Author Question: What is the ultimate base level, and why is it called that? What will be an ideal ... (Read 9 times)

sabina · **on:** Jul 15, 2018

What is the ultimate base level, and why is it called that? What will be an ideal response?

Question 2

What is the significance, in terms of geological time, of the word temporary in temporary base level? What will be an ideal response?

Eunice618 · **Reply #1 on:** Jul 15, 2018

Answer to Question 1

The ocean is called the ultimate base level because the ocean is here to stay geologically. This is not
to say that sea level itself is constant. It varies as a function of climatic fluctuations that affect global
ice volume. But the ocean is where river erosion ultimately ceases. Perplexingly, there are temporary
base levels that lie below sea level. The Dead Sea in the Middle East is a good example of this. It is a
body of water in an arid region that has no outlet to the ocean.

Answer to Question 2

Features associated with temporary base levels are geologically impermanent or temporary. Lakes,
for example, may last for a considerable length of time from a human perspective, but will eventually
disappear over the course of geological time. Even mountain ranges are temporary features when
viewed this way. Other causes for temporary base levels are even shorter lived. A landslide that blocks
a river, for example, will soon be removed by erosion. Hydroelectric dams also form temporary base
levels of very short duration (geologically).