To investigate the history of plate subduction-when one of Earth's tectonic plates slides beneath another-Sarah M. Aarons and colleagues compared ancient rocks from the Acasta Gneiss Complex in Canada to modern rocks. Using isotope analysis, the researchers found that Acasta rocks dating to about 4.02 billion years ago (bya) most strongly resemble modern rocks formed in a plume setting (an area in which hot rocks from Earth's mantle flow upward into the crust)By contrast, they found that Acasta rocks dating to about 3.75 bya and 3.6 bya have an isotope composition that is similar to that of modern rocks formed in a subduction setting. Aarons's team therefore concluded that __ Which choice most logically completes the text? Choose 1 answer: A the majority of the rocks in the Acasta Gneiss Complex formed through subduction B subduction-like processes began occurring in some locations no later than 3.75 bya C the rocks in the Acasta Gneiss Complex are of a more recent origin than scientists previously thought D subduction replaced mantle plume formation as the most common

Question

To investigate the history of plate subduction-when one of Earth's tectonic plates slides beneath another-Sarah M. Aarons and colleagues compared ancient rocks from the Acasta Gneiss Complex in Canada to modern rocks. Using isotope analysis, the researchers found that Acasta rocks dating to about 4.02 billion years ago (bya) most strongly resemble modern rocks formed in a plume setting (an area in which hot rocks from Earth's mantle flow upward into the crust)By contrast, they found that Acasta rocks dating to about 3.75 bya and 3.6 bya have an isotope composition that is similar to that of modern rocks formed in a subduction setting. Aarons's team therefore concluded that __ Which choice most logically completes the text? Choose 1 answer: A the majority of the rocks in the Acasta Gneiss Complex formed through subduction B subduction-like processes began occurring in some locations no later than 3.75 bya C the rocks in the Acasta Gneiss Complex are of a more recent origin than scientists previously thought D subduction replaced mantle plume formation as the most common

Answer 1

## Step 1The problem presents a scenario where researchers are investigating the history of plate subduction, a geological process where one of Earth's tectonic plates slides beneath another. They are using isotope analysis to compare ancient rocks from the Acasta Gneiss Complex in Canada to modern rocks.## Step 2The researchers found that Acasta rocks dating to about 4.02 billion years ago (bya) most strongly resemble modern rocks formed in a plume setting, which is an area where hot rocks from Earth's mantle flow upward into the crust.## Step 3On the other hand, Acasta rocks dating to about 3.75 bya and 3.6 bya have an isotope composition that is similar to that of modern rocks formed in a subduction setting.## Step 4Based on these findings, the researchers concluded that subduction-like processes began occurring in some locations no later than 3.75 bya.

Problemas

Roztwór

Respuesta

Explicación