Author Question: What is the meaning of the half-life of a radioactive-decay process? What will be an ideal ... (Read 50 times)

jjjetplane · **on:** Jul 16, 2018

What is the meaning of the half-life of a radioactive-decay process?

What will be an ideal response?

Question 2

What are the three types of unconformities? How does each form?

What will be an ideal response?

Tonny · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

The time interval during which the number of parent isotopes decreases by half.

Answer to Question 2

Angular unconformity occurs between inclined layered rocks and horizontal rocks.
The missing time includes the period between tilting and eroding the rocks, and deposition of the more horizontal overlying unit.
Disconformities occur in rocks which are all at the same angle (horizontal or inclined), but are represented by a surface of erosion. The time missing includes the period when the sediments were eroded until the overlying unit was deposited.
A nonconformity occurs when sedimentary or volcanic rock overlies crystalline (igneous or metamorphic). The time missing includes the period after the metamorphic rock was formed and ultimately exposed at the Earth's surface until the overlying sediments or lava was deposited.