The Story of Haystack Rock

(EXPLANATION from checkpoint #1)-The surface of Earth has changed over time by the geologic processes of erosion and deposition. Erosion carries bits of broken rock to new locations, and deposition drops sediments in new places.

Some evidence that supports this is from labs. At the wave erosion station, some of the sand from the beach was moved out and the shape of the beach changed. The stream table showed how deposition changes the shape of land at the mouth of a river. The water carried the sand down the stream until it was dropped at the bottom forming a delta.

This evidence supports my claim because the energy in the waves was able to carve away parts of the beach and gravity pulled the broken pieces of rock (sand) down the stream and dropped it off. This shows that the shape of earth is changed by erosion and deposition.

(Inference from checkpoint #2) I infer that Haystack Rock was formed by wave erosion because in class we did an experiment all about wave erosion. I learned that when waves come up on the beach it pulls the beach with it. This causing me to think that Haystack Rock was formed by wave erosion.  I also think this because when I visited Cannon Beach I went right next to haystack rock and the tour guide person who was there to tell you all about said that this who rock what part of the shore that was once around it was eroded by the waves that come up on the shore making wave erosion.  To support how Haystack Rock was formed initially, Oregon Geology says, “that it is composed of basalt, Haystack Rock was formed by lava flows emanating from the Blue Mountains and Columbia basin about 15-16 million years ago. “ This tying back to my big idea because it says that “Haystack Rock was formed by lava”.

Since Haystack rock is at the ocean shore, the waves and wind are constantly at work weathering this large rock. Smaller rocks are nearby suggesting that this is all part of the same very large rock.

Many thousands of years ago, Haystack rock looked very different. The agents of weathering and erosion had not yet separated the rocks and worn the smaller rocks down. The nearby rocks were once connected and the spaces between were smaller.

At one time all of these rocks were probably just a shelf of igneous rock that had spilled into the oceans. Wind, rain and wave broke weathered the rock which means they were broken down. Those same agents also cause the sediments to be washed away. This shows how the land-form could have looked long ago.