When the discovery of fossilized (化石的) footprints made in what’s now New Mexico was made public in 2021, it was an astonishing moment for archaeology (考古学), seemingly rewriting a chapter of the human story. Now new research is offering further evidence of their significance.
While they look like they could have been made yesterday, the footprints were pressed into mud 21,000 to 23,000 years ago, according to radiocarbon dating of the seeds of a water plant that were preserved above and below the fossils. This date dramatically pushed back the timeline of humans’ history in the Americas, the last land to be settled by prehistoric people. The 61 dated prints, which were discovered in the Tularosa Basin, near the edge of an ancient lake in White Sands National Park, were made at a time when many scientists think that massive ice sheets had stopped human passage into North America, indicating that humans arrived in the region even earlier.
However, some archaeologists questioned the age of the footprints established by those initial findings. They noted that water plants such as Ruppia cirrhosa — the one used in the 2021 study — can acquire carbon atoms from the water rather than the air, which can result in a misleadingly early date.
In a follow-up study published Thursday in the journal Science, researchers said they have produced two new lines of evidence to support their initial dates. “Even as the original work was being published, we were speeding up to test our results with multiple lines of evidence,” said Kathleen Springer, co-lead author on the new Science paper, in a news release. “We were confident in our original ages, as well as the strong evidence.”
When and how early humans first moved to the Americas has long been debated and remains poorly understood. Current estimates range from 13,000 years ago to more than 20,000 years ago. However, the earliest archaeological evidence for the region’s settlement is insufficient and often controversial, making the footprints especially important.
12. What is Paragraph 2 mainly about?
A.The purpose of the new research | B.The method of the dating |
C.The significance of the footprints. | D.The efforts of the scientists |
13. Why did some archaeologists question the age of the footprints?
A.It goes against the prior knowledge. |
B.The prints seem to be made recently. |
C.The previous research method is improper. |
D.The then massive ice sheets are misleading. |
14. What will the author probably talk about next?
A.The doubt about the age of the footprints. |
B.The new evidence of the fossilized footprints. |
C.An agreement between the two sides of the debate. |
D.Early humans hardship of moving to the Americas. |
15. What is the purpose of the text?
A.To explain the process of archaeological study. |
B.To report the discovery of fossilized footprints. |
C.To introduce a debate on the age of the footprints. |
D.To present the progress of the footprint research. |