Biology: The Unity and Diversity of Life (MindTap Course List)
14th Edition
ISBN: 9781305073951
Author: Cecie Starr, Ralph Taggart, Christine Evers, Lisa Starr
Publisher: Cengage Learning
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Chapter 16, Problem 1DAA
Discovery of Iridium in the K-Pg Boundary Sequence In the late 1970s, geologist Walter Alvarez was investigating the composition of the K-Pg boundary sequence 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 sequence in Italy and Denmark. They discovered that it contains a much higher iridium content than the surrounding rock layers. Some of their results are shown in FIGURE 16.18.
Iridium belongs to a group of elements (Appendix I) 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 sequence must have originated with extraterrestrial material. They calculated that an asteroid 14 kilometers (8.7 miles) in diameter would contain enough iridium to account for the extra iridium in the K-Pg boundary sequence.
FIGURE 18.16 Abundance of iridium in and near the K-Pg boundary sequence in Stevns Klint, Denmark. Many rock samples taken from above, below, and at the boundary were tested for iridium content. Depths are given as meters above or below the boundary.
The iridium content of an average Earth rock is 0.4 parts per billion (ppd) of iridium. An average metecrite contains about 550 parts per billion of iridium.
The photo shows Luis and Walter Alvarez with a section of the boundary sequence.
l. What was the iridium content of the K-Pg boundary sequence?
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How much more iridium was found in the K–Pg boundary layer than in rock 0.5 m below it?
41.35 ppb
41.60 ppb
41.24 ppb
39.62 ppb
Activity 5.2
Match This To0
Directions: Match the following terms in Column A with their definitions in Column B.
Column A
Column B
_1.Original horizontality
A. principle which states that sedimentary rocks
are deposited in horizontal layers
B. a gap in the rock record
C. principle which states that oldest rocks are at
the bottom and that each successive layer is
_2. Superposition
_3. Unconformity
younger
_4. Correlation
D. matching of outcrops from one geographic
region to another
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d-ons Help
Last edit was 22 minutes ago
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https://www.youtube.com/watch?v=Wzo UFSZLUA
Watch the video and use ONLY the video to answer the following questions.
1. Is phosphorus found in the atmosphere?In the atmosphere phosphorus can mainly be found as
very small dust particles.
2. Name 5 things that phosphorus does for our planet and for us:
b.
C.
Chapter 16 Solutions
Biology: The Unity and Diversity of Life (MindTap Course List)
Ch. 16 - The number of species on an island depends on the...Ch. 16 - Prob. 2SQCh. 16 - Prob. 3SQCh. 16 - A trait is adaptive if it ______. a. arises by...Ch. 16 - Prob. 5SQCh. 16 - Discovery of Iridium in the K-Pg Boundary Sequence...Ch. 16 - Prob. 2DAACh. 16 - Which of the following is a fossil? a. an insect...Ch. 16 - If the half-life of a radioisotope is 20,000...Ch. 16 - Prob. 8SQ
Ch. 16 - The dinosaurs died out ______ million years ago.Ch. 16 - On the geologic time scale, life originated in the...Ch. 16 - Prob. 11SQCh. 16 - Forces that cause geologic change include ___...Ch. 16 - Radiometric dating does not measure the age of an...Ch. 16 - If you think of geologic time spans as minutes,...
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- Discovery of Iridium in the KPg Boundary Layer In the late 1970s, geologist Walter Alvarez was investigating the composition of the KPg boundary layer in different parts of the world. He asked his father, Nobel Prizewinning 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 Earths crust. The Alvarez group concluded that the KPg 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 KPg boundary layer. Iridium content of rock samples above, below, and at the KPg 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 KPg boundary layer in Stevns Klint. How much higher was the iridium content of the boundary layer than the sample taken 0.7 meter above it?arrow_forwardDiscovery of Iridium in the KPg Boundary Layer In the late 1970s, geologist Walter Alvarez was investigating the composition of the KPg boundary layer in different parts of the world. He asked his father, Nobel Prizewinning 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 Earths crust. The Alvarez group concluded that the KPg 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 KPg boundary layer. Iridium content of rock samples above, below, and at the KPg 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 KPg boundary layer in Stevns Klint. What was the iridium content of the KPg boundary layer?arrow_forwardWhat area would an area look like if a mineral look like if found in an area of volcanic activity?arrow_forward
- A sample of a igneous rock contains small amounts of radioactive potassium and argon. Using the ratio of 40Ar to 40K, it is determined that only 25% of the original parent isotope remained. How old is this rock sample? Please include thought process and a therefore statement. Thank you very much, have a good day!arrow_forwardMost people tend to think that if the sun ever stopped emittinglight, all animal life on Earth would soon end. Populations ofhydrothermal-vent animals might continue to exist for thousands ofyears, however. Explain.arrow_forwardThe heaviest elements during the Earth’s formation were what? What part of the Earth did they form? The lighter elements that formed the Earth included what? What part of the Earth did they form? Where do scientists believe the Earth’s water came from? How old was the Earth believed to be when the first stable land masses formed? What type of rock formed the first stable continents? Why is granite less dense than other rock in the mantle? The tectonic plates “float” on what layer of the Earth? Heat escaping from the Earth’s core creates what? How many tectonic plates can be identified today?arrow_forward
- Highlight one: HOT/COLD What is just like a volcano, but instead it erupts with boiling wate Answer here in a complete sentence: A geyser is like a volcano but shoots oL boiling water. 6. What type of plates that float on top of the mantle do scientists believe that the Earth's crust is made up? Answer here in a complete sentence acer & $ % 7 8 口arrow_forwardRelative dating of sedimentary rock is location specific due to O Differences in fish assemblages between a river and a lake. Sedimentary rocks form in layers, where the top layers represent more recent deposits than lower layers. Differences in sedimentation rates between different bodies of water. O Differences in the rates of carbon 14 accumulation in fish from different water bodies.arrow_forwardIn lakes around the world, some have thick deposits of limestone, which is made up of calcium carbonate, and are resistant to the effects of acid rain. What parallels can you draw between these lakes and the smokestack scrubbers being used in coal-powered factories?arrow_forward
- Question 21 Use the information in the diagram below to answer the questions. R A \U N. A) Which rock layer is oldest (laid down first), J or K? Explain. B) Did Fault N occur before or after rock layer J was deposited? Explain. C) Which happened first, igneous intrusion M or Fault N? Explain.arrow_forwardChanges in the Air To assess the impact of human activity on the carbon dioxide level in Earth's atmosphere, it helps to take a long view. One useful data set comes from deep core samples of Antarctic ice. The oldest ice core that has been fully analyzed dates back a bit more than 400,000 years. Air bubbles trapped in the ice provide information about the gas content in Earth's atmosphere at the time the ice formed. Combining ice core data with more recent direct measurements of atmospheric carbon dioxideas in FIGURE 46.20can help scientists put current changes in the atmospheric carbon dioxide into historical perspective. FIGURE 46.20 Changes in atmospheric carbon dioxide levels (in parts per million). Direct measurements began in 1980. Earlier data are based on ice cores. 4. Was the rise in the carbon dioxide level between 1800 and 1975 larger or smaller than the rise between 1980 and 2013?arrow_forwardChanges in the Air To assess the impact of human activity on the carbon dioxide level in Earth's atmosphere, it helps to take a long view. One useful data set comes from deep core samples of Antarctic ice. The oldest ice core that has been fully analyzed dates back a bit more than 400,000 years. Air bubbles trapped in the ice provide information about the gas content in Earth's atmosphere at the time the ice formed. Combining ice core data with more recent direct measurements of atmospheric carbon dioxideas in FIGURE 46.20can help scientists put current changes in the atmospheric carbon dioxide into historical perspective. FIGURE 46.20 Changes in atmospheric carbon dioxide levels (in parts per million). Direct measurements began in 1980. Earlier data are based on ice cores. The industrial revolution occurred around 1800. What was the trend in carbon dioxide level in the 800 years prior to this event? What about in the 175 years after it?arrow_forward
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