Tertiary Extinction Essay

This researcher proposes that the dinosaurs did not die of heat, in fact she thinks the opposite, that they froze to death instead. Both articles have the same idea about a meteorite hitting the earth yet there is no concrete evidence as to what caused the meteorite to strike and what it did when it got here.

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).

It is difficult to envision that one of the greatest impact craters on Earth that measures up to 180km wide and 900m deep could just vanish just from sight. There have been many different dinosaur extinction theories offered in the recent decades. These range from poisonous plants to mass suicide by dinosaur herds. Although one concept as to how the dinosaurs became extinct has gained a wide acceptance since the 1980’s, involving a major earth impact by a meteor or comet (Icr.org, 2014). This horrific catastrophic event is thought to have extinguished up to two thirds of all animal and plant species, leaving behind a large crater found in Chicxulub, Mexico (LiveScience.com, 2014).

In Stephen Jay Gould’s “Sex, Drugs, Disasters, and the Extinction of Dinosaurs”, Gould investigates three possible theories hypothesizing the reason behind the extinction of dinosaurs. The first theory suggests that dinosaurs became extinct due to a rise in temperature, which caused sperm to die, leading to the sterilization of male dinosaurs. The second hypothesis offer that many dinosaurs consumed bitter plants that contained psychoactive agents which their lives could not detoxify out of their systems. The last speculation about the dinosaur’s extinction is that a large cloud of dust formed in the atmosphere after an asteroid hit Earth’s surface. This dust cloud blocked out the sunlight, causing temperatures to drop and made photosynthesis impossible. Gould uses these three theories to lead to his central claim that science isn’t just about making fascinating claims, but should have a well developed hypothesis.

who theorize that volcanic eruptions could have been the cause for the extinction of dinosaurs

According to Gould essay, the theory of disasters is “a large comet or asteroid struck the Earth some 65 million years ago, lofting a cloud of dust into the sky and blocking sunlight, thereby suppressing photosynthesis and so drastically lowering world temperatures that dinosaurs and hosts of other creatures became extinct.’(50).The theory of disasters proves worthy of more research when compared to the theory of sex and drugs. This is because the disasters theory “generates tests, provides us with things to do, and expands outward” (55). Cowell’s hypothesis (the theory of sex) “has generated nothing for 35 years” because scientists can do nothing with it and the theory of drugs “will win a few press nots and fade into oblivion (54-55). Although talking about asteroids, dust and darkness is no more entertaining than talking about fried testicles or terminal trips “it’s the iridium – the source of testable evidence – that counts and forges the crucial distinction between speculation and science.”(55).The iridium bridges the gap between science and speculation because it is a source of testable evidence. The iridium is testable because geologist determined when high iridium first formed and related it to the comet that struck the Earth. Therefore, the theory of disaster is the most superior evidence for dinosaur extinction when compared to the method of sex and drugs due to its abundant

Scientists gear up to drill into ‘ground zero’ of the impact that killed the dinosaurs

Many people often assume the asteroid completely wiped off the land and marine species with just the impact of the asteroid, but was rather the tipping point of what came next. In fact Choi stated that “ "We have shown that these events are synchronous to within a gnat's eyebrow, and therefore, the impact clearly played a major role in extinctions, but it probably wasn't just the impact.” ( Choi). The ultimate reasons for the dinosaurs and other species extinction was the blockage of sunlight which initially darkened and chilled to earth to extreme temperatures ( Jones). At this point many animals and even plants started to die off because of the chilling conditions, but that wasn't the only reason for the extinction of these species. Soon after the dust had settled and the earth was able to receive light, the planet initiated a greenhouse affect. Which not only put the remaining species at high temperatures, but their food also became inhabitable (Choi). The evidence of an asteroid theory is supported by the impact crater, rare metal, melted rock, fractured crystals, and the fossil record (Jones). The impact crater is actually one the main key examples of why the asteroid may have been responsible for the cretaceous mass extinction. It showed the asteroid landing on the Yucatan peninsula, and traveling at 30 kilometers per second (Jones). Not

The Cretaceous-Paleogene boundary that occurred around 65 million years ago marks one of the three largest mass extinctions in the past 500 million years. The hypotheses of Cretaceous-Tertiary boundary impact on Yucatán Peninsula, Mexico shows evidence in the Gulf of Mexico of turbidity currents, and giant waves occurring because of the impact. There is also other evidence that impact ejecta were distributed all over the world. The mineral that was ejected during this impact was iridium. Iridium is a mineral that is commonly used to indicate a rock layer from the K-T boundary. Iridium is only found naturally on extraterrestrial bodies. In addition to Iridium, shocked quartz is used to indicate the K-T boundary. Shocked quartz is unique and

Some scientists have attributed the extinction to an extraterrestrial event. In 2009, another group of scientists found nanodiamonds in the sediment layer dating back to the Younger Dryas a period of glacial dewarming. Because these nanodiamonds needed conditions similar to that of cosmic impacts to form, they concluded that a large group of comets might have impacted the Earth, causing the Pleistocene extinction (Kennett et. al, 2009). Although the research done on late Pleistocene extinctions was extensive, the conclusions for these explanatory models contradicted one another.

The End Cretaceous impact hypothesis states that an asteroid impact on the earth caused the extinction. The evidence that supports this hypothesis include the crater found in the Yucatan Peninsula, the rare metal Iridium, and fractured “shocked quartz” crystals that have been shown to cause high-energy explosions. The End Cretaceous flood volcanism hypothesis states that a giant volcano eruption, or a series of volcano eruptions caused the extinction The evidence that supports this hypothesis includes immense lava flow, and volcano explosions, which happen to exposed iridium.

Luis Alvarez was a Nobel Prize-winning physicist, inventor and pioneer in the field of radiation and nuclear research. He and his son, noted geologist Walter Alvarez, were conducting research in Italy when they discovered a centimeter-thick layer of iridium-enriched clay at the K-T boundary. Iridium is rare on earth, but more common in space. The Alvarezes published their findings in 1981, postulating that the thin layer of iridium was deposited following the impact of a large meteor, comet or asteroid with the earth. Furthermore, this bolide impact (the meteor, comet or asteroid colliding with the earth's surface) could have caused the extinction of the dinosaurs. At the time, the Alvarez theory was so farfetched from prevailing hypotheses that it was derided. Slowly, other scientists began finding iridium evidence at various places around the globe that corroborated the Alvarez theory. There was, however, no smoking gun in the form of an impact site.

Walter was a geologist, not a paleontologist, however, while researching tectonic plates and magnetic flip-flops, he observed certain sedimentary layers had a sudden lack of fossils. The extinction of dinosaurs was predominantly viewed as a gradual event, but this looked abrupt and catastrophic. Physicists, including Walter’s father, and chemists discovered a surprising amount of iridium, a rare meteorite dust. Additional questions expanded the direction of

According to the research made by Alvarez (1980), it was due to an asteroid impact that single-handedly destroyed dinosaurs to extinction. Advocacy of this mechanism has been aided by the availability and tangibility of supporting evidence in the form of impact craters- the Chicxulub crater in the Yucatan Peninsula's date and timing of impact (dating produced an almost exact date of 65 million years ago), location, enormous size-170 km (Hildebrand et al.1991) and its high iridium content ( a metal not commonly found at the Earth's surface) make it seem that with a theoretical asteroid 10 km big caused the crater great damage at the end of the Cretaceous (Alvarez et al. 1980).

These techniques led to the discovery of the boundary between the two eras. A single thin layer of clay found within predominantly limestone rocks established this. By comparing the marine life found in, above, and below the clay, the marine life, like the dinosaurs, had been terribly affected by the extinction event. The percentage of life in the upper layers was dramatically lower than that in the lower. This was far more compelling than what was suggested by dinosaur’s fossils.