They sent samples for chemical analysis to scientists at the Carnegie Institution of Washington, who dated the rocks by measuring isotopes of the rare earth elements neodymium and samarium, which decay over time at a known rate.
其實.....
The oldest rocks, termed "faux amphibolite", were dated within the range from 3.8 to 4.28 billion years old.
個range係3.8 - 4.28億年
Besides, 今次發現是" the oldest rock", 而 the oldest mineral 是zircons (ZrSiO4),4,404 +/- 8Ma作者:
c7 時間: 2008-10-7 01:10 PM