Abrasion In Crestview Park EarthCache

• Welcome to Crestview Park. This park is a great representation of Fluvial abrasion. 
• This Cache is based on Abrasion. Abrasion is the process of a rock being on the shoreline of a body of water, being hit by water and sediment. The constant impact and grinding of water carrying sediment can physically wear away parts of the rock, potentially forming tunnels or holes in the rock.  As these sediments move downstream, they collide with each other, the riverbed, and the riverbanks. This constant grinding and impacting action gradually wears away the rock surfaces, smoothing and rounding them over time.
•  Rivers and streams carrying sediment (like sand, gravel, and even larger rocks) cause abrasion as these particles collide with each other and the riverbed and banks. Fast-flowing water leads to more intense abrasion, shaping riverbeds and creating features like potholes, gorges, and smooth, rounded pebbles and cobbles. And even causing holes to form in rocks. 
• Fluvial abrasion is a key process in shaping the dynamic landscapes sculpted by rivers and streams. It's a form of erosion where the river's moving load – the sediment it carries, like sand, pebbles, and even boulders – acts like natural sandpaper, wearing away the bedrock of the riverbed and banks. This continuous grinding and scraping causes both vertical erosion (deepening the river channel) and lateral erosion (widening the channel). 
• How does it happen? Well, as the river flows, it picks up and transports sediment. These sediments, particularly those that are more angular or jagged, collide with the riverbed and banks. The impact and friction generated by these collisions gradually erode the rock, smoothing its surfaces and carving out features like potholes – rounded indentations formed when eddies (swirling water) cause sediments to scour the bedrock in a circular motion, according to Seneca Polytechnic. Over time, these actions contribute significantly to the erosion and modification of the river channel, according to Wikipedia.
• Smooth, rounded river rocks: These rocks are a testament to the constant collisions and grinding that occur as they're transported downstream.
• Polished surfaces: The friction of sediment against rock can create polished surfaces on the riverbed and banks.
• V-shaped valleys (in the upper course): In the upper reaches of a river, where the gradient is steeper and the water flows faster, vertical abrasion is more dominant, resulting in deep, narrow valleys, sometimes referred to as V-shaped valleys.
• Wider valleys (in the middle and lower courses): As the river's energy decreases downstream, lateral erosion becomes more prominent, widening the valley and creating features like floodplains and meanders. 
•  What we see as the San Joaquin Hills today, where Crestview Park is located, was once the bottom of the Pacific Ocean. Around 10 million years ago, the San Joaquin Hills began to uplift, possibly due to a hidden San Joaquin Hills blind thrust fault deep below the surface. This uplift pushed the marine sedimentary rocks above sea level. Aliso Creek, which originally flowed through the area, continued to cut through the rising land, carving out the dramatic Aliso Canyon, a major feature of the region.

• Explore the area and observe the evidence of fluvial abrasion that has shaped this landscape!

To log this cache as a find, please visit Crestview Park and answer the questions below. Please send your answers within 3 days of logging the cache. Don't write your answers in your log; send them to The_Gr8_Cacher via the Geocaching message center or email. If I don't receive the answers, I may delete your log. Have fun and happy caching!!!

1.  Cache identification: on the first line, include "Abrasion In Crestview Park," then the answers to the questions below.
2. Take a look at the rocks: Carefully examine the rocks, what signs that sediment and water are causing these rocks to form these formations and other shapes in the rock. Like Smoothness, Wholes, or Bridges. Explain what you see in one specific area. 
3. Observe the texture of the rocks: Look closely at the surfaces of the rocks at ground zero. Are they smooth or rough? Do you see any scratches or grooves? Describe the texture and suggest how it might have been formed.
4. Describe the shape of the rocks: Are the rocks generally angular or rounded? How does their shape reflect the process of abrasion by water?
5. Take a picture of you facing the rocks. Include this in your answers. 

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Thanks to Rock Abrasion,.org this earth cache was possible. AI was used to write this cache, but I relied on original sources.

https://www.earthsciweek.org/resources/classroom-activities/rock-abrasion/