00:00For 20 years, scientists have been investigating a major mystery in the fossil record.
00:05More than 7,500 marine fossils from around the world were dated and analyzed.
00:10The goal was to understand why fossils from different time periods can appear in the same sediment layer.
00:16This process is known as time averaging.
00:18Researchers examined fossils from environments ranging from shallow coastal waters to continental shelf edges.
00:25They used radiocarbon dating, along with amino acid analysis, to determine fossil ages.
00:31The study found one factor mattered more than the others.
00:35Sedimentation rate.
00:36When sediment builds up quickly, remains are buried faster and are less likely to mix across generations.
00:42But slow sedimentation can allow fossils from different periods to accumulate together.
00:47Carbon-14 dating also limited the analysis to fossils roughly 55,000 years old or younger.
00:53Researchers say the massive dataset could now support new studies of Earth's ancient environments.
00:59Disclosure.
01:00This video contains stock footage and content created or enhanced using AI-assisted tools.
