Above is a picture of the collection of rocks that I gathered from an area here in Fresno, just off of Friant Road north of Shepherd. In this area there are homes and different types of structures spread out, but there are many different rocks all over the land due to the fact it once was the San Joaquin River bottom. This is the second longest running river in the United States. Naturally over thousands of years this part of the river has dried up and when Millerton damn was built it began to flow even less. This left many different rocks around that are still there to be identified, giving us an idea of what was in the area during that time. I will explain and give a description of each one how I was able to identify what they are.
This rock is a Basalt rock which is an extrusive volcanic rock. I was able to come to this conclusion due to the dark color and the fine grains. It is considered under weathered because of how dark the color actually is and is considered an igneous rock.
Amphibolite is a metamorphic rock that is non foliated and forms through recrystallization under severe conditions of high viscosity and direct pressure. It is composed primarily of amphibole and plagioclase, usually with very little quartz. I was able to identify this type of rock due to the weight and the black and white specks. Up close it has a flaky like appearance which these rocks are known for.
Quartzite is a non-foliated metamorphic rock that is produced by the metamorphism of sandstone. It is made up of primarily quartz. I was able to identify this rock as Quartzite due to the color of white and gray and the individual quartz grains that have been recrystallized.
Gabbro, whichis a coarsegrained, dark colored rock that is considered to be intrusive igneous,contains feldspar, augite and also depending on the situation, olivine. These rocks are similar to Basalt and also have the chemical equivalent. Due to the dark color, spotting, and the coarse grains I was able to identify this as Gabbro.
Sandstone is a sedimentary rock made up mainly of sand-size pieces. Environments where large amounts of sand can accumulate include beaches, deserts, flood plains and deltas and this is where they are usually found. I was able to identify this as Sandstone due to the tan color and the gritty texture.
This is a mountain range that has fault lines across the face of it. This would be considered a dip slip fault due to the vertical faults that are parallel to the mountain.
This is a picture of Table Mountain which is located in the foothills of the Friant, California Area. As you can see the top of the mountain is flat from the weathering process. Over time different events has caused this transformation to happen, causing the tops of these ranges to become flat, hence the name Table Mountain. This mountain is a famous area here in California and even has a casino nearby named after it.
This is a picture of Mass Wasting and Erosion. This is on Friant Road in the former San Joaquin River bottom area. Overtime Cliffs will erode and the material will filter down the cliff through the process of mass wasting and will end up at the bottom of the cliff eventually.
This also use to be another area where the San Joaquin River Flowed. You can tell by the water worn trees and the soil that is littered with sediment where the river use to flow. Metamorphic, Igneous and Sedimentary rocks can be found here.
This is a Marine Sedimentary Environment. This picture was taken in Monterey Bay, California. The Monterey Bay is at a certain depth and then it drops off to a deeper part of the ocean known as the Outer Bay.
This is a picture of a Transitional Sedimentary Environment that was taken in Pacific Grove, California which is a neighboring city of Monterey Bay. You can see where the ocean meets the shoreline. As you can tell from the rock formations that many different types of sediment have come to a standstill in this area.
This is a great example of the uses of practical geology. This is a building materials plant located in the San Joaquin River Bottom. Rocks gravel and sand are harvested from this area to use in building and road projects.
This bridge is another example of practical geology. This is located on Rice Road which is off of Friant, north of Shepherd. The bridge is built using the two neighboring cliffs as anchors.
Field and lab assignment pp
Field and Lab Assignment <br />Courtney Perry<br />