New Jersey Geological SurveyGeological Survey Report GSR 40

Hydrostratigraphy of theKirkwood and Cohansey Formations of Miocene Age

in Atlantic County and Vicinity, New Jersey

by

Peter J. Sugarman

New Jersey Department of Environmental ProtectionDivision of Science, Research and Technology

Geological SurveyP.O. Box 427

Trenton, NJ 086252001

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CONTENTS -

Page

Abstract...... "....... . _.............................. •........... I

Introduction ............................................. I

Acknowledgments................... ............................. I

PreviousHydrogeologicInvestigations....................................... 3

GeologicSetting................................................... 6

MethodsofInvestigation................................. _ ............. 8

BoreholeGeophysicalLogs....................... ..................... 8

LithologicLogs ................................................. 8

Hydrostratigmphy.................................................. 8

Hydrostratigraphic-section interpretation .................................. _ . 8

Composite Confining Unit ....................................... .... 8

Atlantic City 800-foot Sand ........................................... 20

Wildwood-Belleplain Confining Unit ...................................... 20

Kirkwood-Cohansey aquifer system ...................................... 21

Summary and Conclusions ........... '. ............................... : . . . 22

References ....................................................... 25

ILLUSTRATIONS

Figures " I. Location of study area in southern New Jersey, distribution of wells, andlocation of cross sections ...................................... 2

2. Correlation chart of nomenclature of hydrostratigmphic and geologic unitsdeveloped in the Atlantic City area over the past century .................... 3

3. Correlation of geologic and hydrostratigraphic units with sequences at the 150X-Atlantic City borehole ....................................... 5

4. Tectonic setting of the New Jersey Coastal Plain .................... ...... 5

5. Geologic and hydrostratigraphic units of the New Jersey Coastal Plain(modified from Zapecza, 1989) .................................. 6

6. Idealized borehole geophysical responses to lithology ....................... 7

7 - 12. Cross-sections ............................................ 9

7. A--A' . ............................................ 9

8. B--B'. ............................................. 10

9.C---C'................... '............................ II

I0.D_D'. ............................................ 12

II.E--E' ............................................. 13

12.F--F' ............................................. . 14

13. Elevation of top of Wildwood-Belleplain confining unit, in feet below sea level ......... 15

14. Elevation of base of Wildwood-Belleplain confining unit, in feet below sea level ........ 16

15. Thickness of the Wildwood-Bellcplain confining unit, in feet .................... 17

16. Thickness of Atlantic City 800-foot sand, where confined by Wildwood-Belleplainconfining unit, in feet .......................................... 18

17. Elevation of top of composite confining bed, in feet below sea level ............... 19

TABLES

Table 1. Well records used in study ....... .................................. 23

Table 2. Altitude of top and base, and thickness ofhydrostratigraphic units ................... 24

HYDROSTRATIGRAPHY OF THE

KIRKWOOD AND COHANSEY FORMATIONS OF MIOCENE AGE

IN ATLANTIC COUNTY AND VICINITY, NEW JERSEY

ABSTRACT

Borehole geophysical logs were usedto producecross sections,equal thicknessmaps,and structurecontourmaps ofaquifersandconfiningunits of the KirkwoodandCohanseyFormationsin Atlantic,and partsof Ocean,Burlington,Cape Mayand CumberlandCounties. Twoobservationwells offshore fromAtlantic City allowed interpretationsto be extended beneath theAtlantic Ocean. Aquifers mappedwith theirassociatedconfining unitsarc, fromoldest to youngest, the composite confiningunit, Atlantic City 800-foot sand, the Wildwood-Belleplain confining unit (named in this report)which commonly contains theRio Grandewater-bearingzone, and the Kirkwood-Cohansey aquifersystem.

Whereconfined, the Atlantic City 800-foot sandcontains a lowersand fromthe unnamed lower memberof the KirkwoodFormationand an upper sand fromthe Shiloh Marl Memberof the KirkwoodFormation. A clay-siR at the base oftbe Shiloh MarlMembermay actin placesas a leaky confining unitseparating the two sands. The confiningbed overlyingthe AtlanticCity 800-footsand, the Wildwood-Belleplainconfining unit, can exceed 400 feet in thickness (in Cape May County), and is correlativewith theWildwoodMemberof the KirkwoodFormationand, in places,the lowerpart of the Belleplain Memberof the KirkwoodFormation.Where the Wildwood-Belleplain confining unit is not present, the Atlantic City 800-foot sand and Kirkwood-Cohansey aquifersystem may beconnected and unconfined.

INTRODUCTION

Rapid population growth in and around This report represents part of a cooperativeAtlantic City (fig. 1) since the 1970's has increased program between the N.J. Geological Survey anddemands on ground-water supply and renewed the U.S. Geological Survey Water Resourceslongstanding concern about water availability and Division. The primary responsibility of the N.J.water quality in the region, including the threat of Geological Survey was to show the extent and

salt water intrusion. Past efforts to manage the thickness ofthe major confining unit overlying theregion's ground water resources have been Atlantic City 800-foot sand (named the Wildwood-hampered by incomplete knowledge of the Belleplain confining unit in this report), and to maphydrogeologic framework. Because of this, the the extent and thickness of Miocene aquifers,New Jersey Statewide Water Supply Master Plan of principally in Atlantic County. These aquifers1981 designated the Atlantic City region as one of supply most of the ground water used by the Newseveral areas in the State needing additional Jersey shore communities from southern Oceanhydrostratigraphic investigation to resolve major County to Cape May, and inland to the westernquestions concerning the Kirkwood aquifer. To limit of the Pinelands.delineate the Atlantic City 800-foot sand, the extent

of the confining unit overlying it required Acknowledgmentsidentification. In areas to the northwest where this

confining unit is absent, the Atlantic City 800-foot An extensive database prepared by Lloyd

sand is coarser, and distinguishing it from the Mullikin over many years was used in the preparationKirkwood-Cohansey aquifer system is extremely of this report. That unpublished data contributeddifficult. The ability to differentiate between the significantly in the report's completion, and istwo is essential because where the tWOaquifers are available for examination at the N.J. Geologicalinterconnected, recharge to the con'fined part of the Survey. Otto Zapecza of the U.S. Geological SurveyAtlantic City 800-foot sand is from this unconfined generously reviewed the report and offered manyaquifer system to the west. In addition, the updip valuable suggestions. The author is also grateful toextent of the confining unit overlying the Atlantic Richard Dalton, Jeffrey Waldner and Robert CanaceCity 800-foot sand required delineation because it for their expert reviews. Borehole geophysicaldefines both the extent of the Kirkwood-Cohansey information supplied by well-drilling contractors

aquifer system and the Atlantic City 800-foot sand. was also useful and appreciated.

I I I I I

75e15' 75• 74o45' 74'=30' 7'4o15.

BURLINGTON

39o45. CAMDEN COUNTY 3go45,_

COUNTY A_°1 OCEAN

2 COUNTYGLOUCESTER

COUNTY "'" "".''" 03

• Batsto .36?.'

SALEM

COUNTY '" 39.Wildwood-Belleplain

confiningunit . "41e. , •

22_ ATLANTIC 39o30, --.." COUNTY

..'" .... " C_,

26

42. 43 CUMBERLAND

COUNTY C'

- 39e151 39°15 . -

CAPE MAY

COUNTY E_29

Dolawsre , Fall Une

_" Atlantic

75015, 75° __._eMay 74o45' 74"3_ 74"15'1 I I I I

Figure 1.- Location of study area in southern New Jersey, distribution of wells, and location of cross

sections. The dotted line indicates the approximateupdip Limitof the Wildwood-Belleplain confiningunit. Table 2 provides information on the wells.

•PREVIOUS HYDROGEOLOGIC INVESTIGATIONS

The earliest descriptionsof the Kirkwood Formation Four water bearing units were typically penetratedcame from field reconnaissancemapping (Knapp, 1904), in artesian wells along the coast of Atlantic and Capeclay mining (pies and others, 1904), and water supply May Counties. These included the 800-foot Atlantic Cityinvestigations(for example, Woolman, 1891, 1894). The horizon and the Atlantic City 950-foot horizon, the 700-Kirkwood was drilledfor water supplyatAtlanticCity and foot Atlantic City horizon occurring just below the basesouthward on the beaches, and described as a miles of of the "Great Diatom Bed," and 550-foot horizonpermeable sandsseparatedby imperviousdiatom-richclays occurring 125 feet below the top of the "Great Diatom(Woolman, 1891,1894,fig. 2). Knapp(1904)recognizeda Bed" at Atlantic City (fig. 2). Woolman (1894) alsomajorTertiarysubdivisionoftheNewJerseyCoastalPlain identified several minor water horizons above the- the outer Coastal Plain - which included the Kirkwood "Great Diatom Bed."

(Miocene) and the Cohanmy(Pliocene?) Formations.Piesand others (1904) described the outcropping Kirkwood Riehards and Harbison (1942) suggested aFormation,including the Asbary Clay to the northeast, the subdivision of the Kirkwood Formation similar to"Fluffy Sand" in the central and southern New Jersey that of Woolman (fig. 2), based in part on correlationsCoastal Plain, and the Alloway Clay and Shiloh marl with the Chesapeake Group of Maryland and(containingMiocene fossils) in the southwest. Virginia. They subdivided the Kirkwood into a thick

lower Calvert Phase, which consisted of: BasalWoolman (1894, fig. 2) subdivided the Kirkwood at Greensand Marl, the Lesser Diatom Bed, the 800-foot

Wildwood into about 300 feet of lower Miocene clays Sand, and the Great Diatom Bed. The Calvert wasand sands (including a major waterhorizon) infrequently also correlative with the Shiloh Marl. In effect,containing the diatom Actinophytcus heliopelta, a thick Richards and Harbison (1942) lumped the 700- andmiddle "Great Diatom Bed" of about400 feet (previously 800-foot sand units of Woolman (1896) into a singletermed the "diatomaceous clay-bed") correlativewith the water bearing zone. Above the Calvert Phase,Chesapeake Group, and an upper St. Mary'sbed ofabont Richards and Harbison identified a thin upper St.80 feet (fig. 2). Mary's Phase in the Kirkwood.

Woolman (1891-189r) Rlchard$ and Zapecz.a Mulllkln Owens andHarbison (1942) (1989) 0990) others (1998) This report

LJllna_ _o4ocene

Cape May Undifferentiated

Recent and Pleistocene Kirk-c_od- Kirkwood-

Cohansay Cobensey Cohanseyaquifer K]_- Formation aquifersystem Cohansey system

aquifer...........................................

minor water horizon Cohansay system..........................................

Bellepisin =St. MaP/s Miocene non-diatomaceous Sand St. Marls Phase upper Member -R

]] confln[ngunit ii

_ SSO-_ot _izon _ [_R being z0ne I_0G_nde _ _0 G_'de

. Diatom Bed 8 x_ lower o Member

confining unit _

_ upper _ _,'_ upper sand700-foot horizon _ --_ _o sandunit • Shiloh Mad

Miocene clay _ .800.foot _O Attantic City _, AtlanUc City Member _ _ confinMgunit""leaky2: Sand' 800-foot Sand confining unit

s00-footmanticcti_ho_on 8 ,_ _ow_ unn_m_ _ _ k,_,sand/

sand unit lower member

Miocene Clay Lesser _ _ • _ _

A. heliopeltadiatomaosousclay-bed Dlatom Sad _ "_"_lPIneyPoint_'E "_ IPiney Po4nt 8..= _"E Piney Point

E_=[ aquifer )_=I aqu_t Adanticl)ty E =m aquiferEocene Basal _ _ _ 8 Formation _ _ L

G_n_nd 9_foot he.on Gmen_nd Mad

Figure2.- Correlationchartof nomenclatureof hydrostratigraphicandgeologicunitsdevelopedin theAtlanticCityarea overthe pastcentury.

3

Isphording (1970)reexamined the outcropping Diatom Zone I as lower Miocene, with anrelationships of the Kirkwood, and defined three estimated age range 19.1-18.9 Ma; East Coastmembers: (1) Asbury Park, (2) Grenloch and (3) Diatom Zone 2 as upper lower to lower middleAlloway Clay. These members were distinct facies Miocene, with an age range of 17.4-15.6 Ma; andinterpreted predominantly as shelf deposits, but East Coast Diatom Zone 6 as middle Miocene,could not be recognized downdip in the subsurface with an estimated age range of 13.8-12.8 Ma.along the coast of southern New Jersey.

Using shell material recovered from

In the 1980's modern hydrogeologic and boreholes, strontium-isotope (Sr-isotope)geologic frameworks were developed for the New stratigraphy was applied to correlate theJersey Coastal Plain, including the Miocene age Kirkwood sequences to the geomagnetic polarityKirkwood and Cohansey Formations. Zapecza time scale (Sugarman and others, 1993), a(1989) developed a hydrogeologic framework based chronology based on reversals of the Earth's

on more than 1,000 geophysical logs, and mapped magnetic field. This technique provides a bettertwo major aquifers and two major confining beds framework for estimating the age and duration of(fig. 2). These include: (1) the composite confining these units: three unconformity-boundedbed, a complex series of geologic units ranging in Kirkwood sequences were confirmed (below) andage from late Cretaceous through lower Miocene, (2) a fourth inferred.

the Atlantic City 800-foot sand, a major water

bearing unit at the base of the Kirkwood Formation Sequence Stratigraphywhose thickness ranges from 40 to 150 feet, and

Sr-isotopecontains a thin (10-30 feet) clay bed in the middle of Kirkwood age estimates Age Errorthe aquifer, (3) a major confining bed overlying the Sequences (Millions of years (Millions of800-foot sand consisting of a massive clay bed, ago) Years)

whose thickness ranges from 100 to 450 feet, and is Upper 13.6to 12.2 +/- 0.9correlative with the "Great Diatom Bed" of

Woolman (1896). In the middle of this confining _ Hiatusbed, from Ocean to Cape May County, is a thin, Middle 17.4to 15.5 +/-0.6

generally 40 feet thick, confined water bearing zone c Hiatustermed the Rio Grande (the Atlantiz 2ity 550-foot

Lower 22.6 to 19.2 +/- 0.6horizon of Woolman, 1891), and (4) the Kirkwood-Cohansey aquifer system, a water-table aquifer thatincludes the upper Kirkwood Formation, the During 1993-1994, three boreholes wereCohansey Formation, and parts ofsurficial sand and drilled at Island Beach, Atlantic City, and Capegravel units including the Bridgeton and Cape May May (Miller and others, 1994). HydrogeologicFormations. Mullikin (1990) presented a slightly and geologic units at the Atlantic City site weremodified version of Zapecza's 1989 identified, along with corresponding Sr-isotopehydrostratigraphic subdivision, identifying a thin age estimates (fig. 3). Sugarman and Miller (1997)Atlantic City confining unit which separates an used sequence stratigraphic information developedupper and lower sand unit within the Atlantic City from these boreholes to develop predictive800-foot sand, and separated the Great Diatom Bed hydrostratigraphic models for Miocene aquifers.into an upper and lower confining unit (fig. 2).

Based on abundant new data from subsurface

In 1984 the first continuous corehole in the cores from the Kirkwood Formation, Owens and

New Jersey Coastal Plain was drilled near Mays others (1998) subdivided the KirkwoodLanding to a depth of 945 ft. Designated ACGS-4 Formation into an unnamed lower member, the(Owens and others, 1988), this marked the Shiloh Marl Member, the Wildwood Member, and

beginning of modern integrated stratigraphic the Belleplain Member (figs. 2, 3). The lowerstudies of the Kirkwood Formation. The KirkwoodMemberistheoldest(about24-21 Ma),

Kirkwoed was shown to consist of three major followed by the Shiloh Marl (about 20.5-20 Ma),Wildwood (about 18-15.6 Ma), and Belleplainunconformity-bounded stratigraphic sequences

correlative with Andrews' (1988) East Coast (about 13.6-12 Ma) Members. DetailedDiatom Zones 1, 2, and 6 (Owens and others, descriptions of these formations can be found in

1988; Andrews, 1988; Sugarman and others, Owens and others (1998).1993). Andrews (1988) established East Coast

4

Io_- -_ne e¢ E

25

} _ so I ,_° ,_°co..

>_ _ PENNA

= 41o

g 75J_0

"o ._ 100"g <:E _? .

0"

:_ _ _ 175

N

= _ _ "200 "C

:E i._--' _ ,3"; "225J_ _- Figure4.-- Tectonicsettingof the New Jersey

- i. _! _ 5oo. CoastalPlain.j _ _ .25o

=

_ u_=-: , -300

unconformity_ _ = = shellbed

clay-slit quartzsand gravel _ o gtauconltesand

Figure3 -- Correlationofgeologicandhydrostrati-graphic units with sequences at the 150X-AtlanticCity borehole. Also included are Sr-isotope ageestimates from Miller and .Sugarman (1995).Formation column on left from Owens and others(1998); and column on right from Miller and others(1994) and Miller and Sugarman (1995).

5

GEOLOGIC SETTING

The New Jersey Coastal Plain is underlain by a Canyon Trough. The Salisbury Embayment has

wedge of unconsolidated Cretaceous to Recent undergone differential movement through time. Itsediments (table l) which thickens from a feather edge appears to have downwa_ed progressively to the northalong the Fall Line (fig. I) to more than 6,000 feet during the early Cretaceous and into the Paleogene, butbeneath southern Cape May County (Zapecza, 1989). the direction of migration shifted to the south in theNew Jersey Coastal Plain sediments occupy two major Neogene. Consequently, in Miocene time the basinst1"ucturalbasins: the Raritan Embayment in the north, accumulated a thick marine section which includes the

and the larger Salisbury Emhayment in the south (Owens major water bearing sands and confining units discussedand others, 1988; fig. 4). Distribution of the aquifers and in this report. The Cohansey Formation marks the end ofconfining units described in this report was controlled in marine deposition in the middle Miocene, and maylarge part by the structural behavior of the Salisbury represent uplift in the Salisbury Esmhayment.Embayment, a landward extension of the Baltimore

8YS'IT.M 8ERIE8 GEOLOGICUNiT LITHOLO(Iy HYDROGEOLOGIC HYDROGEOkOGICCHARACTERISTICSUNIT

Ho4ocene _,_P_ _ Sand;.sta;Mac_mud. "ll. Sun',c_mater_, oornraon_yhy_r.u_k:_

OL_TE_t_RY(Re_mt) Beechsandandgrav_ Sand,medium_ocoanm,light-c_xed, _ oonneaedtounderZythgequ_nz,Locally

qumtz,pe_. someunlthmayact_ confiningunlni.ThUcersan(Isate capa_eofyteidrngnirgequanththsofwater.Maybeincludedin

Rels_cene CapeMayFom_at_n Sand,heterogeneo¢_,I_-cokx_l, quartz, KJrkw_od-cah_zeyar4_r lystem._uk_ F_ Oa.,rf. peb_y.

Foema_SaeconHmGrand Gm'._, llgth.cc_omd,qmrtz,sandy.

Oroun_-wa_roccursgenemrryunderwater-Sand, mediumth coarse, l_M.co_ced. Klthwcod-Cohanaey _ condliiuns.InCape MayCounty.the

CE=nseyForm_tk_ quar=,petYo_,localciaybed=. aquffarsystem CohenmySand• _ _ _o_s.B_dn Me_ _ b,ptclPyclw..nittat_ ba._Member _ wmclat top.

Bdeplath Member-Sthyc_y and mlcaceous

] u_'van:ltoshnilY'laminated_zY_dtt'=dlLmzd Wtktw°°_ _ Thickciay's_tunit_ _ _st a_

MJOCene _ f'_e_d. Beltop_b thea el_ortd_nCe iatand.A thinwatofI_ oonflnb-@ _dr_ ,and occurswru't_thernJdd,_ofthis

z WildwoodM_mper.Mk:aceou_.r,he_ u_ unitInCapeMly.Cumpertand,antiparthofninth_dedday.._t_ veryfine=and. AganticCounty.

_etls,Immbeddedshe_ sirandvex'y-finennd. v,_ o._tyi_ Intomeddedsan¢lend AmaJo¢aqufi'e_akmgtheco==t.Arelativety

_ Marl _ _th_1 peb_yland. AJdan_cCity thinniaybedwithintheaquli_lrseper_tesanMember _.00-(_t_n_i ',._pperend_w_azmnd,m_drr,_'/i_:t_ t_',t.d_

unnamedLowerMs_b_- She_yg_uc_n_ ao_flningunit,unnam_lLo_er =and,_ly _r_, andeandy_t unper_ng

Memt_r qua_ _ v,lth_mcpeO_d niayand _t. l_aOy permeabte_dlmeath.

O:_oceee Att_CityForma_on Semi, flr_to_.quanz;¢zucor_.PointFocr_t_ Point Yinidsmoderatequanththsofwaterlocally,

_u ApeeconthletFonnatWa aquiferz _tu ShlzrkRberF_ Clay,ni]tya_dsandy,gthucontl_ poodypermeeblesediments.

finequartz=end.Man=quartFon_V]ncentown_ds imlaRto moderatequ=nththsofwater

V]ncentownFocnw_o_ Sand,finetoooanl_,quartz,gniuconi_c; cccd_ng equlfar inandnear_tsoutcroparea.

Home.townFormation*_m¢l,_auo0ni_c, Poorlypermuble_dlments.

San¢l,f_neto o0_-_m,quartz,ff,a_cor_.C_'TACE0_ Upper RodBankF_ _-/, rnicaceo_s. RedBank Yieldssmallto moderatequlmtltiuofwaterInandnearitsoutcroparea.

Navm_kFon'n_e_ Sand,ninny,_au¢oni_c. PoodypermeaNesed_menth.

Figure 5.- Geologic and hydmstraUgraphicunitsof the New Jersey Coastal Plain discussedin thisreport(modifiedfrom Zapecza, 1989).

6

Tertiary confining units and aquifers generally The Wildwood Member is overlain by theconsist of unconformity-bounded, shallowing upward, Belleplain Member. A major hiatus of 2.6 m.y. atsilica-rich cycles of sedimentation. They typically Atlantic City separates the two and, typically, a thin

include a thin lower glauconite sand (transgressive), a gravel layer composed primarily of quartz andthicker clay-silt, and an upper coarse quartz sand phosphatized bone material is present between them(regressive). These deposits reflect a transition from (Owens and others, 199g). The Belleplain has amarine-shelf to near-shore marine and non-marine relatively limited distribution compared with the lower

sedimentation. Confining units typically correspond to Kirkwood, Shiloh Marl, and Wildwood Membersthe lower clayasilt and glauconite sands, whereas the (Sugarrnan and others, 1993). The upper contact of theaquifers consist of the upper quartz sands (Sugarman and Belleplain is inferred from the gamma log because coreMiller, 1997). The upper confining unit is commonly the was unrccovered in this interval; it is about 100 ft thick atclay-silt at the base of the next sequence. Miocene and Atlantic City. Sr-isotope age estimates are 13.7-13.1 Ma,Cretaceous sequences are generally similar, except that but at the Belleplain State Forest borehole the estimatestheglauconite sandat thebaseofthe Miocene depusits, if are as young as 12.2 Ma (Miller and Sugarman, 1995;present, is usually thinner than glauconite found at the Sugarman and others, 1993).base of Cretaceous sequences.

The Belleplain also coarsens upward where wellThe lower member of the Kirk-woodFormation (fig. 3) preserved. Middle (?) to inner neritic shelf sediments

is a good example of these cycles of sedimentation. It consisting of burrowed silty clay and micaceous fineconsists of lower, fine-grained marine shelf sediments sand (each containing occasional shell hash) grade(glauconite sand, silty sands and sandy silt) and upper,

coarser deltaic and nearsbore marine sediments (quar_ ¢,_,mA.sands with interbedded silt and clay). RAYLOG ELECTRICLOG

(ohms)The Shiloh Marl Member is another example of an --_ - * --.,-

unconformity-bounded coarsening upward cycle of "'t _ -- Send,finetocoarse

sedimentation (fig. 3). Its base consists ofinterbedded silt 0-_ _

Interbeddedsandand very fine sand, containing mica, finely dispersed 10 andclay-siltcarbonaceous material, and occasional broken shells(Owens and others, 1988). These grade upward at

Atlantic City into massive clayey sands with shells, _ 200-,,__,_i____ '* Sand

interbedded sands and lignitic silts, and pebbly sands. At

ACGS-4, the sand typically consists of olive-gray, w 3oo-medium to coarse quartz grains with thick shell beds Clay(Owens and others, 1988). _ 40o --

Sandwiththinclay-siltinterbeds

The Shiloh Marl Member of the Kirkwood z 5oo-Formation is unconformably overlain by the WildwoodMember, and a major hiatus of about 2 m.y. exists Figure6.- Idealizedboreholegeophysicalbetween the two (20.2-18.1 Ma; Miller and Sugarman, responsesto lithology.

1995). The Wildwood is a fine grained unit consisting of upwards into laminated clay-silt, silt and fine sand whichlaminated clay-silt to fine-sand which is frequentlymicaceous and sometimes shelly, with thin interbeds of is sometimes shelly and often contains mica andclay and sand. Less typical is a massive, burrowed silt carbonaceous material. Interpreted as tidal fiat deposits,

the clay-silt and fine sand lamina grade upward intodeposit. Sr-isotope age estimates date the Wildwood to interbedded fine sand and silt.about 18.1- 16.3 Ma. Sugarman and others (1993) termedthis sequence the Kirkwood (Kw)2 and, using Sr-isotopes, identified a hiatus of about 1 m.y. within it. The Cohansey Formation, unconformably overlying

Miller and Sugarman (1995) then divided Kw2 into the Kirkwood, consists of interfingering marginalKw2a and Kw2b (fig. 3), with a 0.7 m.y. hiatus (17-16.3 marine, barrier island, tidal fiat, and lagoonal sediments

Ma) separating them. An upper quartz sand is typically (Carter, 1978). The Cohansey rarely contains fine-present in the Kw2a sequence. At Atlantic City, a 25 foot grained marine shelf sediments characterizing regionalsection at the top of Kw2a, and in the middle of the confining units of the Kirkwood Formation. Instead,Wildwood Member, contains interbedded sands and interfingering fine and coarse sediments near shore makecarbonaceous silts, up a complex, locally variable aquifer system.

Unconformably overlying the Cohansey Formation May County, the fluvial deposits interfinger withare fiat-lying, late Miocene (?) to Holocene (Recent) estuarine and marginal marine deposits containing lessfluvial sands and gravels. These are mostly thin and permeable materials and form confining units. In Capepermeable, and act as water-table aquifers or recharge May County, the post-Cohansey confining units are ofareas. They are included in the Kirkwood-Cohansey substantial extent.aquifer system. Near the coast and southward into Cape

METHODS OF INVESTIGATION

•Borehole Geophysical Logs Single-point resistance logs show electrical

Distinctive signatures or patterns on electric and resistance of formations. Typically, silt- and clay-richgamma-ray logs mark boundaries between aquifers and layers have lower resistance and show on logs as

confining units more reliably than descriptions of cuttings deflections to the left (fig. 6). The gamma-my log (G), ifof New Jersey Coastal Plain sediments obtained from available, is shown on the cross sections. If unavailable,

water well drilling (Zapecza, 1989). Geophysical logs are a single point resistance log is shown (E).

the primary means of correlation used in this report. Forty-

seven wells with geophysical logs were used in this study Lithologic Logs

(Table 2). Selected logs are shown in cross sections in Cores and cuttings collected during'drilling providefigures 7-12. direct information on the depth and composition of

hydrogeologic units. However, information fromGanuna-my logs show the rate at which ganuna-mys

cuttings may be inaccurate because drillers' logs are notare emitted by the formations penetrated in a borehole. On recorded with any standard method, and travel time of

the gamma-ray log, radiation increases to the right(fig. 6). drill cuttings up the borehole is rarely calculated.In general, silt-and clay-rich sediments show higher rates Without this calculation, assumptions must be made

of gamma radiation than sandy sediments (fig. 6). Quartz concerning the depth from which logged sediments weresands and gravel (permeable sediments) exhibit little drilled. Drilling difficulties, such as borehole cave-ins,natural radiation and show as deflections to the left. may result in a higher proportion of material from above

Consequently, aquifers and confining unit materials are a given zone than estimated, introducing additionalusually easy to differentiate on the gamma-ray log. misinformation.

HYDROSTRATIGRAPHY

Hydrostratigraphic-section interpretation and maps provide the information necessary for water

Cross sections and maps in this report show resource studies and planning. They also illustratehydrostratigraphie units based on correlations related changes in the updip configuration of the Wildwood-to the lithologic composition of materials. Belleplain confining unit, amajor goal of the study.

Permeabilities are inferred from lithologic

identification and geophysical interpretation. The Composite Confining Unit

hydrostratigraphic framework of the study area is The composite confining unit consists of Lateshown in a series ofsix eross sections (figs. 7-12),five Cretaceous to Miocene deposits overlying theof which are dip sections (figs. 7-11), and one a strike Wenonah-Mount Laurel aquifer and underlying thesection (fig. 12). In addition, five maps illustrate the Atlantic City 800-foot sand. The top of this unit iselevation and thickness of the key horizons studied described as the brown to greenish-gray, micaceous

(figs. 13-17). These are: (1) the elevation of the top clay-silt known as the Basal clay or the Alloway clay(fig. 13) and base (fig. 14) and the thickness (fig. 15) of member (Nemickas and Carswell, 1976). Although thethe Wildwood-Belleplain confining unit; (2) the top of the composite confining unit consiststhickness of the Atlantic City 800-foot sand (fig. 16) predominantly of clay-silts and silty and clayeywhere confined by the Wildwood-Belleplain eonfining glaueonitic quartz sands of low to moderateunit ; and (3) the elevation of the top of the composite permeability, it may incorporate fairly permeableconfining unit (fig. 17). The data used to construct sands which form the Red Bank, Vincentown, andthese maps are given in Table 3. These cross-sections Piney Point aquifers. In this study area it correlates

A ==_ _z A'o_-US. Geok>g_l Su_ey (G) zWuJ

02 =_

1O0 - US Geo_ical Sur,,ey(G) z z 100

StateofN.j. {G) 03 za Beachw w Haven

01 _ m el_mughTuckertonBomugh(G) (G)

04 05SEA SEA

LEVEL -

Kirkwood-Cohansey Kirkwoo_-Cohansey

I aquifer system aquifersystem

-100 -

.... ._. ...... ____

-200 - /'t_//c',_t_,_

-300 - -300

u. C "-4

-4OO - _ _.O0

_o - _ c_ L -5oo

-600 -

0 2 miles

hodzontat scale

-700 -

(G)- gamma-ray togextreme vertical exaggerationThe dashed line between Wells 01 and 02 separates the updip extent of the Atlantic City 800-foot sand from the Klrkwood-Cohansey aquifer system.

,.800 _00

Figure7.-- Cross-sectionA-A'.

B B'

uj w _z_Water m _ z (D O

wuJ z¢ 3Commi_10ne_ (e) Mulllca Twp. LandflJI (e) m m LUUJ

100 -- 06 07 StocktonS_ate = ¢_College (E) U.S. Geological 100

08 Su_'ey (E) Brigantine

SEA _ Kirkwood.Coha_ Bo_ (G)• .sey . SEA

LEVEL aquifer sYStem Kirkwo.od-Cohanaey__ LEVELequifsr aystem

-100-- -100

-200-- - -200

-300-- -- -300

-400- -- -400l--

W " I mu_ m

-500- -- -500 "_

-600- -600

-700 - -700

0 2 miles

-800- horizontal scale -600

(E)- electric log; (G)- gamma-ray log-900- extreme vertical exaggeration -900

The dashed line between Wells 06 and 07 separates the updip extent of theAtlantic City 800-foot sand from the Kirkwood-Cohansey aquifer system.

-1000 -1000Figure8.-- Cross-sectionB-B'.

Z ZC -o_ =-_ C'

=_ 100100 - AtJanticCity U.S. Bal_s wuJZUPark m el

water Dept, (El Dept. ofEnergy (G) Pta_ (G) U.S. U.S.

11 Geo_ogk:at Geo_i,:alSEA 12 13 SEASurwy (G) Su_'vey(G}

LEVEL - ._-_'114 15 LEVEL

-1oo- -c_o,_,"Y&'e/_ --

-200 - _ _ _ -200

-300 - _7oW,_.. _ -300

8e#efJla/ncoot?o/n9 "_und -_ ,!_ -- 400-400 -- . f- ,

_,o/t

u. -600 - _ - -600

-700 -- _ - -700

-00o- -oo-900 - "_. - -900

- -1000-lOgO - 0 2 miles

horizontalscale

-1100 - - -1100

(E)- electric log; (G) gamma-raylogextreme verticalexaggeration

-1200 -1200

Figure 9.- Cross-section C-C'.

1!

° ii °'Buena _z

Borough U.S. z o LULU200 -- MUA (G) Geological uJLu z o = ca 200¢luJ UJuj

Survey (G) U.S. = _ Egg Harbor16 " Geological Hamilton Township

100 17 Survey (G) Twp. High School(G) U.SMUA (E} Geological 10018 20 Survey (G)

/_'rk_o<_ 19SEA eg_ e -C.ohan_ 21 SEA

LEVEL r #va.te_ e.v Kirkwoed-Cohanse.v =EVELaquifer system

-100 - ,£. -'_--- - -100

-200 - Pv//e'_..... 200

_- -400 - _ _> - -400

ua _ , m_-500 - - -500

-600 - - -600

-700 - _- - -700>,.

400 -- _ - 400

-g00 -- 0 2 mileshorizontalscale _ - -900

-1000-- (E)- electricallog; (G)- gamma-ray log "_ -1000extreme vertical exaggeration |The dashed line between Wells 16 and 17 separates the updip extent of the AtlanticCity 800-foot sand from the Kirkwood-Cohanseyaquifersystem.

-1100 -- -1100Figure 10.- Cross-section D-D'.

E E'

zoUpper z z LUUj-- ¢0u)

Oeen3eld op- i_z 0 Atlantic m_ --2OO- T_(G) Cumber_nd zo _w City u 200

22 County m_ Electric

Planning Board (G) City oC_Yf Company NJ. NJ.Geological U.S, Arnedcan' _" 23 of

100-- _j; _ _ MI(G_I]Ie MJlMIle (G) SiJrveY(G) Gc°/°gl_l W=iter 100_voO#.Co h

SEA .... equifercv ancey 4LEVEL ........... Y_terl_ " SEA

i_ [ LEVEL

-1OO- con;._ _;,_ - -100

-200 - _bed ;7_ --200

__ -300 - _ _

uJ - -300= lu. -400 - m

P _ - -400

-500 - _ _ - -5OO-600 - / - -600

O 2 mileshorizontalscale

-700 - _ -7OO

-800 - (G)- gamma ray log ---800

extreme verticalexaggeration _- iThe dashedline between Wells22, 23, and 24 separates the updipextent of the AtlanticCity800-foot sand from the Kirkwoed-Cohansey aquifer system.

-900 -900

Figure11.- Cross-sectionE-E'.

F' F_z_

++ +i °+ ++ +!Z_ o_- ww ---- Z_ 3 cue) ZL3 Z_)_ LUuj ww - _

NJ, Ocean C_ LOngl_r t m _ BeachWonder Sea I_Je American C_ Water Water U.S. Balty*s m _ Haven

100 -- Ice City Water Water Serv_ Dept. Geo_tcal Park B_anUne N.J. BOm_h 100CO. (G) NO. 6 (G) CO. (G) CO (EI (G) (G) SUn*'ey(G) Ptac4 (G) BorOUgh(G) D.E.P. (G) (G)

SEA 35 34 29 33 32 31 21 13 10 30 05 SEALEVEL - LEVEL

-100- ---100d.COhansey

F.irk'WC°.=r sYstem-200 - aquJ+e -- -200

-300 - -- -300

_" , witdwood.Belreplainconfining unit-400- -- -400

u."uJ-500- • _ _ Widdwood.BefJeplain confining unit ---800-600 -- -600

t=,-

J

-7oo _ i --7oo

-800 - composite confining bed -- -800

-900 - --_ ' -- -900

-1000- horizontalscale -- -1000

(E_-electric log G)- gamma-ray log-1100 exlreme vertica exaggera on -1100

Figure12,- Cross-sectionF'-F,

I I I

75o15, 75° _ I I I74o45, 74o3_ 74o15,

39=45- CAMDEN 39o45._COUNTY BURLING TON

OCEAN _COUNTY , COUNTYGLOUCESTER ,. " "

COUNTY .. • "

ATLANTIC ."

SALEM COUNTY

COUNTY

of -'Wildwood-Be#eplain_, .

confining unit .. "

e.194 39o30' --

CUMBERLAND .... . • "COUNTY

• . . . . e.180

• , . e.148 e-147

_580

- 39o15- 39o15,-

Atlantic

Delaware Ocean

Bay .245e

N,4L

_ 39a 00, 0 5

miles CAPEMAY 39°°c_-COUNTY

75° 15- 75o 74=45' 74o3_ 74o15•I I I I I

Figure 13.- Elevationof topof Wildwood-Belleplainconfiningunit,in feet belowsea level• Contourinterval50 feet.

15

75° IS" 75• 74°4S' ".r4°3G' 74° 15'

- 3_45' CA 39*'45'

_.._ COUNTY _. BURLINGTON OCEANCOUNTY COUNTY

GLOUCESTER _ / _ ..

\ / ATLANTIC .'""SALEM\ y COUNTYcouNTY _ / .."

approximate limit of ..""/_ /\ /_,o,._',_:'_.confiningunit ..

xd _eCUMBERLAND ... ,

COUNTY " " "

,;2o3;I_ __

.#"238o ._,ge

-39015 , 39o15,-

AtlanticOcean

DelawareBay

NA

-- 39"00' [ 0 5 39"0(T-

[ miles CAPE MAYCOUNTY

75o15' 750 74=45' 74030' 74=15'I I I I i

Figure 14.- Elevation of base of WUdwood-Belleplain confining unit, in feet below sea level. Contourinterval 50 feet.

16

I I I I /74=15'75o15' 75_ 74o45' 74030'

_ 39o45, CAMDEN OCEANCOUNTY BURLINGTON COUNTY 39°45 '

COUNTY

GLOUCESTERCOUNTY " "

ATLANTIC " "SALEM COUNTY

COUNTY ,"

Wll_-Belleplaln _:.. •confining unit ."

,. 39=30_-

CUMBERLAND

COUNTY ....... " _.eo

. " • " 44

e262

.286

-39015 , 39015'-

/

DelawareBay

Nz_ _ Atlantic

0 1 .e Ocean39"0_ 5 CAPE MAY 39=°°'-

miles / COUNTY

75° 15' 75= 74=45" 74o3_ 74o15'I P I

Figure 15.- Thickness of the Wildwood-Belleplain confining unit, in feet. Contour interval 50 feet.

I?

75115 , 75 a 74o45 . 74o30 ' 74=15 ,

39o45. CAMDEN 39=45'-COUNTY BURLINGTON OCEAN

COUNTY , COUNTYGLOUCESTER . " "

COUNTY

ATLANTIC •" "

SALEM COUNTY "COUNTY

,nitofWildwood-gelleplaln_, . .

confiningunit . • "

CUMBERLAND /COUNTY . . . . " • " /

• , "" "" ' 112m

45i

_'_ e116 134

./8o

- 39°15 • 39=15 ' -

DelawareBay

NA CAPE MAY Atlantic

COUNTY Ocean_ 39o00, 0 5 39o0(T -

miles

75015 • 75 ° 74=45. 74=3G ' 74 ° 15"I I I I

Figure 16.- Thickness of Atlantic City 800-foot sand, where confined by Wildwood-Belleplain confiningunit, in feet• Contour interval 50 feet•

18

75°IS' • o 74o45. 74°30' 74° 15'BURLINGTON

CAMDEN COUNTY OCEAN

'3s°45' COUNTY COUNTY 3s°4s'-

GLOUCESTER _ .'..300COUNTY

\SALEMCOUNTY

ATLANTIC

,_'_ CUMBERLAND-39o15'COUNTY _°15"-

DelawareBay

CAPE MAY

N COUNTYA Atlantic

-39.o_ IO 5 ] Ocean

39000'-miles

75°15' 75° 74°45+ 74.3_ 74o15•I I - I I I

Figure17.-- Elevationoftopofcompositeconfiningbed,infeetbelowsealevel. Contourinterval50 feet.

19

with the lower clay-silts and glauconitic sands of the occasional thin interbeds of clay. The upper sand unit atlower member of the Kirkwood Formation which Atlantic City is more variable, it includes massive clayeyunconformably overlies glanconitic sand, silt-clay, and sand with shell hash, pebbly coarse sand, and micaceousglanconitic quartz sand deposits of Eocene to Oligocene fine to medium sand interbedded with silty clay.age.

Approximately 5 miles offshore of Atlantic City atThe composite confining unit is as much as 100 the U. S. Geological Survey marine observation well 2

feet thick and includes local sandy layers. At Atlantic (well number 15, table 2), the Atlantic City 800-footCity, it is 73 feet thick (Miller and others, 1994); about sand is 180 tt thick (figs. 9, 16; table 2). The lower sand20 miles updip, at the ACGS-4. borehole near Mays is much thicker here.Landing, it is about the same thickness. It dips fairly

uniformly to the south east at about 25 fi/mi. Along the Updip, at the ACGS..4 borehole (well number 18),coastline in Atlantic County, the top is about 850 feet the Atlantic City 800-foot sand consists primarily of thebelow sea level (fig. 16). upper sand (90 feet) of the Shiloh Marl Member, and

about 24 feet of the upper part of the lower Kirkwood

Atlantic City 800-foot Sand member (fig. 10). The lower clay-silt of the Shiloh Marlmember, which forms the leaky confining unit, is about

The Atlantic City 800-foot sand is the principal 40 feet thick at the ACGS-4 borehole, significantlyconfined aquifer supplying water to Atlantic City, and thicker than at Atlantic City.points north along the barrier islands to Harvey Cedars(Ocean County), as well as south to Stone Harbor (CapeMay County) (Zapecza, 1989). It consists of sands from Wildwood-Belleplain Confining Unit

the lower Kirkwood and Shiloh Marl members, and is Between the Atlantic City 800-foot sand and theinformally subdivided in this report into: (1) a lower Kirkwood-Cohansey aquifer system is a massive clay-sand, (2) a leaky, relatively thin confining unlt and (3) an silt bed that is typicany rich in diatoms. Referred to byupper sand. The lower sand overlies the composite Woolman (1892, 1895) as the "Great Diatom Bed," it isconfining unit, and corresponds to the upper quartz sand also the confining bed of Zapecza (1989), composedof the lower member of the Kirkwood Formation (or largely of the Wildwood Member of the KirkwoodKwla sequence of Miller and Sugarman, 1995). The Formation. The bed is here called the Wildwood-

confining unit and the upper sand correspond to the Belleplain confining unit because the lower part of theShiloh Marl Member of the Kirkwood Formation and the Belleplain Member of the Kirkwood Formation formsKirkwood Kwlb sequence (fig. 3). Mullikin (1990) the upper partofthis unit (fig. 3) in southeastern Atlanticcalled it the Atlantic City confining unit. Aquifer testing and Cumberland counties (Sugarman and others, 1993).in Atlantic City showed that it is leaky (Johnson, 1980).

Zapecza (1989) cited unpublished evidence that Midway withintheWildwood-Belleplainconfiningsignificant amounts of water can pass from the upper to unit at Atlantic City is the Rio Grande water-bearingthe lower sand. zone (fig. 3). This was first recognized in Atlantic City

as a 554-foot-deep water-beating sand (Woolman, 1889,The Atlantic City 800-foot sand is about 150 feet p. 90), but is now used for water supply only in southern

thick along the barrier islands in Atlantic County. At Cape May County (Zapecza, 1989). It typically is a grayAtlantic City (fig. 3) the aquifer is about 140 feet thick sand with some interbedded silt and clay, and ranges inand consists of a lower sand (808-741 feet below land thickness from 10 to 105 feet. Throughout the coastalsurface) and an upper sand (733-666 feet below surface) areas of Atlantic and Ocean Couuties it is generally lessseparated by a thin bed of clay-silt (741-733 feet below than 40 feet thick. Its silt content increases north and west

land surface) which is probably too thin at this site to act of Atlantic City. The Rio Gmnde water-bearing zone isas a leaky confining unit. The upper sand unit of the thickest at well 28 in Upper Township, Cape MayAtlantic City 800-foot sand ranges in thickness from 10 County, where it is 105 feet. As depicted in cross section

to 105 feet, and generally contains finer sand and more - E-E' (fig. 11), where the Rio Grande water-bearing zoneinterbedded clay and silt than does the lower sand unit. is thick, it effectively divides the Wildwood-BelleplainMost of the production wells along the Atlantic County confining unit into an upper and lower unit.coast with_aw water from the lower sand unit; in Ocean

County the production wells are typically in the upper The lithology of the confning unit is similar abovesand. At Atlantic City the lower sand is generally a gray and below the Rio Grande water-bearing zone. It is amassive medium to coarse quartz sand, with some dark-anlored, diatomaceous clay-silt. Thin interbeds oflaminated layers of fine to medium sand at the base,and sand occur throughout the unit (Andrews, 1987), but are

20

especially common in the Cape May area (Zapecza, well 1. On section D-D' (fig 9) through southern Atlantic1989). The thickness of the confining bed increases County, the Wildwood-Belleplain confining unit isdowndip from 61 feet in the vicinity of Mays Landing to thickest (290 feet) at the Egg Harbor Township Highabout 260 feet near Atlantic City (Miller and others, School. A little more than 10 miles updip at the U.S.1994). At the ACGS-4 borehole near Mays Landing, the Geological Survey ACGS-4 well, the confining unit is 61Wildwood-Belleplain confining bed is an olive-gray to feet thick, and is interpreted to pinch out just updip fromdusky-yellowish-brown clayey silt and fine sand, this site. At well 17 in Hamilton Township, thelaminated to massively bedded, containing diatoms, Kirkwood-Cohansey Aquifer system is 390 feet thick,small pieces of wood, and mica (Owens and others, this increased thickness due to the termination of the

1988). At Atlantic City, the lower part of the confining confining unit, and the interconnection oftbe Kirkwood-unit below the Rio Grande water-bearing zone is a dark Cohansey and Atlantic City 800-foot sand.gray, micaceous clay-silt and fine sand, with scattered

intervals of shells. Above the Rio Grande, the upper Kirkwood-Cohansey aquifer systemconfining unit is a massive bioturbated to laminated clay-silt, commonly with shells (Miller and others, 1994). The Kirkwood-Cohansey aquifer system is

predominantly unconfined and consists of the upper part

Elevations of the top and base of the Wildwood- of the Belleplain Member of the Kirkwood and all of theBelleplain confining unit are shown in figures 13 and 14, Cohansey Formation. Where the Wildwood-Belleplainand given in table 2. In the study area, the top of the confining unit is absent, this aquifer system also includesWildwood-Belleplain confining unit updip is about -100 the lower Kirkwood and Shiloh Marl Members of thefeet (relative to sea level); along the shoreline, downdip, Kirkwood Formation. The Kirkwood-Cohansey aquiferthe top of the unit is approximately -390 feet. system can also include the Beacon Hill, Bridgeton, andCorrespondingly, the base of the Wildwood-Belleplain Cape May Formations (Rhodehamel, 1973). It isconfining unit at wells located updip in the area is at confined beneath fine-grained, post-Cohansey, estuarineabout - 130 to -160 feet, whereas downdip along the coast deposits throughout much of Cape May County (Gill,the base is at-650 feet. 1962) and locally along the coast, as at Leeds Point,

Atlantic County, and Bamegat, Ocean County. Along

The thickness of the Wildwood-Belleplainconfining the coast and for several miles inland, the base of theunit (including the Rio Grande water-bearing zone) is Kirkwood-Cohansey aquifer system overlies the top of

shown in figure 15. In general, the unit thickens toward the Wildwood-Belleplain confining unit (for example,the southeast. Along the coast of Atlantic County, its figs. 8 and 11). The Kirkwood-Cohansey aquifer systemthickness is fairly constant at about 270 feet. It is over typically contains sandy beds at the top of the Belleplain400 feet thick in northern Cape May. The updip limit of Member and coarser quartz sand in the Cohanseythe Wildwood-Belleplain confining unit is shown in Formation. Within the Cohansey Formation local clayfigure 1; this areal representation is based on beds, some of them reaching several tens of feet thick,

interpretations shown on figures 7-11. The termination of create perched water tables and semi-confinedthis confining unit is based on lithologic mapping and conditions (Rhodehamel, 1973).correlation, and requires hydrologic testing to verify.Where the Wildwood-Belleplain confining unit is not In the western part of the siudy area, confining unitspresent, the Kirkwood-Cohansey aquifer system may within and above the Atlantic City 800-foot sand pinchalso contain lithologic equivalents of the Atlantic City out, become sandy, or are tmncated at the unconformity

800-foot sand (figs. 7, 8, 10 and 11). On section A-A' at the base of the Cohansey Formation. West of this, the

(fig. 7), the Wildwood-Belleplain confining unit loses .Kirkwood-Cohansey aquifer system extends downwardits competency between wells 2 and 3 in Bass River to the top of the composite confining unit (figs. 7, 8, 10Township, resulting in a thick Kirkwood-Cohansey and 11).aquifer system at the U.S.G.S. Oswego Lake observation

21

SUMMARY AND CONCLUSIONS

The Kirkwood Formation of the New Jersey Coastal includes several overlying post-Miocene fluvialPlain consists of four major hydrostratigraphic units formations within the study area. The Kirkwood-based on lithologic composition and permeability. From Cohansey aquifer system is predominantly under water-bouom to top these are: (1) the composite confining unit, table conditions, but locally includes perched andwhich is predominantly the lower part of the lower semiconfined zones.member of the Kirkwood Formation in this study, (2) the

Atlantic City 800-foot sand, which informally consists of The confining unit overlying the Atlantic City 800-a lower sand, a middle leaky confining unit, and an upper foot sand may pinch out to the west or be truncated at the

sand, (3) the Wildwood-Beneplain confining unit unconformity between the Kirkwood and Cohanseyoverlying the Atlantic City 800-foot sand, which includes Formations. Because of this, the Kirkwood-Cohanseythe Rio Gmnde water-bearing zone, used for water aquifer system extends to the top of the compositesupply in parts of Cape May and Cumberland Counties confining unit in the western part of the study area.and, 4) The Kirkwood-Cohansey aquifer system, which

22

Table 1.-- Well recordsused in study.

Well Municipality, County Well Location Elevation (l_)hBorm. No. Name/Ownor (ft)Latitude Longitude

01 Wsshiogton Township,BudiugtonCounty -- 39-43'05"N 74"33'57_N State of New Jersey(Mullica 13D) 41 302 G02 Bass River Township, BudiogtonCounty 32-436 39-42'08"N 74"26'45"W U.S. _ ,_ (Oswego_ (7os.Well 1) 97 600 G03 BossRiver Township, BudingtonCounty 32-10890 39"40'07"N 74"36'30"W U.S. Geolugk_alSurvey 68 540 G04 TuckertonBorough,Ocean County 32-22508 39-36'10"N 74"20'3I"W Tucke_on Borough 10 503 G05 Beach Haven Borough,Ocean County 53-31 39_33'43"N 74"14'30"W Beach Haven Borough 6 656 G06 HammontonTown, AtlanticCounty 51-140 39-3T59"N 74°48'24"W Board of Water Commissoners 90 245 G07 MullloaTownship,AtlanticCounty 32-10935 39-35'07"N 74"40'40"W MuilJcaTownshipLandfill 95 540 G08 GallowayTownship, AtlanticCounty . 36-4982 39_33"N 74'31'30"W StocktonState College 40 680 E09 GallowayTownship.Atlantic County 36-294 39"27'53"N 74°27'01"W U.S. Ganlugical Survey 27 1002 E10 BrigantineCity, AtlanticCounty 56-12 39"23_0"N 74"23'48"W BrigantineBorough 9 840 G11 Egg HarborTownship, AtlanticCounty 36-454 39_26'22"N 7432'12"W Atlantic City Water Oepartznent 20 691 E12 AtlanticCity, AtlanticCounty 56-65 39-22'47"N 74"2Tt3"W U.S. Depadmenl of Energy 5 1004 G13 AtJanticCity, AtlanticCounty 36-1084 3921'25"N 74"26'04"W Bally'sPark Place 7 884 G14 Attanlk:City, AtlanticCounty 36-5615 39-19'55"N 74"25'07WV U.S. GeOlogicalSurvey (Marine Obs. Well 1) -32 931 G15 AttanUcC.;_ty,AUan_cCounty 36-5972 39"1T26"N 74"22'21"W U.S. GeologicalSurvey {Madna Obs. Well 2) -43 1025 G16 Buena Borough,AttanticCounty 35-4559 3931 '48"N 74056'17"W BuenaBoroughMUA 118 474 G17 HamiltonTownship,AtlanticCounty 35-4656 39-29'02"N 74°50'51"W U.S. Geological Survey 92 577 G18 HamiltonTownship,AtlanticCounty 35-4274 39-29'33"N 74°46'O4"W U.S. GeolgicalSurvey(ACGS-4) 40 945 G19 Hami_tanTownship,AUantlcCounty 36-391 39-2T09"N 74'44'39"W HamiltonTownshipMUA 92 577 E20 Egg HarborTownship,Atlantic County 36-5091 35"23'44"N 74*37'49"W Egg HarborTownshipH_h School 50 678 G21 Margate City, AtlanticCounty 36-10548 39"20'17"N 74"30'02"W U.S. Geological Survey 5 1055 G22 UpperDeertleld Township,CumbedandCounty 35-4055 39*30'05"N 75"10'5TW UpperDeenieldTownship 110 730 G23 MilivilleCity,CumberlandCounty 35-1196 39-25'26"N 75"06'43"W CumberlandCounty PlanningBoard 80 560 G24 MitlvilleCity,CumberlandCounty 35-841 39_23'31"N 75"02'25"W City of Millville 7 280 G25 Milivtl]eCitytCumbedandCounty 35-842 35"22'20"N 75"01'12"W Cityof Miliville 20 738 G26 MilivilleCity, CumberlandCounty 35-2569 39"22'15"N 74"58'28"W AttantlcCity ElectricCompany 49 460 G27 EstellManor City, AtlanticCounty 35-4903 39"19'46"N 74"51'25"W N.J. GeologicalSurvey 40 600 G28 UpperTownship, Cape May County 37-01340 39"16'21"N 74"43'35"W U.S. GeologicalSurvey 15 740 G29 UpperTownship,Cape May County 36-13154 39"11'51"N 74"39'28"W N.J. AmericanWater Company 5 870 G30 Uttle Egg HarborTownship,Ocean County 36-05251 35"31'15"N 74°19'10"W N.J. Departmentof EnvironmentalProtection 5 1012 G31 LongportBorough,Atlantic County 5680 39"18'21"N 74"32'08"W LongportWater Department 6 803 G32 Ocean City,Cape May County 36-314 39"17'26"N 74"33'_ Ocean City Water Service 10 922 G33 Ocean City,Cape May County 36-412 39"15'00"N 74"36'45"W Ocean City Water Company 7 902 E34 Sea Isle City,Cape May County 36-10378 39-07'33"N 74"42'31"W Sea Isle City No. 6 10 921 G35 AvalonBorough,Cape May County 56*93 39-06'42"N 74°42'48"W Wonder Ice Company 5 898 G36 LongBeach Township,Ocean County 33-13836 39"3T24"N 74"11'50"W LongBeach Water System 5 616 G37 Long Beach Township,Ocean County 33-1275 39-35'10"N 74"13'27WV Long Beach Water Company 8 697 G38 WashingtonTownship,BurlingtonCounty 32-1525-12D 39"38'32"N 74"36'08"W State of New Jemey 51 370 G39 Bass River Township,BudingtonCounty 32-21761 39=36'42"N 74"26'12"W State of New Jersey(BassRiver) 28 1036 G40 LittleEgg HaYoorTownshiptAtlanticCounty 32-609 39-32'53"N 74"23'08"W MysticIslandWater Company 5 607 G41 HamiltonTownship,AtlanticCounty 32_0173 39-33'33"N 74°44'26WV SchollerBrothersChemicalCompany 90 238 G42 LawrenceTownship,Cumbedand County 34-852 39"18'29"N 75"12'08"W Cumbedand County PlanningBoard 10 570 G43 OowneTownship, CumbedandCounty 35*849 . 39"18'26"N 75"06'58"W PennsylvaniaGlaSs Sand Company 55 413 G44 Maudce RiverTownship,CumberlandCounty 35-4640 39"15'18"N 74"53'55"W BolleptainState Forest 40 600 G45 MiddleTownship,Cape May County 55-81 39-0T04"N 74°4TS0"W Esstem Shore Nurs_ugHome 15 654 G46 MiddleTownship,Cape May County 37-236 39-05'25"N 74'48'51"W NeptunusWaterCompany 17 807 G47 AvalonBorough,Cape May County 37-280 39-04'20"N 74'44'35"W AvalonWater Company 5 905 G

lithologiclog;G- gamma-ray log;E- eloctdc log

Table 2.-- Altitudeof top and base, and thicknessof hydrostratigraphicunits (infeet above or belowsea level).

Klrkwood-Cohansey Aquifer Systmll WUdwood-Belleplaln Confining Unit AUantlc City 800-foot Sand Composite Confining UnitWe41

Top Base Thickness Top Base Thlcknm Top Base Thickness Top Base Thickness

01 41 -179 220 ..... 179 - --02 97 -269 366 ...... 269 -369 1CO03 68 -104 172 -104 -192 88 -192 -352 160 -352 -444 9204 10 -132 142 -132 -396 264 -396 >494 >100 -- -05 6 -266 272 -266 -554 288 -554 --670 116 ....06 90 -128 218 ..........07 95 _7 182 -87 -129 42 -129 -337 208 -337 - -08 40 -194 234 -194 -398 204 -398 -506 108 -506 - --09 27 -197 224 -197 _177 280 -477 -647 170 -647 -°10 9 -379 388 -379 _45 266 -645 -791 146 -791 -11 20 -200 _30 -200 -480 280 -480 -620 140 -620 --12 5 -321 326 -321 -655 334 -655 795 140 -795 -915 12013 ? _ 400 -393 _S93 300 -693 -833 140 -833 --14 -32 -470 438 -470 -732 262 -732 -897 165 -897 --15 -43 -580 537 -580 _70 290 -870 -1050 180 --16 118 -132 250 ..... 132 -272 14017 92 -298 390 - - -298 -428 13018 40 -135 175 -135 -196 61 -196 -344 148 .344 442 12019 20 -154 174 -154 -304 150 -304 °-20 50 -160 210 -160 -450 290 -450 -562 11221 5 -353 358 -353 -643 290 -643 -797 154 -797 -919 ! 2222 110 -54 164 .... 54 -170 11623 80 -148 228 - - -148 -258 11024 7 -109 116 -109 -153 44 -153 -259 106 -259 --25 20 -148 168 -148 -205 57 -205 -321 116 -321 -677 35626 49 -147 196 -147 -203 56 -203 -337 134 -337 --27 40 -104 144 -104 -322 218 -322 -502 180 ....28 15 -239 254 -239 -525 286 -525 -679 154 -679 --29 5 -313 318 -313 -677 364 -677 >_57 >174 ....30 5 -197 202 -197 -550 353 -550 _75 125 -675 -803 12831 6 -362 368 _62 -642 280 -842 ......32 10 -384 394 _84 -644 260 -644 _0O 156 -800 -33 7 -293 300 -293 -643 350 -643 -837 194 -837 -34 10 -316 326 -316 -716 400 -716 _888 -172 _888 --35 5 -345 350 -345 -749 404 -749 .....36 5 -225 230 -225 -513 288 -513 ......37 8 -224 232 -224 -516 292 -516 -654 138 -654 --38 51 -307 3.58 .... 307 --39 28 -106 134 -106 -301 195 -301 -450 149 -450 -.40 5 -189 194 -189 -445 256 -445 -564 119 -564 --41 90 -_ 188 ...... 96 --42 !0 -90 100 -90 -238 148 :238 *262 24 -262 -340 7843 55 -29 84 -29 -229 200 -229 -321 ? 92? -321 ? --44 40 -148 188 -146 -378 232 -378 -45 15 -241 256 -241 -625? 384? - --46 17 -245 262 -245 -663 418 -663 -- >120 °-47 5 -387 372 -367 -795 428 -795 --

REFERENCES

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in Atlantic County, N.J.: New Jersey1988, A revised marine diatom zunation for Geological Survey Report 22, 82p., 1 pLMiocene strata of the southeastem United

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Piney Point Aquifer and the Alloway ClayCarter, Charles H., 1978, A regressive barrier and Member of the Kirkwood Formation: U.S.

barrier-protected deposit: depositional Geological Survey Journal of Research, v. 4,environments and geographic setting of the no. I, p. 1-7.

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T.A., Gonzalez, V.M., and Sugarman, P.J., 1988,Gill, H.E., 1962, Ground-water resources of Cape Stratigraphy of the Tertiary sediments in a 945-

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re-definition of the _ood Formation and Orndorff, R.C., 1998, Bedrock geologic(Miocene) of New Jersey. Journal of . map of central and southern New Jersey: U.S.Sedimentary Petrology, v. 40, no. 3, p. 986-997. Geological Survey Miscellaneous Investigations

Series Map 1-2540-B.Johnson, S.W., 1980, Report of pump test at Bally

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Environmental Protection, Division of WaterKnapp, G.N., 1904, Pa_ IV.-Underground waters of - Resources, Special Report36, 58 p., 1 pL

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Sugarman, P.J., Miller, K.G., Owens, J.P., and

Miller, K.G., Sugarman, P.J., and members of the Feigenson, M.D., 1993, Strontium-isotope andN.J. Coastal Plain Drilling Project, 1994, Island sequence stratigraphy of the Miocene

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