an igneous rock because it did not experience high enough temperatures to melt.

Step-by-step explanation:

The rock did not become an igneous rock because it had not experienced high enough temperatures to melt. Igneous rocks form when magma or lava cools and solidifies. Since the rock fell into the ocean and was buried deep inside the Earth, it did not reach the temperatures necessary for melting and subsequent formation of igneous rock.

Answer 2

The rock did not become igneous because it did not experience the high temperatures required to melt, which is necessary for the formation of igneous rock. It became a metamorphic rock due to high pressure and temperature that altered it without melting it into magma.

Therefore, option D is correct.

Step-by-step explanation:

The reason the 20-pound sedimentary rock, which fell from a mountain cliff into the ocean and later turned into a metamorphic rock, did not become an igneous rock is option D. It had not experienced high enough temperatures to melt. Igneous rocks are formed when magma or lava cools and solidifies, and this process entails the melting of pre-existing rocks into magma, which later cools down to form an igneous rock. Since the sedimentary rock became a metamorphic rock, it was subjected to high pressure and temperatures that were sufficient to induce physical and chemical changes within the rock but not high enough to melt it into magma. This transformational process happens deep within the Earth's crust where tectonic activity can carry surface rocks down to considerable depths.