World Geo 3200/3202 November 2010

Introduction In this lesson you will: Define the terms sea cave, sea arch, and stack. (k) Explain how sea caves, sea arches and stacks are formed. (a) Analyze the processes that result in the “straightening out” of an irregular coastline. (a)

Evolution of Sea Stacks Sea stacks are columns of land standing in the ocean just off shore (many have plant growth on top) Very common in eastern Canada. They are created over a long period of time after a series of other land structures have eroded away.

Evolution of Sea Stacks First sea caves are formed in a headland. Continued erosion turns sea caves in to the second land feature, sea arches. Sea arches are an interesting sight too and have drawn many tourists to the northern Peninsula of Newfoundland. Erosion and eventual collapse of the arch top leaves a sea stack standing in the ocean. Figure 3.11 on pages shows this evolution from three different points of reference. You must look at this figure it will help cement the concepts in your mind.

Sea Cave Sea Cave Formation: "a" in figure 3.11 on page 48 waves strike the headland first; waves refract around the headland and put hydraulic pressure on both sides of the headland; erosion of the weak portions create caves and blow holes in the sides of the headland.

Sea Arches Sea Arch Formation : "b" in figure 3.11 on page 48 eventually sea caves, on alternate sides of the headland get deeper until they connect inside the headland forming a complete passage way or tunnel or “arch” through the head land.

Sea Stack Sea Stack Formation: "c" in figure 3.11 on page 48 continuous erosion, of sea arches, causes the collapse of the ground over the arch; this leaves a pillar or column or “STACK” of land standing alone where the headland was.

Look Familiar????

Straightening of Emerging Coastlines Emerging coastlines straighten in much the same fashion as submerging coastlines; Erosion of headlands creates sea caves, sea arches and sea stacks instead of bay beaches, spits and bay bars; However, the result is similar in that headlands are reduced in size which straightens the coastline. Compare the headland length in figure 3.11 before and after erosion.

Case Study

Human Adaptations to Land & Water Forms Outport Newfoundland fishing villages built on rocky coastline Stilt houses in Bangladesh show how humans have adapted living in deltas

Human Adaptations to Land & Water Forms The Chunnel connecting England with France Canadian railway construction through the Rocky Mountains

Case Study Assigned Readings "Storm surges in Bangladesh" on p in your text book.