T. Rex and the Crater of Doom
   HOME

TheInfoList



OR:

''T. rex and the Crater of Doom'' is a
nonfiction Nonfiction, or non-fiction, is any document or media content that attempts, in good faith, to provide information (and sometimes opinions) grounded only in facts and real life, rather than in imagination. Nonfiction is often associated with be ...
book by professor
Walter Alvarez Walter Alvarez (born October 3, 1940) is a professor in the Earth and Planetary Science department at the University of California, Berkeley. He is most widely known for the theory that dinosaurs were killed by an asteroid impact, developed in c ...
that was published by
Princeton University Press Princeton University Press is an independent publisher with close connections to Princeton University. Its mission is to disseminate scholarship within academia and society at large. The press was founded by Whitney Darrow, with the financial su ...
in 1997. The book discusses the research and evidence that led to the creation of the
Alvarez hypothesis The Alvarez hypothesis posits that the Extinction event, mass extinction of the non-avian dinosaurs and many other living things during the Cretaceous–Paleogene extinction event was caused by the Impact event, impact of a large asteroid on the ...
, which explains how an
impact event An impact event is a collision between astronomical objects causing measurable effects. Impact events have physical consequences and have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or me ...
was the main cause that resulted in the
Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...
.


Content

The book begins by discussing Alvarez's research in the 1970s, before ever investigating the cause of the Cretaceous–Paleogene extinction event, when he was researching
plate tectonics Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large ...
involving the
Apennine Mountains The Apennines or Apennine Mountains (; grc-gre, links=no, Ἀπέννινα ὄρη or Ἀπέννινον ὄρος; la, Appenninus or  – a singular with plural meaning;''Apenninus'' (Greek or ) has the form of an adjective, which wou ...
with William "Bill" Lowrie. 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 Gubbio, they discovered that some of the rocks were not aligned with the magnetic north pole, but in the opposite direction, implying the Earth undergoes geomagnetic reversal over time. This, with the plentiful fossilized material of extinct foraminifera, allowed 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 The Cretaceous–Paleogene (K–Pg) boundary, formerly known as the Cretaceous–Tertiary (K–T) boundary, is a geological signature, usually a thin band of rock containing much more iridium than other bands. The K–Pg boundary marks the end of ...
or the KT boundary. Just above this boundary, there was a thick layer 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
gradualism Gradualism, from the Latin ''gradus'' ("step"), is a hypothesis, a theory or a tenet assuming that change comes about gradually or that variation is gradual in nature and happens over time as opposed to in large steps. Uniformitarianism, incrementa ...
, the 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 In geology, catastrophism theorises that the Earth has largely been shaped by sudden, short-lived, violent events, possibly worldwide in scope. This contrasts with uniformitarianism (sometimes called gradualism), according to which slow increment ...
. Suspecting that the layer without fossilized remains was evidence of a catastrophic event, Alvarez set out to determine how quickly the layer of clay had been deposited, which would either prove or disprove his hypothesis. His father, Luis Alvarez, suggested that the amount of iridium, an 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 (ppb), rather than the 0.1 ppb that would have accumulated naturally in the layer. 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 Stevns Klint, known as the Cliffs of Stevns in English, is a white chalk cliff located some southeast of Store Heddinge on the Danish island of Zealand. Stretching along the coast, it is of geological importance as one of the best exposed Cre ...
deposits in Zealand. Alvarez's hypothesis at the time conflicted over whether an impact was the cause or whether the iridium had been deposited by a
supernova A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or when ...
from a nearby star, which could have also killed most life on Earth due to
gamma ray bursts In gamma-ray astronomy, gamma-ray bursts (GRBs) are immensely energetic explosions that have been observed in distant galaxies. They are the most energetic and luminous electromagnetic events since the Big Bang. Bursts can last from ten milli ...
and
cosmic radiation Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...
. In order to confirm or rule out this alternative hypothesis, Alvarez worked with Frank Asaro and
Helen Michel Helen Vaughn Michel (born 1932) is an American chemist best known for her efforts in fields including analytical chemistry and archaeological science, and specific processes such as neutron activation analysis and radiocarbon dating. Her work ...
to determine if the clay layer also contained
plutonium-244 Plutonium-244 (244Pu) is an isotope of plutonium that has a half-life of 80 million years. This is longer than any of the other isotopes of plutonium and longer than any other actinide isotope except for the three naturally abundant ones: uranium ...
, a 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 An impact event is a collision between astronomical objects causing measurable effects. Impact events have physical consequences and have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or me ...
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 Krakatoa The 1883 eruption of Krakatoa ( id, Letusan Krakatau 1883) in the Sunda Strait occurred from 20 May until 21 October 1883, peaking in the late morning hours of 27 August when over 70% of the island of Krakatoa and its surrounding archipelago w ...
, he 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. By 1980, evidence of the KT boundary and high iridium levels had been independently reported on at dozens of other sites, moving Alvarez's hypothesis toward a global hunt for the impact crater, in competition with several other scientists such as Jan Smit. 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 The Deccan Traps is a large igneous province of west-central India (17–24°N, 73–74°E). It is one of the largest volcanic features on Earth, taking the form of a large shield volcano. It consists of numerous layers of solidified flood ...
was dated to the same time period of the boundary, making the eruption hypothesis stronger. The search for an impact crater caused Alvarez to turn to evidence of a tsunami, which 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 The Brazos River ( , ), called the ''Río de los Brazos de Dios'' (translated as "The River of the Arms of God") by early Spanish explorers, is the 11th-longest river in the United States at from its headwater source at the head of Blackwater Dr ...
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 Alan Russell Hildebrand (born 1955) is a planetary scientist and Associate Professor in the Department of Geoscience at the University of Calgary. He has specialized in the study of asteroid impact cratering, fireballs and meteorite recovery. His ...
that notified Alvarez of the evidence of a crater on the Yucatan peninsula, which had never been published in the scientific literature by the Mexican 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 due to the crater having been buried over time and the
core samples A core sample is a cylindrical section of (usually) a naturally-occurring substance. Most core samples are obtained by drilling with special drills into the substance, such as sediment or rock, with a hollow steel tube, called a core drill. The ...
obtained by the geologists having been lost. 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.


Style and tone

In a review for '' Geological Magazine'', Simon Conway Morris noted that the controversy and debate over the impact hypothesis had led to comments against it that are "querulous, petulant, otiose, and sometimes simply poisonous", but that Alvarez's book "acknowledges the differences that have arisen, but never does he descend to insult and injury", leading to a "gracious and generous book". Timothy Ferris, writing for '' The New York Times'', stated that Alvarez "gets the facts across in a lighthearted, almost playful manner", but still manages to present "solid science" that presents a "clear and efficient exposition that conveys plenty of cogent detail while keeping an eye on the subtle interplay of thought, action and personality that makes scientific research such arresting human behavior."


Critical reception

Clark R. Chapman, writing for '' Nature'', stated 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." In a review for '' Scientific American'' of ''T. rex and the Crater of Doom'' and the opposing theories presented in ''The Great Dinosaur Extinction Controversy'',
Michael Benton Michael James Benton One or more of the preceding sentences incorporates text from the royalsociety.org website where: (born 8 April 1956) is a British palaeontologist, and professor of vertebrate palaeontology in the School of Earth Sciences ...
advocated reading the book "for an excellent account of the pro-impact position and for insight into how scientists pose questions and seek to resolve them by sometimes roundabout means". For '' The Quarterly Review of Biology'', paleontologist
Mark Norell Mark Allen Norell (born July 26, 1957) is an American paleontologist, acknowledged as one of the most important living vertebrate paleontologists. He is currently the chairman of paleontology and a research associate at the American Museum of Na ...
reviewed the book, criticizing it for not presenting more connective evidence between the impact and the saurian extinction event, stating, "the evidence marshaled by Alvarez is conclusive. Just over 65 million years ago an impact happened. But is this responsible for "the crime"? The jury is still out." William Glen, in the journal '' Isis'', explained how the book presented in "simple, compelling language a fascinating autobiographical chronicle of cutting-edge scientific research that includes much not yet known to history" and that it was "indispensable for anyone interested in the science, the history, or life in science." '' Los Angeles Times'' writer Dave A. Russell said that the book was "very well written and so engrossing that a reader with little or no background in the earth's geologic history will enjoy an easy and vastly entertaining summary of how we came to our present understanding of the past." Douglas Palmer in '' New Scientist'' described the historical story as a reading similar to "Arthurian legend, full of temptations which lead the hero astray and distract him and his followers from the true path" and that "this personal account of the search for a geological Excalibur makes fascinating reading."


References

{{reflist


External links


''T. rex and the Crater of Doom''
on the
Princeton University Press Princeton University Press is an independent publisher with close connections to Princeton University. Its mission is to disseminate scholarship within academia and society at large. The press was founded by Whitney Darrow, with the financial su ...
, Publisher website 1997 non-fiction books Dinosaur books Paleontology books Geology books