U_Pb_Geochronology

4 08 207 pb206pb age 3496 101 pb loss array 04 040 041

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Unformatted text preview: lverine Porphyry • How do we interpret this now because we have two concordant fractions? • Because it is a young rock we use the 206Pb/238U ages (due to steepness of concordia curve; in older rocks, i.e., Archean, we’d use the 207Pb/235U ages). Fraction 206Pb/238U age +/- %2σ A 347.8 1.2 G 348.4 0.8 Wednesday, 15 August, 12 Example: Wolverine Porphyry • How do we interpret this now because we have two concordant fractions? • Because it is a young rock we use the 206Pb/238U ages (due to steepness of concordia curve; in older rocks, i.e., Archean, we’d use the 207Pb/235U ages). Fraction 206Pb/238U age +/- %2σ A 347.8 1.2 G 348.4 0.8 Fraction 206Pb/238U age +/- %2σ Max Age Min Age A 347.8 1.2 349 346.6 G 348.4 0.8 349.2 347.6 Wednesday, 15 August, 12 Example: Wolverine Porphyry • How do we interpret this now because we have two concordant fractions? • Because it is a young rock we use the 206Pb/238U ages (due to steepness of concordia curve; in older rocks, i.e., Archean, we’d use the 207Pb/235U ages). Fraction 206Pb/238U age +/- %2σ A 347.8 1...
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This document was uploaded on 03/06/2014 for the course ES 4502 at Memorial University.

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