Practice Questions

<h3 style="color: rgb(255,255,255);">Gabbro: An Igneous Rock Deep Dive</h3>

<ul style="color: rgb(255,255,255);">
  <li>Gabbro is classified as an <b>intrusive igneous rock</b>. This means it formed from magma that cooled and solidified <b>beneath</b> the Earth's surface.</li>
  <li>The slow cooling process below the surface allowed for the formation of large mineral crystals, giving gabbro a coarse-grained texture. This is a key characteristic differentiating it from extrusive igneous rocks like basalt, which cool rapidly on the surface and have fine-grained or glassy textures.</li>
  <li><b>Mineral Composition:</b> Gabbro is primarily composed of the minerals <b>plagioclase feldspar</b> (a calcium-rich variety) and <b>pyroxene</b>. It often contains smaller amounts of olivine and amphibole.</li>
  <li><b>Color:</b> Due to its mineral composition, gabbro is typically a dark-colored rock, ranging from black to dark green.</li>
  <li><b>Formation Environment:</b> Gabbro is commonly found in the lower parts of oceanic crust and in the lower layers of continental crust. It is also a major component of the Earth's mantle.</li>
  <li><b>Uses:</b> While not as widely used as granite or basalt, gabbro can be quarried for crushed stone in construction and sometimes used as an ornamental stone or for monuments.</li>
  <li><b>Relationship to Basalt:</b> Gabbro is often considered the intrusive equivalent of basalt. When magma similar to that which forms gabbro erupts onto the surface, it cools quickly to form basalt.</li>
  <li><b>Examples in India:</b> Significant gabbro formations are found in parts of the <b>Sillamannar Complex in Tamil Nadu</b> and the <b>Koilsar region in Rajasthan</b>. These regions are important for geological studies and mineral exploration.</li>
</ul>

Challenger App

No.1 PSC Learning App