阅读机经考古 [美洲大陆] 狗主已确认 4月10号

michaelqiao

狗主qq341163712 (ID: 742895)已确认, 原贴http://forum.chasedream.com/GMAT_Math/thread-701364-1-1.html

狗主机经
说是由于坐船去美洲大陆的说法太不靠谱，科学家在多少年以前一直对此不以为然，普遍认为是在冰川时期从阿拉斯加走过去的。
然后根据研究，在多少年之前，不具备走过去的条件。然后在多少年（大概1000年左右吧）之后，就有证据表明美洲有人啦。
所以他们得在这段时间从北走到南。作者认为这样是feat（还是什么词的），大概就是说这个速度很不靠谱。
于是第二段就开始讨论，有人就觉得从海上划船过去挺好，不过划船的话，很难找到证据来证明。（这边是有题的，好像是个细节题）
因为有当初证据的地方被水淹了，成深海区啦。在最后就说什么，就挺有必要去探索深海区，发掘证据什么的。
有个主旨题，其中有一项就是给理由，要去探索深海区什么的，不过狗主没选这个，大家可以讨论下。


考古
63. 美洲
人们在什么时候以何种方式到美洲  共两段，一屏多（有整段高亮（第二段的结构）基本可以靠数字定位,全靠关键定位）

人类何时到达美洲，还有争议。考古的发现显示的最早时间的14,700年前。
第 一个假说是，通过陆路。说人们可以通过COASTAL JOURNEY 沿海岸走，因为爱斯基摩皮船(kayak)太小不太可能做跨海的交通工具。由于ice age，人类不可能于15,700年前通过陆路到达美洲(讲了原因“冰呀，海呀什么的”)。还讲了什么向南走，一个月可以走20里。多少年后到了南美。
第二个假说是，通过海路。但没有证据。由于ice age结束后海平面升高，即使有证据也被淹没了。到海底去挖掘有不太可能。所以还是没有结论。

有主旨题。
第二段全highlight了，问作用。
好像有个15,000到15,500的数字题~


文章大意:
人类经由怎样地方式到达南美洲，还有争议。考古的发现显示的最早时间的14,700年前。旧观点是，通过陆路。因为独木舟(kayak)太小不太可能做跨海的交通工具。由于ice age，人类不可能于15,700年前通过陆路到达美洲。但是旧观点有个问题，就是人移动的速度太快了不合理。学者F提出新观点，通过海路，支持的理由是坐船移动的速度合理。但是因为冰河融化，当时沿岸可住人的地区现在都在海底，很难证明。转折，最新海底考古有证据支持沿岸的确有住人，但是这个证据对於支持海路说还是薄弱的。结论是陆路或海路尚无定论，但对於F学者提出的海路迁移开始时间点(14,000~15,000年前)是普遍被接受的。


**** 下面的文章不是原文，经狗主确认是改写过的 ****

Transportation to the New World is a big topic for debate. 提出问题If the early Americans did cruise巡航 around the continent in canoes and kayaks, might the first settlers have arrived by boat as well? For decades the archaeological community rejected this notion (Ice Agehunters could never have carried all their weapons and left over mammoth meat in such tiny boats!), but in recent years the idea has gathered more support.旧观点反对经由海路假说
One reason for the shift: the nagging困扰的 problem of just how fast people can make the journey from Alaska toTierra del Fuego. 旧观点的问题症结点Consider Dillehay's 14,700-year-old Monte Verde site. According to the previously accepted timeline, people could have made the journey from Asia on foot no earlier than 15,700 years ago(before this time, the ice sheets extending from the North Pole covered Alaskaand Canada completely, making a land passage impossible). If this entry date is correct, the Monte Verde find would indicate that the first settlers had to make the 12,000 -mile trip through two continents in only 1,000 years. In archaeological time, that's as fast as Marion Jones(地球上跑得最快的女人). 提出反对旧观点的理由:行走速度太快? One way to achieve this pace , however,would be by traveling along the Pacific coastlines of North and SouthAmerica in boats. 转折, F提出海路假说新观点Knut Fladmark, a professor of archaeology at Simon Fraser University in Burnaby, BC, first suggested this possibility in the 1970s and remains an advocate of a coastal entry into the Americas. If people had a reason to keep moving, he says, they could have traversed both continents in 100 years. 支持理由:速度符合Fladmark estimates that traveling at a rate of 200 miles a month would have been quite reasonable; the settlers no doubt stopped during winter months and probably stayed in some spots for a generation or so if the local resourceswere particularly tempting. Fladmark's theory, though enticing won't be easy to prove. 让步,提出缺陷Rising sea levels from the melting Ice Age glaciers in undated thousands of square miles along the Pacific coasts of both continents. Any early sites near the ocean that were inhabited before 13,000 years ago would now be deep underwater. 新观点的弱点Recently a few enterprising researchers have attempted to dredge挖出 up artifacts from below the Pacific. In 1997, for example, Daryl Fedje, an archaeologist with Parks Canada (which runs that country's national parks system), led a team that pulled up a small stone tool from 160 feet underwater just off the coast of British Columbia. 提出证据证明新观点The single tool, which Fedje estimates to be around 10,200 years old, does establish that people once lived on the now submerged land but reveals little about the culture there. Excavating underwater sites might turn out to be the only way to prove when humans first arrived on this continent.提出对证据的质疑? And for many researchers this is still a very open question 因为证据力不足，海路说尚未定论, with answers ranging from 15,000 years ago to as far back as 50,000 years ago. When Fladmark first proposed the idea of a coastal migration, the entry date of 14,000 or 15,000 years ago was orthodoxy.公认的,持普遍赞同的
结论是有关F的新观点的开始时间点(14,000~15,000年前)是被普遍接受的

rex44391

小弟也來野人獻曝一下，幫大家補充背景知識，因為最近有看這類的書
白令海峽走過來說
就是有人對clovis point(印地安人用的矛尖，OG12的SC有)做檢測發現其年份約為13500~12900年前。因為和冰河期年份(由地質證據發現)接近，所以有人推測印地安人是西伯利亞的人趁冰河時期跑過來。但這個說法必須解釋印佬怎麼走過白令海峽並穿過加拿大的西部冰原，抵達美洲中部和南部。
大概的說法是印地安人趁著冰河時，白令海峽結冰跑到阿拉斯加。然後”恰巧”加拿大西部冰原在此時解凍，形成了一條走廊讓印佬往南走過去。(注意，這個恰巧是很多人質疑這個理論的地方)
下面有一部分原文(摘錄自一本書:1491)，非考試原文
During the Ice Ages so much of the world’s water was frozen into glaciers that sea levels fell as much as four hundred feet. The strait between Siberia’s Chukotsky Peninsula and Alaska’s Seward Peninsula is now only 56 miles wide and about 120 feet deep, shallower than many lakes. The decline in sea level let the two peninsulas join up. What had been a frigid expanse of whale habitat became a flat stretch of countryside more than a thousand mile wide. Beringia, as this land is called, was surprisingly temperate, sometimes even warmer than it is today; masses of low flowers covered it every spring.
然後又有些證據支持西伯利亞當時適合居住
In Siberia and Alaska, for instance, paleoentomologists(古蟲蟲學家) have discovered in late-Pleistocene sediments fossil beetles and weevils of species that live only in places where summer temperatures reach the fifties.

接下來是說冰原解凍出一條走廊
Beringia was easily traversable. Western Canada was not, because it was buried beneath two massive, conjoined ice sheets, each thousands of feet deep and two thousand miles long.
There was a short period, though, when the barrier could be avoided --- or at least some scientists so believed. The Ice Ages drew to a close about fifteen thousand years ago. As the climate warmed, the glaciers slowly melted and sea level rose; within three thousand years, Beringia had again disappeared beneath the waves. In the 1950s, some geologists concluded that between the beginning of the temperature rise and the resubmergence of the land bridge the inland edges of the two great ice sheets in western Canada shrank, forming a comparatively hospitable pathway between them.

跳島戰術說
接下來，就是有人質疑走廊理論沒證據，不怎麼靠譜。首先就是JJ說的那部份印佬的擴散速度快的太驚人(有人在南美洲最南端發現有印佬的證據，檢定出一個年份，加上前述冰河期的年份，這群傢伙似乎只花了若干年就到南美洲，不過我在另一本書看到這個速度其實符合是正常)。此外有些證據指向印佬更早就來到美洲，不過他們怎麼穿越加拿大的西部冰原就是個問題(因為沒有那個時代冰原曾經解凍的證據)。於是有科學家提出說印佬是用船划向南邊，類似跳島戰術的方式前進。不過這個學說也還正在發展，估計GMAC的王八們也不敢多寫什麼，免得落人口實。以下原文
By examining pollen in the ocean sediments near the pacific coastline, researchers have recently learned that even in the depths of Ice Age warm southern currents created temperate refuges along the shore --- islands of trees and grass in a landscape of ice. Hopping from refuge to refuge, paleo-Indians could have made their way down the coast at any time in the last forty thousand years.(有人提出理由說Even primitive boats could traverse the entire Pacific coast of North and South America in less than 10-15 years.)
然後是證據很困難找到
Evidence for the coastal route is sparse, not least because archaeologists have never looked for paleo-Indian settlements on the shoreline. Future searches will be difficult: thousands of years ago, the melting glaciers raised the sea, inundating coastal settlements, if they existed. But it may not be impossible: in 2008 and 2009, archaeologists reported finding coprolites(印佬留下的屎化石) and a scraping tool that was older than Clovis in a cave just hundred miles from the Pacific Coast. And in 2011, Mexican archaeologists scuba-diving through an immense water-filled cave network in the Yucatan Peninsula --- caverns flooded by rising sea levels after the Ice Age--- announced the startling discovery of the mingled skeletons of a human being and a mastodon in a pit at the end of an underwater tunnel four thousand feet long. Still, the coastal idea has little empirical backing; its supporters tend to endorse the idea mainly because it seems to make sense.(也就是他們也不確定) In addition, the image of a seagoing people fits into a general rethinking of paleo-Indian life.(因為在現代還有很多西岸的印佬靠打魚維生)