1. 【本月原始】 M.M冰河世纪的理论

　　【V1】

　　还有一个是M.M关于冰河世纪的理论，一开始就说这个M.M很牛逼，不仅预测了地球orbit改变对冰河的改变，也预言了冰层里的内含物，说是冰河世纪其实是温暖与寒冷交替这个样子的。大家都觉得他很了不起之类，但是没有技术去证明

　　但是到了1950年后期，貌似是欧洲和另外一个地方的挖掘证明了M.M的理论很荒谬之类的，然后1950年M.M理论成为笑谈。后面应该还有一些细节，有题目是这个里面。貌似有一个argue是关于这个的。。。

　　到了1970年由于新技术的发展，人们又发现这个M.M的理论是正确的，然后则个M.M的理论又被人所接受。

　　【考古待确定…】

　　P1 astronomer M.M提出了冷热交替的观点，是由于地球沿着太阳的运转轨道导致太阳照射的周期性变化。这个理论一直没有得到广泛的认可，知道J.I通过研究一个跟氧有关的东西(不好意思。。。忘了)才证明了M.M的理论(有题问什么时候M.M理论才被广泛接受or认可or类似的意思)

　　P2 但是最近的调查表明M.M的观点是不对的。好像是叫W的一个人通过调查内华达州的沙漠的一个地方取样得出了不一样的结果，反驳p1中M.M的观点

　　p3 反驳p2中W的观点，认为他这个取样不具有普遍性。支持P1中M.M的观点。这里有对于前边观点的评价。

　　原谅我这不爱背单词的懒人吧。。。好多不认识的，总的来讲不难。。就是不认识

　　Q1印象中问主旨。。。忘了选什么了

　　Q2 从什么时候开始M.M的理论被认可。定位第一段结尾，我选的J.I提出他的研究结果之后

　　Q3 貌似是跟最后一段有关系，但是题目忘记了。。。

　　【疑似背景知识】

　　参考文章

　　(!!!狗主确定不是原文，虽然里面人的名字啊，理论啊是差不多的，但是考试时在第一段里一笔带过了)

　　Milankovitch proposed in the early twentieth century that the ice ages were caused by variations in the Earth’s orbit around the Sun. For some time 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.

　　P1.M提出一个理论, 指出其缺陷

　　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 (calcium carbonate: n.[化]碳酸钙) 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.

　　P2.一个新发现可弥补M理论的缺陷

　　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.

　　P3.新发现的优点

　　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.

　　P4.其他的理论也不容忽视

　　P4.其他的理论也不容忽视

　　补充：参考资料

　　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。他认为，北半球高纬夏季太阳辐射变化是驱动第四纪冰期旋回的主因。这个理论的核心是单一敏感区的触发驱动机制，即北半球高纬气候变化信号被放大、传输进而影响全球。最近，由于大量高分辨率及精确定年的气候变化记录的获得，从以下4个方面构成了对米氏理论的挑战：1)一些低纬地区并没有明显的10万年冰量周期，而是以2万年岁差周期为主，表明北半球冰盖的扩张、收缩变化并没有完全控制低纬区的气候变化;2)在最近几次冰消期时，南半球和低纬区的温度增高，要早于北半球冰盖的融化，表明冰消期的触发机制并非是北半球高纬夏季太阳辐射;3)大气CO2浓度在第2冰消期的增加同南极升温相一致，表明该时大气CO2 浓度增加亦有可能早于北半球冰盖消融;4)南半球的末次冰盛期有可能早于北半球。这就说明单一敏感区触发驱动机制已难以圆满解释所有观察事实，天文因素控 制下轨道尺度气候变化机制研究正面临理论突破的新需求和新机遇。