O BEDROCK GEOLOGIC MAP OF NEW JERSEY JERSEY GEOLOGICAL AND WATER SURVEY 2016 N 183 5 N E W U J E R S...
Transcript of O BEDROCK GEOLOGIC MAP OF NEW JERSEY JERSEY GEOLOGICAL AND WATER SURVEY 2016 N 183 5 N E W U J E R S...
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Bridgeton
Salem
Woodbury
Camden
Mount Holly
Trenton
Elizabeth
Morristown
Newton
Belvidere
Newark
PatersonHackensack
Jersey City
NewBrunswick
Freehold
Toms River
Mays Landing
Cape MayCourt House
Flemington
Somerville
SUSSEX
PASSAIC
BERGEN
HUDSONESSEX
UNION
MORRIS
WARREN
HUNTERDONSOMERSET
MIDDLESEX
MONMOUTHMERCER
OCEAN
BURLINGTON
CAMDENGLOUCESTER
ATLANTIC
CAPE MAY
SALEM
CUMBERLAND
DelawareWater Gap
Franklin
Phillipsburg
Milford
Andover
Mahwah
Gladstone
Boonton
Carteret
Atlantic City
Asbury Park
0 10 20 30 km
0 5 10 15 20 mi
Scale 1:1,000,000
Department of Environmental Protection
NEW JERSEY GEOLOGICAL AND WATER SURVEY
2016
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NEW
JERS
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EOLOGICAL AND WATER SURVEY
BEDROCK GEOLOGIC MAPOF NEW JERSEY
PALEOZOIC
CENOZOIC
MESOZOIC
MESOPROTEROZOIC
MESOZOIC
DESCRIPTION OF MAP UNITSSedimentary Rocks
Igneous and Metamorphic Rocks
DESCRIPTION OF MAP SYMBOLS
Paleogene and Neogene: sand, silt, clay
Holocene: beach andestuarine deposits
Cretaceous: sand, silt, clayJurassic: siltstone, shale,
sandstone, conglomerateTriassic: siltstone, shale,
sandstone, conglomerate
Devonian: conglomerate, sandstone,shale, limestone
Ordovician: shale, limestoneCambrian: limestone, sandstone
Silurian: conglomerate, sandstone,shale, limestone
marblegneiss, granite
Jurassic: basaltJurassic: diabaseCambrian: schist, gneiss
limit of late Wisconsinan glaciation
limit of pre-Illinoian glaciationlimit of Illinoian glaciation
Highlan
ds
Piedmon
t
Valley and Ridge
Coastal P
lain
Foranareaofitssize,NewJerseyhasauniquelydiverseandinterestinggeology.Thestatecanbedividedintofourregions,knownasphysiographicprovinces,whichhavedistinctiverocksandlandforms. The Valley and Ridge Province is underlain by faulted and foldedsedimentary layers of sandstone, shale, and limestone that range in agefromCambriantoDevonian(570to345Ma[millionsofyearsago]).Theserocksoriginatedassand,mud,andlimesedimentdepositedinformerseasandfloodplains.DuringOrdoviciantime(approximately450Ma)andagainduringPennsylvanianandPermiantime(approximately300Ma)therocksweredeformedbycompressionintofoldsandthrustalongfaults.Asaresultof the deformation, the originally flat sedimentary layerswere tilted andnowoutcropaslinearbelts. Alternationofbeltsoferosion-resistant sandstoneandeasily-erodedshaleandlimestonecreatesthelong,parallelnortheast-southwesttrendingridges and valleys characteristicof this province.Resistant sandstoneandsiltstonelayersunderlieKittatinnyMountainandWalpackRidge;shaleandlimestoneunderliethevalleyofFlatBrook, theDelawareValleyupstreamfrom the DelawareWater Gap, and the broad valley between KittatinnyMountainandtheHighlandstotheeast. The limestone is quarried for construction material and cementaggregate. Some of the limestone units yield large quantities of ground-water.Theshalesandsandstonesandsome limestoneunitsaregenerallylessproductiveaquifers. On theeasternedgeof theValleyandRidgeProvince,alonga linefrom Franklin through Andover to the Delaware River just north ofPhillipsburg, an irregular escarpment averaging 500 feet in heightmarks the boundary of theHighlands Province. TheHighlands areunderlain predominantly by granite, gneiss, and small amounts ofmarble of Mesoproterozoic age. These rocks, the oldest in NewJersey,wereformedbetween1.3and1Ga(billionsofyearsago)by melting and recrystallization of sedimentary rocks that weredeeply buried, subjected to high pressure and temperature, andintensely deformed. TheMesoproterozoic rocks are interrupted byseveralelongatenortheast-southwesttrendingbeltsoffoldedPaleozoicsedimentaryrocksequivalenttotherocksoftheValleyandRidgeProvince. Thegranitesandgneissesareresistanttoerosionandcreateahilly upland dissected by the deep, steep-sided valleys of majorstreams. The belts of sedimentary rock form long, parallelridges and valleys (for example, Bearfort Mountain, LongValley, and theMusconetcongValley) that extend throughtheprovince. The Highlands contain magnetite iron ore depositsthat formerlysuppliedan industryofnational importance.AmineralogicallyuniquezincoreintheFranklinMarbleinSussexCountywasworkeduntil1987.Theore,whichfluorescesbrightredandgreen,isinmuseumsthroughouttheworld.Inplacestherocksofthe Highlands are quarried for crushed stone. The Mesoproterozoicrocksaregenerallyunproductiveaquifersexceptwheretheyarefracturedorweathered. Themoreproductive aquifers of the region are the glacialdepositsandsomeofthePaleozoicsedimentaryrocks. Rocksof thePiedmont Provinceare separated from the rocksof theHighlandsProvincebyaseriesofmajorfaults.Themoreresistantgneissesandgranitesontheupthrownnorthwestsideofthefaultsmakeaprominentescarpment, 200 to 800 feet in height, extending fromMahwah throughBoonton and Morristown to Gladstone, and from there westward in anirregularlinetotheDelawareRivernearMilford. South and east of this escarpment, interbedded sandstone, shale,conglomerate, basalt, and diabase of the Piedmont Province underlie abroadlowlandinterruptedbylong,generallynortheast-southwesttrendingridgesanduplands.TherocksofthePiedmontareofLateTriassicandEarlyJurassicage (230 to190Ma).They restona large,elongatecrustalblockthatdroppeddownwardintheinitialstagesoftheopeningoftheAtlanticOcean,oneofaseriesofsuchblocksineasternNorthAmerica.Thesedown-droppedblocksformedvalleysknownasriftbasins.Sedimenterodedfromadjacentuplandswasdepositedalongriversandinlakeswithinthebasins.Thesesedimentsbecamecompactedandcementedtoformconglomerate,sandstone,siltstone,andshale.Theycommonlyhaveadistinctivereddish-browncolor. Inthecourseofrifting,therocklayersofthePiedmontbecametiltednorthwestward, gently folded, and cut by several major faults. Volcanicactivitywasalsoassociatedwiththerifting,asindicatedbythebasaltanddiabaseinterlayeredwithsandstoneandshale.Diabaseisarockformedbythecoolingofmagmaatsomedepthinthecrust;basaltisformedbycoolingofanidenticalmagmathathasbeenextrudedontothesurfaceaslava.Both
basaltanddiabasearemoreresistanttoerosionthantheenclosingsandstoneand shale, and therefore they form ridges and uplands. The Palisades,RockyHill,SourlandMountain,andCushetunkMountainareunderlainbydiabaselayers.TheWatchungMountains,LongHill,andHookMountainareunderlainbybasalt layers.Valleysand lowlandsbetweentheseridgesareunderlainby shale and sandstone.Along thenorthwesternmarginof thebasinafewareasofhighlyfoldedandfaultedlowerPaleozoicsedimentaryrocksareexposed.AlongthesouthernmarginhighlymetamorphosedrocksranginginagefromMesoproterozoictoOrdovician(1.3Gato450Ma)occurintheTrentonareaandinHudsonCounty. Thebasaltanddiabaseareextensivelyquarriedforcrushedstone.Inthe past, “brownstone” was widely quarried from sandstone units. Also,minor quantities of copper were extracted from sandstone and shaleassociatedwiththediabaseandbasalt.Thebasaltanddiabasegenerallyarepooraquifersbutthesedimentaryrocksare,inplaces,capableofyieldinglargequantitiesofwater. Southeast of a line roughly between Carteret and Trenton,unconsolidated sediments of the Coastal Plain Province overlap rocksof the Piedmont Province. These sediments, which range in age fromCretaceous toMiocene (145to5.3Ma),dip toward thecoastandextendbeneath the Atlantic Ocean to the edge of the Continental Shelf. TheCoastal Plain sediments thicken southeastward from a featheredge alongthenorthwesternmarginoftheprovincetoapproximately4,500feetnear
AtlanticCitytoamaximumofmorethan40,000feetintheareaoftheBaltimoreCanyonTrough,50milesoffshorefromAtlanticCity.The
sediments consist of layers of sand, silt and clay depositedalternatelyindeltaicandmarineenvironmentsassealevelfluctuated during Cretaceous, Paleogene and Neogenetime (120 to 10Ma). These layers of sediment cropout inirregularbandsthattrendnortheast-southwest.Wideareasof
theCoastalPlainarecoveredbyathinveneerofNeogeneandQuaternary(10Matopresent)sandandgraveldepositedbyrivers. ThetopographyoftheCoastalPlaingenerallyisflattoverygentlyundulating.However,erosion-resistantgravelor iron-cemented sediment underlie upland areas and isolated hills,suchastheAtlanticHighlands,TelegraphHill,MountHolly,andArneysMount. CoastalPlainsedimentshavebeenminedinthepastforbog iron, glass sand, foundry sand, ceramic andbrick clay, themineral glauconite for use in fertilizer, and titanium from the
mineralilmeniteinsanddeposits.TodaytheCoastalPlainsedimentscontinuetosupplyglasssandandareextensivelyminedforsandand
gravelconstructionmaterial.Thesandformationsareproductiveaquifersandimportantgroundwaterreservoirs. Withineachofthesephysiographicprovincestherehavebeenmajorchanges during the past two million years. In this time New Jersey hasundergone threeglaciations, referred toas thepre-Illinoian, Illinoian,andlateWisconsinan.The lastglacier (the lateWiconsinanadvance)begantomeltbackfromitsmaximumextentapproximately20ka(thousandsofyearsago).Northofthelimitofthelastglaciationmuchofthesurfaceiscoveredbyglacialdeposits.Uplandareas in this regionare thinlydrapedwithtill,anunsortedmixtureofsand,clayandbouldersdepositeddirectlyfromtheglacier.Valleysandlowlandsarefilledwithupto350feetofsandandgraveldeposited from glacial meltwater and silt and clay that settled in glaciallakes. The sand and gravel deposits are important sources of constructionmaterial,andproductiveaquifersarefoundwheresandandgraveloccurinburiedorfilledvalleys.SouthofthelimitofWisconsinanglaciation,therearediscontinuouspatchesoftillfromolderglaciations.ThesedepositsoccuronuplandsandarefoundasfarsouthastheSomervillearea. During each glaciation, sea level dropped aswater from the oceanswastransferredto icesheets.Riversextendedanddeepenedtheirvalleystoconformtothelowersealevels.Whentheicesheetsmelted,sealevelrose, flooding the deepened valleys and establishing new shorelines. Thepresentconfigurationofthecoastistheresultoftherapidpost-glacialriseinsealevel,whichslowedapproximately7ka.Manyoftheestuariesalongthecoastarethedrownedlowerreachesofformerrivervalleys.Totheeastofthemainland,barrier islandswereformed,andcontinuetobeshaped,byerosionanddepositionofbeachsandbywavesandcurrents.Mudandsandtransportedbyriversandfromoffshoreisgraduallyfillingthebaysandestuariesbetweenthemainlandandthebarrierislands,creatingextensivewetlands.
BEDROCK GEOLOGY OF NEW JERSEY