The Cause of the Dinosaur Extinction Essay

The author and his colleagues specifically chose to focus on 375 million year old rocks in their search for fossils because this was the time frame that provided fish that would be useful to study from. The 385 million year old rocks provided fish that look too similar to the ones we have now and the 365 million year old rocks have fossils that don’t resemble fish. The 375 million year old rocks, however, provide fossils that show the transition between fish and land living animals.

Sedimentary rocks interpret dinosaur habitats through encased environmental structures of the past. Through sedimentary rocks, paleoecologists’ can examine the arranged formation of sedimentary structures to specify what type of environment the dinosaurs’ lived in. An example of a specific sedimentary rock structure can be seen through formed weathering and ripple marks by how wind and sand formed distinct patterns in the past layered sediment. These arrangements provide interpretations on the structure of the sediment and the habitat of encased fossils, through modern day comparisons

He narrowed his hunt down to a location in Denmark, where he had sent a colleague to perform an iridium analysis test at ("Asteroids and Dinosaurs: Unexpected Twists and an Unfinished Story," n.d.). When the results came back, Alvarez knew that whatever happened had not been a small-scale disaster. Once again, Alvarez was back to asking questions. What caused the increased iridium levels at the KT boundary? Except this time, he realized that his observations supported the ten year old hypothesis that had been proposed by paleontologist Dale Russell and physicist Wallace Tucker ("Asteroids and Dinosaurs: Unexpected Twists and an Unfinished Story," n.d.). They brought up the possibility of a supernova being the cause of dinosaur extinction. Supernovas are known to release high amounts of iridium, so such a hypothesis fit perfectly with Alvarez’s team’s discovery. However, the hope of having found a conclusion was short-lived. Luis Alvarez had mentioned that if said supernova had occurred that it would have released amounts of plutonium which would have been found alongside the iridium; no plutonium was found at either site. After more digging, the team came up with a new hypothesis ("Asteroids and Dinosaurs: Unexpected Twists and an Unfinished Story," n.d.). Perhaps an asteroid had struck Earth towards the end of the Cretaceous period, blowing enough dust into the atmosphere to

The fossils in the lower silty layers were most likely formed below water by normal geological processes. The sea level rose covering the organisms and the layers of silt settled above them. In the upper sandy layers the fossils could have been formed above water by a sudden catastrophic event as a result of ongoing erosive processes. The conditions in which the fossils formed were likely a result of wave action which eroded the coast line until it was unstable. When the sea level receded there was a landslide covering the

Dinosaurs ruled the earth for over 65 million years and thankfully for the human race, they became extinct. Ultimately, only a major catastrophe could completely wipe out an entire species, let alone an entity of dinosaurs and the debacle on the causes of dinosaur extinction have flooded the minds of paleontologists for centuries. Geologist and zoologist Stephen Jay Gould published “Sex, Drugs, Disasters, and the Extinction of Dinosaurs,” to compare scientific and speculative causes of dinosaur decimation. Personally, I found this passage very informational and enjoyed reading it. Gould provides three theories that capture the reader’s curiosity, allowing room for pondering in one’s mind.

Assess the different hypotheses put forward for the mass extinctions at the end of the Permian and Cretaceous (KT) Periods.

of a rich Ir anomaly on a global scale within the K/T boundary layers of both marine and continental facies has been interpreted as highly impressive evidence for an impact origin. Another discovery that may serve as a marker of an event is microspherules. A variety of microsherules have been discovered in the PTB layers of the Meishan section (Xu et al., 1989). The origin of the microspherules could be multiple. They are small circular indentations in the rocks and the most abondent elements are Si or Si-Al. Mircospherules are similar to cosmic dust. Since a large amount of microspherules occurs in a thin layer of PTB layer it can serve as another event marker.<br><br>Maxwell (1989) who got his information from Clark et al. (1986) said that<br><br>The elemental in boundary clays across China suggest that there is a remote possibility that the predominantly illite boundary clay is a remote possibility that the predomonantly illite boundary clay resulted from the alteration of ejecta dust from a comet impact, but the most likely source was ash from a massive volcanic eruption.<br><br>The trace elements suggested that the dust was highly acidic and the ratios of TiO2 and AL2O3 are low enough to support the volcanic dust scenario

The asteroid colliding with Earth left evidence in the planets core and mantle with iridium and shocked quartz. Iridium is present in extraterrestrial objects like asteroids and meteorites. The asteroid impact

The most recent and debatably best-known, the Cretaceous–Paleogene extinction event, which occurred approximately 66 million years ago (Ma), was a large-scale mass extinction of animal and plant species in a geologically short period of time.

Further more you can begin to wonder what could have been the explanation for these land and marine species to become extinct. Their have been many explanations and hypothesis to try to explain why these land and marine species became extinct including the belief of plate tectonic shifts. This particular explanation goes along with the belief that shifts in plate tectonics ( which includes the shift in the earths outer most layer) have moved certain species that are more heavily adapted to the sun and shifted them to colder regions and vice versa (Smith). In the text Smith explains how the particular hypothesis used is known as being intrinsic (meaning a natural; and gradual, taking some time to occur (few millions years). The evidence of this particular theory actually being the cause of the cretaceous mass extinction is placed on the sea levels and fossil record. The rise in seas levels have made million year old fossils appear above thousands of feet of present day sea level, which would give the hint that ocean levels fell drastically as the cretaceous period came to an end (Jones). Not only that , but the fossil record shows that dinosaur species didn't dramatically become extinct but gradually declining millions of years before the cretaceous mass extinction actually happened (

Over 98% of all organisms that have lived on Earth are now extinct. A mass extinction event occurs when a large number of species die out within a small time frame (relative to the age of Earth). Mass extinctions are intensively studied for both cause and effect, as there is usually room for debate regarding catalysts that precede the extinction and the massive influx of new biological species that follows. There have been five major mass extinctions, dubbed the “Big Five,” that have wiped out at least 50% of the species living at those times. The most well known mass extinction of the Big Five, with the decimation of every species of non-avian dinosaur, is the Cretaceous-Paleogene

“A minority disputes this theory, arguing that other events-such as volcanic eruptions, sea-level changes or a series of impacts-were to blame for the spectacular loss of species that occurred at the transition between the Cretaceous and Tertiary periods…”

Dinosaur extinction: An analysis of events and theories that possibly led to the dinosaurs' demise.

Gerta Keller, professor of geosciences at Princeton University, has recently conducted research on the Chicxulub asteroid in which she analyzed new core samples taken from the asteroid site (Botzer 2004). These samples indicate that the impact that occurred at Chicxulub actually predated the mass extinction of the dinosaurs, which occurred at the Cretaceous-Tertiary boundary about sixty-five million years ago. Keller claims that the Chicxulub impact occurred approximately 300,000 years before the extinction (Keller 2004). Although previous researchers estimated that the Chicxulub asteroid was the cause of the extinctions, there had always been doubts about the exact age and size of the crater, and about the origin of the “mega tsunami deposits” that were located within the crater (Keller 2004). The focus of Keller’s recent research was on finding some answers to these questions. To do so she analyzed Cretaceous limestone, dolomite, and anhydrite deposits as the site of the Chicxulub crater (Keller 2004).

Rapid climate change also ends up on the suspect list of possible dinosaur extinction events. During the latter part of the Cretaceous Period continents broke up causing volcanoes to erupt and fill the sky with gas and ash resulting in a drastic climate change (“Dinosaurs Climate Change and Biodiversity”). The shifting of continents changed the Earth’s landscape, altering weather patterns and overall climate (“Dinosaur Extinction Theories”). Also, over a long period of time, climate gradually changed. Ocean habits changed, temperatures grew much more extreme causing scorching summers and frigid winters (Norell, Dingus, and Gaffney). Radical temperature changes like these led to a green-house effect, making life for the dinosaurs a lot