哈工大考博英语真题及答案

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1、GeneralEnglishAdmissionTestForNon-EnglishMajorPh.D.program(HarbinInstituteofTechnology)PassageOneQuestions1-7arebasedonthefollowingpassage:Accordingtoarecenttheory,Archean-agegold-quartzveinsystemswereformedovertwobillionyearsagofrommagmaticfluidsthatoriginatedfrommoltengranitelikebodie

2、sdeepbeneaththesurfaceoftheEarth.Thistheoryiscontrarytothewidelyheldviewthatthesystemsweredepositedfrommetamorphicfluids,thatis,fromfluidsthatformedduringthedehydrationofwetsedimentaryrocks.Therecentlydevelopedtheoryhasconsiderablepracticalimportance.Mostofthegolddepositsdiscovereddurin

3、gtheoriginalgoldrusheswereexposedattheEarth’ssurfaceandwerefoundbecausetheyhadshedtrailsofalluvialgoldthatwereeasilytracedbysimpleprospectingmethods.Althoughthesesamemethodsstillleastoanoccasionaldiscovery,mostdepositsnotyetdiscoveredhavegoneundetectedbecausetheyareburiedandhavenosurfac

4、eexpression.Thechallengeinexplorationisthereforetounravelthesubsurfacegeologyofanareaandpinpointthepositionofburiedminerals.Methodswidelyusedtodayincludeanalysisofaerialimagesthatyieldabroadgeologicaloverview,geophysicaltechniquesthatprovidedataonthemagnetic,electrical,andmineralogicalp

5、ropertiesoftherocksbeinginvestigated,andsensitivechemicalteststhatareabletodetect:thesubtlechemicalhalosthatoftenenvelopmineralization.However,noneofthesehigh-technologymethodsareofanyvalueifthesitestowhichtheyareappliedhavenevermineralized,andtomaximizethechancesofdiscoverytheexplorerm

6、ustthereforepayparticularattentiontoselectingthegroundformationsmostlikelytobemineralized.Suchgroundselectionreliestovaryingdegreesonconceptualmodels,whichtakeintoaccounttheoreticalstudiesofrelevantfactors.Thesemodelsareconstructedprimarilyfromempiricalobservationsofknownmineraldeposits

7、andfromtheoriesofore-formingprocesses.Theexplorerusesthemodelstoidentifythosegeologicalfeaturesthatarecriticaltotheformationofthemineralizationbeingmodeled,andthentriestoselectareasforexplorationthatexhibitasmanyofthecriticalfeaturesaspossible.1.Theauthorisprimarilyconcernedwit