时间轴的考古题 我迷糊了 请指教! 答案D

bernadotte

Charcoal from a hearth site in Colorado, 2,000 miles south of Alaska
, is known to be 11,200 years old.  Researchers reasoned that, since glaciers prevented human migration south from the Alaska-Siberia land bridge between 18,000 and 11,000 years ago, humans must have come to the Americas more than 18,000 years ago.




Which of the following pieces of new evidence would cast doubt on the conclusion drawn above?



A.   Using new radiocarbon dating techniques, it was determined that the charcoal from the Colorado site was at least 11,400 years old.

B.   Another campsite was found in New Mexico with remains dated at 16,000 years old.

C.   A computer simulation of glacial activity showed that it would already have been impossible for humans to travel south overland from Alaska 18,500 years ago.

D.   Using new radiocarbon dating techniques, it was proved that an ice-free corridor allowed passage south from the Alaska-Siberia land bridge at least 11,400 years ago.

E.    Studies of various other hunting-gathering populations showed convincingly that, once the glaciers allowed passage, humans could have migrated from Alaska to Colorado
in about 20 years.

biantaishabi

Var så god

bernadotte

tack så mycket!

biantaishabi

18,500 ago---18,000 ago---16,000 ago---11,400 ago---11,200 ago---11,000 ago---now

结论美洲大陆的人一定是在18,000 ago过去的
A: at least 11,400 ago, 可能是18,000之前过来的人活动的痕迹， 不能weaken
B: 16,000 ago, 新墨西哥的人可能是从阿拉斯加走过去的， 不能weaken
C: 在18,500年以前就有人， 不能weaken结论
D: 那个landbridge在11,400 ago还能用， 所以人可能是在11,400 ago和18,000之间过来的， weaken了一定是在18,000 ago前过来的结论
E: 人可以在二十年内从阿拉斯加移动到科罗拉多， 对结论没有影响