![Biology: The Unity and Diversity of Life (MindTap Course List)](https://www.bartleby.com/isbn_cover_images/9781337408332/9781337408332_largeCoverImage.gif)
Concept explainers
Discovery of Iridium in the K–Pg Boundary Layer In the late 1970s, geologist Walter Alvarez was investigating the composition of the K–Pg boundary layer in different parts of the world. He asked his father, Nobel Prize–winning physicist Luis Alvarez, to help him analyze the elemental composition of the layer. The Alvarezes and their colleagues tested the K-Pg boundary layer in Italy and Denmark, and discovered that it contains a much higher iridium content than the surrounding rode layers (FIGURE 16.17). Iridium belongs to a group of elements that are much more abundant in asteroids and other solar system materials than they are in Earth’s crust. The Alvarez group concluded that the K–Pg boundary layer must have originated with extraterrestrial material.
Sample Depth | Average Abundance of Iridium (ppb) |
+2.7m | <0.3 |
+1.2m | <0.3 |
+0.7m | 0.36 |
boundary layer | 41.6 |
–0.5 m | 0.25 |
–5.4 m | 0.30 |
FIGURE 16.17 Abundance of iridium in and near the K–Pg boundary layer.
Iridium content of rock samples above, below, and at the K–Pg boundary layer in Stevns Klint, Denmark. Sample depths are given as meters above or below the layer. ppb, parts per billion. An average Earth rock contains 0.4 ppb iridium; the average meteorite, 550 ppb. The photo shows Luis and Walter Alverez next to the K–Pg boundary layer in Stevns Klint.
What was the iridium content of the K–Pg boundary layer?
![Check Mark](/static/check-mark.png)
To determine: The iridium content of the K–Pg boundary layer.
Introduction: The iridium is a chemical element that is abundantly found in the Cretaceous–Paleogene (K–Pg) boundary layer. The iridium level in an average rock is about 0.4 ppb, and in an average meteorite, it is about 550 ppb. This allows scientists to conclude whether the origin of the rocks is from the Earth or from any other sources.
Explanation of Solution
As given in the problem statement, Researcher W examined the composition of the K–Pg boundary layer in various parts of the world. He took help from his father to examine the composition of elements in the layer. Researcher L and his colleagues tested the K–Pg boundary layer in Country D and Country I. They discovered that the iridium content was found to be in large quantity than the surrounding rock layers. They also concluded that the boundary layer may have originated with the extraterrestrial material.
Refer to Fig. 16.17, “Abundance of iridium in and near the K-Pg boundary layer”, in the textbook. The given table shows the average abundance of iridium (ppb), and the sample depth (in meters) in Country D. The chemical element iridium was found in abundance on an average of about 41.6 ppb in the K–Pg boundary layer.
The iridium content was 41.6 ppb in the K–Pg boundary layer.
Want to see more full solutions like this?
Chapter 16 Solutions
Biology: The Unity and Diversity of Life (MindTap Course List)
Additional Science Textbook Solutions
Genetics: From Genes to Genomes
Biological Science (6th Edition)
Laboratory Manual For Human Anatomy & Physiology
Campbell Biology in Focus (2nd Edition)
Chemistry: Structure and Properties (2nd Edition)
- What type of stain is the image below: capsule stain endospore stain gram stain negative stain ASM MicrobeLibrary.org Keplingerarrow_forwardWhat is the result of the acid-fast stain below: Stock Images by Getty Images by Getty Images by Getty Images by Getty Image Getty Images St Soy Getty Images by Getty Images by Getty Images Joy Getty encapsulated O endosporulating negative ○ positivearrow_forwardYou have a stock vial of diligence 75mg in 3ml and need to draw up a dose of 50mg for your patient.how many mls should you draw up to give this dosearrow_forward
- You are recquired to administer 150mg hydrocortisone intravenously,how many mls should you give?(stock =hydrocortisone 100mg in 2mls)arrow_forwardIf someone was working with a 50 MBq F-18 source, what would be the internal and external dose consequences?arrow_forwardWe will be starting a group project next week where you and your group will research and ultimately present on a current research article related to the biology of a pathogen that infects humans. The article could be about the pathogen itself, the disease process related to the pathogen, the immune response to the pathogen, vaccines or treatments that affect the pathogen, or other biology-related study about the pathogen. I recommend that you choose a pathogen that is currently interesting to researchers, so that you will be able to find plenty of articles about it. Avoid choosing a historical disease that no longer circulates. List 3 possible pathogens or diseases that you might want to do for your group project.arrow_forward
- not use ai pleasearrow_forwardDNK dagi nukleotidlar va undan sintezlangan oqsildagi peptid boglar farqi 901 taga teng bo'lib undagi A jami H boglardan 6,5 marta kam bo'lsa DNK dagi jami H bog‘lar sonini topingarrow_forwardOne of the ways for a cell to generate ATP is through the oxidative phosphorylation. In oxidative phosphorylation 3 ATP are produced from every one NADH molecule. In respiration, every glucose molecule produces 10 NADH molecules. If a cell is growing on 5 glucose molecules, how much ATP can be produced using oxidative phosphorylation/aerobic respiration?arrow_forward
- Biology Today and Tomorrow without Physiology (Mi...BiologyISBN:9781305117396Author:Cecie Starr, Christine Evers, Lisa StarrPublisher:Cengage LearningBiology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781337408332Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage LearningBiology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781305073951Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage Learning
- Biology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStax
![Text book image](https://www.bartleby.com/isbn_cover_images/9781305117396/9781305117396_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781337408332/9781337408332_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781305073951/9781305073951_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781305967359/9781305967359_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781947172517/9781947172517_coverImage_Textbooks.gif)