Question:
Which one of the following is the CORRECT pair of radioactive parent isotope and the corresponding radiogenic daughter isotope?
Which one of the following is the CORRECT pair of radioactive parent isotope and the corresponding radiogenic daughter isotope?
Show Hint
Recall the standard parent-daughter isotope pairs used in radiometric dating: Rb-87 to Sr-87, Sm-147 to Nd-143, U-238 to Pb-206, U-235 to Pb-207.
Updated On: Jul 20, 2026
- \(^{87}\text{Rb} \rightarrow {}^{86}\text{Sr}\)
- \(^{147}\text{Sm} \rightarrow {}^{143}\text{Nd}\)
- \(^{235}\text{U} \rightarrow {}^{206}\text{Pb}\)
- \(^{238}\text{U} \rightarrow {}^{207}\text{Pb}\)
Show Solution
Verified By Collegedunia
The Correct Option is B
Solution and Explanation
Step 1: Recall the main radiometric dating systems used in geology.
Radiometric dating relies on a radioactive parent isotope decaying at a fixed rate into a stable daughter isotope. Each dating system has its own correct parent-daughter pair, and geologists must know these pairs to date rocks correctly.
Step 2: Check option (A), the Rb-Sr system.
In the rubidium-strontium system, radioactive rubidium-87 decays by beta decay into strontium-87, not strontium-86. Strontium-86 is a separate, stable, non-radiogenic isotope of strontium used as the reference isotope in Rb-Sr dating, not the daughter product. So option (A) is incorrect.
Step 3: Check option (B), the Sm-Nd system.
In the samarium-neodymium system, radioactive samarium-147 decays by alpha decay into neodymium-143. This is the correct parent-daughter pair used in Sm-Nd dating of old igneous and metamorphic rocks. So option (B) is correct.
Step 4: Check option (C), the U-Pb system with U-235.
Uranium-235 belongs to the actinium decay series and decays through a chain of steps into lead-207, not lead-206. Lead-206 is instead the end product of the uranium-238 decay series. So option (C) is incorrect.
Step 5: Check option (D), the U-Pb system with U-238.
Uranium-238 belongs to the uranium decay series and decays through a long chain into lead-206, not lead-207. The daughter isotope given here actually belongs to the uranium-235 chain. So option (D) is incorrect.
Step 6: Final answer.
Only the samarium-neodymium pair is written correctly among the four options.
\[ \boxed{^{147}Sm \rightarrow\ ^{143}Nd} \]
Radiometric dating relies on a radioactive parent isotope decaying at a fixed rate into a stable daughter isotope. Each dating system has its own correct parent-daughter pair, and geologists must know these pairs to date rocks correctly.
Step 2: Check option (A), the Rb-Sr system.
In the rubidium-strontium system, radioactive rubidium-87 decays by beta decay into strontium-87, not strontium-86. Strontium-86 is a separate, stable, non-radiogenic isotope of strontium used as the reference isotope in Rb-Sr dating, not the daughter product. So option (A) is incorrect.
Step 3: Check option (B), the Sm-Nd system.
In the samarium-neodymium system, radioactive samarium-147 decays by alpha decay into neodymium-143. This is the correct parent-daughter pair used in Sm-Nd dating of old igneous and metamorphic rocks. So option (B) is correct.
Step 4: Check option (C), the U-Pb system with U-235.
Uranium-235 belongs to the actinium decay series and decays through a chain of steps into lead-207, not lead-206. Lead-206 is instead the end product of the uranium-238 decay series. So option (C) is incorrect.
Step 5: Check option (D), the U-Pb system with U-238.
Uranium-238 belongs to the uranium decay series and decays through a long chain into lead-206, not lead-207. The daughter isotope given here actually belongs to the uranium-235 chain. So option (D) is incorrect.
Step 6: Final answer.
Only the samarium-neodymium pair is written correctly among the four options.
\[ \boxed{^{147}Sm \rightarrow\ ^{143}Nd} \]
Was this answer helpful?
0
0
Top GATE GG Geology Questions
- A type of fold which is relatively sharp and angular at its synformal and antiformal hinges is known as:
- Which of the following time boundaries correspond(s) to major mass extinction events?
Consider two intersecting, north-easterly striking and south-easterly dipping dikes Y1 and Y2, which are exposed on an east-west trending vertical wall of a granite (X) quarry as shown below.
The angle that the dikes make with the horizontal on the quarry wall is
- Which one of the following statements explains why elements Li, Be, and B have low cosmic abundance?
- During a geochemical exploration survey in a hilly terrain, Cu concentration of stream sediments from a third order basin outlet was measured to be 3000 ppm. Considering a catchment area of 10 km\(^2\) and a Cu background value of 200 ppm, which one of the following options is the productivity of this catchment for Cu?
View More Questions
Top GATE GG Questions
Is there any good show __________ television tonight? Select the most appropriate option to complete the above sentence.
As the police officer was found guilty of embezzlement, he was ___________ dismissed from the service in accordance with the Service Rules. Select the most appropriate option to complete the above sentence.
- The sum of the following infinite series is: \[ 1 + \frac{1}{1!} + \frac{1}{2!} + \frac{1}{3!} + \frac{1}{4!} + \frac{1}{5!} + \dots \]
- A thin wire is used to construct all the edges of a cube of 1 m side by bending, cutting, and soldering the wire. If the wire is 12 m long, what is the minimum number of cuts required to construct the wire frame to form the cube?
The figures I, II, and III are parts of a sequence. Which one of the following options comes next in the sequence at IV?
View More Questions