Abstract:
Prompted by the finding that the eucrite Piplia Kalan could have retained Pu fission Xe earlier than the eucrites so far studied and hence be very ancient, we have measured a precise internal 147Sm-143Nd isochron for this meteorite. The age and initial Nd ratio relative to CHUR are 4.570 +/- 0.023 Ga and -1.3 +/- 0.7 εu, respectively. A Rb-Sr whole rock (clast) isochron for this meteorite corresponds to an age of 3.963 +/- 0.119 Ga and initial 87Sr/86Sr ratio of 0.69902 +/- 3. But initial 87Sr/86Sr ratio calculated for an age of 4.57 Ga is 0.698956 +/- 25, which is indistinguishable from 0.698970 +/- 15 reported for the angrites LEW and ADOR dated at 4.5578 +/- 0.0005 Ga. These results indicating that Piplia Kalan could have formed within only a few million years of the earliest condensates in the Solar System are strongly supported by the recent discovery of live 26Al in it.