Using the potassium-argon laser experiment (KArLE) to date ancient,low-K chondritic meteorites |
| |
| Authors: | Fanny Cattani Barbara A Cohen Cameron M Mercer Agnes J Dahl |
| |
| Institution: | 1. The Catholic University of America, Washington, DC, USA;2. Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA;3. U.S. Geological Survey, Geology, Geophysics, Geochemistry Science Center, Denver, Colorado, USA;4. Department of Earth Sciences, University of Gothenburg, Göteborg, Sweden |
| |
| Abstract: | Several laboratories have been investigating the feasibility of in situ K-Ar dating for use in future landing planetary missions. One drawback of these laboratory demonstrations is the insufficient analogy of the analyzed analog samples with expected future targets. We present the results obtained using the K-Ar laser experiment (KArLE) on two old and K-poor chondritic samples, Pu?tusk and Hvittis, as better lunar analogs. The KArLE instrument uses laser ablation to vaporize rock samples and quantifies K content by laser-induced breakdown spectroscopy (LIBS), Ar by quadrupole mass spectrometry (QMS), and ablated mass by laser profilometry. We performed 64 laser ablations on the chondrites to measure spots with a range of K2O and Ar content and used the data to construct isochrons to determine the chondrite formation age. The KArLE isochron ages on Pu?tusk and Hvittis are 5059 ± 892 Ma and 4721 ± 793 Ma, respectively, which is within the uncertainty of published reference ages, and interpreted as the age of their formation. The uncertainty (2σ) on the KArLE ages obtained in this study is better than 20% (18% for Pu?tusk and 17% for Hvittis). The precision, which compares our obtained ages to the reference ages, is also better than 20% (11% for Pu?tusk and 4% for Hvittis). These results are encouraging for understanding the limits of this technique to measure ancient planetary samples and for guiding future improvements to the instrument. |
| |
| Keywords: | |
|
|
