Reference no: EM132848311

Lab worksheet

Description

In this lab we will Investigate the vast intervals of time in which geologists work. The geologic record, as visible in rocks, is a natural work of art that can tell much about the events that occurred in a certain region and even what organ ,SRIS lived there. Its just a matter of knowing how to interpret the clues. First, we will explore the gec logic time sca le using this interactive appl et (also accessed as the link in the first page of the background PDF). In a section on relative tme, we will explain how early geologists unravel the sequence of events that gave us our present Earth. Finally. we will explore the concept of numerical time as we examine how scientists determine the ages of geologic features events and estimate the age of Earth.

Question 1: Based on scientific evidence, the Earth formed roughly 4.5 Ga. By when did the Earth form its first continents and oceans?

Question 2: When did the first multrellular animals appear in the fossil record? They are noticeable with the appearance of shells and other skeletal features appearing in the fossil record at this time.

Question 3: Comparing the divisions in the geologic timescale to their ages, you might notice that they are not evenly spaced out Why might the timescale be much spars, before 550 Ma? Use 2-3 sentences. explain. Hint: read the text from different time periods on the interactive model of the Earth,

Question 4: At which time does cross-cutting first occur?

QUESTION 5: At which time are inclusions first present?

QUESTION 6: At which time are angular unconformities first present?

QUESTION 7: At which time are nonconformities first present?

QUESTION 8: Interpret the sequence of events in the relative time diagram below?. Place the rock units (A-F), unconformity G, and fault H A the correct sequence from youngest (1) to oldest (8). Then answer the following questions (#9- 12) based on your conclusions.

QUESTION 9: Is the fault lire H older than than the rock units B and D?

QUESTION 10: Is rock unit C older than rock units A and F?

QUESTION 11: Is rock unit F younger than rock unit D and E?

QUESTION 12: Is rock unit D younger than rock unit F?

QUESTION 13: Using Steno's Laws of Stratigraphy, interpret the sequence of events to the relative time diagram below. Place the rocks in the correct sequence from youngest (1) to oldest (11).

QUESTION 14: Complete the following table to identify the proportions of pa rent and daughter isotopes that would he formed for an equivalent number of half-lives.

QUESTION 15: Which graph correctly represents the relationship between a parent isotope undergoing radioactive decay and its daughter isotope?

QUESTION 16: The relative proportion (ratio) of parent and daughter isotopes can be used to determine how many half-lives have passed since the formation of the mineral that contains the radioactive isotopes. Complete the chart attached.

QUESTION 17: If a rock started with 1,000 atoms of a parent but now contains 250 parent atoms, how many half lives have passed?

QUESTION 18: The half life of radioactive isotope X is 2 billion years Approximately how much of the parent isotope and its daughter product s present in a rods that is 4.5 billion years old?

QUESTION 19: Using data from the table on the spreadsheet and graph from numbers 15 & 15, complete the table bel ow to estimate the approximate relative proportions of parent and daughter atoms in the oldest dated rock in the Appalachian Mountains which is 1.8 billion years old. For 9 of half-lives, round your answers to 2 decimal places 5e. 1.10}. For% Parent and % Daughter, round your answers to the nearest whole percent (ie. 77).

QUESTION 20: C14 can only he used when we have organic materials which are not present in most rocks. If we were to have organic material in a 1.8 billion year old rock, how many half lives would have passed for the C14 isotopes? Round to the nearest whole number.

QUESTION 21: If 100 grams of Potassium 40 starts to decay, how much Argon 40 will he present in 3.75 billion years?

QUESTION 22: Which of the following radioactive elements would be the best to use to provide an accurate date on rocks that are approximately 9 million years old? Use the table from question 16

QUESTION 23: Could scientists use carbon dating techniques to determine an age for the oldest rocks in the Appalachian Mountains?

QUESTION 24: Imagine that you're investigating the formation of the oldest rocks in the Appalachian Mountains. If it was up to you, would you use fossils to date these rocks? Use 2-3 sentences to explain why or why not.

QUESTION 25: Regardless of fossils, you have collected a sample of one of the oldest rock formations in the Appalachian Mountains, and you'd like to analyze its age using radiometric methods. You take it to a geochronology lab that measures isotopes in rocks for this purpose. The lab's manager says it is up to you to decide which parent-daughter isotope pairing they should treasure for you. Which of the radioactive elements in the table -Half-lives for Common Radioactive Isotopes" (See question .6) would be the best option for measuring a precise date b your rock sample? Provide an clear explanation in 2-3 sentences.

Attachment:- Worksheet geo.rar