Introduction
Meteorites have impacted the Earth surface many times since its formation. Geologists have recently taken an interest in the structures left behind by these formations and have begun defining and organizing these structures. There are, also, debates as to what rock formations currently being studied, such as Upheaval Dome, actually qualify as meteor impact structures. But what exactly are these common formations and structures related to meteor impact structures?
Body
Craters are the most common structures associated with meteor impacts. There are two general types of craters that geologists use to identify different craters: simple craters and complex craters. Simple craters are generally bowl shaped with diameters between 2 and 4 kilometers depending on the rocks impacted (Ferriere, 2011). Generally speaking the craters in sedimentary rocks is smaller than the craters found in crystalline rocks (Ferriere, 2011). Complex craters are well named since they are a lot more complex in comparison to simple craters. The rocks in the center of the craters are generally up lifted and the walls tend to crumble inward (Ferriere, 2011). The rocks that make up the central uplift of complex craters is rock from deep beneath the floor of the crater that has been uplifted by the tremendous force from the initial impact of the meteorite (Gaz et al., 2009).
There is also a form of breccia that is found on the floor of craters. Like most breccia’s, these are made up of fine grained sediment with other fragments of rock set inside; however, the rock fragments are mixed violently and chaotically rather than the more orderly formation found outside of the crater’s rim. This particular type of breccia was first noticed by Danie...
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...large uplifted center and the rock layers are extremely and violently warped and folded similar to a complex crater. However, there is no definite evidence proving or disproving that this formation is a meteor impact site.
Conclusion
There are several common structures associated meteor impact sites. Perhaps the most common and well known is the impact crater, which can be either simple or complex. Another structure is an impact breccia. The breccia is generally located inside along the floor of the crater. Shock-deformation is also a common structure at meteorite impact sites due to the immense velocity meteorites travel at as they impact the Earth’s surface. Due to the nature of shock-deformation, chemical and isotopic signatures can be left behind in the crater from the meteorite. These all together can allow one to identify meteorite impact structures.
However, asteroids are much more deadly. If over-sized meteor can wreck buildings and injure people, then a normal sized asteroid can easily wipe out species if it lands in the right place. As mentioned before, asteroids are much bigger than meteor and much more rare. According to the “Mail Online” 12,000 years ago some type of asteroid slammed into the Northern Canada and some scientist believe that wiped off the mammoths and caused the “Younger Dryas”. Another famous event of asteroids striking, that many scientist believe, was around 65 million years ago asteroids rained and killed of all the dinosaurs 75% of all the life on earth.
The site visited on this day was informally known as the Bedrock Knob (NTS grid reference: 120 342). It is in an area where patches of limestone and exposed bedrock are common. The bedrock is part of the Preca...
...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.
Tarbuck E., Lutgens F., Tasa D., 2014, An Introduction to Physical Geology, 5th Ed, Pearson Education, Upper Saddle River, New Jersey.
Plummer, C.C., McGeary, D., and Carlson, D.H., 2003, Physical geology (10th Ed.): McGraw-Hill, Boston, 580 p.
and Metamorphic rocks can be found. There are also a lot of crusted plates, and violent
about to take place. All a meteor is, is a chunk of rock of that is being
Lipshie, Stephen R. Geologic Guidebook to the Long Valley-Mono Craters Region of Eastern California. Second Edition. South Coast Geological Society. Santa Ana. 2001.
Crater Lake is a result of a volcanic explosion that happened about 7,000 years ago. A long time ago, the pacific oceanic plate was gradually moving under the pacific continental plate in the process of plate tectonics. The pressure shaped the land to move upward and create a line of mountains that are currently located on the Cascade Range. These lavas piled and cooled on top of each other resulting in mountains like Mazama and Hood. Mount Mazama was built by successive flows of both andesite and dacite lavas. Mount Mazama was a stratovolcano, which was about 12,000 feet high after series of ash, cinders, and pumice explosions built it upward. During it?s final eruption the magma chamber was emptying and the underlying support for the mountain was lost and the walls of the volcano began to collapse. In just a matter of days the top of the mountain was destroyed and left a caldera. A caldera is a word used by geologists to describe large basin-shaped volcanic depressions. The destruction Mount Mazama was what marked the beginning of the formation of Crater Lake. The caldera was about 3,000 feet deep and over time, snow and rai...
remains in highest regards among seismologists, engineers and geologists. It is said to be a
The extraterrestrial impact theory is that scientists have found logical evidence for if there was a large asteroid. The biggest point of evidence for it being an asteroid was that there was a 150 kilometer wide crater that was found off the coast of the Yucatan peninsula. Scientists calculated that the asteroid or comet was traveling at 30 kilometers per second. For months, scientists concluded that after the impact, clouds of dust blocked the sun and cooled the Earth to a deadly level for plants, and inturn many animals. After the dust settled, greenhouse gasses created a smolder...
Thousands of years ago when sea levels dropped over years at the Southern end of Muriwai, the sedimentary rock and sandstone was exposed to the air. Rock from volcanic activity mixed with the sedimentary rock; this is called Breccia -- a mixture of all rock. An example of this is at Maori Bay.
In the early morning hours on January 17th, 1994 a very violent tremble took place across Los Angeles, California area that left fifty-seven people dead, more than 7,000 injured, more than 20,000 homeless and left over 40,000 buildings damaged. Around 4:30 a.m. a horrific 6.7 magnitude earthquake, that tested building codes and earthquake-resistant construction, shook Los Angeles, San Bernardino, Ventura, and Orange Counties with the most intense damage occurring in Sherman Oaks and Northridge. The earthquake caused several bridges and overpasses to collapse closing sections of the Santa Monica Freeway, Simi Valley Freeway, Golden State Freeway, and the Antelope Valley Freeway. There were also several fire outbreaks throughout the San Fernando Valley, Malibu, and Venice area because of underground gas lines that had been ruptured during the earthquake that caused additional damage.
inferred for the reservoir (4). The magma ascent to the surface occurred through a conduit of possibly 70 to 100 m in diameter (5). A thermal model predicts that such a reservoir should contain a core of partially molten magma (6) that can be detected by high-resolution seismic tomography.