Author Question: How do sedimentary rocks reveal ancient environments? What will be an ideal ... (Read 55 times)

Arii_bell · **on:** Jul 16, 2018

How do sedimentary rocks reveal ancient environments?

What will be an ideal response?

Question 2

What did Tuttle and Bowen observe in their experiment that helps geologists try to understand how magma is made?

What will be an ideal response?

cloudre37 · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

Answer: Different sedimentary rock types indicate the physical and chemical processes active in ancient depositional environments. Sedimentary structures reveal details about physical processes in the depositional environment. Cross-beds also reveal the direction of moving water and air currents that transport sediment. Changes in environments or processes produce boundaries between beds of sedimentary rock. Observations of vertical successions of rocks with different features allow geologists to interpret environmental change over time.

Answer to Question 2

Answer: The melting temperature of granite is much lower than that of peridotite. Partial melting in the presence of water begins at lower temperature as the pressure increases. This result also is seen for peridotite and is, indeed, a characteristic shared by all magmas. As pressure increases, more water dissolves into the magma, which means that magma can hold more water at high pressure than at low pressure.