大学新概念英语阅读一

1、大学新概念英语阅读（一）【篇一】PlateTectonicsandSea-floorSpreadingThetheoryofplatetectonicsdescribesthemotionsofthelithosphere,thecomparativelyrigidouterlayeroftheEarththatincludesallthecrustandpartoftheunderlyingmantle.Thelithosphereisdividedintoafewdozenplatesofvarioussizesandshapes,ingeneraltheplatesareinmotion

2、withrespecttooneanother.Amid-oceanridgeisaboundarybetweenplateswherenewlithosphericmaterialisinjectedfrombelow.Astheplatesdivergefromamid-oceanridgetheyslideonamoreyieldinglayeratthebaseofthelithosphere.SincethesizeoftheEarthisessentiallyconstant,newlithospherecanbecreatedatthemid-oceanridgesonlyifa

3、nequalamountoflithosphericmaterialisconsumedelsewhere.Thesiteofthisdestructionisanotherkindofplateboundaryasubductionzone.Thereoneplatedivesundertheedgeofanotherandisreincorporatedintothemantle.Bothkindsofplateboundaryareassociatedwithfaultsystems,earthquakesandvolcanism,butthekindsofgeologicactivit

4、yobservedatthetwoboundariesarequitedifferent.Theideaofsea-floorspreadingactuallyprecededthetheoryofplatetectonics.Initsoriginalversion,intheearly1960's,itdescribedthecreationanddestructionoftheoceanfloor,butitdidnotspecifyrigidlithosphericplates.Thehypothesiswassubstantiatedsoonafterwardbythedis

5、coverythatperiodicreversalsoftheEarth'smagneticfieldarerecordedintheoceaniccrust.Asmagmarisesunderthemid-oceanridge,ferromagneticmineralsinthemagmabecomemagnetizedinthedirectionofthegeomagneticfield.Whenthemagmacoolsandsolidifies,thedirectionandthepolarityofthefieldarepreservedinthemagnetizedvol

6、canicrock.Reversalsofthefieldgiverisetoaseriesofmagneticstripesrunningparalleltotheaxisoftherift.Theoceaniccrustthusservesasamagnetictaperecordingofthehistoryofthegeomagneticfieldthatcanbedatedindependently;thewidthofthestripesindicatestherateofthesea-floorspreading.板块结构与海床扩展板块结构理论描述岩石圈的运动。岩石圈是相对坚硬的

7、地球外层，包括全部地壳和部分地幔。岩石圈被划分为几十个大小不同形状各异的板块，一般来说这些板块都处于相对运动之中。一道中海脊是板块之间的边界，在那里新的岩石圈的物质从下部注入。当板块从中海脊脱离时，它们滑向在岩石圈基部较易变形的地层上。因为地球的大小本质上是不变的，只有同等数量的岩石圈物质在其它地方被吞没，新的岩石圈才能生成。销毁旧岩石圈的地方形成另外一种板块边界：一块潜没的区域。在这里，一块板块潜没到另一板块的边缘之下并结合入地幔之中。两种板块边界均与地层系统、地震以及火山活动相关，但在两种边界处观察到的诸般地质活动却迥然不同。海床扩展说实际上早于板块结构理论。在20世纪60年代它的理论雏形

8、中，描述了海底的生成和毁灭，但没有详细介绍坚硬的岩石圈板块。这个假定不久之后为发现所证实。该发现表明地球磁场周期性的逆转被记录在海洋地壳中。当岩浆从中海脊下涌起的时候，岩浆中的磁铁矿物质按地磁场的方向被磁化。岩浆冷却并凝固下来后，地磁场的方向和磁极被保留在磁化了的火山岩中。磁场的逆转形成一系列与断层轴线平行的条形磁区。这样海洋壳就扮演了磁带的角色，记录下能够鉴定时间的地磁场的历史。条形磁区的宽度表明了海底扩展的速度。【篇三】OilRefiningAnimportantnewindustry,oilrefining,grewaftertheCivilwar.Crudeoil,orpetroleu

9、madark,thickoozefromtheearthhadbeenknownforhundredsofyears,butlittleusehadeverbeenmadeofit.Inthe1850sSamuelM.Kier,amanufacturerinwesternPennsylvania,begancollectingtheoilfromlocalseepagesandrefiningitintokerosene.Refining,likesmelting,isaprocessofremovingimpuritiesfromarawmaterial.Kerosenewasusedtol

10、ightlamps.Itwasacheapsubstituteforwhaleoil,whichwasbecominghardertoget.Soontherewasalargedemandforkerosene.Peoplebegantosearchfornewsuppliesofpetroleum.ThefirstoilwellwasdrilledbyE.L.Drake,aretiredrailroadconductor.In1859hebegandrillinginTitusville,Pennsylvania.Thewholeventureseemedsoimpracticalandf

11、oolishthatonlookerscalledit"DrakesFolly".Butwhenhehaddrilleddownabout70feet(21meters),Drakestruckoil.Hiswellbegantoyield20barrelsofcrudeoiladay.NewsofDrakessuccessbroughtoilprospectorstothescene.Bytheearly1860'sthesewildcattersweredrillingfor"blackgold"alloverwesternPennsylva

12、nia.TheboomrivaledtheCaliforniagoldrushof1848initsexcitementandWildWestatmosphere.Anditbroughtfarmorewealthtotheprospectorsthananygoldrush.Crudeoilcouldberefinedintomanyproducts.Forsomeyearskerosenecontinuedtobetheprincipalone.Itwassoldingrocerystoresanddoor-to-door.Inthe1880srefinerslearnedhowtomak

13、eotherpetroleumproductssuchaswaxesandlubricatingoils.Petroleumwasnotthenusedtomakegasolineorheatingoil.【篇四】译文炼油一种重要的新兴工业一一炼油业在国内战争后成长起来。未加工的石油，或原油一一一种深色的地下的稠浆一一数百年来一直为大众所知，但是人们却很少使用过它。在十九世纪五十年代，萨缪尔M科尔，宾西法尼亚西部的一位制造商，开始从当地的溢出物中收集石油并将它炼成煤油。与冶炼矿石一样，石油提炼是一个从未加工的原料中除去杂质的过程。煤油被用来点灯。它是鲸油的一种便宜的替代品，而鲸油正变得越来越难以获得。不久就产生了对煤油的大量需求。人们开始寻找新的石油供应。第一口油井为EL瑞克，一个退休的火车检票员所钻得。1859年他开始在宾西法尼亚的泰特斯维尔钻井。整个的这项冒险事业看起来是如此不现实和愚蠢以致旁观者称之为“鸭子的蠢行”。（译者注：DrakesFolly,drake在这里意含双关，即指瑞克的名字，又指该词的本义即鸭子。）但当瑞克往下钻至70英尺（21米）的时候，他发现了石油。他的油井从此每天生产20桶原油。瑞