Glossary from Physical Geology地质术语名词解释文档格式.docx
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abyssalplain:
Avastflatareaontheseaflooradjacenttothecontinentalrisesofpassivecontinentalmargins.
activecontinentalmargin:
Acontinentalmargincharacterizedbyvolcanismandseismicityattheleadingedgeofacontinentalplatewhereoceaniclithosphereissubducted.Seealsopassivecontinentalmargin.
alluvialfan:
Acone-shapedalluvialdepositformedwhereastreamflowsfrommountainsontoanadjacentlowland.
alluvium:
Ageneraltermforalldetritalsedimenttransportedanddepositedbyrunningwater.
angularunconformity:
Anunconformitybelowwhicholderrocksdipatadifferentangle(usuallysteeper)thantheoverlyingstrata.Seealsodisconformityandnonconformity.
anticline:
Aconvexupwardfoldinwhichtheoldestexposedrockscoincidewiththefoldaxisandallstratadipawayfromtheaxis.
aphanitictexture:
Anigneoustextureinwhichindividualmineralsaretoosmalltobeseenwithoutmagnification.
arê
te:
Anarrow,serratedridgeseparatingtwoglacialvalleysoradjacentcirques.
artesiansystem:
Aconfinedaquiferinwhichhighhydrostatic(fluid)pressurebuildsupcausingwatertoriseabovetheleveloftheaquifer.
aseismicridge:
Aridgeorbroadarearisingasmuchas2to3kmabovethesurroundingseafloorandlackingseismicactivity.
ash:
Pyroclasticmaterialmeasuringlessthan2mm.
assimilation:
Aprocessinwhichmagmachangescompositionasitreactswithcountryrock.
asthenosphere:
Thepartofthemantlethatliesbelowthelithosphere;
behavesplasticallyandflows.
atom:
Thesmallestunitofmatterthatretainsthecharacteristicsofanelement.
atomic:
massnumberThetotalnumberofprotonsandneutronsinthenucleusofanatom.
atomicnumber:
Thenumberofprotonsinthenucleusofanatom.
aureole:
Azonesurroundingaplutoninwhichcontactmetamorphismtookplace.
B
barchandune:
Acrescent-shapeddunewiththetipsofthecrescentpointingdownwind.
barrierisland:
Along,narrowislandcomposedofsandorientedparalleltoashorelinebutseparatedfromthemainlandbyalagoon.
basal:
slipAtypeofglacialmovementinwhichaglacierslidesoveritsunderlyingsurface.
basalt:
plateauAlargeareabuiltupbynumerousflat-lyinglavaflowseruptedfromfissures.
baselevel:
Thelowestleveltowhichastreamcanerode.
basin:
Thecircularfoldinwhichallstratadiptowardacentralpoint,andtheyoungestexposedrocksareinthecenter.
batholith:
Adiscordant,irregularlyshapedplutonwithasurfaceareaofatleast100
.
baymouthbar:
Aspitthathasgrownuntilitclosesoffabayfromtheopensea.
beach:
Adepositofsedimentextendinglandwardfromlowtidetoachangeintopographyorwherepermanentvegetationbegins.
bed(bedding):
Abedisanindividuallayerofrock,especiallysedimentaryrock,whereasbeddingisthelayeredarrangementofrocks.Seealsostratification.
bedload:
Thepartofastream’ssedimentloadtransportedalongitsbed;
consistsofsandandgravel.
berm:
Thebackshoreareaofabeach,consistingofaplatformcomposedofsedimentdepositedbywaves.Bermsarenearlyhorizontalorslopegentlylandward.
BigBang:
Amodelfortheevolutionoftheuniverseinwhichadense,hotstatewasfollowedbyexpansion,cooling,andalessdensestate.
biochemicalsedimentaryrock:
Asedimentaryrockresultingfromthechemicalprocessesoforganisms.
blacksmoker:
Asubmarinehydrothermalventthatemitsaplumeofblackwatercoloredbydissolvedminerals.
bodywave:
AnearthquakewavethattravelsthroughEarth.BothP-andS-wavesarebodywaves.
bonding:
Theprocesswherebyatomsarejoinedtootheratoms.
Bowen’sreactionseries:
Amechanismaccountingforthederivationofintermediateandfelsicmagmasfrommaficmagma.Ithasadiscontinuousbranchofferromagnesianmineralsthatchangefromonetoanotheroverspecifictemperaturerangesandacontinuousbranchofplagioclasefeldsparswhosecompositionchangesasthetemperaturedecreases.
braidedstream:
Astreamwithmultipledividingandrejoiningchannels.
breaker:
Awavethatsteepensasitentersshallowwateruntilitscrestplungesforward.
butte:
Anisolated,steep-sided,pinnacle-likehillformedbythebreachingofaresistantcaprock,whichallowsrapiderosionofthelessresistantunderlyingrocks.
C
caldera:
Alarge,steep-sidedcirculartoovalvolcanicdepressionusuallyformedbysummitcollapseresultingfrompartialdrainingoftheunderlyingmagma