By noting rocks with both normal and reversed magnetism, the scientists determined that the site dated to the last magnetic reversal, which is known to have occurred about 780,000 years ago.
(the scientists; determined; ) (the site; dated; to the last magnetic reversal) (the last magnetic reversal; is known; ) (the last magnetic reversal; to have occurred; T:about 780,000 years ago)
the scientists the site the last magnetic reversal the last magnetic reversal
determined dated is known to have occurred
to the last magnetic reversal
T:about 780,000 years ago