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T. rex and the crater of doom essay

Content[ edit ] The book begins by discussing Alvarez's research in the 1970s. The method of this research was to use the evidence of the Earth's magnetic field to show that the plate upon which the rocks of the mountains rested had rotated over millions of years. While investigating limestone deposits in Gubbiothey discovered that some of the rocks were not aligned with the magnetic north polebut in the opposite direction, implying the Earth undergoes geomagnetic reversal over time.

This, with the plentiful fossilized material of extinct foraminiferaallowed them to date the time differences between each reversal and catalog the species of microscopic life found in each era.

In doing so, they discovered that a certain time period had resulted in very few foraminifera fossils being formed, a boundary of little life now known as the Cretaceous—Paleogene boundary or the KT boundary. Just above this boundary, there was a thick t. rex and the crater of doom essay that had no evidence of fossils at all, pointing to an almost complete extinction of microscopic sea life.

This discovery was in direct opposition to the theory of gradualismthe leading belief of the period that evolutionary change occurred slowly across large time periods, rather than in bursts of short, distinct events, a theory known as catastrophism. His father, Luis Alvarezsuggested that the amount of t.

rex and the crater of doom essayan element deposited from cosmic dust at a fixed rate, might provide evidence for his claim. If the amount of iridium in the layer was higher than would be expected, that would imply an asteroid or comet impact had caused impactor dust to fall in high amounts all around the world, building up a higher concentration of iridium.

The amount of iridium when tested was found to be 9 parts per billion ppbrather than the 0. The next step was to determine whether this high concentration of iridium was unique to Gubbio or whether it could be found worldwide, as would be expected for a catastrophic impact event. While locations with clear rock layers of the KT boundary were rare, Alvarez was able to confirm his findings with the Stevns Klint deposits in Zealand.

In order to confirm or rule out this alternative hypothesis, Alvarez worked with Frank Asaro and Helen Michel to determine if the clay layer t. rex and the crater of doom essay contained plutonium-244a distinctive isotope that a supernova would also have deposited if it had been the cause.

While their initial testing came out as positive for the isotope, it turned out to be a false positive under further scrutiny and testing. This caused Alvarez to abandon the supernova possibility and focus singularly on an impact event being the cause. However, Alvarez was uncertain on how such an impact could have wiped out species all around the world. After investigating the effects of the 1883 eruption of Krakatoahe determined that a large enough impact could force enough ash and dust into the atmosphere to block out the sun, leading to a global mass extinction.

Many teams continued to dispute the impact hypothesis, instead theorizing that a volcanic eruption could have been the cause of the mass extinction. An eruption in an area known as the Deccan Traps was dated to the same time period of the boundary, making t. rex and the crater of doom essay eruption hypothesis stronger. The search for an impact crater caused Alvarez to turn to evidence of a tsunamiwhich a large impact would have likely caused if it had occurred in the middle of the ocean.

By the late 1980s, he found evidence at the Brazos river that a tsunami has swept across the Gulf of Mexico millions of years earlier. The discovery was made thanks to a graduate student named Alan Hildebrand that notified Alvarez of the evidence of a crater on the Yucatan peninsulawhich had never been published in the scientific literature by the T. rex and the crater of doom essay petroleum geologists that had found it.

The age of the crater needed to be determined if it was going to be a candidate for the KT boundary impact, but access to the region was limited by the crater being buried over time and the core samples obtained by the geologists had been lost.

T. Rex and the Crater of Doom

The only option Alvarez had left was to find undisturbed sediment left over from the impact still on the surface rock layer somewhere in northeastern Mexico. After several weeks of searching, his team found evidence in a riverbed named Arroyo el Mimbral with the exact signature of the impact that was expected. Several years later, in 1991, the core samples were re-discovered and confirmed the findings from Alvarez's expedition.

Alvarez writes the way he t. rex and the crater of doom essay - with verve, charm, and conciseness. He understands, as Voltaire maintained, that the adjective should be treated as the natural enemy of the noun. Clearly, such a narrative can grow only from intimate understanding of the complex and varied scientific material that, for Alvarez, has fostered poetic, lucid simplification without simplism.

T. Rex and the Crater of Doom Summary

William GlenIsisMarch 1998, pg. Chapmanwriting for Naturestated that Alvarez's "slim" book can be read "in a single sitting and I recommend it highly - if only as a jumping-off point to other perspectives on this dramatic scientific revolution. Just over 65 million years ago an impact happened. But is this responsible for "the crime"?

The jury is still out.