A vesicular igneous texture generally indicates rapid cooling.
Fine or glassy igneous texture indicates the rapid cooling of the molten material from which the rock was formed.
they formed over a long period of time
1. Over long period of time
The rock is conglomerate. The other rock would be Breccia if its grains were not rounded.
due to the large crystal grains of the rock and existence of feldspar and mica the rock could either be of igneous or metamorphic origin.incase it is of igneous origin the rock is intrusive igneous rock that form deep in the earth crust and cool at a relatively slow rate developing large crystals.in case of metamorphic origin the rock is high grade metamorphic rock that have experienced high metamorphic condition (high pressure and temperature);that is it is a gneiss that has characteristic coarse grains crystals.
It is neither. Pumice is an extrusive highly vesicular igneous rock composed of volcanic glass and very tiny mineral crystals.
Phaneritic rock has visible identifiable crystal grains. Aphanitic rock has crystal grains that are too small to be visible with the naked eye. In igneous rock, the difference is due to the amount of time spent in cooling. Long term cooling of magma underground leads to large crystals, rapid cooling of lava above ground leads to small crystal texture.
1. Over long period of time
d. on the surface of the Earth
Slow cooling of igneous rocks typically forms large crystal grains. This is because slow cooling allows more time for mineral grains to grow, resulting in larger crystals. Examples of rocks formed through slow cooling and having large crystal grains include granite and gabbro.
Intrusive igneous rock.
intrusive
That is correct.
The rock is conglomerate. The other rock would be Breccia if its grains were not rounded.
The size of the mineral crystals in an igneous rock is related to the rate of time spent in cooling from magma. Longer exposure to the crystallization temperature means larger crystals. Less time means smaller crystals, or in the case of obsidian, which cools extremely quickly, no crystallization.
due to the large crystal grains of the rock and existence of feldspar and mica the rock could either be of igneous or metamorphic origin.incase it is of igneous origin the rock is intrusive igneous rock that form deep in the earth crust and cool at a relatively slow rate developing large crystals.in case of metamorphic origin the rock is high grade metamorphic rock that have experienced high metamorphic condition (high pressure and temperature);that is it is a gneiss that has characteristic coarse grains crystals.
It is neither. Pumice is an extrusive highly vesicular igneous rock composed of volcanic glass and very tiny mineral crystals.
Intrusive Igneous rocks. Examples: obsidian, magma
Phaneritic rock has visible identifiable crystal grains. Aphanitic rock has crystal grains that are too small to be visible with the naked eye. In igneous rock, the difference is due to the amount of time spent in cooling. Long term cooling of magma underground leads to large crystals, rapid cooling of lava above ground leads to small crystal texture.