B. In dating geologic materials, age determinations are often cross-checked by u
ID: 285832 • Letter: B
Question
B. In dating geologic materials, age determinations are often cross-checked by using different isotopes from the same sample. Why is this good science? 2 C. To which geologic Era can you assign the basal granite (uraninite and zircon samples)? 1 pt D. To which geologic Era can you assign the younger granite intrusion (mica samples)? 1pt E. To which geologic Era can you assign the volcanic ash bed? 1 pt F. Combining the radiometric ages and the relative age principles you know, construct a sequence of events for the block diagram. 2 ptsExplanation / Answer
Ans (B) - Radiometric dating! Radioactive elements were incorporated into the Earth when the Solar System formed. All rocks and minerals contain tiny amounts of these radioactive elements. Radioactive elements are unstable; they breakdown spontaneously into more stable atoms over time, a process known as radioactive decay.Thats the reason we used age determination of rocks.
Answer(C) & (D) and (E) - The Basal Granite is from the Permian Period of the Paleozoic Era. Younger granite categories Triassic period of Mesozoic era. The volcanic ash bed is from the Paleogene Period of the Cenozoic Era.
Explanation - Minerals containing Zircon granite its radioactive parents is Uranium 238 and its daughter product is Lead 206 Having Half life of 4500 m.y. Hence older granite categories Archean age.
But Younger Granite categories Triassic period of Mesozoic Era because. Granite that contain Biotite minerals Muscovites Mica minerals and volcanic ash they exist parent product of Potassium 40 and its Daughter product is Argon 40.
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