Gerta Keller
Encyclopedia
Gerta Keller is a paleontologist who contests the Chicxulub crater
as the location of the meteorite impact, postulated as the cause of the Cretaceous–Tertiary extinction event 65 million years ago by the Alvarez hypothesis
. Keller is currently a professor of Geosciences at Princeton University
.
on a dairy farm, the sixth of 12 children. She grew up in poverty; the unheated room in which she shared a bed with her sister who grew icicles inside the room during the winter. In the one-room schoolhouse where she was educated, boys were given training in math and science while girls were taught cooking and cleaning, the skills they would need to be proper housewives. Her hunger for knowledge led her to read the textbooks assigned to her elder siblings, and she would prepare summaries of the material for her brothers and sisters.
She attended a vocational school starting at age 14 and learned sewing. There she organized a protest against rules that required female students to wear skirts, as she rode her bicycle three miles each way to school and wanted to be able to protect herself from the cold. The female students won the right to wear pants from then on.
After receiving her vocational certificate at age 17, she went to work for Pierre Cardin
, where she was paid the equivalent of 25 cents per hour to sew luxury gowns that would sell for as much as $1,000 for which she was paid $12. She traveled around the world, learning English and working in England
, followed by travel to North Africa, Spain
and Australia
. She survived being shot in a bank robbery in Australia in 1965, despite awakening in a hospital intensive care unit to find a priest asking her to confess, telling her that she was going to die.
After ending up in San Francisco in 1968, Keller was "freaked out" by the shots and tear gas launched at student protests; she chose to focus on education and took a high school equivalency exam. She received her undergraduate degree at San Francisco State University
and received a doctorate in geology
and paleontology
from Stanford University
in 1978.
and Stanford. She came to Princeton University in 1984 and after a few years started studying the K–T boundary
, the geological signature of the Cretaceous-Tertiary extinction event
. Keller's research has led her to conclude that the Chicxulub impact played a major role in the demise of the dinosaurs, but that the mass extinction did not occur until 300,000 years later as the result of a second meteor impact whose impact site is unknown but may lie at the bottom of what is now the Indian Ocean
(Shiva crater
). Keller's analysis of the sedimentary evidence led her to conclude that the K-T boundary layer had been laid down over a 300,000-year period, stating that "I'm sure the day after, they had a headache," but that "we vastly overestimate the damage to the environment and to life that this Chicxulub impact had" in killing off the dinosaurs.
The main evidence for the Alvarez hypothesis
that a single impact resulted in the Cretaceous–Tertiary extinction event that killed the dinosaurs has come from the presence around the world of shocked quartz
granules, glass spherules and tektites embedded in a layer of clay with extremely high levels of iridium
, all signs of an asteroid impact. Keller's research found layers where the glass spherules and the iridium clay are found separated by as much as 8 feet (2.4 m) of sandstone and other material. Supporters of the Alvarez theory believe that the sandstone is the result of a massive tsunami
that sandwiched the sand from the massive waves triggered by the impact between the shocked quartz layer and the iridium clay. Keller's analysis of the strata between the spherules and iridium clay contain signs that the material was laid down over as much as 300,000 years based on signs of plankton, worms and weathering found on the intervening material.
Chicxulub Crater
The Chicxulub crater is an ancient impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is located near the town of Chicxulub, after which the crater is named...
as the location of the meteorite impact, postulated as the cause of the Cretaceous–Tertiary extinction event 65 million years ago by the Alvarez hypothesis
Alvarez hypothesis
The Alvarez hypothesis claims that the mass extinction of the dinosaurs and many other living things was caused by the impact of a large asteroid on the Earth sixty-five million years ago, called the Cretaceous-Tertiary extinction event. Evidence indicates that the asteroid fell in the Yucatán...
. Keller is currently a professor of Geosciences at Princeton University
Princeton University
Princeton University is a private research university located in Princeton, New Jersey, United States. The school is one of the eight universities of the Ivy League, and is one of the nine Colonial Colleges founded before the American Revolution....
.
Early life and education
Keller was raised in SwitzerlandSwitzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
on a dairy farm, the sixth of 12 children. She grew up in poverty; the unheated room in which she shared a bed with her sister who grew icicles inside the room during the winter. In the one-room schoolhouse where she was educated, boys were given training in math and science while girls were taught cooking and cleaning, the skills they would need to be proper housewives. Her hunger for knowledge led her to read the textbooks assigned to her elder siblings, and she would prepare summaries of the material for her brothers and sisters.
She attended a vocational school starting at age 14 and learned sewing. There she organized a protest against rules that required female students to wear skirts, as she rode her bicycle three miles each way to school and wanted to be able to protect herself from the cold. The female students won the right to wear pants from then on.
After receiving her vocational certificate at age 17, she went to work for Pierre Cardin
Pierre Cardin
Pierre Cardin Cardin was known for his avant-garde style and his Space Age designs. He prefers geometric shapes and motifs, often ignoring the female form. He advanced into unisex fashions, sometimes experimental, and not always practical...
, where she was paid the equivalent of 25 cents per hour to sew luxury gowns that would sell for as much as $1,000 for which she was paid $12. She traveled around the world, learning English and working in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, followed by travel to North Africa, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. She survived being shot in a bank robbery in Australia in 1965, despite awakening in a hospital intensive care unit to find a priest asking her to confess, telling her that she was going to die.
After ending up in San Francisco in 1968, Keller was "freaked out" by the shots and tear gas launched at student protests; she chose to focus on education and took a high school equivalency exam. She received her undergraduate degree at San Francisco State University
San Francisco State University
San Francisco State University is a public university located in San Francisco, California. As part of the 23-campus California State University system, the university offers over 100 areas of study from nine academic colleges...
and received a doctorate in geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
and paleontology
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
from Stanford University
Stanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
in 1978.
Paleontology
After earning her doctorate, Keller worked for the United States Geological SurveyUnited States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
and Stanford. She came to Princeton University in 1984 and after a few years started studying the K–T boundary
K–T boundary
The K–T boundary is a geological signature, usually a thin band, dated to 65.5 ± 0.3 Ma ago. K is the traditional abbreviation for the Cretaceous period, and T is the abbreviation for the Tertiary period...
, the geological signature of the Cretaceous-Tertiary extinction event
Cretaceous-Tertiary extinction event
The Cretaceous–Paleogene extinction event, formerly named and still commonly referred to as the Cretaceous-Tertiary extinction event, occurred approximately 65.5 million years ago at the end of the Maastrichtian age of the Cretaceous period. It was a large-scale mass extinction of animal and plant...
. Keller's research has led her to conclude that the Chicxulub impact played a major role in the demise of the dinosaurs, but that the mass extinction did not occur until 300,000 years later as the result of a second meteor impact whose impact site is unknown but may lie at the bottom of what is now the Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
(Shiva crater
Shiva crater
The Shiva crater is a sea floor structure located beneath the Indian Ocean, west of Mumbai, India. It was named by the paleontologist Sankar Chatterjee after Shiva, the Hindu god of destruction and renewal....
). Keller's analysis of the sedimentary evidence led her to conclude that the K-T boundary layer had been laid down over a 300,000-year period, stating that "I'm sure the day after, they had a headache," but that "we vastly overestimate the damage to the environment and to life that this Chicxulub impact had" in killing off the dinosaurs.
The main evidence for the Alvarez hypothesis
Alvarez hypothesis
The Alvarez hypothesis claims that the mass extinction of the dinosaurs and many other living things was caused by the impact of a large asteroid on the Earth sixty-five million years ago, called the Cretaceous-Tertiary extinction event. Evidence indicates that the asteroid fell in the Yucatán...
that a single impact resulted in the Cretaceous–Tertiary extinction event that killed the dinosaurs has come from the presence around the world of shocked quartz
Shocked quartz
Shocked quartz is a form of quartz that has a microscopic structure that is different from normal quartz. Under intense pressure , the crystalline structure of quartz will be deformed along planes inside the crystal...
granules, glass spherules and tektites embedded in a layer of clay with extremely high levels of iridium
Iridium
Iridium is the chemical element with atomic number 77, and is represented by the symbol Ir. A very hard, brittle, silvery-white transition metal of the platinum family, iridium is the second-densest element and is the most corrosion-resistant metal, even at temperatures as high as 2000 °C...
, all signs of an asteroid impact. Keller's research found layers where the glass spherules and the iridium clay are found separated by as much as 8 feet (2.4 m) of sandstone and other material. Supporters of the Alvarez theory believe that the sandstone is the result of a massive tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
that sandwiched the sand from the massive waves triggered by the impact between the shocked quartz layer and the iridium clay. Keller's analysis of the strata between the spherules and iridium clay contain signs that the material was laid down over as much as 300,000 years based on signs of plankton, worms and weathering found on the intervening material.
External links
- Keller's faculty page from princeton.edu
- "Chicx comes home to roost", Geoscientist Online, June 18, 2007
- "Impact Factor", Geoscientist Online, June 18, 2007