Author Question: How does a fringing reef around an oceanic island become an atoll? ... (Read 166 times)

jhjkgdfhk · **on:** Aug 7, 2018

How does a fringing reef around an oceanic island become an atoll?

Question 2

What causes spring tides and neap tides to have different tidal ranges?

Loise Hard · **Reply #1 on:** Aug 7, 2018

Answer to Question 1

As a volcanic island subsides, the fringing reef grows upward, keeping pace with the seafloor subsidence, becoming a barrier reef when a lagoon develops and finally an atoll when the only solid material is the outer ring of coral.

Answer to Question 2

Spring tides occur every two weeks when the alignment of the Earth, Moon, and Sun increases the tidal range. During a neap tide, the Moon's gravitational pull is exerted at a 90 degree angle to that of the Sun, and so the pull of the two detract from each other.