The Granite Rock Cycle

The Rock Cycle and the Transformation of Granite

• Granite formed from magma deep within the Earth's crust or mantle and was uplifted to the surface due to tectonic movements.
• Rocks at the surface undergo weathering, erosion, and alteration due to different environmental conditions.
• Weathering and erosion expose the granite to new surface environments, leading to unseen processes such as expansion, cracking, and disintegration.
• Rock dust from weathering accumulates over thousands or millions of years, eventually being washed into streams and rivers as sediments.
• Sediments from the Himalayas have formed up to 20 kilometers of sediment on the ocean floor in the Bay of Bengal.
• Sediments undergo compaction, cementation, and transformation into sedimentary rocks such as sandstone, limestone, and coal.
• The collision of tectonic plates and the formation of the Himalayas led to the compression and metamorphism of rocks, resulting in the formation of metamorphic rocks like gneiss.
• Metamorphic rocks are harder, more compact, and resistant to weathering compared to their original forms.
• The rock cycle involves continuous alteration of rocks over millions of years, with pathways including the transformation of igneous rocks into sedimentary or metamorphic rocks, or their re-melting and recrystallization.
• Each piece of rock has a unique story shaped by processes both on the surface and deep within the Earth, with some dating back millions of years.
• The text concludes by introducing the topic of plate tectonics and acknowledges the importance of learning about the history of the land and its original inhabitants.
• Crash Course encourages learning about the history of the place one calls home through resources like native-land.