Final answer:
Ultramafic igneous rocks like peridotite help improve the environment by sequestering atmospheric carbon dioxide (CO₂) through a chemical reaction with minerals like olivine, potentially mitigating the greenhouse effect.
Step-by-step explanation:
Ultramafic igneous rocks, which are very high in magnesium and iron and have low silica content, have great potential in improving the environment due to their ability to absorb and store atmospheric carbon dioxide (CO₂). These rocks, such as peridotite, contain minerals like olivine and pyroxene, which can undergo a chemical reaction with CO₂ to form carbonates. This process not only sequesters CO₂, potentially helping to mitigate the greenhouse effect, but also transforms rocks into more stable and environmentally beneficial forms.
The presence of abundant magnesium and iron in ultramafic rocks is due to their mineral composition, which includes olivine, distinct for its green color. Mafic rocks, similar in composition but less rich in magnesium and iron, are also important in geological processes, contributing to the makeup of things like large igneous provinces. By utilizing the natural carbon sequestration properties of ultramafic rocks, scientists hope to harness a natural process for environmental restoration.