Contact Metamorphism and Hornfells

Contact metamorphism occurs when rocks are altered by heat from nearby magma, causing changes in mineralogy and texture. This process happens at shallow depths with high temperatures, leading to the formation of rocks like hornfells, scars, and quartzite. The extent of alteration depends on factors such as magma temperature, contact duration, and rock composition. The mechanism involves heating rocks through conduction, convection, and radiation, resulting in chemical and physical changes. Specific rock types formed include marble and Sky marble, depending on original rock type and conditions.

What is the primary cause of contact metamorphism?

• Heat from nearby magma

• Pressure from tectonic plates

• Erosion by water

• Wind abrasion

Which of the following temperatures is typical for contact metamorphism?

• 1300 to 1600 degrees Celsius

• 900 to 1200 degrees Celsius

• 200 to 800 degrees Celsius

• 50 to 150 degrees Celsius

How is heat transferred to surrounding rocks during contact metamorphism?

• Only by conduction

• By conduction, convection, and radiation

• Only by convection

• Only by radiation

What happens to minerals in rocks during contact metamorphism?

• They evaporate

• They break down and new minerals form

• They remain unchanged

• They dissolve completely

Which mineral is commonly found in hornfells?

• Gypsum

• Halite

• Quartz

• Calcite

What type of rock is formed by the recrystallization of sandstone?

• Gneiss

• Slate

• Quartzite

• Marble

Which rock is formed in the contact zone between magma and carbonate rocks?

• Hornfells

• Basalt

• Scars

• Quartzite

What is a characteristic texture of hornfells?

• Granular

• Porous

• Layered

• Glassy

What is the main factor that determines the type of rock formed during contact metamorphism?

• The location of the rock

• The size of the rock

• The color of the rock

• The original rock type

Sky marble is a special type of contact metamorphic rock formed in which location?

• Hawaii

• Greenland

• Sky, Scotland

• Iceland