Original: By using radiometric dating techniques , the volcanic tuffs and lavas , faunal correlation and magneto-stratigraphy , the strata in which the fossils were found were estimated to date between 6.1 and 5.8 million years ago , during the Miocene .
Simplified: Orrorin tugenensis which the fossils were found were estimated to date between 6.1 and 5.8 million years ago , during the Miocene .