GK
GENERAL SCIENCE
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
smooth and shiny with no visible rain
|
|
|
multicolored and banded
|
|
|
course grained
|
|
|
made up of jagged grains
|
Detailed explanation-1: -Quick cooling means that mineral crystals don’t have much time to grow, so these rocks have a very fine-grained or even glassy texture. Hot gas bubbles are often trapped in the quenched lava, forming a bubbly, vesicular texture.
Detailed explanation-2: -Aplite-A light-colored, fine-grained intrusive igneous rock with sugary texture emplaced at relatively shallow depths beneath Earth’s surface, consisting mostly of feldspar and quartz. Obsidian-Black or dark-colored volcanic glass, usually of rhyolite composition.
Detailed explanation-3: -Porphyritic:a mixture of large and small crystals-perhaps a two-stage cooling history with the large crystals (the phenocrysts) cooling slowly and the small crystals (the groundmass) cooling more quickly. The rock to the right has a phaneritic texture; individual grains can be seen.