Weathering Process. The weathering process occurs when rocks are exposed to the hydrosphere (water) and atmosphere (air).  These agents can change the physical and chemical characteristics of rocks.  As rocks are broken down (weathered), they can be classified as different types of sediments, which are: o boulders, cobbles, pebbles, sand, silt, clay, and colloids. See page 6 of the Earth Science Reference Tables explains the sizes of each of these sediments.
Lagoon is a water body that is formed near coastal areas. It is shallow and has a small link with sea or the ocean though it is also separated from the ocean water with reefs or a low sandbank. Arial view of a lagoon.
Barrier reefs also border shorelines, but at a greater distance. They are separated from their adjacent land mass by a lagoon of open, often deep water. If a fringing reef forms around a volcanic island that subsides completely below sea level while the coral continues to grow upward, an atoll forms.Atolls are usually circular or oval, with a central lagoon.oral reefs begin to form when free-swimming coral larvae attach to submerged rocks or other hard surfaces along the edges of islands or continents. As the corals grow and expand, reefs take on one of three major characteristic structures fringing, barrier or atoll.