学习英语很简单.doc

1.Although the Mesozoic Era has generally been regarded as dominantly ice free because of the presence of tropical to subtropical fauna and flora at high latitudes，there is some evidence for relatively cool periods，possibly characterized by the local presence of polar ice and，more equivocally，by glacio-eustatic changes in sea level.尽管由于在高纬度地区存在热带和亚热带动植物群，中生代被普遍认为是无冰期的，但是仍有证据表明中生代存在相对凉爽的时期，它很有可能以局部出现的极地冰为特征，更笼统的说，它很有可能以冰川性海平面的升降变化为特征。2.Appreciation of the concept of plate tectonics and its consequences has reinforced the notion that the Earth is an integrated whole not a random collection of isolated parts.板块构造的概念和它的后果鉴别一直被加强观念说地球是一个综合的整体，并不是各个孤立部分的一个随机结合。3.As we enter the 21st century,when the Earths finite resources will be further strained by explosive population growth,earth scientists must strive to better understand our dynamic planet 随着我们进入21世纪，当地球上有限的资源随着爆炸的人口增长变得进一步的紧张的时候地球科学家们必须努力去更好的理解我们的动态行星。4.Below the crystalline hydrates, free gas is commonly present-day. 在水晶水合物之下,游离气在当今是比较普遍的。5.But while much is known about Pangaea(the most recent supercontinent on Earth),the earlier Rodinia supercontinent remains shrouded in mystery.但是当盘古大陆（地球上最近代的超级大陆）的很多东西被知道的时候，更早的罗迪尼亚超级大陆却保持着被遮蔽的神秘。6.By analysing,for example ,the carbonate tests of both benthic and planktic foraminifera ,it is possible to determine the different temperatures of surface and deep ocean waters under which the hard tissue was secreted.比如说，通过分析底栖和浮游有孔生物的碳酸盐实验是有可能确定表层和深层海洋水的不同温度的，在此温度下分泌的硬组织。7.Consequently, residents and State and local officials have become more diligent in planning and preparing for the next day big earthquake. 因此，居民和当地官员对于计划和准备第二天的大地震更加的用心了。8.Despite this almost bimodal approach to paleoceanographic reseach ,a strong common thread is the information provided by isotope proxy signals.尽管这几乎是研究古海洋学的双峰式方法，一个明显的共同点是同位素代理信号提供的信息。9.Detailed work in stratigraphy，sedimentology，paleontology，especially micropaleontology，geochronology，geochemistry，paleomagnetism，physical and geotechnical properties have all contribute to a burgeoning database on paleoceanography extending back to the mid-Mesozoic.在地层学、沉积学、古生物学，尤其是微体古生物学、地质年代学、地球化学、古地磁学、物理和地质技术等方面的细致研究都有助于形成早至中生代中期以来的古海洋学日益丰富的资料库。10.Earths surface is divided into a dozen tectonic plates that either drift apart,creating new oceanic crust,or collide,generating mountain belts such as the Himalayas.地球表面被分为12个构造板块，要么是漂移部分创造的新的海洋地壳，要么是碰撞产生的山体地带像是喜马拉雅山脉。11.Further back in time，he interpretations are less precise and the exercise of reconstructing the ancient paleogeography and paleoceanography becomes a challenge of securing similar data not only from the cores but from sedimentary rocks and crust that now remain on the cratons,，on the margins，or which have been abducted or accreted to accreted to the continental margins. 越往前追溯，这种解释就越不准确，重建古地理学和古海洋学也就成了确保来自地核和沉积岩及地壳类似数据准确的一种挑战，这些沉积岩和地壳有的依然存在于克拉通或地块边缘，有些甚至已经仰冲或增生到大陆边缘。12.Here the focus is on similar but apparently much larger events many tens of 表明了millions of years in the past. 这里的重点是相似的，但是很显然的更大的事件发生在数百万年的过去。13.In this account，I examine those intervals of Jurassic-Cretaceous time where，at least in the context of resolvable time for the Mesozoic Era，abrupt shifts in climate have been recognized.这样，至少在中生代可分辨的情况下，我研究了侏罗纪到白垩纪的一段时期。在此期间，气候的骤变得到验证。14.Many of the Earths natural resources of energy,minerals,and soil are concentrated near past or present plate boundaries.许多能源、矿产和土壤等地球资源都集中靠近在过去或者现在的板块边界。15.More recently ,explanations for anomalous volcanism based on plate tectonics have come to rival the plume model .最近，对于基于构造学板块的反常的火山作用的解释已经能与羽流模型学说相比较16.Most coal originated as peat in ancient swamps created many millions of years ago,associated with the draining and flooding of landmassescaused by changes in sea level related to plate tectonics and other geologic processes.大多数煤都是以泥炭的形式起源于数百万年前的沼泽环境，与由板块构造和其他地质作用而引起的海平面变化所造成陆地的水退和水侵有关17.Most of the metallic minerals mined in the world,such as copper,gold,silver,lead,and zinc,are associated with magmas found deep within the roots of extinct volcanoes located above subduction zones.世界上开采的大多数金属矿物，如铜、金、银、铅和锌等，都与位于消减带上的死火山山根深处所发现的岩浆有关。18.Much of the evidence for rapid climate change in the Palaeocene-Mesozoic interval has been recently interpreted in terms of possibly catastrophic introduction of methane into the ocean-atmosphere system from dissociation of gas hydrates. 在古新世到中生代期间的气候快速变化的许多证据近期已经被解释，这个解释是根据从天然气水合物中分离出来的甲烷引进海洋大气循环系统中可能造成的灾害。19.Of particular importance is the pattern of complete continental assembly during the late Proterozoic and Permian which resulted in a single major ocean on Earth.在元古宙晚期和二叠纪出现的大陆完全拼合的格局是尤其重要的，这种格局造成了地球上一个完整的海洋。20.Only since the advent of high-resolution carbon-and oxygen-isotope stratigraphy in the 1908s have rapid changes in global temperature and carbon cycling been identified in the Mesozoic：such changes are not normally resolvable using classical sedimentary and palaeontological methods.由于二十世纪八十年代出现了高分辨率的碳和氧同位素地层学，认识到中生代发生过全球全球气温和碳循环的迅速变化，这种变化通常不是通过传统的沉积学和古生物学方法就能解析的21.Oxygen isotopes reveal information on ancient temperatures of seawater.氧的同位素揭示了一个古海洋水温度的信息。22.Paleomagnetismthe study of the permanent magnetism in rocks,which provides the latitude and rotation for a continenthas been used to reconstruct the timing of the growth and dispersal of Rodinia.古地磁学是对岩石中永久磁性的研究，它能指明陆块的纬度和旋转等信息，并且已被应用于重建罗迪尼亚超级大陆形成和分解的时间。23.Plate tectonics may turn out to be even more powerful for explaining global volcanism tha was at first sight realized. 板块构造轮也学会比当初的认识更能解释全球火山作用的原因。24.Such a discussion necessary involves some consideration of oceanic anoxic events(OAEs)，recognized as associated with thermal maxima；the implied context is that of a greenhouse worldcharacterized by relatively high levels of atmosphere CO2.这样的讨论必须包括有关海洋生物的缺氧事件的考虑(OAEs),确认为与热极大值有关系；隐含的环境是一个温室里的世界以高含量的二氧化碳为特征。25.Such effects, on millennial time-scales , have been postulated for the Quaternary of the Californian continental margins, based on both carbon-isotope changes in foraminifera and biomarkers in the sediments that indicate the former presence of aerobic and anaerobic methanotrophes .这样的作用效果，在一千年的时间尺度上，被假定作用为第四纪加州大陆边缘上，基于在有孔虫类中碳同位素的变化和沉积物中的生物标记表明了曾经存在有氧运动和厌氧的甲烷微生物。26.The discussion so far has covered the different approaches and issues in paleoceanography that have a physical ,chemical and biological emphasis.目前为止的讨论已经覆盖了在古海洋学中重点在物理、化学和生物方面的不同的方法及存在的问题。27.The emergence of new oceanic crust at oceanic spreading centres is by the eventual destruction of this crust down subduction zones. Movement of ocean floor is typically of order of 5-10cm/yr.在海洋扩张中心的新的海洋地壳是伴随着地壳向下俯冲带的最终尖灭而出现的，典型的大洋底部的运动是以约5-10cm/yr为准的.28.The geochemical fingerprint of methane is singular in that case it is characterized by extremely low carbon-isotope ratios :rapid introduction of this material into the oceans and ocean-atmosphere, and its subsequent near-immediate oxidation to CO2,leaves an obvious geochemical trace as well as as potentially leading to global warming .甲烷的地球化学标记在那种情况下是很奇特的，它的特点是它的碳同位素比率极低，这种物质在快速进入海洋后便会很快氧化为二氧化碳，会留下一个明显的地球化学微量，同时可能导致全球变暖。29.The global effort to better understandthis revolutionary concept has helped to unite the earth-sciences community and to underscore the linkages between the many different scientific disciplines.全球努力去更好的理解这次革命概念有助于团结地球自然的各个团体和强调在很多不同科学学科之间的联系。30.The long-term benefits of plate tectonics should serve as a constant reminder to us that the planet Earth occupies a unique niche in our solar system.板块构造的长期效益应该是做为对我们的一个不变的提醒，地球板块在我们的太阳能系统中占据了一个独特的小生境。31.The metals,originally scattered in trace amounts in magma or surrounding solid rocks,become concentrated by circulating hot fluids and can be redeposited,under favorable temperature and pressure conditions,to form rich mineral veins.原来散布在岩浆和周边固体岩石里的微量金属，通过热体流动而汇集，并且在适当的温度和压力下再沉积，从而形成丰富的矿脉。32.The methane, which derives largely from microbial activity within the sedimentary pile acting upon organic matter that has escaped oxidation by dissolved oxygen, nitrate and sulphate, constitutes a major component of the global carbon cycle .甲烷很大程度上来自微生物活动，它主要是由溶解了氧气、硝酸盐、硫酸盐的有机物沉淀物(避免了氧化)之中产生，它是全球碳循环的一个重要组成部分。33.The models assumed that the geometry of the supercontinent after its formation,remained static until it broke up around 700 million years ago,when AustraliaEast Antarctica rifted off the western margin of Laurentia.这些模型假定超级大陆的几何形状在其形成后保持静止不变，直到7亿年前，当澳大利亚南极大陆东部从劳伦古陆西侧陆缘剥离开后，它才分裂。34.The oceans comprise nearly 70% of the Earths surface，yet as drilling of the ocean crust and overlying sediments progressed under DSDP and ODP，it became evident that the oldest ocean crust，in a few areas such as the northeast Pasific，was only of Late Jurassic age about 160 Ma.海洋占地球表面积的70%，然而，随着深海钻探计划和大洋钻探计划对大洋地壳及其表面沉积物的钻探，清楚地证实，在太平洋的东北地区，最古老洋壳的年龄只是距今约1亿6千万年的晚侏罗纪。35.The Parkfield experiment and other studies carried out by the USGS as part of the National Earthquake Hazards Reduction Program have led to an increased official and public awareness of the inevitability of future earthquake activity in California. 在加利福尼亚，由美国地质勘探局进行的帕克菲尔德试验和其他研究被作为国家地震危害减少计划的一部分已经引起增加公众对未来发生地震的必然性的认识。36.The plate tectonics model ,first proposed in the mid- 1960s ,elegantly accounted for the distribution of most volcanism on Earths surface-that which occurs at plate boundaries .板块构造模型，首次被提出是在1960年中期，充分的说明了大部分火山活动分布在地球表面板块边缘37.The primary observations at otspotsare usually excess magmatism at relatively normal temperatures and unusual geochemistry. 关于“otspots”的主要观察通常是指在相对正常的温度下的多余的岩浆活动和地球化学异常。38.The stick will bend fairly easily , up to a certain point, until the stress becomes too great and it snaps. 这根棍子可以很容易的被弯曲，一直到某一点，一直到压力变得太大以至于棍子断裂。39.The stress that accumulate along a locked segment of the fault and the sudden release can be visualized by bending a stick until it breaks .积累而来的压力随着断层的堵塞段以及它的突然释放可以被想象为弯曲一根棍子知道它断裂。40.The utilization of these readily availableresources has sustained human civilizations,both now and in the past.在过去和现在，这些轻易可用的资源的利用一直维持着人类的文明。41.The volcanic chains associated with many of these melt anomalies (or hotspots ) appeared to all trend in the same as direction and to age regularly along the chains ,suggesting that the hotspots are fixed relative to one another .这些与许多熔融异常有关的火山链似乎朝向相同，而且沿着火山链年龄有规律地增大，这表明热点彼此之间是相对固定的。42.There are few data for the Triassic (although general circulation models suggest an arid Pangaea with no land ice)，but long-term climatic change during the Jurassic-Cretaceous interval，on a scale of stages，has long been recognized，based on faunal，floral and sedimentray evidence.有一些三叠纪的数据（虽然一般的循环表明在干旱环境下不存在冰川），但在从侏罗纪到白垩纪长期的气候变化区间内，长期以来被公认，作为动物，植物和沉积物质的证据。43.These crystalline substances, composed of gas , typically methane and water, are stable under certain pressure-temperature conditions, gas concentrations and water activities, and are known to be present at within the sedimentary prisms that lie along many present-day continental margins at a few hundred metres depth below the sea floor. 这些透明的物质，由气体组成，主要是甲烷和水，在一定的压力温度以及气体浓度和水活力的条件下比较稳定，被已知出现在沉积柱状体之上，即在海底以下几百米的大陆边缘地带。44.This record of past ocean rocks is therefore incomplete and the manner of undertaking paleoceanographic research is significantly different prior to and after the mid-Mesozoic interval.因此，关于过去这份海洋岩石学的记录报告是不完整的，而且从事古海洋学研究的方式在中生代前后是显著不同的。45.This model can radically simplify our view of convection wi