What Are The Erosional And Depositional Features Located at Botany Bay and by Hectors River Jamaica Caused by Wave Action?
School: Wolmer’s Boys’ School
Candidate Name:Wade Williams
Table of Contents
Aim of the study
Location of Study Area
Presentation and analysis of Data
Aim of Study
The aim of this study is to observe wave patterns, features located along Hectors River and Botany Bay to identify how the sea waves have affected the various landforms. Also to identify the different type of coastal features observed.
On Thursday October 4, 2012 the study area Botany Bay, St. Thomas and Hectors River, Portland, Jamaica were visited and a camera was used to take pictures of landforms and observations were done. Pictures were taken of important landforms and notebooks and pens were used to record information on the landforms that was of spoken by the teacher. A stopwatch was used to record the number of wave break patterns per minute and a calculator was used to computate the frequency of the wave breaks. Drawings of the landform were also done.
Further research was done on coastal features, data was taken from the text book and drawings were made from topographic maps from the internet.
Location of Sudy Area
Map of Jamaica showing location of study area.
Map of Portland showing study area.
Map of Hectors River, Portland.
Map of St. Thomas
Map of Botany Bay, St. Thomas
Presentation of Data
Picture1.1 shows a headland.
Headlands are formed along discordant coastlines in which bands of soft and hard rock out crop at right angles to the coastline. Due to the presence of hard and soft rock, differential erosion occurs. The crashing of waves against the rock causes loosening of rock particles from the main mass this is called hydraulic action. The loosened rock fragments are mixed with the physical action of the waves and are hurled at the landform this is called attrition. The softer less resistant rock is worn away much faster.
Fig 1.1 showing the formation of Bays
Picture 1.2 show
This is caused by breaking waves which attack lines of weaknesses on both sides of the headland. Through a process of abrasion and hydraulic action, fissures and joints are gradually enlarged and these develop into caves.
Picture 1.3 shows a Natural Arch
Natural archs are formed when erosion leads to formation of caves on both sides of a narrow headland so that they meet an arch is formed.
Picture 1.4 showing a picture of the stack observed at folly point A stack which is a geological landform consisted of a steep and often vertical column or columns of rock in the sea near a coast, isolated by erosion. Time, wind and water are the only factors involved in the formation of a stack. They are formed when part of a headland is eroded by hydraulic action, which is the force of the sea or water crashing against the rock. The force of the water weakens cracks in the headland, causing them to later collapse, forming free-standing stacks and even a small island. Without the constant presence of water, stacks also form when a natural arch collapses under gravity, due to sub-aerial processes like wind erosion.
Picture 1.5 shows stumps
A stump which is formed by continuing wave action attacking a stack until it collapses.
Fig 1.1 shows how the erosion of a headland leads...
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