Matthew Sewell 6/9/15 Historical Geology 204 Historical Geology Final 1.) There are three clear landslides; the southwest landslide is stream-laid sand and gravel from the quaternary that was located on a steep slope resulting in gravity pulling sediments down the steep slope. The northeast landslide appears to be tuff sediments that have fallen upon biotite-quartz diorite rocks. The northwestern landslide is the largest of the landslides. The landslide occurred just south of the creek; erosion must have lowered the creeks elevation creating a steep decline resulting in Bena gravel to fall. The alluviam sediments (sand, gravel, and silt) were deposited in a fluvial environment along the creek. Sand, gravel, and silt-sized grains are commonly …show more content…
The Walker formation was formed by a volcanic eruption that deposited in large amounts of ash fall that mixed with the lower sediments to form tuff breccia and tuff conglomerates. I believe the Walker formation was deposited first because it is only present now at high elevations, meaning other sediments have covered up the lower ash fall. The Bealville fanglomerate, composed of unsorted granitic boulder debris, could have been formed from active seismic activity. Large earthquakes strike the west coast of California frequently. These earthquakes could have smashed the already laid down granitic sandstone and formed the multiple …show more content…
According to Levin, “This subduction created batholiths, compressional structures, volcanism, and metamorphism that accompanied Mesozoic and Cenozoic orogenies.” The dense oceanic crust was subducting beneath the continental crust more quickly than it was being created at the mid-ocean spreading ridge. The oceanic crust was part of the Farallon plate, which has now almost completely disappeared because it was consumed by the North American plate (Levin). Once the Farallon plate disappeared, this brought the North American plate in direct contact with the Pacific plate. Initially the Pacific plate had being moving north, so when it first came into contact with the North American plate it didn’t subduct, but they rubbed against each other. This formed the San Andreas Fault
Marshak, S. (2009) Essentials of Geology, 3rd ed. New York: W.W. Norton & Company, ch. 11, p. 298-320.
Illinois State Geological Survey, 2005, Time Talks – The Geology of Starved Rock and Matthiessen State Parks
Yes this feature is the result of erosion and depositional processes however, it is not associated with the current water course. This feature may be the result of a Gilbert type delta that once occupied this area. Gilbert type deltas have three main components; topsets, foresets and bottomsets. Topsets are fluvial sediments (primarily sandur deposits) that were deposited on the subaerial delta surface. Erosive events occurring on the upper forslope can result in downslope channels and chutes. These features are then eroded by either strong currents or by debris flow resulting in these channels and chutes to become filled. Foresets are a combination of sand and gravel facies. The are deposited by gravitational processes on the delta foreslope and the grains tend to become finer and more angular downslope. Bottomsets consist of fine grained silts and clay and are deposited at the foot of the delta front.
...e morphed it into the quartzite that is seen surrounding the butte (4). Rocks that undergo this process are called metamorphic rock, which is the same as the rock seen years ago by dinosaurs and other extinct creatures. The quartzite rocks were formerly seafloor sediment that was forced upwards, and then surrounded by lava basalt flows. Once erupted through fissures and floods through out most of the area, lava flow eventually created enough basalt to form a thickness of about 1.8 kilometers (1). All of this basalt flow eventually led to the covering of most mountains, leaving the buttes uncovered. The igneous lava flows and loess is reasons that the Palouse consists of such sprawling hills, and rich soil for farming (2). In result of the lava flows, the Precambrian rock Quartzite was formed. And lastly covered by the glacial loess, which were carried by the wind.
Earthquakes are a natural part of the Earth’s evolution. Scientific evidence leads many geologists to believe that all of the land on Earth was at one point in time connected. Because of plate tectonic movements or earthquakes, continental drift occurred separating the one massive piece of land in to the seven major continents today. Further evidence supports this theory, starting with the Mid-Atlantic ridge, a large mass of plate tectonics, which are increasing the size of the Atlantic Ocean while shrinking the Pacific. Some scientists believe that the major plate moveme...
The Franciscan Terrane of central California represents an accretionary complex formed by long-term subduction of an oceanic plate under the Western margin of the North American craton. The Franciscan complex is composed of three distinguishable belts: the eastern belt (Yolla Bolly and Pickett Peak terranes), the central belt, and the coastal belt. Age and metamorphic grade of the belts decreases to the west (Blake and Jones, 1981). Formation of the accretionary complex began during the late Jurassic in the eastern belt and has continued into the Miocene along the western coastal belt. The complex trends NNW and is bounded by the San Andreas Fault to the east and by the coastal range fault to the west. The coast range fault separates the Franciscan complex with the partly coeval Great Valley sequence. Debate exists over the tectonic evolution of the Franciscan, centered around the geographic origin of the Franciscan rock units.
The scenario mentioned above was based on the rupture located along the Cascadia fault line. This fault system runs from Northern California to Vancouver Island about 700 miles off the shore (FOX5). Scientists use to believe that the San Andreas Fault was where a large earthquake tsunami would originate, but recently their attention has shifted to the Cascadia subduction zone which is now said to be much more dangerous than previously thought (FOX5). Recent earthquake events have added even more tension and possibility for a large-scale tsunami. On March 10, 2014, a 6.8 magnitude earthquake struck off the coast of Northern California, which put a lot of stress on the Mendocino Triple Junction (Davidson). The Mendocino Triple Junction is where three tectonic plates collide, and is very unstable (Davidson). This junction has all this built up pressure and is about ready to explode. Scientists believe that this junction will be the origin of a tear along the 680-mile long Cascadia Subduction Zone. (Davidson). The disaster that follows will be considered the United State’s largest modern-day earthquake.
...ified rocks are usually inclined due to the structure folding and faulting because of the Paleozoic rock. (Adams, Butts, 23). Charles Butts states, “In its general relations the Paleozoic area of Alabama falls into the large geographic division of the eastern United States known as the Appalachian Highlands which extends from the Coastal Plain on the east to the Interior Lowlands of the Mississippi Valley region on the west.” (Adams, Butts, 43)
Before examining the Northridge event, understanding the naturally occurring hazard that is an earthquake will help to better understand exactly what happened and why it was such an important geological event. With four distinct layers, two layers, the crust and upper portion of the mantle, compose the skin that is the surface layer of the Earth. The crust is not a single, continuous piece. It is actually several different pieces, or plates, that come together to form the puzzle that comprises the surface of the Earth. These plates are in constant motion rubbing against one another. These areas, known as fault lines, where the plates rub up against one another have spots where one plate ”gets stuck while the rest of the plate keeps moving. When the plate has moved far enough, the edges unstick and is how most of the earthquakes around the world occur” (Wald, 2012). The energy stored from the friction of the two plate...
study of the San Andreas fault system." (USGS) When the 1906 earthquake struck scientist set
The Don Valley Brickwork consists of many different layers of geological deposits, allowing us to observe and have a better understanding of how the sediments we see today are formed. The most bottom layer in the Brickworks are from the Georgian Bay Formation, and consists of grey- shale bedrocks. Fossils are often found in this layer and it is estimated that this deposit of sediments is around 445 million years old. Above the bedrocks is a thin layer of grey clay sand and gavels left behind by the Illinoian Glacier. This layer is called the York Till and occurred around 135,000 years ago. The next layer consists of a sandy deposit called the Don Formation, which is formed by the Sangamonian Interglacial Stage. Many plant and animal fossils are found in this layer due to warmer climate around 120,000 years ago. Above it lies the Scarborough Formation, which consist of clay and sand. This sediment likely occurred 115 - 106,000 years ago. The next layer above is the Poetry Road Formation, and consist of sand and gravel. This layer is likely formed during the early Wisconsin glacial substage around 106- 75,000 years ago. Higher is the Sunnybrook Drift which was formed 60 – 75,000 years ago. And on the surface, is the Halton Till, which was left behind by the final push of the Wisconsin Glacier.
"NPS: Nature & Science» Geology Resources Division." Nature.nps.gov » Explore Nature. Web. 05 Dec. 2011. .
The High Falls was deposited first, then the Binnewater, and, finally, the Rondout formation. The oldest formation, or the High Falls, consisted of thin red and brown mudstone. Through observation, it may be described as red shale. The rock is this color due to the presence of hematite and iron oxide. Therefore, it can be inferred this rock formed in a floodplain, where it was in an oxygenated system. Rivers must have deposited mud to form the red shale that is fine-grained. Proceeding the High Falls formation, the Binnewater formation consisted of a light tan rock that was a few centimeters thick. This was a clastic sedimentary rock with coarse texture. When tested with hydrochloric acid, the sedimentary rock reacted, therefore it may be defined as a quartz sandstone. The cement holding the rock together allows for a reaction. This layer formed in marine conditions. Finally, the Rondout Formation, or the youngest layer, consisted of a chemical sedimentary rock. This layer was grey and approximately five centimeters thick. It may be identified as dolostone due to its ability to react with hydrochloric acid in the powdered form. Dolostone has a microcrystalline texture. This layer formed in the environment of a shallow ocean. Additionally, this structure may be seen as a monocline. In other words, a shorter inclined limb connects two nearly horizontal limbs. Finally, this structure is approximately
...These rocks include indurated conglomerates, coarse-grain granites, and Arkosic and breciated granites. Furthermore, there are evidences to indicate that faulting took place in the area. Hydrothermal and epithermal action must have intruded the rocks in the Goldfield area forming small stringers of quartz. There are also evidences of sedimentary rocks such as sandstones, limestone and conglomerates found near Roosevelt Lake (Eppinga, 2006).
The concurrent convective circulations in the mantle leads to some segments of the mantle moving on top of the outer core which is very hot and molten in nature. This kind of movement in different segments occurs as tectonic plates. These tectonic plates are basically seven on the earth surface as major ones, although, several small ones exist also. The plates motions are characterized by varying velocities, this variance results to sub sequential collision of two plates (leading to formation of a mountain in a convergent boundary), drift of two plates (leading to formation of rifts in a divergent boundary), or parallel movement in a transform boundary(Webcache 3).