You will determine the ages of various materials found in/on the block diagram s

Question

You will determine the ages of various materials found in/on the block diagram shown in Figure 7.7 (in Lab Module 3, labeled as Data Chart and Block Diagram). See below to determine the ages of rock/fossil samples A-E).

Once you determine the ages of the samples and record them in the data table of Data Chart and Block Diagram, you will fill the geologic period (from the Geologic Column found on page 2 of the lab manual or back of front cover of textbook). You will use terms like “Proterozoic, Ordovician, Pleistocene,” for example.

For Sample A,

To determine the age of Sample A on Data Chart and Block Diagram:

1.You are given the percentages of Pb (lead) 206 as 22% and U (uranium) 238 as 78%. Figure 2.6A on page 23 of the lab manual is a graph showing how the ratio of these two elements varies over time as the uranium decays into lead.

2.You need to find the ratio of Lead/Uranium or 22%/78%. We can drop the percentage symbols and merely divide 22/78. Once you have that ratio (decimal number), find that value as carefully as possible on the vertical axis of this graph (Fig. 2.6), read over to the graph line (black sloping line) and at that intersection read down to the time in billions of years.

3.Record this value in the Age column at the top of the sheet and determine and record the geologic period for the “Geologic Column” on this sheet.   Be sure to indicate whether the years are in thousands, millions, or billions.

For Sample B,

1.To determine the age of Sample B, you are given the Argon/Potassium ratio as 0.030. This means that 0.362 half lives have elapsed (my calculation for you to use). You can find the half life of Argon and Potassium (in years) on page 18, Table 2.1.

2.To find the age of Sample B, you need to multiply the number of half lives elapsed (my calculation) times the number of years in one half life from previous step.

For Sample C,

To determine the age of Sample C, you need to use the following formula and the decay constant for Rb/Sr as 1.42 X 10-11.

T = { ( 87Sr / 86Srmeas.) – ( 87SR / 86Srinit. ) } / { (87Rb / 86Srmeas. ) X decay constant }

This is a bit confusing, but I do want you to see that we can do the math. Here’s the substitution of values you need to calculate the age of Sample C.

Sample Cage = (.75) - (.70)   /   (5) X (1.42*10-11)

To determine the age of Samples D and E, use the chart below.

4. LaB You read the 3 Module, Barth History Lab Manual (Eighth Ed open both files and pages and print tn the block Module 3, labeled as Data Chart and Block Diagram) Once you determine the ages of the samples and will determine the ages of various materials found Edition) Dating Lecture in Unit 1 pages and print them out. 5. in/on the block diagram will fill the geologic period (from the Geologic to determine the ages of rock/fossil samples A- nd Block Diagram, cover of textbook). You will use terms like "Protero of Data Chart a ouncne data table For Sample A To determine the age of Sample A on Data Chart and Block Diagraranium) 238 asver time as of the lab manual is a graph showing how the ratio of these two elermer 2oic, Ordovician, Pleistocene, for example. Ordoviciaage 2 of the lab manual or back of front ou are given the percentagesof Pb (lead) 206 as22% and into lead. varies over time as the uranium decays 2.You need to find the ratio ot Lead/uranium or 22%/78% Wer divide 22/78. Once you have that ratio (decimal tlae fnd that value as carefully as possible on the vertical (black sloping line) and at that intersection read down to We can drop the percentage symbols and merely 3 Recobillions of : 2.6), read decmaln 3.Record this value in the Age column at of the as the time in billions years. nd this vals of years. '… over to the gra number Be sr thte top o the sheet and determine and record the geologic period for the whether the years are in thousands, millions, or bililions. For Sample B, 1.To determine the age of Sample B. the Arg half lives have elapsed (my calculation for you to use). You can tind years) on page 18, Table 2.1 2.To find the age of Sample B, number of years in one half life from previous step. you are given the Argon/Potassium ratio as 0.030. This means that 0.362 you to use). You can find the half life of Argon and Potassium (in you need to multiply the number of half lives elapsed (my calculation) times the For Sample C, 1.42 X 1011 1.42 X 10he age of Sample C, you need to use the following formula and the decay constant for Rb/Sr as ) X decay constant) confusing, but I do want you to see that we can do the math. Here's the substitution of values you need to calculate the age of Sample C. Sample Cage (75) -(.70) (5) x (1.4210") You do this math... If you need help with this, please ask on the bulletin board. Be specific in your question, please.

Explanation / Answer

SAMPLE A:

PB/U =0.2821= 1.3 BILLION YEARS FROM TABLE 2.6

SAMPLE B:

POTTASIUM TO ARGON = 1.3 BILLION YEARS HALF LIFE

AGE= 1.3 X .362

    = .471 bilion years

SAMPLE C = 704225352 million years FROM GIVEN EQUATION

SAMPLE D , ACTIVITY IS 1 CT/M/G = 22000 YEARS

SAMPLE E , ACTIVITY IS 8CT/M/G = 6000 YEARS

ALL AGES ARE GIVEN ABOVE, REFERENCE GEOLOGIC COLUMN IS NOT PROVIDED, HENCE PLEASE REFER THE PROVIDED SOLUTIONS WITH GEOLOGIC COLUMN IN YOUR TEXTBOOK AND SOLVE FILL TABLE 7.7.....ALSO, IF YOU THINK I HELPED YOU, PLEASE HIT LIKE

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