地质学基础地质构造Word文档格式.docx

地质学基础地质构造Word文档格式.docx

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Theconformitymeansthatstratawasformedinastablesedimentaryenvironment,thedipandstrikeofstrataarebasicallythesame.Seediagram（a）.

Theunconformitymeanthereisabreakinsedimentation,aperiodoferosionoranepisodeofdeformation,Unconformitiesrangefromminorerosionalbreakstostrongangulardiscordancesinbedding.Anunconformityindicatesaperiodwherenorockrecordisaccumulated.Theyaretime-breaksofindeterminatelength.Thediagrams（b）,（c）illustratevariouskindsofunconformities.

（b）Therelationsamongigneousrock

Cross-cuttingrelationshipsamongigneousrocks（seediagrambellow）indicatethatintrusionrocksmustbeyoungerthantherockstheycut.

（c）therelationbetweensedimentaryrockandigneousrock.

Cross-cuttingrelationshipsbetweenigneousrocksandsedimentaryrock

Indicatethatsedimentaryrockincludedpebblesandfragmentsmustbeolderthanthehostrockcontainingthem.

Deformationanyrockseffectedbyadeformationevent（foldingortilting）mustpre-datethedeformationepisode.

二Chronologicalscale

Thegeologictimescalewasoriginallyasetofrelativedatesbutthevariouseons,eras,periodsandepochshavenowbeenaccuratelydatedwiththeaidofradiometricmethods.

Theimportantdatesare:

4,600My-theageoftheEarthandSolarSystem

3,600My-theearliestlife

570My-thefirstappearanceofabundantandvariedorganicforms

200My-thebreak-upofthesupercontinentPangea

66My-thedisappearanceofthedinosaurs

Thegeologictimescaleisusuallypresentedinadistortedform-87%ofthetotaltimespanisrepresentedbytheProterozoicandArcheaneonsofthePrecambrian.

GeologicalTimeScale

EON

（宇）

ERA

（代）

PERIOD

（纪）

EPOCH

（世）

MILLIONYEAR

（距今百年）

顯生宙

Phanerozoic

新生代

Cenozoic

第四纪

Quaternary

Holocene

全新世

現代Today--0.01

Pleistocene

更新世

0.01--1.8

第三紀

Tertiary

上新世

Pliocene

1.8--5.3

中新世

Miocene

5.3--23

漸新世

Oligocene

23--36.5

始新世

Eocene

36.5--53

古新世

Palaeocene

53--65

中生代

Mesozoic

白堊紀

Cretaceous

65--145

侏羅紀

Jurassic

145--208

三疊紀

Triassic

208--248

古生代

Palaeozoic

二疊紀

Permian

248--290

石炭紀

Carboniferous

290--360

泥盆紀

Devonian

360--410

志留紀

Silurian

410--438

奧陶紀

Ordovician

438--510

寒武紀

Cambrian

510--570

元古宙

Precambrian

元古代

Proterozoic

震旦紀

Sinian

570--800

800--2,500

太古宙

Archaean

太古代

Archaeozoic

2,500--4,600

Initialstageofearthformation（before3600）

Archaeozoicera:

（3600--2500）→Ar

crustmovementintensively,nowater,nolife,atheendthiserasea

Proterozoicera:

（2500-570）→Pt

（Pt1→upperpro…

Pt2→lowerpro…）

Sedimentaryrock’sformationalgae（earliest）appeared

Paleozoicera:

（570-230）→Pz

InPz1:

theseaintrusion,attheendofOrdovicianreachitspeak,hugeofsedimentaryrockwasformedintheinthisenvironment;

flourishinginthesealivingthing

InPz2:

landvegetabledeveloped,foresthugecoalwasformedatthistimethrivinginamphibiousanimal.

（两牺）

（Flourishingthriving,prosperous）

Mesozoicera:

（230-65）→Mz

T:

North→land

South→shallowsea

J:

MostpartofChinaland→land

Dinosaurpopular（breast-feedanimals）

K:

Crustmovementmagmaactivities

Volcanicmaterialsdeposited

（ash,bomb,debris,gas）

Cenozoicera:

（65-now）→Kz

R:

breast,birddevelopedanddividedabruptly

Q:

loess,glacierhasformed,humanbeing…

2-2Basicshapeandclassificationofgeologicalstructure

Geologicalstructureisthestudyofthepermanentdeformationandrockfailurecreatedbythechangesinstressthroughgeologictime.Itisbyfarthemostimportantaspectofgeologyfortheengineertounderstand.Tectonicprocessesareresponsibleforthemanydiscontinuityplanes（fractures,faults,joints）thatpermeaterockmassescontrollingtheirstrength,stress-straincharacteristicsandthetransmissionandstorageoffluids.

Structuresmaybeconvenientlysubdividedintotwogroups:

brittlestructures-recordingthebrittle-elasticfailureofrocksinthepast.Faultsandjointsfallinthisbroadcategory.

ductilestructures-preservingthepermanentviscoplasticdeformationofrockthroughoutgeologictime.Foldsandmetamorphicfoliationsaretheexpressionofthistypeofstructure.

Themoststrikingfeaturesofrocksasengineeringmaterialsisthattheyarenotsimple,isotropic,elasticandcontinuousbutverycomplex,stronglyanisotropic,anelasticdiscontinuous.Itisvirtuallyimpossibletodeducethestresshistoryofrocksfromtheirobserveddeformation.Therearealwaysmanyambiguousdeformationpathsthatcouldhavebeenfollowedtoproducewhatisobserved.

Thestudyofstructureinvolvesthecarefulrecordingoftheorientationoflinesandplanesinrockmassesinordertodeducethethree-dimensionalgeometryofthedistortedcrust.

一、岩层的产状要素

Planescanbedefinedinspacebytheirinclinationordipandtheirstrike,thebearingofthelineofintersectionoftheplaneandahorizontalsurface.Noticethatthebearingoftheprojectionofthediponahorizontalsurfaceisinadirectionatrightanglestothestrike.Thisiscalledthedipdirection.

Thelayerofsandstoneistiltedtothenorthatanangleofabout45degrees.Thedipandstrikeare45N/180.Thedipanddipdirectionare45/090.Noticethatifthedipweretothesouthwewouldwrite45S/180and45/270forthedip/strikeanddip/dip-directionrespectively.Engineerspreferthesecondnotationbecausethedirectionofdipisambiguouswhendip/strikepairsarerecorded.

二、水平构造和单斜构造（Horizootalandinclinedstructure）

三、Folding

1Thedefinitionoffolding

Foldsresultfromtheplasticdeformationofrocksatlowstrain-rates,usuallyunderelevatedtemperatureandpressureconditions.

2Theshapedescription

Foldsarebroadlysubdividedintoanticlines（upwardsconvex凸的）andsynclines（downwardsconvex）.

Insynclinesandanticlines,theaxialplaneistheplaneofsymmetrypassingthroughtheapex（顶点）ofthefold.Thelineofintersectionofthefoldapexandthehorizontalplaneiscalledtheaxisofthefold.

3theclassificationoffolding

（1）AccordingtotheOrientationofaxialplane

Theorientationoftheaxialplanerelativetothehorizontaltogetherwiththeorientationoffoldlimbsallowsubdivisionintoupright（axialplanevertical,limbssymmetric）,overturned（axialplanemoderatelyinclined,onelimboverturned）,orrecumbent平卧的（axialplanenearhorizontal,onelimbinverted）.

（2）accordingtopivotlocationstate

（3）Accordingtothetightnessoffolding

Thetighnessoffoldscanbedescribedasopen（limbsdipgently）,tight（limbsdipsteeply）orisoclinal（limbsareparallel）.

一、Fracturingstructure

Fragilerock

Fractureplane

Faultandjointing

block

（一）Jointing

1ThedefinitionofJointing

Jointsarediscontinuitiesonwhichtherehasbeenlittleornodisplacementinshear（incontrasttofaults）.Jointsareubiquitous（普遍存在的）inigneous,metamorphicandsedimentaryrocks.Theyareevidenceofbrittlefailureoftherockmassatsomestageinthedeformationhistory.

2thefeaturesofjoints

Jointshavemanyimportantpropertiesasplanesofweaknessinrockmasses:

Orientation

-strikeanddipordipanddip-direction.

Spacing

-thefrequencyornumberofdiscontinuitiesperunitlength.

Aperture（口径，）

-themeandistancebetweenwallrocksurfaces.

Persistence（连续性）

-thecontinuityofjointsortracelength.

SurfaceRoughness

-thepropertycontrollingfrictionbetweensurfaces.

Infi