月度 冰河时期考古。。。去年11-12月寂静

jaychoujj

2.3.3 Milankovitch Cycles关于气候变化和orbit@1讲的是M关于气候变化和orbit的假说，
第二段讲技术发达后发现这个假说有问题然后又说在一个条件下，这个假说还是有价值的，所以又被慢慢接受。
V2
第三篇讲关于地球orbit和气候的改变,两段,第二段整段highlight

作者一开始就说 , 一个人M 在以前做了研究, 好像是用化石层的分布然后发表了理论.说ice age发生是有一定的时间规律..

第二段就说,但是呢,1950年人们用了新科技发现这个M是错的 (有考点). 用着甚么其他地方的化石还是甚么的. 但是呢作者接着说, 1970年人们又用了新科技证明M是对的!!!!! 最后说到虽然到现在M的许多理论都还没被证实 (有考点)
问题

1.有问第二段的作用,  

2.这篇文章的主旨,  

3.那些1950年的人如果用更新的科技的话就不会怎样

(我选就不会不支持M的理论)



V3这篇有点长，先陈述M的研究，第二段又人否认了M的研究，但是接着又有人通过新技术发现，M的研究正确的。尽管M的研究仍然存在一些待解决的问题 12.5

V4 luopite 720 12.6

米兰科维奇的orbit理论，JJ讲的比较详细了，冒个泡而已
题目：

1.如果反驳orbit理论的那波人，他们的evidence 更accurate一些，会如何如何。看了看跟着JJ上对的答案选了，会比较小概率的去质疑M的理论，觉得挺靠谱。

2第2段有highlight的作用

一开始有个研究反驳，然后又出来一个研究为米兰的研究做辩解。最后的结论就是米兰的结论是acceptable的。

V5

还有Milankovitch Cycles Theory ，这篇狗狗超级给力，题目完全一样，就是主旨，第二段highlight，1950年的人如果用更新的科技的话就不会怎样。



考古 2.3.3
Milankovitch Cycles Theory
Milankovitch cycles theory is about the frequency of ice age. Milankovich proposed that the temperature of earth has something to do with the position of the earth in the orbit around sun. However it did not gain acceptance until 1968 when Dr. Imbrie presented additional evidence for M theory. He meassured the isotope level in small seashell deposit and the change of isotope abundancy corresponds with the temperature change.

However, later on, a geochemist tested the samples from Devil's Hole, a place in south Nevada
and the results did not match with the previous results.
Even thought Dr. Imbrie still think M theory was valid, he conceded that many other factors contribute to the isotope level. It maybe why the results did not match.

OLD JJ

V1

是讲某人MM的理论，关于change in earth‘s orbit影响气候什么的，也没看懂……
V2

03/21 第二篇是change in earth orbit. 第一段讲M的理论多牛B，第二段讲50年代的什么试验证明M是错的，然后第二段的后半部分又说原来50年代的试验方法（还是数据？）是错误的，这样的话M的理论又被证明是对的了。

V1

1.先是陈述了这个理论然后说当时人们只能在实验条件不足的情况下大体的承认这个理论

2.但是1950年出了个A.B 研究了一些东西说是理论错误了。导致一段时间内人们都不再接受M的理论了

3.随着科技的进步新的方法（或旧的改良）出现了证明了AB的证据索取是比较片面的  M再次被人们接受

V2

1.先是陈述了这个理论然后说当时人们只能在实验条件不足的情况下有些人研究了一下化石一类的，大体的承认这个理论

2.但是1950年出了个A.B 研究了一些东西，carbon rating之类的，说是理论错误了。（我觉得段时间内人们都不再接受M的理论了.随着科技的进步,应该是旧的改良结合很多其它新的technology, 出现了证明了AB的证据索取是比较片面的  M再次被人们接受。

问题：1. A..B. 对MilankovitchCycles Theory的看法

理论错误了
2. 主题题：

选的不同的方法对某一科学推断的研究和看法(没有一个选项提到了Milankovitch CyclesTheory,所以猜测某一科学推断指代Milankovitch CyclesTheory)。

3．Infer: 说如果第一段那些“当时人们”有accurate carbondating technologies 的时候，他们会怎样？

4. 不记得了MilankovitchCycles Theory的看法

V3

某教授在1920S研究发现冰河期和地球轨道有关，然后是通过化石做了张表来说明。第二段突然说1950S科技进不了，发觉他理论不对了。然后1980S，科技有进步了，说其实1950S是不对的，以前那个教授其实是对的。

V4

米兰先生那个冰河时期的理论，jj的考古很有用，居然4道题！
第二段有考点，就是那个infer的题目，说以前如果也用了carbon那个方法，会怎样
还有就是新的学者（高亮了）认为米兰先生的theory的一个评价。。。

V5

关于Milankovich理论的，
P1.该理论的贡献
P2。该理论受到新的基于quantative和radiocarbon方法的挑战，被数据证实有误，但后来的研究证明上述方法有问题，新的更精确的方法验证了M理论的正确性，因而M理论重新得到认可
问题：1。如果基于quantative和radiocarbon方法得到的结果是正确的，那会有什么结果。（答案都忘了，但此题不易解，干扰项严重）

补充背景知识

http://forum.chasedream.com/GMAT_Math/thread-424461-1-1.html



有益补充1：地球轨道根数变化与第四纪冰期Changes of the Earth's Orbital Elements and the Quaternary Glacial Epoch

米兰柯维奇(Milankovitch)天文气候学理论和第四纪地质时期以来冰期的研究进展.研究结果表明,地球上的冰体积具有近10万yr的变化周期,并伴有近4万yr和2万yr的变化周期,它们是由于地球的轨道根数变化导致的气候变迁所致;不同的地球物理资料中均存在上述类似的变化周期,表明气候变迁所导致的变化是全球性效应,证实米兰柯维奇天文理论是基本正确的。这个像不像jj里讲的mm理论？冰川变化地球轨道



大全上的
Milankovitch proposed in the early twentieth century that the ice ages were caused by variations in the Earth’s orbit around the Sun. For sometime this theory was considered untestable, largely because there was no sufficiently precise chronology of the ice ages with which the orbital variations could be matched.
To establish such a chronology it is necessary to determine the relative amounts of land ice that existed at various times in the Earth’s past. A recent discovery makes such a determination possible: relative land-ice volume for a given period can be deduced from the ratio of two oxygen isotopes, 16 and 18, found in ocean sediments. Almost all the oxygen in water is oxygen 16, but a few molecules out of every thousand incorporate the heavier isotope 18. When an ice age begins, the continental ice sheets grow, steadily reducing the amount of water evaporated from the ocean that will eventually return to it. Because heavier isotopes tend to be left behind when water evaporates from the ocean surfaces, the remaining ocean water becomes progressively enriched in oxygen 18. The degree of enrichment can be determined by analyzing ocean sediments of the period, because these sediments are composed of calcium carbonate shells of marine organisms, shells that were constructed with oxygen atoms drawn from the surrounding ocean. The higher the ratio of oxygen 18 to oxygen 16 in a sedimentary specimen, the more land ice there was when the sediment was laid down.
As an indicator of shifts in the Earth’s climate, the isotope record has two advantages. First, it is a global record: there is remarkably little variation in isotope ratios in sedimentary specimens taken from different continental locations. Second, it is a more continuous record than that taken from rocks on land. Because of these advantages, sedimentary evidence can be dated with sufficient accuracy by radiometric methods to establish a precise chronology of the ice ages. The dated isotope record shows that the fluctuations in global ice volume over the past several hundred thousand years have a pattern: an ice age occurs roughly once every 100,000 years. These data have established a strong connection between variations in the Earth’s orbit and the periodicity of the ice ages.
However, it is important to note that other factors, such as volcanic particulates or variations in the amount of sunlight received by the Earth, could potentially have affected the climate. The advantage of the Milankovitch theory is that it is testable: changes in the Earth’s orbit can be calculated and dated by applying Newton’s laws of gravity to progressively earlier configurations of the bodies in the solar system. Yet the lack of information about other possible factors affecting global climate does not make them unimportant.

1. In the passage, the author is primarily interested in
(A) suggesting an alternative to an outdated research method
(B) introducing a new research method that calls an accepted theory into question
(C) emphasizing the instability of data gathered from the application of a new scientific method
(D) presenting a theory and describing a new method to test that theory
(E) initiating a debate about a widely accepted theory
2.    The author of the passage would be most likely to agree with which of the following statements about the Milankovitch theory?
(A) It is the only possible explanation for the ice ages.
(B) It is too limited to provide a plausible explanation for the ice ages, despite recent research findings.
(C) It cannot be tested and confirmed until further research on volcanic activity is done.
(D) It is one plausible explanation, though not the only one, for the ice ages.
(E) It is not a plausible explanation for the ice ages, although it has opened up promising possibilities for future research.
3.    It can be inferred from the passage that the isotope record taken from ocean sediments would be less useful to researchers if which of the following were true?
(A) It indicated that lighter isotopes of oxygen predominated at certain times.
(B) It had far more gaps in its sequence than the record taken from rocks on land.
(C) It indicated that climate shifts did not occur every 100,000 years.
(D) It indicated that the ratios of oxygen 16 and oxygen 18 in ocean water were not consistent with those found in fresh water.
(E) It stretched back for only a million years.
4.    According to the passage, which of the following is true of the ratios of oxygen isotopes in ocean sediments?
(A) They indicate that sediments found during an ice age contain more calcium carbonate than sediments formed at other times.
(B) They are less reliable than the evidence from rocks on land in determining the volume of land ice.
(C) They can be used to deduce the relative volume of land ice that was present when the sediment was laid down.
(D) They are more unpredictable during an ice age than in other climatic conditions.
(E) They can be used to determine atmospheric conditions at various times in the past.
5.    It can be inferred from the passage that precipitation formed from evaporated ocean water has
(A) the same isotopic ratio as ocean water
(B) less oxygen 18 than does ocean water
(C) less oxygen 18 than has the ice contained in continental ice sheets
(D) a different isotopic composition than has precipitation formed from water on land
(E) more oxygen 16 than has precipitation formed from fresh water
6.    According to the passage, which of the following is (are) true of the ice ages?
I.    The last ice age occurred about 25,000 years ago.
II.    Ice ages have lasted about 10,000 years for at least the last several hundred thousand years.
III.    Ice ages have occurred about every 100,000 years for at least the last several hundred thousand years.
(A) I only
(B) II only
(C) III only
(D) I and only
(E) I, II and III
7.    It can be inferred from the passage that calcium carbonate shells
(A) are not as susceptible to deterioration as rocks
(B) are less common in sediments formed during an ice age
(C) are found only in areas that were once covered by land ice
(D) contain radioactive material that can be used to determine a sediment’s isotopic composition
(E) reflect the isotopic composition of the water at the time the shells were formed
8.    The purpose of the last paragraph of the passage is to
(A) offer a note of caution
(B) introduce new evidence
(C) present two recent discoveries
(D) summarize material in the preceding paragraphs
(E) offer two explanations for a phenomenon
9.    According to the passage, one advantage of studying the isotope record of ocean sediments is that it
(A) corresponds with the record of ice volume taken from rocks on land
(B) shows little variation in isotope ratios when samples are taken from different continental locations
(C) corresponds with predictions already made by climatologists and experts in other fields
(D) confirms the record of ice volume initially established by analyzing variations in volcanic emissions
(E) provides data that can be used to substantiate records concerning variations in the amount of sunlight received by the Earth

OADBCBCEAB

fishmoon29

哇，LZ太伟大了

zhangyina

感觉寂静描述的那篇应该不是大全上的那篇呢~

jaychoujj

感觉寂静描述的那篇应该不是大全上的那篇呢~

-- by 会员 zhangyina (2011/4/12 15:03:31)

恩。对。我觉得也是。把那段几经全复制过来了。前边的是。

conniewang910

考过的同学们来确认
谢谢

moneygmu

感谢LZ。我也觉得大全上的不是JJ的篇。