Alaska Open-File Report 127 ASSESSMENT of THERMAL SPRINGS SITES in SOUTHERN SOUTHEASTERN ALASKA---PRELIMINARY RESULTS and EVALUATION

June 1980

Alaska Open-File Report 127 ASSESSMENT OF THERMAL SPRINGS SITES IN SOUTHERN SOUTHEASTERN ALASKA---PRELIMINARY RESULTS AND EVALUATION

BY Roman J. Motyka, Mary A. Moorman, and John W. Reeder CONTENTS

Abstract ------. ------i Introduction ------1 Ilse of the report------2 Hydrothermal convective systems------4 Field techniques and sampling procedures ------5 Lnhoratory aonly~es:Methodr used and precision------h Gpotl1~>r~~(~~~etry- - - - - .------0 Silica gpotllprmometzy - - - . ------10 Silica mixingmodels- - - .- - - -. ------12 Sodium-potn~;sirlm-cali.ium gcott~errnornet-ry------1 3 Accur- icy oi grotl~ermometry------15 Descl ipl ion oL individ~~altherrni~l-spring sites ------I6 1. (:hi& Shalces hot c;prings ------18 2. Harnes Lake (paradise) warm springs------24 3. Fowler Hot Springs (Canada)------2 8 4. Twin Lakes (West Shakes) warm springs------33 5. Mt. Rynd~(South tik kine), reported warm spring------3 7 6. Vank Island, reported hot sprlng, unsubstantiated------38 7. Virginia Lake, reported hot spring, unsubstantiated------39 8. Bretlfic>id hot qprings------40 9. Bell Island hot springs------44 10. Bailey Ray Hot Springs ------5 1 11. Saks, reported hot springs, unsubstantiated------5 9 12. Unuk, reported thermal springs, unsubstantiated------60 13. Raker Island Hot Springs ------6 1 Summary, southern Southeastern Alaska thermal springs------6 3 Acknowledgments------6 5 References ------66

1' IGIJ RES

Figure 1. Locat ion of reported thermal springs, southern Southeas tern Alaska- - - .------. ------Solubili ty of quartz as a function of temperature------Silica mixing model examples ------Geologic map of tik kine River area ------Geologic map of Fowler Hot Springs area------Location map, Bradfield hot springs------Gcologic map of Bell Island and Bailey Bay Hot Springs area- Bailey Bay Hot Springs - - - .------1,ocation map, Baker Island Hot Springs ------

iii TABLES

--Page Table 1. Methods and expected precision: DGGS water chemistry - . -. - .- - - - -. ------Cl~emical composition and physical proper ties of Chief Shakes hot springs------. ------Chief Shakes hot 8pring.i geother~nometry- -. - - - - - .- - - - Chemical composition and physical properties of Barnes Lake warm springs------Barnes Lake warm 8pring~#c.othermometry------Chemical compoeition and physical propcrtics of Fowler Hot- Springs - - - . ------Fowler Hot Springs geothermometry------Chemical composition and pkzysi.cal properties of Twin Lakes warm springs------Twin 1,akes warm springs geothermometry ------Chemical compoai tion and physical properties of Brad field hot springs---- - .------Bradfield hot springs geothermometry ------Bell Island Hot Springs temperatures, 10/5/79------Chemical cornpov it ion arid physical properties of Be1 l Is land Hot Springs ------.* ------Bell Island Hot Springs geothermometry ------Temperatures and flow rates, Bailey Bay Hot Springs- - - - - Bailey Bay llot: Sprir~g~,upring-3 water jet height and temperature- - .- - - - ... - -. ------.. - Chemical composition and physical properties of Bailey Bay Hot Springs ------.... ------Railey Bay Hot Springs geothetmometry------Summnry, southern Southeas tern Ala~ikan thermal springs sites ------. - .------

APPENDIXES

Appendix A - Abbrev~ationa, unit symbols, and conversion factors - - - 70 Appendix B - Precision of water analyses ------7 1 Appendix C - ICAP determinations of minor and trace elements ------72 ABSTRACT

information has been gathered on 13 reported tl~erm,+l--springsites, 12 in southern S0utheast:ern Alaska and one in western British Columbia. Five of Ihc reported sites could not be substarltiated hy DGGS. The eight know1 t:herrrinl spring sites are associated with granitic terrain and, except for Baker Tslaud Hot Springs, occur within or near intensively Erae tured Cretaceolrs-ape plutons of th~Coast Range Bac?~olith .

Thermal -spring surface temperatures range from 21"~ win Lakes) Lu 91.5"C (Bailey ~ay). The greatest discharge occurs at Chief Shakes hot springs (450 I pm). Bell Island Hot Spririgs, which has about a 100--1pm discharge and a 70°C temperature, ha6 had the most development. Two previo lsly unreported thermal-spring sites, Barnes Lake warm springs and Bradf ield hot springs, have a low rate of discharge and respective surface temperatures of about 25" and 54°C.

The known tliernlal springs probably originate from circulation of izetporic waters through deep-seated fracture and tault systems. The chemical const i rrl~n~sof the alkal i-sulEate to alkal i-chloride thermal waters are probnb ly derived from interaction of the deeply circcll~tingmeteoric waters with tll~ granitic wall rocks. Chemica t gr-othermometry suggests nubsl~rface temperatcrrps of '>So to 151°C. Tf waters are beix~gheated ~olelyby col~clnction from wall rocks, circulatinrr d~pthsinust bp about 1.5 to 5 km, as~rlmin~geotiiermal gradients of 30" to 50°C/km.

Variations in temperature, discharge, and chemistry were noted at several ermal springs for wliich previous records are available. A major decrease. in 1 ica nnd potassium concentrations at Chief Shakes hot springs is suggested by comparing recent analyses of water chemistry to Warjng's (1917) arigin,~l analysis. The rate of discharge at: Bell Island Hot Springs may have increac,ed by a Eactor of two since Waring's visit to the springs.

Subsurface reservoirs associated with thermal springs in southern Soutli- caasttArn A1a1~;lcaRTC of low t:vnper~turt-? and are probably iimitetl in exceiit, cornpared to geothermal fields now being used elsewhere in the world. Only the Beel Island and Bailey Bay sites now off~rany potential for generation of electric; ty; rhese sites could a190 be used for a variety of direct uses such as space heating, wood or luntber processing, and perhaps auuaculture. The other sirt.s have less potential but could be used locally for space heating or ;igricnlturc enhanremerit.

INTRODUCTION

The Alaska Division of Geological and Geophysical Surveys (IIGGS) in PO- operation with the U.S. Bep.~rtmentof Energy, in 1979 embarked or1 a 3-y~13r program of assessinp the ~eoth~rmalenergy resource potent jal of thermal- spring sircis in Alaska. Evaluation ,)f these sites is based on geological clr~d geochemicjii (jato, gsntllc?rmometric modcl s, anti geophysical data where avai l- able.

More than 100 hot-.spring qi ti,<; have been reported to exist in Alaska. 1"re sites are d isperscd t1i~-oughouL the state but Y ignificar~tconcentrat ions and be119 of rlrclrnlal sprin~ec1i.c ur along r:lle AJeutian Range, in Southessterr~ Alil~kii,and across crnL~.iilA1clsh.a. Th,? firsC comprehensive inven~oryof the t1,enrral springs of Alas1c.l \.;:Is, pub1 islit ii in 1'11 7 h y Waring. Since then brief silnnnar ies of A1;nak.m ther mizi spr ~IIL:~nave appeared in Waring ( lP651, Mill cr (1973): White and Willinrll:, (199')), end Muffler (1979). The inn~rrecent rom- pr c.llcxrlsivc surlvricary 01 hl lzskat itlcr~nllspring ~~IVCHIigttt. ~OIIHWL~S romp i l f'tl ' *,r K<~rklc(1979).

'Ilhe scope af the i.nitl.ii! ,at:se.ss~neiltof geothermaI resources ar; undertalcerl by I)i:G% i.nc1udr.s 1) invcsi:i~;ating all thermal--spri.ng sites previously reported but not as yet visited or- s~u:li:~dby n scie~~~.;fi.cteam; 2) providing up-to-- date data ancl more d6ita.i l.eci ..ii:urli.es of previously ia~vestigai::edsites ; anc! 3) 'I,ocat i.ng and iitvcs t igat i,trg; add it i.onal thrrrnil-spr.~i.ng sites not previously rr2ported. The assessment work includes recorlrraissance of site geol.ogy and hydrology, ir~trestigation iiil t:tlt:r~nal.--spring charac teristic s in,clwing temperatures and flow rates, :!ud ~e~ic:l-ic~~iiicalsatiipl.ing and t-lnalysis of the rocks and thermal waters at: the sit<.. 'l'hi:; inlormati.on .Is used to describe the site, to estimate reservoir. temper~itui-e, to evaluate tilt: extent of mixing of thermal waters witit colder witter!g, .,and to detern1i.n~the geotl-lermal energy potential. of the si tt!. Thcse da tn for ,:'I,l 1.h~tlrerrnni~l sy.)ri.ng nites of Alaskcl will be cola-. p.ilc?d j.nto u geotl.~esmaliitl.an, 'TI-ltt inf:)rnluti.on i.3 also being used i:o se'tect: s i t-es with the highest. pt:i:t:n t i-zl for geothermal energy use and to recornmenti f:~llow-up stlld ien at s~lcil s:i l:cs .

Thi *< report psc?ilent lht. ptcli.r~inaryresults of investigatiotis on thar~nal springs in southerrx SourIl-.astcrl! Alaska, mar PeLersburg, Wrangell, Ketchikan, 1 a,i. 1j . 'Ckl ec. of ~11cq;o sites, which had bee11 reported by War in): (131 7) (~ankIsland, Unuk, and Sska Cove), could not be substantiated and

F ir ld inv -53l 1 g,ii 3 oils wt., ~~erforrncdon sevl-.ii thermal spring n i t-es dur ing La~rScpl cvnher i.rl-1 ciiriy O~tol,-'1., 1979 Four r~fthe sites occur nlotng the St iir~ncRiver (Ch4el Shsltrs , Twin I,akes, Rarnes Lake, ~owler), one ~llor~gthe Bradfield ir~v~.r(~rndiieili), :xnd two on iind nt.nr lie11 Island (Bell Island an,!

Bailry t\ay). Two OF 1-lit: !i i+(ao invest :gated, Jjarnrs Lake and Erridfield, lrave not- bre~irckurted in any prcavio~is con~pilation of thermal springs in A1ar;ka. 'I'll( tcActr~t ~L.:CGV~?X.Y of thr* i%r:~~ifieldhot springs in a remoic* area c)f fhe Coar , Lt6iri[~r\ C/iour\t~in.~.;uggeh tm, i~~llprI-ha-r nkal 6prircfi.r tax ist but hclvc not yt- t bctan rlr t-rc.tc.3.l F'.i.g111t+ 1. L,oc:atiorrs of repl.tr.ted t?~~rrnal~priitg:-i, eotrthern Southcastes/rl Alacika. An upen 1,indicates :!\at e,:i.s7telice of s!~r.i.l:,kjhas 1 iwen :.:!~i)-- 8 t-an!:iar i.6 rind is present1 p ;!i.scour;seii LocaL i.nn i-11lri;i-rer.: arc! k;>yt:ii ro !:G!.' i- Elnil. to th~Cab'l(.: oa pat:.: frl;. Rase !rli$p: iicl'ku~an, 10'75 I.c~.L)o~I~c(*Hnrid the i + mcbthr~dt~of i.nvr:a t i pa t i 011, car1 clrr* my part of rile t,t+po~i separately.

The first rwctiot~ is .I brief dis'cusuion of hydrothermal convt~ctivc sy.4 t(*~ris. The next ncvrsal sect ionis deal with data acquitri tion and .;tmi;ll kng ;~tocedurrs,rnethocirr ,~tld pr~ci~iorlof Lr3boratory analyses, iuid gcin!hcr!i~co~;trjc ittotl~ls. 1Icta"ed diecus~:icrnool ericll ti ite ir~vesrigaeed fol low liext ~~ltl rior mally include for eacll ~itethe locatiorr, general description, p,eolnt,>)v, spring character iut jcs, rerrervoir properties, and co~m~nts.The final serl io11 prov ides a general sulmnary of eoutliern Southeaster-11 Al asks thermal spr iri),~.

IIYIIIIOTHEHMAI, CONVECTION SYSTEMS

Hydrothermal. convection systcnir; consi~tof a heat: source, a fluid, a.td a rock medium with tiranup11 verr ical perntenbility to allow hot, low--density f1.111c?s to r.i.se while denser, cooler I'l~lii!~descend elsewhere in the systern. Ln hydrothermal. co~svectioneys ilenrs , moxt of the heat is transported by convec:. i,ve circulation of f:i.uids rather. than by thermal conduc:tion through solid r.o,:!r!;,

IIydroiher~n:aZ, sysPem.-: ore (-I.jq~~ifitldinto two rnairl types---vapor cWomin:ii.cd ar~lhot water------acc3?ding LU l.11~ phase t:o~~tr~llil~gheat and sass trclnofer irr the deep thermal reservoir (bh~ie arid others, 1971). Tn vapor-dominate?. :iys terns, the deep rescbrvorrs are cont ro l led predominantXy by stearn, usna! l y 31- temp~ratrnretl of 12/30°~. T11r.ir uurfnc~activi.%y is characterized by furnarol6=s, acid-sulfate sprirlgr-i, and aci.i--leachcd ;;round with hot-spring chloride level r: usualiy below 50 ppm. Such ~?yor-crn:,arch economicully attractive for elect ric power getleratior~because they arta vetacrally clean and cheap-----they require littLr more klhlrnrl tlrni.lling into steam I-ceervoir tor the developmc~rit of pow" I IJnfortun~ataly, thr?se 8) s!etns, occur only ~lnderunusual [:eo 1 og iraal renditions. One example of 8 vapw-domjnated system in the Ilniteu S'tati.a is thi> Geyser-s in uurfhern Cal iforn ia, wbich huve bpen uwed to generate * 1ec.t 1.i city for several d6:~adea. ho vapor-dominated systems: have yet 'been ~t3vnli l ie(i ii, ALaska,

Ilot--wetc:r sypjLc*rn,: ;rca r:cljn~n:t+c :i by rircul lit inp; I iriuid, vh ic-lr rt ar,#jt ~t-~4 most of the 11e~ratld i iisgely c olrt YO^ b WL~~IHUT~PIC:~Y)Z.(?RNU~PH (ol rhoukk: iluaricr-rt~t arnotintu of eteanr may nlso !at ~L~HCIII).Their t:i~rfaceactivity is chal-ar . terized by presence of s-rprinp,r: \f;wc)larp;ing tlrermal. water witlr rhloridt. lxvei c; above 50 ppm and wj th ~letitriti tu :tlkaTjne pH level. Some hot-water eystc3al~i boil at depth, and the et?raptii&: gleam pives rise to ftlmaroles a~iid acid-ballate springs, similar to Lhr suri iei~1lea tureq nC vapor -dominated !:ysi.eins. Xot - water convection syete~nsale divided int.c~ three ternpexature I- mgeo (WhI t c. arid Will is~ne,1975) :

I) Wi"gh-.teray,erfat~lrc: rsys,:ews: re:;cv-sr0j.r tc?rnper:atu.r-(2s are ;iboire 150*~. Slrcl~ systems cu~xl~r. ancd for a variety of: appiicat:ionr;, inc:lurlinl; f:C:e g~+~,erationof clec tric i.1-:y, space ileai~in;:, and prc?cessi.ng, At lessk tbzr.;?t. high-tt-mper;r ture c.;:. :+ tcms 11ave tkius far been li.blc?nti.fied .ivt rf2aska: Bailey Hay in ij~~~.tli:>r:;Ciouthc-astern A.Ltr.ska and Geyetars ilj.g,i.!.!. and Hot spring^ Cove, both located on Umnak Island (Brook and others, 1979).

2) Intermediate-temperature systems: reservoir temperatures lie I)ctt.reca 90°C and 150°C. Such systemo can be used for space heating, some industrial processing purposes, and perhaps aquaculture. Future technological advances may eventually make el ec tr icul gellrrar ion lrorvl intermediate syst~mapractical. At lrt~~t28 intermcdi:itc? temperol \Ire aysteme have been identified in Alsska; some may prove to be hlgh temperature hot water systems as more detailetl irtformation is obtained.

3) Low-temperature syg &ems: reservoir temperatures lie below 90°C. Such systems can be used for hoat and perhaps agriculture purposes (Lor exanrple, greenhouses), but mo8t likely only in locally favorable c ir- cumstances. Over 80 low-temperature systems have yo far been idcnti- fied in Alaska (Turller and others, 1980). Some of these nay prove to have higher temperature reac~voi~-son closer examination.

FIELD TECUNZQUES AND SAMPLING PROCEDURES

A ~tandtlrtipntLot-11 of ~arnplt>RII~ data ncqui~itianwae fo1lowed a1 cbncIl tl~ermnlat ert VLR~LP~.At aiie~with mu] t iple Rprrngs, wntt.r saol))ies wc?r- norn~allyob t.ained from the chermal spring with the highest tcmpernture and grt?atest disi.harge. At same sites morr than ont7 thermal spring WHY sampleti When cold ground-water springs were f:~und in the immediate area, samples wprc normally taken for silica analysis needed for silica-mixing models.

Water samples were coll,ected, filtered, and treated following yrocedur.es described in Presser and Barnes (1974). The samples were always obtai.ned :it or as close to the spring source as possible. Filtration was usually thr011gI1 a O.4S-micron fi.l.ter (although some samples wi?r.e filtered through il 0.05- s!!: 0.1-micron filter for aluminum and iron determi.nations) . Thermal-.wnt.e~ samples obtained for silica analysis were normally diluted in a 1 :LO ratio with deionized distilled waier to prevent preci.pitation and pol.ymeri.zaf ion nf silica as the sampled coo2ed. IIydrocliloric acid was u~edfor !:hose samp1.e~ requiring ecidi fication.

Flicilrbonnttr and pli were deterlnir~ed in the Lieltl by using mett~odsde- scribed by Barnes (1964). Field pH values were defcrntined to the rwnres t 0.05 pll t~riitwith either u Digi-serine digital pH meter, rnodel 5995-40 or an Orion Kcsc~~lrchspec ifit: icpn meter, model 401, The pH meter wali normilily cel if~rittctl ;I):R inst xtnridard b\af t c.t snlut ions I)cbforr and :at ter each men~urement Rcl-!J in!:#: were nornlully reproducible to -: 0.05 pi1 unitra. Warem were titrated wit11 0.0 1639N sulfuric acid for bicarbunato determinations.

Water conductat~cewan meanured by using an F:lectronics Inutrumeut ~td. Model MC1 MRV portable c~r~ductivity,lieasuring set. Conductance is reported iri micromhos per centimeter at 25'C with i? measurement accuracy uf +3%. The manuf ac tui tar's calibration of conductivity cells was verified against standar rl solutions prior to departure for the field. Ii,li-rr trmper,~turesand shallow soil temperatures were measured wit11 t>ril~c.r arr 1':nviro-lal9s digi tar therrni s tor prube D'T-10 1 or a Brooklyn di a1 thc>ru~on~ct~r.All meas~~reinents .:1 ~3 rrpc1rted in degrckes ce isius . The resolu- tion and accuracy crf the cli~,it-alth( rmonieter are 0.05"C and 0. lUC, respectively; for the dial. ther~no~llet~?~~thcay are 0.25"C and 0.5"C. Spring-temprra-- tur~nlt3anurements were ur;llall y made at t1.12 spring orif ice or as close i-o it as poC,s113Ie.

Whrr ever possib 1 e , ~pr-ingtiischarge wils mt>dsured with a Sr ientific lnt,?ruiitentu, Tnc . pygmy rlo-ml~rtt~rand sr>ported in 1 item per minute (lpm). Accurtrcics ol L~PRP nleao~~:-c~~lrc?ntnnwet'@ cor~mnnlyimpaired by shallow chi~r~nel*, , low wilt~rvt3l ncj tie',, itrlrl rr ;c !-iol~iri tl~t- vane brarings. A,t some spl ivgs tile discl~argcwas tlett>rinil-t~ilby the tjrn:. lic~dedto fill a 4--liter bucket. When jr was not. possible to measurca discharge by either OF these two methods, an rt: t l~nateof the dischar~,cbwas IXI~~V.

A rt:ronrza issance of si tt. n!eolo#y WiiN llorrnally mode at each thermal area, 'I'tlis erltn iled exernir~~ltion and a'tmjrl ;rig of l ucal l-)edrock, determination ol local fntll?s arlcl fracture s~y:jtcms, and examination and sampling of hot-sprinp deposits (if any).

IbA140RA'1'OKY :L.L\~ J',I,Y SP:S : EqrCTHODS USEC AND PREC lS ION

hll~rrlcver po~!~ihic~,1r1hc)rdtory nnethotls of determirrat ion used by DGCS wrlre taken tiom the lifb( OP 111etl10dljof choice for each chemical species as pre- .;c r ibed by Presvcr t:nd liarnes ( 1974) . Tab1 e 1 ~c~nm~arizesthe methods used clncl pres~nts tLhe cxpec tecl prac ision of laLoratory analyses for 12 cons ti client s c omrnor~ly found in water as d~.~er.minedby U.S. Geological Surv~y(USGS) 1,abor.ator it~s. Atornir-absorption ctilalyses were rtxn on a Perkin-Ehner rriodcl 603 at ornic.- absorption hpec trcrlrl-tr~tomet-er using air.--acetylerre and tlirrous-oxide- ace t ylrbnc~ flamed ulitler ct~ndit ion:. I ii:irri JII the rnanuIac ttlrerss procedtli-t* it1.11111? 1. ~i'j~c~et T ic wid Cut Ljdjlnti t r ic absorp~iIIITIS were read on ;I Bc,~.krrtanJJU Vis.TlV single -La>:i~n spec1 rophof omc-tcr, r~singa matched set of four 10 Imli ccrlls. Ar, Orior rnodol 709 dig itill pH litel-ex mid Orion sprcif ic iorr and refetc.~lcc% ~lectrodewere usrti in dtcl rttc~~lstirPmPt1t.l;of GI"'-, F-, and Br".

IlL;CS waCer annlyrir ptc~ceritrrsn i:i-~current-ly rrndergoing it process of ..itandardi:!ation r r, conlotrrt tts I1ScS ect ablisi~ed neth hods and quality assurance.

'I'he IJSGS lf ranch o: Wntcar Keeortrceq is performing dupl icate arialyses 0x1 splccted samplcr: :ad is servirlg o:j a reference Lab for the initial stages of the 1)C;rf-i water aalinlysis progriirn, Tile final results will be presented in :In I)GCQ; open-.f i 1 e I-el~or-t.

Ma-:I t. of tlie pr Pr is ;c;ns givt 11 iri iabl L, 1 for Tl-rc vziriou~; meti~odsc~f :~rlrrly.;i!i ,Ire 1)afied crr~ i iihu ctbkai~-(id tI1rt111gh 1i111l ti lat)ortitory anal ysin c~f 1 cc,t M~~II~~,IL~J11rcpnrrtl hy 11.:;. 6::3010~;:i(-iil Survey Inbo~ntc~ric:s (Sk~rt~t~trirland oll~c~s, 9 9 Wl~ert?l,os~ihlc, the p~c,cisionin rxpre>..ised it1 terms of 3 reg^ essiorl ibrltrni ii,n ovcr a qtnted rnilge. lhe precisio;:, expressed in !-errns of UI~. rci:if ibc3 deviation (the r:rk:'o or f-he brnrldard (levjilt-ion to the mean tirnrs 100 prrcerlt for varior3.r I~l,r~rnl.olcydc~erminotionc; is given in Append ix R. (A1tl~tai~rli x C l iH tr indue: ivcl y c.tlup1 etl ergon-plrdnrn:r detcrmir~rttions . a1 r-l P m C.4

Ct~emicnl geothcrmome try has becomc ttn important tool for esr irnutil~g, reservoir temperatures of hydrotl.lc~rmii! systems and has proved very 1iseflil 11, tie ternlining the geothermal i csource pocent ial of a specific r egion. ?T)erp- fore, much of the DGGS assessment work 3s aimed at providing accurate getrtl zr- niorrle try for. the individual [:cotherma1 s itee investigxted. Surmnarics of I tir varjorls geotl~e~~liomtssthat h~vebeen npp lied to geothermal syqti>mt; ,.an be tound in Fournier ( 1977) and in 131lis and Mahon (1977). '%e geothermomc~t<~rs are bascd on temperature-ticpendent water-rock reactions that control the chemical and isotopic compusii-ions of the thermal waters. The roost re1 Iahlp and most rreque~ltlyrr~crl cirl:tnLi tat ivc r;r~oth~rmnm~ter~are rclLiltt!rl I-o the. r; i 1 i cn rorl tent nntl It1 Chca riod ; rtm, po i.i~iri clnrl, rind cn lc: iu~n~:onl.~*~rt. of I lrc-t 1n8t l wn tc.r.l;. fieccxnt appl icutit n (:I sil~lfaie-~at er , oxygen- isotope geothclrmometr y to geothermal dys tems inrl ica tes thit; mc:thc;d nlay become a third irnpor,allt geothermometer , particularly io~h; gher terrlperature systems (McKenzie and l'ruesde I 1, L977).

Assumptions infierent ji) uslnp; compositions of thermal waters to es t irntite subsurfac.c! temperatures hnvr: been sulilmari zed by Fournier (1977) :

1 . 'Temperatt1re-depericit1:11 renc~ion~involving rock and water t ix tiit. amounts of dissolved "i~~dicator"constittrents in the water. 2. There is an ad?1uatcs fiupply of a1 1 the reactant?;. 3. 'l'lrt~re is squil ibrirm 'rr the' reservoir or aqui fez with respect to the specific indicati)~.reaction. 4. iVo rt~tlqui1 ibrat ion c7f the indicator conwt ituentii occurs nFter the watt'+ I PBVVN tlli* rt'brt TVO~Y. 5. No mixing with diffvl.(~~itwnt't:rs ocrlrra (luring muvcvnttrrt to thc sur- filre.

'l'hi. at tninrnc~rt of VCIII~ L I I-IL I tilit i ti thv ri-' :(~rvoird~pt~ncls 011 c riilr~ll>~t-of t :lc Lor!: sucll as Lhe kit1~l.i~~of Ltle par L icu?nr react inn, thr t t*~iper,itur~ c>i' the reservoir , the reac tiv~t y of the wal lr-ock, the runcentrat.ir)ns of tl~t indicator clernents in the rc.ttcr, and the residence time of t-hc 1~att.rin r:lc, reservoir at the rrartic~rlar tempf~~aeure.Thus, In Rome si tuatiorls, qui-- libritrm In the reservcri; nlay bc attained for somta reactions and not for others.

Whether a water re~quili'ul-atiasafter leaving a reservoir d~Lingflow tr) tllr surface depends or1 siniilnr facrors: the rate of flow, the pall1 of ascer t , tht. typ~and rcrrctivity of wall rock Lravers~d,the lnitinl temperrairlrc. oL lie

xc?sct-voir, arid the kincati..-s 05' the ver-jous reactions that: may of -

fi)x a,, tlrt, iiplrartlrtt I rrRt tc-rnpi~is~llrcl ol tuclu i 1 ibrrrt inn mny l,t* d i flrr cbnt for tl i I I (*- 1.11 I c*hv~nirrll gclot hcrr-r~o~nt~tr-rri .

Vor this rcpurr tltc hi 1 ic.- ~.IICI Nu--K-Cu gc'o ther~nomet.ere have, heell used ctc* i cl::ivc!l y for ostimatiup subt;usEa~ca tcmy~>ratures. Silica Gec>thermometry

'Re silica geothermome ter is based on the experinlentally derived relationship between ~ilica ~lolubility, temperature, and pressure (Fournier and Rowe, 1966; Fournier, 1973). Dissolved silica found in thermal waters may be supplied by temperature-deperldent reactions between the thermal water and either quarlz, chalcedony, amorphous si lica, or cristobalite. Figure. 2, Curve A shows thr solubility of quartz as a functioti of temperature in equilibrium with saturated steam. Curve B s11ows the amount of silica that would be left. in t11c residual liquid aft-ez ~naxirr~urnLoss of steam on adiabatic cooling to 100"~and 1 bar preHsure. Similar curves can he constructed lor the other a~ineralogicphn~en of ~il~CR.

Fournier (1973) found that above 150QC, quartz controls the silica eclu i- librium and that thr quartz geothermometer generally works best in the rallgr?. 150-225°C. When initial temperatures are above 22S°C, silica is likely cn precipitate on ascent to the surface owing to t-he relatively fast rates of react ion at higher temperatures p,nd the attainment of st.~persaturationwith respect to amorphou~silica as the solution cools. For reservoirs below 150°C , Fournier (1973) found that chalcedony and sometimes cristobalit(a -.or amorplaous sil ica, rather than quartz, may control the dissolved silica con - tent. However, in granitic rocks Yournier reported that quartz may be the controlling mineral down to temperatures as low as 90°C rook and others, 1979). Thus, ambiguities i#an arise from the npplicat-ion of silica geothermometry in the range 90"--150°C.

Figure 2 or similar ctlrves for tllc other phases of silica can be used to r~timatereservoir temper t~i.eB. If the water sample is likely to have cooletl mninl y adiabatically (by boil in$;), Ct~rve8, hich corrects for the maximum possible steam losa, is used. Zf the sample cooled mainly by condt~ctiot~, Curve A is used.

Filrtiica 2, Solubility of qrrai-tz at; R function of temperature. Curve A shnws tk~snXubi1 ity in liquid water iu cquil ibriuln with ~aturatedsteam. Cltrve R al.rswo the amount OF ~ilics1-lirtt, wtrttld he left in the resi~lt~nlliqrrici eftcar mnxi.mum logs ~lt~anitrli ~tdiabntir ~r>ctl in^ t:r> 100U6 atrd I blir I,r.c3rl riui a. Frunr Fourrric?r snrP Howo (?966), The fol.lowing empirical relationships can alternatively be used t.o estimate reservoir temperatures up to 250'~.

731 Amorphous silica T, "C = ------r1,3- -i (5 4.52 - log C

Beta-cris tobalite

T, "C 21'3.15 = - . ------4.78 - log C

1032 T, "C = --- - 273.15 4.69 - log C

Qua.rtz conductive

Q~~artzadiabat i.c (after steam loss) T, "C = 273.15 ----.- --- - 5.75 - log C

"C" i.s the concerltration of Si02 i.n milligrams per kilogram oE water.

Brook and others (1979) reviewed the problems associated with inter- prtat ing high Si02 levels in hip,hly alkaline spring waters (pH i8). In dIlc:i-- line waters, hydroxide rervcte with sil icic acid to reduce the proportion of silicic acid to total dissolved silica:

The lotal concentriir_i\)n of di ssolvec! silica measured in the I aborat ory, however, is H4Si04 plus H3SiO-4 and must therefore be reduced by the concentrat:ion of H35iO'"r, to obtain an accurate estimate of the snbsur- fare reservoir tempernttlre.

To correct fo7. rhe rlissocia~ioriof silica in alkaline waters, a simplt correct ion suggested by Brook and others (1979) has been adopted .in tllir; renort. TIlc concentration of silicic acid is determin~dat the spring temperncure and pH. This con!.entration, rec~lstns Si02, it then used in Il~c appropriate p~:otl~~~rmometer.There J r considerfib le disagreement about th~ va 1 r~eof' the fir~tdissocintiot~ const:~nr of ~j 1 icic acid fir ternpernttlrea nl>ovc. ?OU[' : :;c-wnrtl, 1974) . 'Il1rl vnitrr~~iscld iil t 11 it1 ~-c*portwcarrb rnktjri iron1 ltyxl~rnko ( I . Cot rrec t ion^ tor tltt* r!i:ridi)ciirl LOII of 'sil icic. ticid nrcx ~uotnl~rlc~ urr lt.s:i tlit. coi-reccion in IO°C or rrlcjrc.. Si'lica Mixing Models

One of thr assumptions inherzt~t in using geothermometry is thst tnt3rtnal- spring waters are undilutrd. However, the waters issuing from many (ir' not most) thermal springs probnbly consibt of mixtures of deep hot water and ohal- low cold water. Pournjer and Tr-~esdell(1974) described two mixing nndc ls that may be appl ied to springs wi ~h l arge rates of flow and temperatures below boiling. These ~nodelsare based on (.he relationship between the erlthalpy and silica content CPF the ascending thermal water, the cold ground water, nrxd the resultant mixed thermal-"spring water. In the first model the enthalpy of the hot water plus stcam that mixes with and heats the cold water is the same as the initial enthnlpy of the deep hot water; the deep hot water may boil belok mixing, hut all the steam condenses in the cold water, In t-he second model the enthalpy of the hot wnter in the zone OF mixing is less than the enthalpy of the hoL water at depth owing to escape of steam during ascent.

Barrett and Pearl (1378) surrsnari~ed tkir additional assumptionu, given below, which are implici t in the uFe of these n~ixingmodels:

1. Tnitial silica content is controlled by the ternperatuce-depe~derit- reactions between the deep tl~erinalwater and the various silica phases. 2. Additional ~i l ica is n~iitterdissolved nor deposi ted ~ftermixing. 3. The ternpernturt.? and ei: ica content of cold sptir~gsare uin~ilar ti> of: the ground wnt:.r t-h;it. mixen wirh UI~ascending liot water.

'Truesdell and Pourriier (1977) devised a simple. prcrcedure for applying these models, in which a plot of dissolved silica vs enthalpy is used (Ekg. 3). For the situation in which tro steam i8 lost before mixing, tho silica and heat contents (enthalpiea) of the cold and warm spring waters are plotted as two points, A and B. A straight linl. is draw through these poL~lerj 'co inter- sect the quartz solubility curve (note that below 100"~the temperature in degrees Celsius is numerically equivalent to cal/g). T'oinc C th~ngives the origrnal si lien content and enthalpy of the deep hot watex . The ctriginal temperature oT the hot-water comporierrt is then obtained from steam tablen (Keenan and otliers, 1969). 'Ihe fractton of hot water in the warrn spring is obtained by dividing the distance AB hy AC,

For the situation in which the ln~ximun~ati~ortnt of steam i.8 loet from the hot water belvrc mixing, the ~ilic~kind heat corltc.nts of t.hc cold and warm spring waters srr p1ottc.a utg two points, A and 11, in figure 3. A strai~:'i1e line i~ drttwn thrt)~q;h th~ct~~p.i;nt~ n.rd extpnd~dto the enthalpy of the r t2r:idual liquid wnter at hrc assumed temperattlre of separation and escape of stcam, taken here to be 100°C. Tn thie case the residual liqrrid water heforc mixing wii 1 have znt c+nthsllpy of 100 cal/g, poilrt E of f:igure 3. The original ~nthalpyot the hot-water component is obtained by moving hozizor~tall~across the diagram from pomt E tu the inaxim~~msteam ~CLScurve, point Y. The original silica conl-cnt of the hot--water cornpomelrt is given by point G. Tlie frast-ion of hot watet (after steam lous) in the warm spring ir obtained by tiividing the distance AD hy AE. If stem is assumed to escape from water at n ternpenatrxre shove 100eC, Che oripiual enthalpy of Lhcrl hot water will 'lie at a val se along ,i horizonttil I jnv, bt:Lwe2n the rnaxinlum stcam ioss curve and tlkc quartz solubility curvt. (no :team ioss). 0 100 200 300 tr~lholpy. ~uk/g Figure 3. Srlic~~rllixillg 1nodt.1 ~lxamples. The graph, which gives clisso~v~~d silica vs. enthalpy, is used for determining the temperature of warm ~prillp water derived by mixing a hot-water component with cold water. From Truen- dell and Fournier (1977).

Broolc and others (1979) pointed out that the problem with any unexplored hydrothermal Bystem is nn proving that the water issuing at the surface is indeed mixed. One proof would be a linear trend between measured spring temptrtures and chloride concentration (for example, Fournier, 1979). Nornal ground-water usually has I ow chloride concentrations, whereas thermal watel s from high-temperature systems usually contain about sevci a1 hundr ed mill igrnms per liter of chloride. A linear trend between the isotopic composition of the water (deuterium or oxygen-18) and dissolved chloride is another proof of mixing (Mariner and Willejr, 1376). Ttcfortunately, very few areas have sufficient springs of different chemncal and isotopic composition to prove mixing by suclr rigorous criteria.

Sodi.um-Potass ium-(':t~lciurn Geothermometer

T(1c1 Nn-K-Ca gtsothzrtnorncter i 3 13aeecl on an empirical re1 lit ionship 1st~twr~t~11 tl~tamolar concentrations of sodium, pntansjurn, and calci~imions and water

rcrni*er.tt:ure. Fournier and Truesdell (1973) presented a detai 3ed accouni (lf thi. geochemical theory involved in the development of the Na-K-Ca genther-- mumet:cr, Temperature is rel eted to water camposition, in molality, by the fol I owing empiriccilly derivr.1 equation:

1644 T, "C - 273.15 - ---- < - "-"- log Na--. + B logf6-. t. 2,?4 K 1J o Na, K, Ca = ionic concentratiori i.n mles/liter of the odium, potassiun~, and calcium ions in the hot water. T, " C =: es tirnated subsurface ten~perature in degrees celsius B = 113 for T > 100"~ B = 4/3 for T < 100"~

The equation is first tested to see if setting R equal to 413 yields a temperature bel.ow 100°C; if it does fiot, a value of 113 is used for 1% to estimate the equiLihration tc.=m p eratltrc.

Barret and Pearl (1978) summarized the .assumpti.ons for rhe use of the Na-K-Ca geothermometer.

1 ) No nrixing occutqh: hqtwtmn the ancending LhpPr_ninl water and dlttt l nw ground.------water --- -- Mixing between the hot thermal wtlter and shall.~~,dilute, groutid water will have little effect on the sodi~m-potaesium ratio but may affect the calculated calciurn-sodium ratio because of the square root of calcium terra. If the original calcium content of the undiluted thermal water is low, mixing will have little effect on the? geothermometer results. If the calcium content of the undiluted thernlnl water is hlgh (greater than 50 to 100 mg/l) , mixing with dilute ground water will cause tl~ct subsurface temperature estimate to be too low.

2) .--Sodium,------potassium, ------and -- calciilsn - --concentrations ------in-- the thermal water- are controlled by temperature-dependent------equilibra with albite,-- potassirlm-- felds~ar_ - _- --?_, and -calc i.um-bearink------carbonatc! - . -minerals. -.------

l'he sodium, potassium, and calcium r~eiotlare strongly affected hy the bedrock mineral suite. Depending on thich mineral suite controls the water composition, a wide range in temperature estimates is possible. At similar water temperatures, the sodium-potass ium-calcium ratios are widely vtlriabl e in solut~onsequilibrated wit11 potassium feldspiar and albite, muscovite and albite, al ka li-bearing carbonates, or other ~nirkeral suites.

For exaniplt?, waters equilibrated with mineral suites containing pota::sium feldspar but no albite (sodiunr.deficient mineral suites) will provide exces - sive subsurface temperature estimates. On the other hand, waters equilibrated with mineral suites containing albite but no potassium feldspar (potassium- deficient mineral suites) will yield temperature estimates that are too low. Waters in equilibrium wit11 alltali-bearing carbonates (evaporite sequences) generally yield excessive temperature es timates. However, equilibration with zeoli-tes may yield minrinum 1:einperature estimriteu.

3) Little or no ree~uilibrationoccurs during ascent -A ------. ------.- Changes in the ~odium-~potassium--.~~i~lci~~rnratios in thermal waters may he great or negligible, depending 011 the rate of dscdnt and the relative I eact ivity OF the rrwkn and minerals along the flo~'ipath, Low-calciu~nthrt-mni waters generally yield lob srdbsurface cemperature est;rttat:es because of on- t inued renc tions betwctw wiil e? dtrd wallrock during aarsont ( incrpe:,eri UC~I~PC)II~, calcium ion concc=ntratic)n). riigh.-r.alci~~sn-cnntentwatei 5, however, nt'2.v ylcl d excevaivr geothermomreer tcmperaturr- es iima tes because of calc iurn-cerbonai,, deposition (decreased aqueoua cc!r ium ion concentration) during ascent..

Fnurnier and Potter il9lH) relacrrted that the high concentrat;nrr of magnesium or larpe magrleqium-to-c-11cium rarios in some waters was ineer*fcrsng with the Ns-K-Ca p,eothi*rmomr.ters. A mod it t cation Lo the ru'a-.K-Ca geothpr - mo~neter used in this asses.~a~~:;~Lwas recently devised by Fournjer ,md Potter to correct FOE" these adverse cff~tis of ~nagnesilln~. Graphs or empirical Fo,rn~rl~~; are tined Lo determine terqper ature c orrec clans wh6.1~ waters have Ha-K-(;a ra1 culat~dtcnipcratures above 70°C c~nd , rtl it1 r of 12. 1t.s~ thntr 50, whet-ca R = M~/(ME + Ctl + KI x 100 in nu~lareq~i~~l~~~r~!r. Wnirra with valr~esnf Ii grratcr tl~~~il.0 artb t-lrotlb;l~t to ccme from re1 ct~v~?iv C~CI~ aqurferu about equal to th~mc>~aurcd ~pringtemperature, ccgayrl.les~~uf wnac:l~ higher calculated Na-K-Ca tempcrritur 1'8.

The accuracy of Lhe geotheraiu~n~ters dept?uds ori the accu7-acy of t!le lab - oratory analyses for the various cc:,lstiruetit.tj used in ehe geothermometcr~. The following exar~~pleil iu:.t~-~~i-esthe pno~ible varjat ion5 in subsurface t~m, perature estimates resu1tii>i! trrrnk i1oznlaJ 1aboratav.y 6~t41yti~aEerrbr. 'l'h~9') percent corrfideilc~ limy tb (t I ,,.re3 bh~. stardard deviztion) can be deterni1nc:d from table 1 and Appeudjx r. using 6, t,! Frotu Be1 l rslanci hot spring;, the

\rnriotions in conntCtuerits I19 &i/ in he ril.;ca and cation #c?othermoraet~ersarc2:

Applying tht~seranges of v&Tl~c's tr, the silica arid the Na-K-Cn ge3therruo- meters gives the followi~igre:,ultfi :

Si3 ice g<~otl-~errnoniet cr te1ape-i atures ( ' C) I,ow Reported Iligh -* -.. .------Concentration (mgx)------"-'"-' -----' LOO 108 116 Ad i abad ic Concluc t ive Cllalcedony Cristohnlite I)pa l

Car ion . C;eo thernmi\rl ter t ernper uture f; ("r3) il if:h -.--Na-K-Ci4 -*- (" ,,r-iT--'c--c------""-. ------.--* Low.- Repr- --.- ted ---- 179 144 158 Nu-K-Cn (/,/?) 103 11 1 1 30

'Ihe Lc~w nr1.i high tetr~l~elatlirP gj /r?n above tor tile cat ;on geotherrno- meters trrp based on usiklp Lhe r(;b:'ective* ~l~ii~i~nt~riland maximum val~lesin the 95 per-cent confurlenct. range for N'i an 1 Cn, atid the rriip~ctivernaxin~rr~n .~nd 1n;ulrnlirn vnl trcq ill thr. 95 percc3nt c,-.nfidet~ceranp,e ror K. These r.ho ices givt tc\t;. widct:t po~ui ble sprcnci in .c+rnperarrr -r es tim;ii re, DESCK [PTLON Of+' INDIVIDUAL THERMAL SPRl NG STTKS

The location of thermal spring area; in southern Southeastern Alaska are shown in figure 1. T'hr numbers arc keyed lo the discussion of individual sites arrd to the table on paRe 64. The exiui-ence of several thermal spl-itip si tes tlitlt 11~dheen prev iucru'l y rrl,orlrd rnulcl trot: be substantiated and nrc d iscouritf?d. 111e thi*rmaJ urc%a.asare cie~cribedin riumer ic-nl order a~ith thermal nrenR in the Rttcne grnrr~1 region diwc-u,isc.d tnxe ther .

't'tir. tollowing fo1.111 is uaed ~n di~cutlsin~each thermal spring sltr* investigated:

2, 1,ocation: inclitdes lntirride 2nd longitude to the nearest tenth of a minute ; the topogrtlpi~ir:cjr1adx.ang1.e map and township, range, section, and one-quarter section irr diict~Ule site is locatecl.

3. ----General descr>i- -- iolL"..-- I rlci~tdc~xd i sLai,ce ancl directiorls LC? t-he area from the nearest iota) or othrr prominent geographic Eeatnrc ; typz of surface activity; 1ocat;on and number of springs ; riren of slrl-face cxpresaiott; local. rlr-.iiuage.; ~opagu'sphyand terrain; veget~tion;type? of development if any; Lurid F;tatus,

4. -Geologx: --.. includes ciiscussiort of thermal, spring host I-ock; local roclc types and contuc t ti, aid I oca! RLI~regional faul ts, fractures, artd photo interpretet1n:t lineclrnent8. A geologic map of the area is normally provided. mapa P~Pusually adapted from previou~ly published geologic maps of the arcAn, modified by nny findings; obtained during DGCS rertmraaissancc of the area.

5. Spring ctraracterisiiirs:- irtclirdes ternperratrrrc? iileasuremens; rissuciated deposits ; gases ; unustlal charscteriat ics ; water chemi.stry; wat:c!r type; other phynical. propettirs; and conrpnrisoris with earl ier. studies.

6. .-.-Reservoir properticr;: includes discussion of geothermometry; mixing models wb&.~~'appl;~Able;alrd estiraates of reservoir temperature,

Tilt? tcchni clues tlsocr i bet1 bv ?he IJSGS for t.tr t irnat int: retler~roi pee)-- pcartics have braen ncloptec! in ti-iicr report (lirook and otliers, 1919; Mariner and otlrer h, 1978; Natlierisorl, 1978), A j~~rlgnierrtis trtade as to the niin irnum, tnt~xi.ci~_tm,and ilic>rit l i kePy nubaur f:ir:e t emperat ure linsed on geolc~~yiind gccatI~t~rmr,cnc?try,imd OII geol,hy~ic~and clownhole nren:ilrre- ment.s where avail able. (Strht-iurfaca ternper atcircs derived Frcm Y il ica mixing niodpl s ar~?ttlot used i i estimating reciervoir tempcrtu~esin this repnrt unle.:~~~i,~-rahur;,tivc cwide-nc for ~nixir~gex ;st::;, kor example, r-hloridr-?n rhal rip <.?xirlyse*lor wilt cr o~tygcnisokopc analyeee. j A meat1 ret;esvola. rrcmperatrlre and stanrlerd deviatiori are tit-her1 calcr~latedfoilowru;: l~*eeIicrdsdescribed by Natherrson (1978).

Esti.mates off reservoir volutne are made from avail able geol o~ic,geophysical, and bort5-mholr: data, I~PWthermal sites in Alaska, howt.:ver, have had even cur gory geophysical explor ai.ion and only one site, Pilgrim Springs (~urnerarrd others, 1980), llas undergono expl.oratory dl i l.l :ng. Except for some skal low seismic stud~esaL Bell. Island hot spr.ing?: (~yle,1978), there has 'nee11 no geophys it a1 exploration of thermal qites in Southeastern Alaska. To ot>t.aiu ;1 speculative PR timate of the thermal-energy co~itentof unexplored

hydrothermal syst-em +, a standard mean reservoir volume based on general geologic11 and resources-axpl~oitation constraints was adopted for ouch sites (Mariner and others, 1976). 'Ibe standald reservoir is taken to nave 3 circular area OE 2 km2 and a thickrless of 1.7 km centered at a depth ok about 1.5 km.

The accessible rzAsourc.e base for a hydrothermal system, defined by Brooks and others 11979) ao the amount of geothermal eliergy within a specif iecl volunie of roclt and nt tr ~lpecified temperlator-cl refcr~ncrdt 15"C, has bcerr adopted for Lhi~report. The depth limit of economic production drilliag for geothermal resources is cr~rrentlyabout 3 km; any system or pnlt of ; system below 3 km is therefore not con- s idered,

Thermal erlergy (0) of each gystenr is then calcnlated froln the rquatio~z:

where:

PC = volurrtetric specific hent of rock plu~water (pc = 7.7 .J/cni3 - 'c) V = mean volurne (cor~vcrtedto cm 3 ) 'r = mean t-cn~r,ereture ("c:) To a reference temperature (15°C)

The volumetric specifi~heat (pc) is calculated assumirlg the rock specific heat Lo be 2.5 .T/cro3 - "@ and the reservoir porosity to be 15 percent. '&e rnctbod of caiculating the standard dtavia&it)n is given in Nathcrrson (1978).

7. --Comment8 : th is scctiun discusses speculations on the cau:;c of tht thermal springs; potential use?ulness of the geothermal resourcc ; unusual charac teristlcs ; and other miscellaneous items,

8. Tables:------.- 1) E'RYIJ~CHI proprl-ti6?~III~ chernicnl rompo8ition ot thtlrmal w,~tti..,, inc.ludirrl,: rlnarplc :>orrrce, c*allr!ctiorl date, ma lor elemrut c*trrltnic.:~i composition, ~~SC~IRTHPriitca of t~pring~arnples , temperatur cl, ~tc. 2) Geothk?rrnornatty, ;~itluding: rill cation, .rll ~i 1 ica, mixitlg rnodi~lr; where applicnble .

9. --Fipreo: ---- 1) Gt3nlogir mup grncrri! ized flnm available literature.

hppertdix C provide, n table cf mi1,or .:nd trace. elentent cous~ituerits0: tho thcraal wnl:ern as det.:r,nii~ed by inductively cctlpled argon-plasm? ana1y~e.1, Locat---- ion Latitude 56' 43.0' N.; 1.ongitrlde 132' 00.3' W.; Petersburg C-1, 1:63,%$0 quadrangle1 (1953) T. 59 S., R. 85 G.; sec, 74, SE 1/4 of ME 1/4 of Copper Ri.ve~-Mrriciian.

--Genersl -- Descr-----. iption Chief Shakes hot springs are located north of the Stikine Ri.vcr, abottl: 35 km NNE of the village of Wrangell, Alaska (fig. 1). l%e springs are acros-- sible by boat via the Atikine River tcj the Ketil i River (a side slough of the §tikine), thence 3 km up a west-flowing tributary located about 4 knl Prom thra mouth of the Ketili (fig. 4). During high water, a shallow draft boat cart bc floated to within 200 m of the springs. The springs are within the Tongass National Forest and are rltunagcd by the U.S. Forest Service.

The Stikine Valley ia a cipectcacular glaciated valley flanked by riumerous harlging valleys rand steep granitic walls that are nearly vertical in place:i . ~laciersstill cover much of the higher. el-evations. Shakes Glacier, NW oP. the springs, descends nearly to river level.

The hot springs 1 ie aZ,,iig the bu~eof (P steep glaciated granitic c. l iff that forms the north side OF the Stikine Valley. The prinicipal spring (spring 1) emerges from beneath bould~rsat- the cliff base, about 15 In above average slough-water level. Pert of the waters frorn this sprj.ng arc! chan- neled through a pipe to a large wooden tub enclosed in an A-frame structure, about 100 rn downslope from the spring source. The hot tub and enclosure were constructed by residents of Wrangell, who csrmnonly use the hot springs for recreational purposes.

At least wven additional hot: springs are located from 50 to 200 m downslope from the A-f :-&me. 'X3lese springs emanate from small f isstires rn the ~~nniticcliff near Ltle bas(? of the cliff and from rl~ealluvium Cloor, Pirrrit CIE thcse are minor springs wit-h very low discharge. One of the springs, however (spring 2), hae a discharge and temperature comparable to the principal spring. The npring at the lowest elevation in the series lies about 5 111 above mean lou ugh water level.

The hot: springs waters drain through a gently oloping meadow about 700 m by 300 m, located norrth of the cli.fE, and thence into the slough. TZle rneadoir is surroratnded by willow snd tall stands of ~itkaspruce and l~emlock.

Redrock in the viciaif-y nf Chief' Shakes hot springs has been rzpnrLed as $:r.anorljorit~and qutlrt? clior r t:e of Tertiary-Cretaceous age (fig. 4) (Beikrnul~, J9fi; I$udrlirrl;ton und Ghapi~~,1929). The hedr-oc:k is though to be part of L\LP Coast Range Batholithic co~~iplex.Ilre caritact between the layercacl gneir~~c.arlti

'~%i~iFf'-fKi~-krshot sprirlgs actat l.ly lie about 3 km due east of tile posi tiou shown on the USGS tormgraphic maps. Fi:;ue:: , Gec*l~.r);icLLL*~~ ctt SL~kine iliver are;^.

-1 3 phyllitic schists, which are 1.1tlrt of the Wrangell-Revillagigedo belr of regionally metamarphosrd r~cks,with the west margin LIE the Coat Rangr Br4ii~tr kith occurs about 15 lrn~to the wesC of Chief Shakes.

Rudd ington and Ct-laprn'x mapping was compiled at a 1 :500,000 recunrld i t, sance scale. No detailed qeologic mapping has yet been done i.n the Cliitt Shakes area. During our reconnaissance, bedrock in the immediate vici.11i t y of tkrv >lprings was found ti1 be a flne- to n16-dium--grained granitic gneiss with ditit in(-t ttr faint fol iat ion defined by nl i.gnment of rnafic minerals arid pot;lt-l- sium fcltlsyar crystal u. Tile rc~ckn are composed primrtri 1 y of plagio~lan~, pots<

The basa of. the cliff at tht: spr in~sis covered with colluvium; the vat -- ley is Floored with river fllli~vium.

Vie Cnas t Range 1 irir!azicvnt. which ex tends a1 on:: the wes tarn border of the

Cuasl Range Batholith, ibJ located 15 lun weat of Chief Shakes hot springs (TwenhoFel and Bainsbury, ?958) No major l-tnear occurs at the springs it.sca1 t but the rocks of the ilrea art3 lieavily fractured. Several joint sets are observable orr aerial photos of the area, The most prominent sets trend 1V,-S., E. .W,, N. 60 E . , and N. 55 Id. The cl iff face above the springs is apprnxi- rnatt.1~ parallel. to R.hv N. 55 W. tread.

During our reconr~:dissunc.t!, a large fracture with rnl attitude of N. 57" E. , 10' N. was noted in th2 c 1 i Ef face ~evera!feet above t.he principal hot spring. Several other joiuts with thit~general. attitilde occur in the im- ~nrdiatevicinity of Lilt? hot springs. Another joint ~et:observed at the nprin~~harl nxr t~ttituilc. of strike N. 48" E., dip 80" N.

Spring Characteristics A- " ------'Cable 2 gives the chc~nicalcomposition and sunmari~esphysical propei-riels of thc two hot springs at Chief Shakes with the greatest discharge. Earll~r analyses are included for cornparisol). l'hc principal spring measured 50 -4"c; spring 2 was 45°C. 'he other springe ranged from 26"~to 50'~.

i~iscilargesfron~ spx ings 1 and 2 were measured by using a pygmy Elo.wm~~cr and we;e determine6 f-o be 230 Zpm (+ 10%) and 135 lpm (+ 20%), respectively. "I'lc Plod From the remaining spr-ii~ga-iswry low, che combined discharge est-imatecl to be xtot more char. 1% lpm. 'l'he total discharge of thermal spri~lgc at Chief Shakes is fstimfited at 470 Ipm,

Wariilg (191 /) rc.portr+~i3 diszharg~of 31s0 1 pnl .md n temperature of 17"~' ;~ltp:art=ntlyfor apiing ?, itp I:oief S~PL~(~R.Floem@ rert3ntly SIORII (1976) rrr)orttatl it flow of :I00 X prn rtnd c. &jpringtrmpar&trtl c! of 90.5'~. '('ho q~rnli ty /t~lti i~c.~~~t.rir.y(3I' e l~searl irt5 rlov rnt!dlt$utompiits wtirib not H tttted.

N\Ic>ndr~, 14 wcrte. dcatuc.tec~ AT A!I~of tl)t. (,hic-E Shaketi: hot ~pringw. Slip,i.h !:us bubSi irlg was ~~otecia; dpring 2, probnbl y W2. Bright blue-green alga. rnnt.4 liuc~cL spring c1kann~~l.rwhere tpmperatures were about 40°C or higher. Wi-ti r. ish ~*irrl>oiaa~odepc?sitti v-rre~,rl~tddry parts of the hot spring channels, Table 2. Chemical composition and physical proper ties of Chief Shakes Hot Springs. (Previous IJSGS analyses included for comparison; all chemical analyses in mg/l,)

IIEGS DGGS uscsa LISGS!> P ------Spring 1 Sprfng 2 Spring 1 Spri ag 1

Si02 A1 Fe C a MR Na K Li HC03 C03 $04 C 1 F Br U pH, field Dl ssolved solids Hardness Sp conductance T, "C Flow rate, Ipm Date sampled -- --- "Water quality analysis file, USGS Central Laboratory, llenver, CO, collected by C.F, Sloan. '>wi~r-f.n~(lC117)- yses perfor~ncdor1 wat.er sam[rIes Ft ltrbred througli 0.0') rnlcron FitLCY, Or1 Lhc hari~of rhe r:l~einifitry giver1 ixr table 2 the waters are cknscified a?; tr rnodera~telyconcentral-c:d t;odiurn-sul fate water. The conttmt of ch Joride ccrmpared to nulfatc? ih 11ot.aktty low,

Reservoir------EJr.operl L~H Tnblc 3 aum~ari zerl t.11~ appl i cati on of silicis and cat ion geo t11urn1omc.f-ry to CA~ief Shdkes hot spr irjgr: 'Il,e NLI-K-C;X (4/3) geottrermoineter 01 66°C jricl ;c:qt.es subsurt.,ic.r eclui.1 ibliqt icrl ?-or)k plii~eat. temperatures below 100°C. The Na--K (:a (4/7) ternperra ture i:i sl $lrt v(.ry siini lar to the cristohol ite groth~rrnorneter reslrlt 01. GOaC. (!oris ider ing the granztjc g~rei~shost rock, however, ir. -if; douls~ful~L.car CT istoba I ifc vocl Id be the controlli~rgniineralogic phaljta tar 9i B ic-a cquilibratitrri. For gr 8.n~tic socke, chalcedony or quartz are prc~kabl~r irtoti! l ike Ly to c-urlti-c, l n i l ic.3 eqli i ! ibratiorl $hen reservoir Lemperatures arr be Low 150"~(~'ourn~c - , Piurirrcr end o(:hero, 1979). In view uf the uuc:el-tainty of the roratrolilily, inineralogy and of the indication of subsurface equilibration below 100" (, , the Na-84.1 (413) geothermometer is chosen as representative of the rrail~imual r.esc?rvoir temperature, the clialcedony as !he most Jikeiy, find Ltle qltar-,z i;onductriv~as the maximum temperature:

Min Max- - Mohr------likely Mc all- Std-- - --Dev - Subsilrfitct. '2 ("C) 6h I 18 9 0 9 1 10

:hr ~alv~ocllcscn are ut~sedon DGGS spring-] water chemiqtry (table 2). l'lles~ rc~cirvoirL-S~ ilfl:4~1~ ~duper~ede earlier estimates appearf ng in USGS C-ir-- cular 790 (Muffler , ? 97Q), which were based on Waritlgss analyses. Although the quality of Sdar lng's chemical analyses is unknown, both tile cation and the .; il i (.a geotl~ermnm~tc~~,r Xjused on h in reported analyses give much highel- reservoir t Prnyerat.ur;.s ehun Clie more recent analyses. In itddit ion, Waring reported n spring ternperat-\are s1jf:lltJ.y higher than exists now . This st~ggests that r+iiher reservoir temperaturrar; have actually BecP ined or perhaps mixing of col dpr wa tcr has ;ncrensed,

'rile twt~princ ipal 11o~r4prj.ngs AL Chief Shakes issue from the sbcface ar tenq)c.r oturtis be LOW boiling, have large Flow rates, and cation ~eolhermometer krrn[rer3turen cortl;iderably above orif-ic P ~e-ernperatures. These: frac tors suggest rn~xing, of colder w,rtt:rs ;b'oui-n~er ntlcl Truesdell , 1974). A cold spriny; bil tkLP area WCIH found Lo Il:wc a te~~~pprdtureof 14°C and a silica corktent of 8 i)plks ltc~1 Jowirig the met llutl of Trti?~cle1 i ~rlrlIbu? n ber (19771, application oJ r-'i~al-- r:edtrny ifiixing niodelr~ giveu .the to! 1 owing i.esnlts :

Parent hot water M i:.inp: model. &pffee) t;io2 (pPnl) Frractioa (%) I. M~~.iti~tun~1:c~aiti lu:~~ - (32 136 4 6

Ikere Ja no clbser-vallia ~:i-earnIosr, tit the ground surf,zce, If stean~ hcpLtrai-rs iLcrither. J,OC~O in iietri ing WH~PTH other than that ~rncrgjnp,at the qpt ~~ipr:n1.d ~norlel 1 alrrp be ~ppiJ cable, or the steam remains and heats col ti c:lc8, a1rs rr~ixinp wi ti1 fi1c hot watctr Erac tion and 1nodeJ 2 may apply.

'i'ern~t?c~tur~sFroin thulc,~~~ntr.r.lnixing nrr~rlels inlist be used wrtls iiluejon. N 1 c o~ roho~.-,r~i-iv~zvrdenre rxie tb lur n~ixi~~g.Iurth~r , residence tjtne in th.> granitic rock of cold spring waters sampled may have be~nrelatively shor; an? not representative of waters actually mixing with the hot-water fraction,

No geophysical c?xplorntion has been done at Chief Shakes and tl~ra e~t-en4 of the subsurface reservoir ia not known. Using the I7SGS auggc?s::ed starlda~d resc?rvoir volume aid the mean reserv0i.r temperature of !9l0C giver, tllc fcrl-- lowing estimates:

Volume (km3) = 3.3. std dev = 0.9 Thermal energy (loi8 J) - 0.67; std dev = 0.22 These values must be viewed as highly speculative estimates.

Comments --- -- w- The hot springs probably resi~ltErom deep circulation nf meteoric waters along fractures and Isul ts . F1~1ctuat-ionsin spring discharge arc indicated by comparing reported flow nlcasurerrtetzts For spring 1. The difference , howevez., could be attributed to Jifferenc~in measuring techniques and the error inherent in measuring water flow in tihal low channels,

The springs emerge at the G,c~eof :, grauitic cliff at and near th~contact with colluviurn and ri vey cil luvium. Some of the nstsenrl ins; thermal wnl rl may di.schargn htv~rnth rhr sltrface into river a1 luviirla aild ale0 perhspu irrf il trtlte the Stilcine Hivtlr crntl go undetect.erl.

Geot!lermornetry irlclicates .eservoir temperatures are well below that required for generat ion of elecirical power. Chalcedony mixing rodcls , however, suggest reservoir temperatures may be higher than that indicated strict1y by genthermomctsy.

Table 3. C:-i!.et Shakes hot springs gen~llt~rmometry. jgeo~herrnornetry b;,st~ti on wilt er chemistry given in table 1 ; a3. L temperatures in degrees celsl us .)

Cation geothermometers Ma-K--@a ( 1/ 3 ) !23 116 127 17 5 Na-K-Ca (4/3) 6 6 66 b3 k 0r,

Silic+d euotlre rmometc-.rs Ad 1abat ic I1 J !12 117 136 Conductive 118 113 118 1/42 Chalcedony '3 0 8 4 9 (1 L 11 c:ri btobali te 0 il 6 2 b8 11 <)pal 0, 1 -4.5 -0. 1 7 1 2. BAItNKS LAKE (PARADISE) WARM SPRINGS

3 -,oc - rl L ion . - !.r~tlitu~it~56" fiO.oY I?,) Icsngit~lde 131- 57.9' W.; Bradfield Canai C.-6 j:63,360 Quadrtlngl~ (1455) T. 60 S., 8. 80 E,, nec. 9, SW 1/4 of SW l/l4 nf Copper River Meridian.

Ceni. - P a1 Uet-1~:t-ij~tlon ------+ --. Sarnes i,olce warm springs (also local l y known as Paradise warla spiings) art' i'ic~lterl %,L) lun rwrtl oj. the Stikinc. River and ahout 2 km due w~stof 1-k~t* . - 31 to. 1 ) These springfi had not been rc:p*rtecl in :my J isompi1 a' iois of A1 aslran thert11~113pr ings and were brought tc) our. att en- ion by r'ttr- ai.S, F'~9rest Service in Wcangell and Petersburg, Alaska, The spsjngs are siiunittl 1/2 km E;NE of Burncs 1,ake iir a narrow valley cut through bedrock (fig. 4)" 'I'hc hpriiigs SIT(% accessible by boat up the Stikine River, thc.~rce up Gut~~inYllr~ugh,

'kc; region's t.opo,:rd,jhy i:, a seqult of intense glacier scour. GI.a~ie~.s fr~ir l renidq* ati ?It. Cri.1 lat in, ti '3, l0I)-ft: peak directly north of Marnt?a T,~lte. 11 t1:in vaarlurr of r:c~l lu'v !ixr!l qlarl river a1 tuvium f lonr the: trib~lttaryvallpys ~i1it.j i)i111d4rtg R~rlle~X.,alrc-

l'l~cre are LVKI WRT)rl t,r)tint;dg one (111 eit-her side c9f the stream that: flow5 thi01lg11 uhe rt:irrow be lrock ,?alley. The springe are di Fficult to find bccallse of thick ~mderbrurh,altd low temperature. of the waters. The First: spring rbrnery,es rn H shul low paor in alluviclm mar the base of the granitic bedrack knc>h np (-he weGt ic~dstrl the narrow valley. Zlie pool is about 35 m west of rhr, qtrt?am and :,t an eievation of about 75 ni, The secorld spring Lies on thc. ecl.lol- bank e3F tll~dti-q~nt, ribour 2ilc! m upstream From ?he first sprint. The .qi~~-~hi)r;orcur.. .i~a [gaep in warc.r.-saturated [nerds and is located or tlw base of il ,c:r,~i,l~LC cl ii i' that fur~nri the east. wal 1 of the: valley. A cleft F-n 'rI~is , 1 ; r ii~out', krr wide, ~cc:~.~t~~rtirt*~tl y above the warrn seep,

11,~mt!n r.ul l.a~u~id:up p);c rprings is thickly vegetated wit lr willows,

14 7 ' , l uh, arrtl Fc~s,,~, :i f:le.* rprure and 11~mloc+k:~l.ao occur ikl [:he :rrc3ta , th*(rio~,y ~;(dr(~t:ki.n t1-1;. rsrc;l llas .hc~rlrz-ported ti# Cretaceous g.rurtitic rorka: !q -+~iloriic)riti):: ~11~1q~artz cljorite~ IJ~. the Coast Range Rahhoiith ( f i::, 41, in,?; I~,~I,~~I,X87'i; :3111

8 . ~xt,i~i(-dC~IIY oili- ~.r~c:r,~~n~tisbat~t:ewi~sfound to bc a medium-grained foliated t* t @>r t-.> p,r~eiss cm~trsirlLii~ r dl ,ye r~oduli!~of q~tl~rr-~.Fol iatlon attitude as

~.).~lrr>rihy o~irtni-:$. en r.V'~?rf.it~crystals w:m stri~eN. 59" W., dip 48" W.

I I !; !.otj f.. * I OY*~!L iq, to 11.0 pezcetlt OE the rock. Other can~titue~nt~ 1 . ~CI~HS~;EIIC~121dsp~r, and plagioclaee.

,';r 1 IL trrhct8t .tb ,riii.t. ,=il!~\+hs rb Pppt?atr orx aerial phot ou of the Barnes i,akc .8 :! {.?St Id, 61)" F' . I!. 75" id., IV, GO--55" W. . mir? N. -6. One prominent fracture trendinla N. 60" E . lies jtts t north of the springn. 'l'l~espri11gt5 :-tq selves are aligned along N. 60" E. The WR~~Hof tt~c1 cleft ahovt? the act tjnri spring alno have this twrnc? general trend and a dip of 66" N.

-.----Spring Characterigt------ics Table 4 providec: a eilrrnnary of the physical propert ies ant1 3 part igj chemical arkalysis of water(, from spring I . Tlre pool into v~l~irh1-his ;:,r;ny issues measures about 3 m in diameter and is li2 m deep. Noticaab!e g,,b lietb bl ing occurred 'ntermittently at the pool, la~ting1-5 sec with a per iotli*ity of 30--60 R~C. Po01 tempercltilre was 26°C: and water flow out of the poni rd,rc, estimated at 30 lpm. Thie flow joins cold springs and eventually drairls luLn the main valley ~tream.

Flaw at the rei:ond spr~tlg w9,3 a trickle from saturated mudfi. Temlrer ,li at 10 cm depth registered 27'1;.

Oti the basis of wart>r chemi~tcyof ~pringI, the wntet~rare cl,~c;t~jf~cci :II moderately concentrated ersdium--sul {.ate \gatex-s sirnil-ur t.o Chief Shakes hat springs.

-Reservoir --" ----- Pro2ert- ---- jes-"-. Table 5 sr~imnnrizes t-llc, r-~ppli.c--+t~.ot~- - of ~ilica and cation ~eut.heimo~nc>~F:I

Barnes I :*kt. warm springs. '$'lie Na-Y,-l:s (4/7) geothermotneter of 62°C in<;6 lf 5, subsiln.fuce uquilibrat-ion rrlolc place ,~ttemperatures below TOOuC, l"ne Wee- 1: ';.I (4/3? tenlperature is nl sc, very sirni1:ir to the c-r istobw l ite geothermometei result of 68'~. Tn vicw of the granitic gneisn host rock, however, c~iul_ol)l- lire is probably not 1-hc cor~trnllingminerslagic phase Eor silica equilii>~-~- ton. For graoitic rock^) ;t~aXc,edony or quartz are more likely to cont r-c.: si l ica equilibrai ion when reservois- tmperatures are brlow 150°C (Fodr~kica:, 1913; Mariner nud others, 1979). Becciusc. of t$e uncertaint-y in the contmot ling mineralogy artd thc indizbrt ion of oub~iirfaceequilibration below LOO" ', the Na-K -Ca (4/3) geothernio~ne~ryis chosen as represrctative of the m-iniinr o reservoir tentpcr.qture, the ct~a!cedony as ~Ixcmost 1ik.rly, and the quar.r.3 cunductive as the niaxinnurn:

Min Ya:r MG?~likely Mean Std Dev ------.-L ------Sul)srirfacc T ("C) 62 J 18 9 0 90 10

The low flow rdLea of thc springq suggt~st that ChermaL waters cocll~t: drlctively on asceurL. %oms! mixing of ioldel- water at ~tlallowdepths pi s,ljc*li y also occurs.

No goopl~yt~t~tj I vx1)lc~rr\!i:tlt II:I~< t>e-~*t~tio~it* ~tt881 IIC*~I l,aiie~ tit~,i IIIW tatk8 i7 ? $!I ! tit' HLIO~~Z\LI-I"~CCY*~!WCX'V(I~ : is lot known , Iltr irlg tilt? u t andard rnesti r-r.etJr\-lii r vulumc~ arid the meilrl resrrvoj K tcrnperuLtl:e of 9u°C gives the following es t-ir~1al.e~:

Volume (km3) = 3.3 - 8 Ld :iev = (1 9 Thermal energ) (10~~.J) 0.67, oLd di.~ 0.22

Thrase valries must. bc VIC\IIP~~ti8 Ft:-f;hiy ~pe~':ul.ariveestimates.

Comments These warm springs probably result from deep circulati.on of meteori~ waters along fractures and faults in the granitic host rock. Soue of the ascending thermal water may discharge beneath the surface and go undetected. Geothermometry indicates reservoir temperatures are well below that required for generation of electrical power. These springs are also very relnote d~~d have low temperatrrres and low flow rates, making them in~practicelfor most geothermal applicat ionn . 3. FOWLER 11OT SPRINGS (CANADA) -----I,oc a t ion : I.atitude 156'50' N., longitude 1'31°45' W.; Bradfield Canal. 1:%50,000 O~radrangle(1955), Copper River Meridian.

------.----Ceneral Descrilption: --- - Fowler Rot Springs are located in Canada about 8 km froin the U.S.- Canadian border (fig. 1). 'fie springs occur less than 112 km east of the Stikine Kiver at the base of Warm Spring Mountain and directly opposite thc terminus of t:ht:. Great Gl.acier (fig. 5). These springs were visited by DGGS while a~se~singo1:hct.r hot sprj..ngf; that occur along the Alaskan part of t:l-re Stikfne River.. Fowler Rot Springs were included in thi8 study because of their possible rel.ntionship to the. hot springs on the lower Sti.kine :md because nf their potenti.al benring on interpreting the nature and cause of hydrotlrcrmal. nctj.vi.ty nlonp, Lire !;tikine Hi.vcr. No other hot ~pri.ngsare kno'wtl t:o exi.nt farther tipr'iver pacat t:L~c! Pnw1.i.r site.

Fowler Hot Springs can kt. i.cached by boat up the Stikine K;ver about 25 km past the {IS-Canadian border. A shallow-draft boat or canoe can then be taken up a small tributary creek d~osernoi~th lies nearly opposite a homenteari cabin on the weRt bank of the Stikine River. This creek drains a series of beaver ponds into which the hot springs either drain or issue. Wright (citcd in Waring, 191 7, y. 25) reported the existence of as many as 18 individual springs issuing at scalding temperatures from fissures i.n bedrock at the base of a g.ranitic wal.2. Nost of tlieur, springs have since been submerged by beavrr ponds. At least: Four low-discharge hc?t springs atill remain above water level. Local travelers conmonly use ehe tepid waters of the beaver ponds for bathing .

As along its lower collrup, the Stikincl Kiver at Fowler Hot Springs flows through a apectaculwr glaciated valley. Higtler elcvatiorls arc still glacier clail and the Great Glacier descends alrnont ro river level. Valley slopes are st ccp hut heavily forested with Si tka upruce, Tree line ranges from 600 ni (2,000 ft) to 900 m (3,000 lt) irk elevation.

Ge--- o 1-o&y : ~e'&rockin t.he vicinitv of the hot springs was reported as horlrblertde and~sinegranodioritt: of ~eiozoicage (fig. 5) (Kerr, i948). The inrrusivc in part of the Coast Range Bathoiitic complex. Contacts with Permian and Pre- Perminti liinestones and schist:s occur sevt:ral kilometers norrh and south of the spril~glocntion.

riock~examined ~t.the !3pritlgs tli r r were found to be mcdiuni- to small- grn i IIP~bioti t.e horlr.hlrndc grnnocliori tes with numerous xenoliths present. In ~I;IC(IFI, niiifiic~ art1 30-40 ~)er~~-nt,of: the ror-k.

At IcaoI. two joint- syatr*rn;: rlcc-rtr nrnr tllo siprjnzs site, Their nrtitucles ar~'ntrike No 36" W., clip 6II" N. and strike M. 16 R., dip 88" S. The clifi' face xhove th~springt~ trends N. 78' W. Pigur,, 5. Ceoiigic ti~~tpof F*o:+lcr Hot. Sprirtga area. vnl lry wall over a lirler~rzone 200 m widr. Ttlc* ~pringsissue from F;N~:LII(ZB just above pond water 1cvt.l. Spr.itl~tentpc:riltrlres range from 50°C to 60°C and the combined flow of the four springs is estimated at 40-50 I prn. Tab1 e h gives the chemical composition and physical properties of waters ol~tained troln tl~espring trri t1i the hot- test temperatur dt~d greatest discharge. The chlor i-dc. rotlt~ritof Fowler Hot Sprln,gs is notably hzg'nel- than that at other Stikintl River hot-spring sjtps. The wale,-:+ arc. class i i-ied as a moderately concentrated ?odium chloride--sulfate water.

Gas hubhl ing wse noticeable over much of the soulllern part of the pond, indicating tht~presencr of sever:~l subrr~t-rgecl sirrings. At least one zone of ~1ywel1ing was observed near thda cl. ifr Facr. 'i'kic? pc~nds cover several acres and surFace temperatures over mtch 3f ehi.5 .qrea WCLE 25'-26'~. Wright itr 1905 (Flaring, 1917, 1). 25) estimred fhe ccJtl11)ined spring flow at Fowler at ahout 3,000 lpm. Judging from the warn pond temperatures, the submerged sprirlgs arp sti.11 discharging at :L higli rate anri -eniperature.

-----Reservoir - --Properties : Table 7 fiummnrizes the t-lpplicatiorr of silica and cation geothcrmometry to Fowler Hot Springs. The Na-K-Ca (' geot he-i-mumet-ar temperature of 85°C indicates subsurface c:qliil lbxation took place at temperat ures below 100 "(:, The Na-K-Ca (413) teirrptbrat-urc is very close to the chalcedony temr~eratureof 86°C. Chalcedony then prol~ablyconrro~s silica equilibration and is dlosen as represeneative of the minimixrn and most 1 ikely I-eservoir temperature. The quartz conductive. geo thermometer Vemperriture is taken as the maximum:

Min Max MOR t Like> Me an Std Dev ------a Subsurface T (OC) 86 1% 86 96 7

Fowler Hot Spring issue from thr surface ht temper.lturps below boiling and ~RVPA combir~~ldlarge rate oj flow rind R cat ion ~~otherlnomete~tt.rnpi.raturt? cons idt

Parent hot water Mixing model Max T ('c) --.----....--...--,--.--- -.--..-., ".. - -- -- .-... . ---. - - .- . .. ?,!~)L.PE!! Fraction- . .- -" - - . (%)-. .-- I. Ma:timum steam loss 114 108 5 6 2. No steam loss I [+ 4 156 3 8

Temperatu~es derived from t hr? cllcllcrtiony inixing raodels must b~ treu te~l wit11 ti~~tion.No corrohorati vc evic1c:ncr exi~dts for mixing. Yut-tiler, the silica content of tht colt1 ~(JA~CL.fracrion may rlnderest imated. A highel si l ica content would decrease 1301 h temperat l~rcestimates,

No geophys:icnl exploration has yet be~ndone at Fowler and the extent of the subsi~rface.r,rserv-)ir is rro? itrlown, Ilsin,g thc mean reserv0i.r ternpel-atur-r of 9/,'~and the etaadard 1nr.m reservoir ~olumeyae-Ids the! follnwirap, estimates : Table 6. Chemical composition and physical properties of Fowler Hot Springs." (All chemical analyses in rng/l.)

S iOZ A 1 F e Cs Mg N8 K L i HC03 co 3 - "04 C1 F Br B ph, Field Di~f30lved eol i.da Hal-dne~s S p Conduc tame T, "C Flow rate lpnl Date fiampled

%a~~~&-performed on waters obtained from spring having hottent temperature and largest discharge.

Table 7, Fawler Hot Spring geothc!rmomet ry. (All temperatures are in degrees celsius.)

Surface temperature (nlen~ured)

Cat ton geothermor~~eters Na-K-Ca ( 1/ 3 ) Na-K-Cc (4i3)

Silica geothermorneters Adiabatic Conduc t-Lve Chalcedoc; y CrL~tol>~~Pi~e Opn 1 Volume (krn3) = 3.3; std dev = 0.9 Thermal energy (lola J) = 0.72; std dev = 0.22

'l'hese values must be viewetl as highly speculative estimates.

Commcsrz t H -q --*.. -- 'I'll(* Ilot ~priIIRR prol~ablyrt~stllt I'rom c*irctllation of metfxorir wntPrlr a! ott): d~cp-s(!?~t-~"If racttlrr~. Gcotherrname try indicates reservoir tenlpttrature~nrrx well below that required For gc~nerationof electrical power. The high flow rate and relatively high surface temperatures of the hot spring waters, how-- ever, make them suitable for space heating and perhaps for heating of greenhouses. 4. TWIN I,AKKS (WISS'I' SIIAKES) WARM SP1t ING!i

140c,;I L i or1 -" - .---*... L,atitude 56" 42,O' N., longitude 113%' 16.8' W.; Petersb~lrgC-l 1:63,060 Quadrangle T. 60 S., R. 84 E., S of NW.

General Description ------, -- - Twin Lakes warm springs are located 25 km NW of WrangelL, Alaska and 16 km west of Chief Shakes hot springs (fig. 1). The springs are situated 117. km north of the Stikine River at the NW end of a Lake labeled Figure Eighr Lake on USGS topcrgraphic maps and locally known as Twin Lakes (fig. 4). These springs are be1 ieved to be the springs Waring (1917) reported as West Shakes Hot springs. The Twin Lakes warm springs are located in the 'Ilongass National Forest and come under the management of the U.S. Forest Service.

A short Far-est Servi(.e trni l It.arln from tllr north bank of the Stikii~c 1tivt.r to $1 narrows bt.twt:t*n ttie t'wo I nkes and afford8 RCCCSR PO t11c' springft . A1 tcrtlstely, aL h i~hwater, u ~11~1k~)w-d~uft boat can be broufr,ht clp n tribiitar y slough almost direct:ly to the springs.

'X'here are two springs. Both lie cLose to the NW lake shore ar. the base of a griinitic cliff that: forms the northern boundary of the Stikine Valley. Spring 1 emerges from under boulders at the bottom of an avalanche chute; spring 3. ernerRe5; From alluvium, riear Chr bafle of the cliff. Twin Lakes water- level fluctuates with Stikinc Rive: stage2, the Latter acting as a dam OIL tributaries. At high wwatpr the springs ntay become submerged.

The Stikine Kiv~rrouth of 'Twin Lakes is multichannelled, about 1.5 km wide and heavily laden with sil: during rurloff months. The river flows thrn~~gha spectacular glaciated valley flanked by steep walls and hanging val leys . Glaciers presently cap the rnountain~ immediately north of Twin Lakes and descend to as low as 600 m (2,000 Ft.) elevcltion. Tree line in the vicinity ranges from 600 m (2,000 ft) in 900 m (3,000 ft) in elevation.

Local el or:^ conr;ists of wll lows, grasses, and shrubs interspersed with stands of Sitka sprure and hemlock.

%(' 1%"~ TI-I~springs are located rwar the conLact between Cretaceous grar~iric rock6 (believed to be part of the Coast Range Ba~holith)and Mesozoic and Paleozoic schists and layered #nc;sses (f:p,. 4) (Beikman, 1975; Bttddington anrl Can, 129 Recirnck in the immediate vicinity of the springs i.8 a fol i ated, medium-grained l~ornblende-biotite quartz diorite wj th well-defined gneissoid structt~re.

The Coast: Range L ineatnent lies i~nmediatel y w~st of the jprings (Twtmhofel and Sainsbury, 1958). Puedon~cnant fracture patterns as detarmined from ael-ial

rf:GiGdid not visit these ~.prjn~sm1~1 re1 ieci on infornla~ionobtalrled from local inhabitants in judp,jug thcii IucclCiorr photos of the area trend N, 55" W. and N. 75"--80" W. The valley wall here trmds E.-W.

A 3- to 4-111 wide cleft occur:r if1 the granitic wal.1 about 10 ni above thr warm springs. The cleft trends N. 50" W. and has nearly vertical walls. Attitude of other joints near th~springs measurer1 strike N. 70" W,, dip 60" S. and strike N. 48" E., dip 85" S.

The base of the graniti.~:wall is covered with colluvium and alluvium.

----.---Spring Characteristics-- The temperature of spring 1 illeasured 21"~;spring 2 was 18"~. Some fluctuation in watcr Lempetnture was noteti at spring 1. During a previous visit waters were notir~eably warrrler ro the touch. A local resident measurrd a winter season spring temperature of 2b°C. Cold surface water flowing down the clitf face was noted above t-he t:prinp,s and some mixing of these colder waters probably occurs during summer months.

Tatrle 8 gives the ciremic.t*l cornposit ion and summarize^ physical propert 1r.s of spring 1, the warmer of the two bprin~;s. Samples were obtained at the point where the spring issires frorn the boulders. The combined discharge of the two springs measured wit11 a pygnry flowmeter was 270 lpm -+ 10 percent.

No odor8 were detected at t11c ~pring~ifp nor were there notic~able hydrotllerrnal deposits of arvy kind.

Regervoir Propert iee ------* - f':nble 9 summarizerr the application of sil ica and cation geothermometry to Twin Lakes warm spring 1. The Na-K-Ca (4/3) geothermomcter temperature of 49°C indicates equilibration took place well below 10U"~, 731e Na-K-Ca (4/3) tempezncure is also similar tn (.he chiilcedony temperature of 41 "C, indirat ing that c.ilalcedony probably controls silicd equil ibration. 'ke chalcedony temperature is chosen as minimum reservoir tenlperatvre, Wa-K-Ca (4/3) as most l ikel y , and quai t z conductive as maximurn:

Mi11 Max Most1,ilcc1.~------.. Mean ---- Stci--- -Dev - .. Subsurface T (OC) &-cl f3- - 4 9 5 4 7

Some rni.xing with colder su'trtjr~rfnccwaters probably occurs. Si l.~cacon-. cc!ntrutions and ~pringternperaturr.8 rzrcs murlt too Low, hnwever, to allow c~c- c~r.~tP ~pplicatiori of NE i icn-nlIxinK IIIO~~l N.

No g~opkry~3ic3nI ~xplrrtrti ion haw br-r*ll rio~lc* fit 'rwjn I,akc*n rrrlrl tlcr* extcbllt or tlir* subsrrrtnct! re~ervoic i, riot IC~OIJII. (Ising t.he meat1 reeervoir temperature oF 511°C and t-he 8Landar.d meon reservoir volunrc gives the following estimates :

Voluma (km3) :- 3.3. rtd llcv 0 9 Thermal enerfiy (loi8 I) = 0.35; std rlev ;6.14.

'I'Lrc.se val~teemust be viewed ao hip,hly bpeculative ~stirnates. Table 8. Chemical composition and physical properties of Twin Lakes (West Shakes) warm springs 1. (All chemical analyses in mg/l.)

Si02 Al. PC CA Mg Na K 1,i KC03 co3 504 C1 F Br B ph, field Dissolved solids Ilardness Sp Conductance T, OC Flow rare Ipm Uetc sampled

.- .-.-- a~ombinedflow rate for springs 1 and 2.

Table 9. Twin Lakes (West Shakes) warm springs geothermornetry. (All temperatures are in degrees celsius. )

Surface temperature (measured)

Silica geo thermometers Adiabatic Conduc tivc Chti Lcedony Cristobs!itr 0 pa f --Comment a These warm springs probably result from deep circulation of meteoric waters along fractures and faults in the granitic host rock. Some of the ascending thermal wnter may discl~argebeneath the surface and go undetected. Geothcrmometry indicates reservoir tenrperatures are well below that required for generation of electrical power. These springs are also very remote and have Low temperatures and low flow rates, making them impractical for most geothermal applications. 5. MT. RYNnA (SOUTH STIKINE) , REPORTED WARM SPKINC;

--I.,ocat ion (~l.,proximate) latitude 56" 39.T1N., longitude 132" 16' W. ; Petersbury, C- 1 1:63,360 Quadrangle (1953) map.

---General ------Description Wari.na (1 917) reported a thermal spring on the south bank of the St ikinc River that he called South Stikine hot springs. Waring did not visit the site but re1ied on information obtained from prospectors and trappers in estimat irrg the location. A local inhabitant informed us that during his winter rxplora- tions at the base of Mt. Rynda (fig. 41, he came across a snow free area sul-- rounding a warm seep. The 1or:ation of this zone approximately fits the loca-. tion of Waring's South Stikine hot springs. The site described by the inkor- mant could not be found during an intensive search for the spring made in September 1979. The thick fall undergrowth, however, could have easily ob-- cured the locrlt ion.

'The area lies 22 km NNE oP Wrangell, Alaska near the mouth of art tire:^ Creek, wtlicl-i can be reached by boat up the Stikine River (figs. 1 and 4). Tht seep was reported to he located on a low ridge south of Andrew Creek at-. an estimated elevation of 30 m (100 ft). The area lies within Tongass National Forest and comes under the management of the U.S. Forest Service.

The slopes are heavily forested with spruce and thick unrlerl~rush. --Geologl The Mt. Rvnda site lies within a heit of Mesozoic and Paleozoic slates, schists, and phyllites with interlayered beds of marble that occur along !-he west flank of the Coast Range Batholith (fig. 4) (Buddington and Chapin, 1929; Beilcman, 1975). The contact wit.!l Cretaceous quartz diorjtes lies about 1 krn east of thc site. 'fie Coost Kangr, linciment follows Andrew Crrelc, jut$! cAirsI of Lht* 9 ite, 't't~r arc8 iu highly fractured. Trlspec t ion 01 iler ~oll~lloto9 show two dom~nilnt trends: N. 54" W. and N. 12' W. The rrgicrn has I>c*c.n interlricrl y glec intc~d,whicl~ ~AP arcentc~nteci t11e rrgional structurn1 )~;r,.rin. 'rhc viil 1 .y ie: flooro~lwith nlluvium and col luvium; thc low~rmountain slopea artx with a thin layer of soil. --Spring Characteristics : The spring is reported to occur as a warm seep in the alluvial cove~..I\lo other information is available.

-.---Reservoir Properties:--.--- No informati.on is available.

------Comments : The spring apparently has a low surface temperature: and a very low (!is- chrirlr,ta, making it impractic.nl for most geoth~rrnal apptirntions. Srtbsuriuco concli (.ions, however, are c~tlknown. An overflight of t-he area in wintt?r corllrl help in locating the spring. 6. VANK ISLAND, REPORTED HOT SPRING, UNSUBSTANTIATED

Locat------ion -- (Approximate) latitude 56" 27' N., 132" 36' W.; Petersburg 1:250,000 Quadrangle (1960); T. 62 S., R. 82 E., Copper River Meridian.

Coinmen------t s On the basis of a second-source accotlnt, Waring (1917) reported a possible hot-spring site on the south end of Vank Island (fig. 1). The existence of these springs could not be substantiated by DGGS. Local residents who had lived extensively on the south end of the island were interviewed. None of them had any knowledge of thermal springs on Vank Island. A cursory search of the southern shoreline by DGGS did not turn up any signs of thermal springs. These springs probably either do not exist or have dried up since Waring's earlier report. 7. VIRGINIA LAKE, REPORTED WARM SPRING (UNSUBSTANTIATED)

-.-Locati.0: T~~~roximate)latitude 56" 28. St N., longitude 132' 09.5' W. ; Petezoburg 1:250,000 Quadrangle (1960); T. 62 S., K. 85 E., Copper River Meridian,

Cornm~n.t R A iona-~irntl r~nidcnt.r,i Illrntlj1,t*l1, A1 a~krjrt.pnrtr!cl Llrc~ c>xiqctcSnccs of wrintcbr wnrm-writ rr Flow near t:'tie south-central shore of Virginin I,ctkc, lo(.ntc:c! uc.vi.ral km rsrlst of Wrangell, Alaska (fig. 1). An int.ensive searr.11 of the reported locatioxi by DGGS failed to disclose any thermal anomalies. The existence of the warrn flow could not: be substantiated by other area residents, including bush pilots and U.S. Forest Service personnel familidr with Virginia Lalce. 1,ocat- - --ion --- l,~titlldt? 56' 13.9' N., longitud6~ 131" 16.2' W.; I5radfieid Canal A--4 1 :Q3,360 Quadrangle (1955); T. 65 S ., R. 91 E., Copper River Meridian.

(;ener;ll- - - -- Description- nradfield hot sprines ore loc:~tea on Ease Fotk Bradfield River about 15 lun c.ilet of Brad field Canal (fig. 1 ) . 2%~. spririgs 1 if:on steep slope about 300 III SE oF tlie river lielnr i-hr conf1ri~nc.rof East Fork Hradfield River wii.1-i :I III,I ior not-t-ht~t-r~t r i 1911ticry to r11.2 r i vc.r+ ( rig. 6). Tl~cs ~pt-iII~!R WPI.C 11 i scovr~r-c*tl (lill-inf<:I rt-L~*c~nt~I~?~ii---cutt inr; opt?~~it itrn on t1.r~ Sb1: slope of tl~r*val loy an(! wet I>rt)~~,r,htto our i~t&tjnt.ionby (ITS. Fl,rthr;r Servicc pcr'ronnel in Jrangel 1, A? aska. The sprin~nran be riaached via :I 1ngt;itrg road ttiai begins at th~mnin loggin>: c:tmp at t.he kicnd of Rr~dfi~ld Canal anrl crrntiuue~past thc springs sitr. Thc springs :Ire within the T~)IIEAS~~Nncir;rral F'orcst nrrd come under the tlranago~nc-.rrl oS the IJSI?!;.

'Ihpr-r are two jr;t oLrps c)t' 'ipl-i~iig~i.'i'h~ f irxt group is compo~adof t'rrrecl springs i ,rsltin# t I om f issilrcs txr t ht gc-iinitic twtlrock abor~t-20 m al)ovi' I-oat( It.vc.1. 'lh~.st>i-ol~d p,!cr~tp ,-o~ir.istioi o~~crlsrirlg ixsr~in): frorr~ n b~ti~-otic fissur-t, ;iud *acbvt*1rrl ad j fl11(*111. L:ln,? 1 1 ..> lltt G 11111E 111)(>1itft'j 11 >il>(>v(,roiid Lc~v~l . 'I'~I,> rc>~psocc.~le. ill tlrc t11in v~~~,c~\rof 'i(Jil r:overi(~p, tiht' N~O~CS.

'Thr. Rast Forb. I3radf ii. Lcl Hivc1r v:tl 1t.y is n 8;'Iacial-ed v<~llcy,heavily forc2:rtttd on its lower 5iop~~annci Eiultked by glacinlly sc.oured bedrock domes at 11ij;h ~'lc~vations.S~nnll ~1ac;ers t;:ill cap th~mountaiiis north and south of tllr spring site. Treth line r:rrkges flora 600 m (2,OUO Tt) to '300 m (3,000 it ),

Ceo1- ogy No geolopic mapping oi the Knst E'r*?-lr pradfirld Riv,.~ area has been done. l$vrlrock ~xamitredaf th,- .,pr irlya srri. wati Fo~lrid to be a olecljtlm- to coarse- grained, hornblende -biot it-e granodj or; te with gn6.i sscrid structure The b~d- rock cor~t~ins many t onsp rclnous , ci,, Ir--gruy f iiic .grn ixied ::ri~cbli ths, :iome over 1/2 nl long. 'Illc~ hojt rock Is pt olrr:i) I y par* of thr Coast Ilangc* Batholith , wli ic-11 ~('CII~N110t'o ll(~rt!i 'it' l .'tr~~llr1)1 tht* Rroli l it* 111 FITPIP.

!>I o~tlii~pf~tI I* ,(:I {it c>*i ?ire> #ti>ij,~t-t~t~:1111 tit-1" is11 ~~IOLOUof tl!~sl>ri~igs HI t\?t 711(,!1(- Lrec~dN. 1 1" I<. , N. '38" E., tir:ci N. 77" E. C)t 111~springs. 'I'he ar- t i tutle of joints lorni-rti 3t. ti~c spring^ rnea(311rcd st r~lceN. (43' 'E., t1 ip lie S.

Sprirtg Ch~racterist:.hcti ...... - - .. . . . -- . - - . . .. - . Water Elow Pram tl~rl :;prinb:s L:: qr>i.tF. low, with tlic combined discharge e~t.i.matedat lass th.ili 40 ip111. Sl)ri.:;g tenperatur-es ranged from 46" to 57'~. 1)ar.k.-grc-:en alg~mattc 1 ir.;: tlii: ((?per d;antie'l.s of: the hot springs. No odors (>I: >:at; hi.;hhl.j.ng .were !jot. i.ct.!.:;$s i ., :-?.: a.17 of t:hc-. s~)ri!igv ,. Tatl1.e 10 gives the phy s.i ca 1 prcrper t let, arid r:l-lvirric:n l c:orrip~i~;1.t 103 of t\i(:rrnal waters obtained from tl:r.! spri.ngs hav i.717, tt~ehighest. ter~i~~~~~*at~~rt?and greatest tl ischarge. 'fl~ewaters ;ir:? < LHC~Mi.f i.ed ;$:; ;I !!totlcrid rely cc1nc~n6r~tedsr~rf ;.rla~-.su l.fa'ie water . Figme h I cca"lni1 nna;,, ilra. Field Hot Springs,

Table 10. Che~nicaZcomposirton and physical properti es of Wrndfield hot: springs.a (All chemical analyses in mg/ 1.3

sio2 AJ. Fc Ca Mi3 Na 1: 1: Li HCO3 co3 so4 C 1 P Br U ph, Field 1)issolved solids Hardness Sp Conductance T, OC Flow rate Ipm Date sampled

--- .-- .- a~nalysisperformed on spring with highest temperature and greatest d tocharee. b~n,lysls performed on acidified 0.05-micron filtrate

'rablc 11. Ilrudfl~1.dlloc spring geotliermometry. (All temperaturea are in degrees celsius.)

Surface Temp,era cure (measured)

Cation Geothermometers Na-K-Ca (1/3 ) Na-K-Ca (4/3)

Silica Geothermoineterv Adiabati.~ Conduc tive Chalcednn y Cris tohali Le Opal , , dl ?(>ti ~,atti,-i~de','I" bC 0. PJ , longitude 131" 33.4' W.; Ketchikan (D-5) 1:63,360

r)l~rrd ntrglr! f 7 9'1'" ;- '(I, 1;8 S., R . YO E,, gee. '31, SE 3 14 cpf NW 114 of ~:il,,pf~i-itiv,:h ?!6.\x- {I I '.I!*, . . i:c~rlr. : :.!I i)e~cr,lp t r cnx . .- . . .. . , .. .. ;it:!., 1 t,l,lg~ t- cq,.PI..~- ,-! "12s E::R '1.ocnted near the southweet end of Br?l l ~. ;.I, : 5 i ilkit' I (f1,) The principal springs ace. ,4ii:(~i~i.c:~loil the ~iort:l~hank oi: ti ~n1;~I.l.creek illat dtain.8 into a narrow cove . , : , "L'htt npr'iriga rlr.%? c?btj?it:4.00 >.rl from and 5 m above high-tide leve'l..

W:ci.iii.j,, (19t.7) r+:p>ilj:i;aci i;'r~:l'r ~k'i i4utarr;i i.osue frorn a narrow fissure abo~~t 1 ii : :itca. : , '!:he springs Li?-a encased i.n five concrete i:I fi rii.:rth spriitX eat >

'I'h?: !:vi'j'otr~ld 411~ t<

7:;.: v i.I I 1 . reof bedrock The is ].and i.6 ,-:~-rr>u:ntit?r.l by Ir i g!-I! ;r sc:ei,ii:.:, loiig, I)HII:OW passages flanked by steep, heavi 1.y i.(jl:<:?i 3 l6.Jpc:s,,

i'he d.:p$ ir~ys,Ira 10 ivat-ely owucd :lad serve as u major attraction for the lit. l i jt3 1 arici F'ig:n i-kg fii.hoxi, 7.h~ rc!:;ort ~ispw the! hut--springs waters to heat tllr rtt;tit, r,,d:,is, 14 crriirl I,rliltlir1gr; f:ad cabinti, arid il large swimmi.ng pool, Tilr ::11. ;11t:5 lru3.t i,~*c31t~,iiati ill '2 t 2rit1 ii'"~I-d~hian pariodically since 1902. The t ..I,- 1 IIC! ?PI ! i .05 ac:t.tA:j :~usvo~t~~rlingtht- ~pring~ arid 1s prenently owrlrti by I I !;UQ jilt~ciit~gli*rirltj IIIC wjthin tire 'I'ongzis~ National F'orcst and

?IL-+~ tt3a~,*k;-Qtby the 1) S, b'c*~*v~jr3~rvice

1%;: I l !B L.31lci i:i!r1 be r:t:i

, , ill t-ttl :,i 3.') ,*. 1 c L>I' -firs irful o~i~ndirai-c: emplacement occurred I , : 1 , UF;~'. Tile: , ta~,~vcrocks arcb cut: t)y ilIIniebroIm dikes and

3~c.~81:lrC ld~.:f>,~ j,;r<~y\+~+-:4ti1c31.i,~1.,~ ~~~i.2~t:5--ft-1i1t3~3~r-~13~~3t:ite-~;~1rt1et)rwgi~tatitts~ if),> t,i :I r.1 9 rc,*liirrs: aai\~rn:Ijttit r>l l ip~oidol dnl-lr inclusiorae tllot cornmoll1 y

2. I j J J L pol ini.ion AI t itud~at ti-ntb >;pi.

i ,r,sll L-ILJI. txti~\ ~-t*~~~~-i~d:>P gcbikt3 JV~ 35' W," dip 75' N- Figure 7. Geo1ogi.c. map uF Bell Islarid and Btliiey Bay Hot Springs area,

-4 5 - c, Ili,. 'i .I. ::;prj'lt!+: I; u ;t)t:i)ti~il=~riki:1,inearnent Chat l~isectsi3cbI I.liland.

"i'hf: ! ineciol~lit: i:ry:?~~t!i.~1.4, :.,jZC ;I;. ,in3 i.r; fit lc:aet: 30 kn lorig, extending :icru:in

A 1.:. i:l-~,a !'!p.~r.tili.:g;js. i!,.:~.!Ill.i<>~b:il B'Li,ntl I'~#Hto the snutht.re~t: (i'ii:, 7). :,!.!+I:(. I !, rrj ,.: .,hi:. .;.i :: i :;: il: .'f:c~-.,ehii; u rs tinctiv~.I r.mea~t~crrt:i.5 clef i.xied by a :.ct~,~~,~,~J~~.~,,~,,, t.;z.f'! !.r. :.i~;;r. rSl.:rla t.'.i~ c?r?.fsi.reIelagth of Bell Island ., The ':iri,c-:a-

;i,.-,!r.~!. rn;.!y j,~;, i'a;~:i-t i 6. i i:t,et':; \.!.a; .in;; (131.7) Eourrtl! t:v-;$ence of Y l.icliensi.d.Lr~g :f lr L.....,r;..: ;3earr i.l*t: :;r>~..ii~j~s,st~ggv:.. ing that: some faulting Elas occurred in the .; ! '-:l>i:l.l:y*

,?ns.pc.lc!. :.(I(; of et: i. ,lrt:l !.ciir>+.)+ strowi the s~ir.i-nut~dirig ~:ee..ion to be high1 y

-i.:~ac irrlr-e.l L: i ;.: I LCII '.r4il~sisi..!'i.::i(i j;l, 60' E . , patallel to the Bell Ls f.at1d lirrea... I ('t.i:c+r: )r!'rti;ijfii?:l~ :j<.'i.i!.!. :~t:-:yis?:.i.lle on Yle phot.os treild N. 75" E. , h. tr[jt' b,, 3 r~.,.~.~., , ii~~ii!$, 30°.-4Li' i;, k. joi.~~~::~y~!:etn examined near the hot spri.rrg:; isi . I 1 5' i 7 N Another 1.ess promitlerlt jtsi.nt ; ? - yj* $;I ,bL t~n,:l i~cii:. PI CF 60'' :<*

':l.tl';i~r ( i- ' i: .:o fdi,\?, *,::.-:, i ir.-tfi i!i:urt;: Ii~~sph~~~,ydikes have !.rt.vaded u runnibes cil" i- i.1~id 6'' I i I.,? +iit: K:!.x;zi.ng ffrorn 20--30 cm in wi.dth, tlilter; ,. " : : it.: k .Ct-i: d;.iic's are prr.hahly relatecl to posptlyri.tic :,-V..L:: f !.I i,*c.d.! qur1'-.;:, n-1i21\.~03.1; :,;-i~:l;:~!:if Mlocerle age reported by 13c.c.g and others ;1 "

,p. ,, .> ,r. ! ley f.! {>illni-!,111. tl?e spri.rmg8 conrj;.~;:R pri.rntprily of granular i~Yluvial arcc! J;IHc'L*A~depouit:fi o~~e~'iyi.rigbudrciek (Pyl.a, 1.978). on the basis of shal- ?,.+;.: .. ."c.:t:itr*? ~t+:i.;t!lii: ,r:.~r.tl.$.:~, !):yli? estiuat~tedsediment fill at t4l.c head of t:,!~~.' CC

7 1; $ " r , .;! c , ,!,, 4i ~IL! cj,\r~..i~.*!~?.ij1.r:: r(~14,::ji: t,.si:i.;.~~ ?:P 6;' .4°~?OX: [:ilk? tlcllrthesstt:rr~rric~t (9 i,i ! IP~J,~.;i.;.:;; i:lO i', ~~

#. #. ..i..i;: ?;.r.~.r!..j, wi-lii:; IJ~:YP~.~$!;<;L3 7 - itl.:: HI)F~I~;S have hecome hotter sirice 1.915.

?jL, ,. -;.(.: p i) 'if-\ t.:,:~IjL:l.i!.i);, occ. .:I -;r. .nil. f iviis has i~isand the waters srraet. 1 ed .I I it I i:'i.'irt: ,i .:f:t; .-ipring mews:lrari 46"~~ source. The estimate is based on measurements of overflow and discharge at the individual cabins and swi.ming pool; the estimate neglects miuor leaks and evaporatiorl from the pool surface. These estimates compere well with other recent estimates of flow (Baker and others, 1977; Sloan, 1976n-c). The measured flow ra,te however, dif ferd substant:ially from Warring's visual estimate of 35 lpm in 1915 and suggests that a significant increase in s~~rlng disc:l.rarge has occurrerl. 'Re estimat:ed flow of the sixth spring .is 2 lpm.

Table 13 gives the chemical compositior. and physical proper~icsrsf watcJrs obtained from hasin 5. Previous analyses indicate that chemical compo~itio~l of the waters had remained relatively stable. The waters are classified aL n sodium ch lor ide-sulphate water.

Reservoir Proper ties Table 14 surnrn~izesthe app1.jcation. . of silica and cation geothermometry- to Bell Island Hot Sprillgs using the DGGS water-chemistry analysis. Previous geochemical analyses give sinrilar results. Cation geothermornetry indica~es subsurface equilibration took place ac tcmperattlres above 100"~and chat therefore the Nri-K-Ca (1/3) ternperaturc applies. This temperature is also very similar to the qilar tz conductive geothermome ter temperature, indicating quartz probably controls r;ubsurfac~silica equilibration. In estimating 'reservoir ternperiittire, the chalcedony temperature is taken as minimum, quartz cond~ictiveas most like1 y, and Na-K-Ca (1/3) as maximum:

Mi11 Most Likely Mean Std - Max-- - .".*-- -- - . ------Dev Subsurface T ("C) 115 144 142 134 7

The hot springs at Bell Island issue from the surface at temperatures below boiling, have a combined flow rate of over 100 lpm, and a cation geothermometer temperature considerably above orifice temperatures. These fucrors suggest die mixing of colder waters (Pournier and Truesdell, 1974), The apparent increase in spring temperatures during winter aloo suggests some mixing of #:older waters. A cold spring in the area was found to tlavc a temperature sf 10°C and a silica ccntent of: 6 ppm. Following the rnetirod of Truesdell and Fournier (197 7), application of quartz mixing models givc s tlie following results:

-Parenc ------l~ot -- - - -water - .------Mixing--- -model - - -- h--- - 'i ("GI -SiO _2-~~?2. ( m Frac----- t 4 on---- -( %) 1. Maximwn steam loss 150 125 73 2. No steam loss %J 7 330 3 1

There is no observable .steam 1~)s~at the ground surface. If steam s(.pslr 8tr.s it eithrr goes to heating water other eltan that emerging at the springs and model i may be applicable, or it remains and heats colt1 t7atc.r~ r~rixingwith the hot-water fraction and mdc:l 2 may apply. The maxirn~nm temperature of 217°C from model 2 seems Ltigh For ;I hydrotfierrnal system circ~ilatingin deep fractures in the granitic. bedrock. The temperature prfldjct-ed by nndel I, t~owevcr, is qu~tcclose to that i.ndicat-ed by g(~othermometrg. i'i~ble12, riel1 Island Not Spring temperatures, 10/5/79. (Pi~lrnbt:~~tzurre:,por~rl to concrete baains going NE to SW.)

'r'ablrx 1'3, r:hrniicat cr>;~Ii~u~l.fic>nand phyeical properties of Bell XnLand Hot Sprin~w. (Pr PY ioi;~artalyees inc l.uded for comparison; :iII chemical analyses in nx/ 1. )

i., ,i,.ii -Jf -qi~t..arit y arr~tl.~sl~$ti 12, USGS cent-ral laboratory, Denver, CO, coElrrttsrl I)y C, I: :> :> ~Oai~&, b )z411*r :LIC~ ot.kw?t (i918).

, !I:;(;:; \ 1 .if)i+t>!3'j > 1

SurFare temperature (measured)

Cation geotkermometers Na-K-Ca (1/3) Na-K-Ca ( 4 / 3)

Silica geothermameters Adiabatic Conductive Chalcedony Crlstobalite Opal !'er~ilk.-rci~tl1r.s f ~i111i111*+ qta~jrtis mixirtg models must: be ttsed wi tt~ciiutiotr No . , G ilor~tE~1VL QS'~l'13ir:e ye i rxiefs for ~t~ixing.information is ineuff icienk t ts

TI, r ilil.nc if,&ink i 12,viip:1 or ttrrl vtd CII Ic)E-ide-concenir~tiontrends, ar~d no i~efo1 LI!~~ i J ctrl is ~fiiliiij lr, (1x1 !\L i ,jcti epic C:

'r ctl~1ly~.t~al<>: ,~.~~.BLXOLL :it l?ell IR !atd ha:; been limited to shul low I !,'I 712 ft ! 1 rvc't i'lll ~':VPB~igt?! ~OIIH; the extg~ntof a deep subsurface sesex boir ,:, ~ici ~rrkrl\.ln. !JLr'r~g \he :;rililii~:-d nmn reseivoir volume and the mean rtBserv~)l~ I ~'l,tp.'r 3 r rirr i: L i 14" gives thcf ;ol lowing estimates of s tored thermal eac2x,gy

'/'ilt!~(.v~~!tiii1. ltii~~t. bv rr~c-:\\/,4 :I~J hlghly speculative estimates.

(httls!y ,e.;riit- f~n~nrlec~p circulation c~fmeteoric 11atr.r.6 qli<31~gf~,~c~bir(~b ii!1<1 j10t~~3it.,~..j t+ar,i.Ls asso~~iatedwit11 the Eel1 lslnnd li.neiirnu~~t.

I'll ("a: (?I ~6i~37<,I Ii,'i 1 J c: I dlid ~

t"g::;r; <, , I~I,,,it el, XL~It?il:i, /:+ hie lc?L aearch the ex i-atence of these springs t i d tin 8-L aL r~cont~aissanceduring winter might: aid it1 10~;tt.lrig ((~iysuc- pl.urne~ I ,>m Llli-a~p reported springs,

bt,nc! ~11t111~ ~~~~cc,LLcL~\L~,t klb~rir~al WB~C L may be untietected, discharging : r)rl. t In LIIP t:all t<~<'r*Ill to the ~~?cliinent,~wee- l ying bedrock SW of the spring . i + !,.~lini~ Il(:i ,i,rz LII~N11ihy z l so he ~~uhmergedbeneath the sea or rrndev lnkeci , 1.. . I ira wl uirt,, il~c: I jne:uaer:t .

(:PC L lit.%,nitru..t* *, ixlci t ~~LPEIthe Y e~t? i t- tT"~iiperaturCsiire helow the min in~rrrn J 1 t t!gr~irrd koi. &PAI.I!P.~~im (~it "i f2cl.t !CAI power. If ~ubsrlrfacemi-xing of

ii 1 : *, WG,~6 i i eu CIICLiq, I~oviev.~r,mixitlg n~odelssuggest reservoir temper:j -

1 bl . L, '1i-j~ 13)11:c-ct1 1 ir:b h t. ZULJ he etxough to gr?nernte electricity.

'['It;-? ti:^^. i;.:Cc .i:t r:r;r.rc :: ,; p::r?~:.?rli::fy bi:i~~g118eil for heating but rrn.icli oi: thi. t-!i:t ..r j.~. L,t!l,tjr, tf ir.ic:i!;i~~:c!rb .i.iii:rl rhe rjea 3t ten1perat:ures of 40-50"~. Addi ti.onal. r.r.c:r...de,! llRPF3 for t'k~t~I:CH~>I.I~.CF: ,.I.(': porj~ilsl.e, perhaps for greenhotlser; sr i.icllla.- r. . ille p~esccii:o.iauc.*? af 14t:LI. %.,J.arid Rot Springs Resort has exprr:i:;c(l

I I ! .t! c,i 6:si #.ti i.he i.11~r ~:;I.J~:YG t.:ir? ti? IL'(LP .E21:- Y4;l.and. geothermal. resources . 10, BAILEY BAY HOT SPRINGS

------Location I,ati.tude 55" 59.0' N., longitude 131" 39.8' W.; Ketchikan D-5 1:63,360 Quadrangle (1952); T. 68 S . , se~. 9, SW 114 of SW 114 of Copper River Meridian .

General------Description ------The Bailey 13tly Hot Springs are located 80 krn north of Ketcllikan, off lrc11r11 Canal nrld near Bailey Bay !f ig, 1) . The springs are 0.5 km up from the rnolltt~ of Spring Creek, which draina into Lake Shelokum (fig. 7). Lake Shelokum il~ turn drains via a steep cascading bedrock channel into the head of Bailey B,ly. 'L'he springs are accessible by boat to the head of Bailey Bay, thence over :m ur~mail~tainedForest Servil.:b trail for 5 k-rr~. Alternately, a float plant. cm be taken to Lake Shelokum Thc 3pr~ngsare within the Tongass National Forest and are managed by the 1J.S. Forest Service.

'Pen principal springe eincl a izurnber of seeps and smaller springs ai-e dispersed over a 12,000-rn2 sri-il on the steep northwest-facing slope of Spring Creel< valley (fig. 8). The springs lie between 112 m (40 ft) to 45 ~u (250 ft.) above Spring Creek and issue from fissures in the granitic bedrock or occur as seeps and pools i:~the alluvial cover.

The region has been l~eavilyglacia~ed. Valley slopes range from 10" to 45". I,cwnl topography rangen i~relevntion from 106 m (350 ft) nt 1,altc. !;hv Iokttm to c,vcar 730 111 (3 ,400 ft ) cit Ll~e crrHL of the ru)rtlrwcst-lrtri~~~;slope. nbovcb the> springs. 7'116~ area is I~ighlyRC!PLI~C with ~teep,glac ic!r-~)oli~ll(~d, granit ic walls remeni scanc of Yosemi te valley. 'RI~soil-cover ed slopes iirrcE valley are densely forested with spruce. The valley bottom is flat as a r~sultof alluvial in-filling snd rnay have once been an arm of Lake Shelolcbar (Baker and others, 1977). The valley is susceptible to flooding.

The springs were morc3 c?xten~ivel~used during the early part of this century and were once developed as a resort with a wagon trail to Bailey 13ay. The resort closed during WIl and a three-sided shelter is a1 1 that rc'mains.

(ie_o1 P_E.,v Bedrock in the Hail cy Ray area is o l incnted, gneissic hor~lblende-biori t~, qtlnr-rz tlit,ritc? and rninor pi anatliori tc. (Fi p,. 7) (~erpt~ncl otl~ern,107Hj. 'l'11~

1)11tto11~11.~0 COIX~P~~IIU :tbrludr~nt vll i!)rioitla! nor-k inrl :tHlonln tl~nt rirrl I):I~ 11 1 I(*! I 11 TI l i y,t~c~clI~ornh l tbudt. cl y~ tdls . FO 1I 81 t io11 att i 1 trdt* ncrni- Ha i l~yllrty Ilc~t Sit, i rlyl. i.4 :IL~.Ikc: N. '35 W. , dip 7';" N. I3ikee alrrl VP~LSHof: li&{ht-g~-~i)wc'al-Iler ill:: c[uarf z-f e'3tlflJ)~r-(biotite-p;tlrnet) pegmu t itc rut the jrltrusive . K-Ar sgr>!l it Ihr wpsterti part of the pluton indicate emplacement took place abo~lt 72 to ;I[, 1n.y. ago.

Inspection of aerial phrbtos shows the area to be llighly fracturect wi1.h a clominarat northeaster1y trcticl. The most prcminent: fractures trend N. bO" L, k'ract~rres at Bailey Bay Hot Springs have trend? ranging from E to N. 60" P,. I'hosr at the head of Bailey Bay measured strike W. 60" E., dip 78" N. ; 6tril.c~ N. 50" h., dip near--vertical; ard strike N-S, dip near-vertical. I- $1 L tir+. i tJy Hay Hot' Spr~ngs. A series of aphanitic to fine-"grained, quartz porphyry dikes have intatled many of the fractures that trend N. 50' E. to N. 60' E. Ranging 20 to 40 ctn in thickness, the dikes are probably related to porphyritic granite stocks and quartz inonzonite stocks of Miocene age reported by Berg and others (1978).

Spring Characteristics *------Ten principal spring~issue from fissures in the granitic bedrock :~rid from pools fvrrneci in alluvi~mcovering the steep valley slope (fig. 8). Niue of these uprings were reported previously (~aring,1917; Baker and other:;, 1977); the tenth opring was found during DGGS investigations, This newly reported spring emerges in a gravel-bottomed pool, located about 50 m SW of Spring 3, and has a temperature of 71°C. The other springs range from 5h,O0 to 91,5"C (table IS).

Cornpared with previous muasurr~tuents, most of the hot springs at Bni ley Bay appear to have fluctrlarerl at: lca~ta few degrees. Theses variance9 ilt measured temperaf~rrc~scould reflect slight changes in the mixing fraction of colder waters. 'hey could also be due to differences in measuring technique and measurement locatior~. Hot spring water temperatures can decrease several degrees just a few centimeters away from the spring sources. A11 ADGGS measurements were made by inserting the sensitive portion of the thermal probe either directly into the spring orifice or as close to it as reasonably yos- sible. Probe location was always adjusted to obtain a maximum temperature reading. The 20' to 25'C increases in temperature at springs 4 and 5 since 1914, however (table 15), are much too large to attribute to differences in measurement techniques, These changes are more likely due to n real increase in the temperatures of waters arriving at the surface.

Where possible, flow rakes were meamred by DGGS using n pygmy flow- mzter; utherwise, flow rates were estintated (table 15). Spring discharge.; ranpet1 Zrom 1 to 70 lpn~,with the largest discharges occurring at springs 1, 7, and 5. The combined October 1W9 flow far all aprirtgs is estimated at 100 1 prn + 15 percent. Given the limited degree of accuracy of flow measmrcments and &cirnates, the rrverall flow rates appear8 to have remained relatively cvnHtanr. Plow at titsee of the individual springs, however, appears to have changed appreciably, with tiprin~s8 and 9 decreasing and spring 7 increasing since 1914.

One of the thrce'sources sf spring 3 issues in a spout or jet of hot water which measured about 17 cm in height on October 12, 1979. This small jet of water is probably due to thermal artesian pressure. Previous observa- tions indicate jet height and temperature fluctuates with time (table 16)..

Analyses of water chcrnistry were performed on thermal waters obtained from springs 1, 3 and 5 (tablc 17). The springs are nearly j-dentical in chemistry and other properties. Somc moderate changes appear to have occurred since 1915 but the accuracy of Waring's earlier analysis is not knuwu.

Waring (1917) rr~pcprtcci considcrahle bril~t~linpof gnu at Bailey tlwy liot Sprinp,~hut no bubbl inp; wne notisr!ahle in 0ctclbt:r 1979. Carbotiattt. tlepon ~tr; Table 15, Temperatures and flow rates, Bailey Ray Hot Springs.

--.-- --.-AL-&m erature OC Flow, (lpm)----

A .--.- ---- a, DGGS, this report. b, Baker and others, 1977, estimated. (.. WarCng, 1917 d, An overall total fl.ow of 274 lptn for ~pringu1-9 wtr~reporter1 by SLo,ln, 1C>70.

'Itable 16. Bailey Bay Hot Springs, spring3 water jet height and temperature

Date------Height: (cm) Temperature (OC) ------References 1905 3 8 9 5 Wright and Wright- , 1908 19 15 30 86 Waring, 1917 1976 15 9 0 Ogle, 1976 1977 2 8 85 Baker and others, 1971 1979 17 8 7 DGGS, this report Table 17. Chemical cornposit Lon and physical propert l en of UaS ley Ray Hot !ipl I I\%:;, (Previous USGS analyses included for compurison; all chemical analyses in mg/L.)

DGGS .-- DGGS ---DGGS -. USGSa ----USGS~ - -IJSGS" -- -- - Spring 1 Spring 3 Spring 5 Spring 3? Spri~~g3

Si02 150 A1 Pe 0.01 CR 2.1 Mg 2.2 Na 89 K 4.3 Li 0.07 I-1C03 1.45 CO3 0 SOL, 43 C 1 5 3 F Hr II 0.03 pH, Firld 8.2 Dissolved Solids 415 Harcllless 14 Sp conductance 444 (lab) T OC 90.0 Uischargc lpni Oate Sampled 7/7/76

------. -- " Water-qudliry-analysis file, lab 216065, USGS Central Laboratory, Denver, CO, collcc*r hp t:,~'. S loan. h~arinerand others, 1978. '~ariag, 1917. (I~nnl~F;er:performed on acid1 Ficd 0,05-mlcron filtrate. o,-:~,i- at and near sprilrgs 1-5. Many of the spring channels are lined will) ;;I i i i ;ant and =.olorful orar:ge-red bacterial mats that change to blue- green ~r Ti.:,>~r~at-.ewhere tPmperaturer~ drop below about 60 "C.

'hi. multiplicity of springs at Bailey Bay indicate that single conduits ijrar rhe srlzfsce are Lao narrow to accommodate the volume of ascending hci~ ~~it~r.Ctianncl permeability may have been reduced by depositio~lof sil~caand otXlt*r llydrothermal minerals on [.the cor~duit wal Ls as the thermal waters cool or1 as,.c~rt, Some of the thermal water must: be discharging beneath the surface, btac t,lsit ri~uch of the soil Laver in the vicinity is 15"-20"~at only a irw ctn tleptil. 'I'hc :,pring waters must ti1 so go to heating some of the local bedrot k; thr s~irfaccof an area mc4;mouring several square meters on a moss -covered tock f tier dix-ectl y above npl irag 5 registered 42°C.

ilc.~r*rvn ia l'r.opnr t i cea * ------*.-.-- "- Table 18 sutnmtlrizcs tile npplicatiotl crf ~ilicaand cation geothr;t~norn:-Lry to Hailcy Bay Hot Springs l'he Nu-*K-Ca (4/3) geothermometer temperature of 142" C indicates subsurface equi llbration took place at temperatures we1 l above 100''~and thet thsbrrf ore the Na--K-Ca f 1/3) geuthermomater temperature of 15'9"~ AR applicable. This tamper atnre ie very similar to the quartz-conduc t ive ten~pct-atureof 157°C. The pH levels rnea~uledby IIGGS for three springs at Eailry Hay IIot Sprilip,s ax,: iit?.~~lyidentical arid notably higher than that reportrd by previous inveutigtit.ors. Applying sl pH correction to these cfprirlgs 11sing tlie IJCGS pIi valuks retl~l~~in a quar tz-corrciuc.tive temperature of 14%'C, ell is L-enq>eratnrei a taken as [.he: nlininlum reservoir temperature, the uncur- ~ecc~xlquartz conductive teniperatrlre is taken as the maximum, and the Na--I<-da (J/3) on the niast likely:

-Mitr --biax ----MoetLikely -.-Mean -.--.-Std Dev Subsurface T ( "c) I42 157 1.53 151 3.4

ilar principal tl*rt springs at Bailey Bay issue from the suvface at temper

-ikzlr L.:J below boiling and have a large combined flow rate and cation geother- 1~rolri*2f,%r tsmperatnres consideratly aboc~t+orif ice temperatures. These factor :; srl{l;ge:;r the mixing of colder waters (F'ourriier and Truesdell, 1974). A ctrld jpriirg near Bell Ks~anclHot: Sp~ings,Located iri similar terrain seve~alktu :our11 of Bailey Bay 1Idt ;;ptjnps, was Found to have a temperature of 8°C ad a :-i' ri a rnrtf ent of 8 ppm.

Using thcs~cparameters Lo characterize the cold water fraction atd fol I ouj nf: the method trS Truesdell and Fot~rt-iier (1 9771, agpl icat ion of cluax.1 z ,I~X;I,~nltrdel~ given the followiu# results :

Parent hot water ,--. A - . .. -- .~". -. -..------.. ---.." Mixing model . ----.------!faxTC"c> ---____s i~~~~n)-- -Fraction -- -. --- .- - - (Z?- - .. . 1 . Maximum steam loss 154 ----- 135 89 , !'I3 Steam loss 225 370 3 6

'I'enq,. :-~CYWG+f rorii ~ilequartz mixi.li~: modeln must be uscad with cauti-on. No (.or Lobo~ua;vr cw~clencrx fox rnixi~,~:sllcli 38 from ch loride-temperature arlcalysis trr w,%!el oxygen imtopc! crnirly~eri if: available. Further, residence titre irl t-l?t. , 8-nii 3 ir lock ot co11.d spriligs watcra which were sampled nlay have been Tablo 18. Bailey Hay Hot Springs geot:hermo~netry. (Rased on spring 3 water chemistry, DGGS analyses; all temperatures are Ln degrees celsius. )

Surface temperature (measured)

Cation geothernrometers Na-K-Ca (113) 153 Na-K-Ca (413) 142

Silica geortrermometer.s Ad1 abatic: 149 Conductive , 157 Conductive, pH corrected 142 Chalcedony 133 Crls tobalite 107 Opal 35 ~elativelyshort and not representative of waters actually mixing with the LloC water fraction.

Although there is no observable steam loss at the ground surface, steritn may he separating below the stirface and heating waters other than that i.mcrging at the springs sumpled. The large area of heated ground atld rl~t. r3imil inri.ey oF temperature estimated by the ateatn loija moi4el to ten~peratitrc~s estimated by geothermornetry suggest6 this may be the ca8e. 111e high ternpera- tuCp predicted by model 2 seems unlikely for waters circulating in fractures in granitic: bedrock.

No geophysical explor&ti.on 11~1s been done at Bailey and the extent of rile subsurface reservoir is not: known. Using the standard reservoir volume and the mean reservoir temperature of 150°C gives the following estimates : Volurne (km3) 3,3 std ctev - 0.9 Thermal energy (lof8 J) = 1.20; std dev = 0.35

'these val.ues must be viewed as highly speculative estimates.

Conaments------: Bailey Bay Hot Springs have both the highest surface temperature and highest estimated reservoir tea~pextature of any hot spring site investigated irr southern Southeas tern A1 askcl. Surface temperatures and flow rate are suff i- cient for a variety of applications requiring thermal energy. The estimated reservoir temperature is above that presently required for generation of electrical power.

Bailey Bay Hot Springs probably result from circulation of mete~ric writers along deep-seated fracturen, Fluctuations in discharge and temperature at individual springs apparently have occurred, as indicated by comparing reported flow and temperature mea8urenlents (table 15). 11 . SAKS , REPORTED HOT SPRINGS, IYNSUBSTANTIATED

Location------(Approximate) latitude 55" 52' N., longitude 131" 05' W.; Ketchik~~~ 1:250,000 Quadrangle (1955); T. 69 S., R. 94 E.

Con~mrnt R -. --.-- ? lielying on information c~btnined from IfSFS in 1915, Waring (1917) reported the existence of hot springs located 8 kin (5 mi) SE of Saks Cove off Rehn Canal (fig. 1). The USPS representative described the springs as similar to Bell Tsland Hot Springs with "water issuing in part at the rock shore and in part directly from a fissure in granite 200 ft back from the shore" (Waring, 1917, p. 23).

DGGS interviewed several persons familar with the Saks Cove region, including representatives f run1 the USFS and the Alaska Department: of Fish and Game, local bunh pilots, and local mappers and explorers. Two of the persons interviewed had searched extensively for the springs but could not find any sign of them: None of the otherti had any kuowlcdgr! of the springs other t-ijan what. had heen reported by W~ririg (1917)" The springs either probably did not exist at the tinre of Wuring's report ~ndWnring was rnibiinforn~ed or perhaps tht. springs have dried up since 1915. 12. UNUK, REPORTED THl3RMAL SPRINGS, UNSUBSTANTIATED

Locat---- ion-- (~~~roximate)latitude 56"08' N., longitude 131°00' W. ; Bradf ield Canal 1:250,000 Quadrangle (1955); T. 66 S., R. 93 E.

Comments Waring (1917) recorded a vague report of thermal springs located about 9 km (6 mi) above the mouth of the Unuk River, which drains into Burroughs Bay (fig. I). The springs were believed to have a small flow and to be neither very hot nor notably mineralized. Several individuals familiar with the Unuk River were interviewed by DECS. None had any knowledge of thermal springs along the Unuk River. Carbonate springs located near the international burdrr reported by Waring (1917) as Boundary Springs were reported to be now under- water as a result of a shift: in river channel. The thermal springs may have either met a similar fate or perhaps never actually existed. 13. BAKER ISLAND HOT SPKXNGS

I,ocat ion-- (Approximate) latitude 55" 17.5' ; longitude 133" 40.5' ; Craig 1 :250,000 Quadrangle (19571, R. 76 E., T, 75 S. of Copper River Meridian.

s ------C omincan t - A hot-springs site was reported by lokal fishermen to be located O(I rh1\ west coast of Baker Island (fig. 1). The existence of these springs was recently substantiated by the USFS office j.n Craig, Alaska. The Forest :%~r victs reported that n cluster of springs iosue from a steep granitic clifi, scvcral meters abovc* tidewater at the head of Veta Aay (fig. 9). The IJSVS plans tu build 3 trail to the spring from Port San Antonio on tile ~'HHF sidt* oi tl~ris land.

Deter israting weather conditions prevented field investigation of thi s site during fa11 , 1979. Tile site will probably be vioited during the 1980 DGGS field season. F~.gur.*:'3 , l,cli'.ar.li=n ttiapa, Seker Tr; I aud Hot Sprinfis

.-:i2-. SUMMARY , Z;OU'rHEKl\I SOUTHE AS'I'EKR ALASKA THERMAL SPRINGS

L(~lctitiorisof ti.c thermal ~prlngbi tcs in southern Southeas tern Alsq'in ,ir c$ shown in Eigure 1. 'Table 19 provides u St-i~fsunntiary of each site., Tf~re<> sitps reported in Warinp; (1Y 17) (~ankl'slmr~d, Saks Cove, and IInuk River) ~i-itld not 1)~verified andl art! ])~<:ti~t.tly di sr:orirrted, These eprbings rnay httve

The Bailey Bay Hot Springs site (No. 10) has the highest surlace watc~ temperature / LO to 91 .5'C) and [.llc highest estimated riubsurface temper .ltilrc (151 "C3 in saut:bcrn Sntrtheaatrrn Alflskil, The largest flow rHte (450 I~III)WFJ~~ measured at Chicf ,;hukes hot Sprill~a(sif.r l), Loc~t~din Shakes Slough ilor tt~ of 1h1. Stkkirre liiver. Bell 1 (Xentl hot: spcings (nitc 9) has liacl tlae mot31 tleve Lo pent . '['l~e five print 7 ttal I1:jt sprirlgs tlrere , which have an averlip,c5 temperiiture of 70°C and r: ~c;~nl)inrdflow rate oE over 100 Lpm, arc used hy ,t fishing resort to heat 14 buildir,~;tlmid arr olympic-size swimming pool. 71rt- BPI 1 [sland Hot Spv ings occur on a protnineut southwest-northeast trend iizf;, J(\ h long lineament that bisects the island.

Two thermal. sprir~gsites rhat Flnrl la~tbean previously reportred in thr. 1i tcl-atrrrc were irrvestigated citii i rrg the September-Oc tuber field excurs LrIrn. The first site, Harr~es Lake warm springs (No. 2), is located abouL 4 km LNI &li of the Stikine Itiv~rnear the Cinadian border and consisrs of a warm pool measuring 25°C drld a wartrl src.1' ~rle~isuriug26°C. The second site, Bradfielti Canal. hot springs (No. a), occur,% on the south bank af the East Fork Hr-adij(.l ti River near the conflue~rcrof the Lwo main tributaria~to the liver. The ~3t.c: rorlsistci of several. sn~iil1 thermstl eprir~~ni~~tling from Fissures In the grarii t,. t~c~irockat temperat.uree ran~inpFroni 33*-S7"~. 'rota1 flow is c+stirnated Lj~20 1 pin . Ex(-ept for EradTield hot sp; i~ags,ali the preseritly kl71~wntherriial iqlr rl,;;s in southern Sot~tl\eastr:rtl 4iauka ocLgr eit.ti~rnear a majoz river or ncam l id67 wat-~u. This correlatiora 1s probably partl, a ref lectiotk of accessib~litya1131 occurrrnCc along travelled routes, The discovery of Bradfield hot spring. ~n a i-~motcarea of tht~CoasL Range tnountailts suggen~sotltilx such si tec exist ?),I, haw rrot yet been Found Payor pltlrne.; from thermal springs are most vi.;ibl<. (luring cold weather.. A I.rt-c-winter atrial reconnaissant:e might diss.:closr liltz locations oE addit ionak c1,ermnl tsp: l71g 8 Ltes in southerla !~c,uttleastern ALd::li.*.

hxccy)t for Baker IsLurr~ihot spkings, all known thermal springs in soiltlrrru Southeastern Alaska ocr:ur ULI or near the wetitern fl,rnk of. th+? r:tr ~~$1 I{angc Rathol ith and plrabirl,l j origin~~tf -om deep sirculcltioti of n~,:~:c>oric- wtltors :~ICIIIP fr-8cl-ures and f:rui ts in qrnrji tic ho~ti-ork,

l?rc* clltmic~~lronlpo:?? t iur~ct of t"t~~sorrltir.r!t Gr)uthr~nvt-c~rrtAlnnli.iil rht i.lnxtl &prinp,s ~ir-~!rouphly nimi lnl snil full ul~tlrr the! caiegciry ot alkali-c.h lor'ti~ i .

alkalr--sulfate waters, 'rhe c,,asl itut2nt.s ot the tliernial waters wt-re: I,I OL~III,Q ciklriv~d1 ?-om deep-s:.:-lterl ln~craciion of hot water wi tli rocl:. Priv~o~ls cfiernical analyses ore svai able foa threc L#L the therm:! -spring sites : c,l l<>i Silakefl, Bell Island, and bui Jcy Bn). Coucencrst ions of rlw~st, of ti-re clre~sjcal constituents appear to have ~11ct(.r,fr tre at least x~~inorvaci,-tt ions. 'The over a, ' chentistry of t-hi. thermal woi-r.1~ from &:I Z Island and Bailey Say appe~tr b.o r\-cs~, rem; ined snhstttntiallj he s~lnie. Two .t~gn;ficant cnangen in ctlen~ieitrv,11o1,

evclr, allpear to Ilavl* occi~rrc-dat Chief Shakes. WnringBrl 141 5 an.-l! ysi:i IS no

tnbly higher in fiilica and potassium than either t-11~IJSCS 19/b e,laXysio cjr the TXGS 3979 analysis. The highthr ccrncrntrat ions of the~rt c~c) c011stL ttler~~:, 1915 suggest ,subsurface watcnrs had been equilibrating at sub.itan&ialLy 111i:;ter ternpcrntures than at present. One po.soible explanatiot~ Eor ~hr~c11an~~ 16 tl~nk the deept~rpart of the conduit system inay have brcorec. seccletf peril ~p::il :I result of seismic ac tivitj or froi~ldeposit a'un of hydrothernidl ~nit~~-alr;.

Fluc~uatinnsin hot dpririg temperatures of 1 "-2"~was noted over several.-day period at Ae1.l Xsland . Winter t:.mperature..i of these d1c~rrnaI w:tf.er can apparrni:ly increase by 5' - !doc: above slllan~er temperatures,

Most of the lev 113~Hi:t Sprjtlqs were l~otlr?r in i>ciol,ca~ iq79 lhali irl t1 i illc~r.June 1977 or .Jcint\ 1914. '~'wo of tt~c*~prit~y, tc*rnpor:at llrlaH inc.rr>ti:~c.rlHII~J -

:!I :till in1 1 y ~~IICV1(#1/1; ~i[)till}! '1 i I( r t$si63tb(l 1)y Y'J''~! #111(1 PIpr ill$: 'b i>y ?')"(:.

1)inc:llarge rale.4 appciir to haw c.iit*nt;c~dfit all Ll~rtlr s L: 1.s l or wlj lctl prevrous records are available, 'I'he ~xcuracyof the car1ier mt~;isu,cmc nts i:, not lcrtown. Measurem~r~Lsand <>stitnates of f low rates artt often :.ut~jtlct lo large errors and it is often dif f icult to judge if any sigrlificarl~ciianges in discharge have ac.~.ually occi r.;ed. The in~nsuredflow rate iiz Scptelrlbcr 1919 and dlr reported flow rate of Jllne 1915 (Waring, 1917) tor spri~l~1 at Chicf Shakes are both notably hl.z;llcr than the rate. rcported For .July 1376 (table 5)' The overall discharge frorn springs at Bailey Bay appear to hav~remained about the same since 1915, although some readjustment. of Flow volume seems to liave occrlrred among tht. sc.veral available conduits. War ing' s visual estimates of discli:~rge from the Dell Island Hot Springs are les.; than ha1 f oir tilt. rnors

rcccnt tninjmum est irnates of I low rate, &ich ind icates that either flow [lily ..;ul>stant i:ill)r i~lvre~sedor Id,~rin!:'ir ,-fitirnn trs wr1-r wrong.

Chrmi~a]~~~~~~~~~~~~~~~~~~~~tr suggest ~ubsurfncceempcra rut i::; jtr tllc. r all):$. (,I 50" to llO0C; for thclmal Ljpting~along, the :itikinc' and f,,lsl H~nc! 4~1~11Zi~t.r:~. If LI~P tnermal-spring waters tlerjvc thelr heat solrly iron1 cleep ~irc~lat ion, they rnrist reach depths of 1 to 3.5 km, arsuming geothermal gradients ot 30" ro SO°C/km. The estimatcld subs~ki-lacetcinperatures for 13ailey Bav a:~d 131.11 Iio~ Springs are in the ranee rr, woerld range froln 3 to 5 km.

Intc>rest has beekt rxpresscd ir~several possible uses of ti1c3 Lliermll spr jngs in southern S~utti~asL~i-rlAlaska, including aquaculture and elect rjc,il penc~rarion. Aside from Bell islaad HoL Spring:;, however, rht. ti~exlnal wati-5s ,)i southern Southeaster11 Alaska remain unused except for oc cas~-c~rirllJ i t-ea- tiorlnl purf)o6~?~.1.'11hc1n Eat-, our invr.st-igations itldlctltcl thnt only tllc R~*ilr;~ tkry nntl Hc.11 ~nlaiiclIlot Sptings nitths offer any pc1tt.ntirnl ic,r fu,irre !nrde-

c,ea lib ctev~lopnent .

This strldy was supported by the Unitecl States Department ot I.;nergy !'~,OE contract ~~-~~07-79F:T2703h)and Isv the State of Alaska. 'rklct at~rltt,r~~?X~YF?SH their appreciation and gratitude to the U.S. Forest

::el IJ ;re and to the Aluska Department of Fish and Game for their g@nerous co- op:'r il ion wif h our field investigations.

Special thanks 3s extended to the many individuals we encountered in PVCI-t oblirg, Wrax?gel1, Kcttchikan, and along the Stikine River who expressed 3 11~~r~_i~fin srllr uttldies, provided valuable information on locations and ac- c iUs4i, rant1 wh\i of ten h?l peci us in our work.

13r perticuLarly wish to acknowledge Lonnie and Betsy Lewis of Bell Ysland

~tt~~LJI , wiioee kind hospitality made our stay at Bell Island both pleasant and \>a1Ill,

We are also grateful Eor "he helpful advice and constructive criticism gjvm cis by Dr. 11.~3, Htlwkin~ of the University of Alaska, Fairbanks and Dr. l.R ilj~l~lecrf DGGS. P?'_nally,we thank R.A. Mann and G.A. Broker for manu- t:cui-pt typing.

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k'::-n

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------1974, Geochemica' in8 icatora of subsurface ccrnperture -part 2 : 1~:itirnatlon OF temperat~rr'~~:lcl Cractiol~of hor water mixed w i f:h cold water: U.S. C:cjol. Suryv~\r.)our. K~rsearch,v. 3, no. 3, p. 263-270.

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Mas~ner,[I.H., Brook, C.A., Stvansorl, J.K. , arid r4cihey, D.M., 14 78, SelecLed data for hydrothermal conv~ctionsytrl ems in the Uni ?tcd States wi tlr estimated temperatures )- ".rOQC: U.S. Ceol. Surrey Open- fkl:? Rept . 73-858,

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dc.krtg/ie , i+J,F'. , md T-r~rsrlcll , A. ti. , 1977, Geothernlal reservoir- I-~rnpc~l.sturt~~~ (1st iti~~ttcv+from tile o~tg'n :sotope conipo~itiernsof dissol+rcld tiulf~tt>~:~il \JLI CI*T I-rt~m Ilcjt t?pringh r.~rd qliril 1 ow ctr i 1 1 liolc!~: ~kothr?$-~lli~:FI , V. 5, p. 51 -hl "

2 , (cu~npiltr) , 1973, Uir+l.r~bur:ionancl rheiaical dnslyf,es of thermal

;;l,r ibI,;% in Alarlca: I1.X. GL5c)l Survey Open-f Lie Map 570. N~Ilrrhr'i!i(l~l, i"lm~rrl, 1978, Pkthodology of determining the uncertainty in tl~c atccrs:~ihle geothermal resource base of identified hydrothermal convection ::ystt?ms: 7I.S. Ik01. Sllrvey Open-file Rept. 78-1003, 50 p.

OgI P, Ihft., 19 /4, Report of a visit to a nurnber of Alaskan hot springs to 8id in t-hu selection trE a ~itefor the poefiible instal-lation of a small h inauy geor:hr,.r.t.nal eJ ert-ric peneratinq plant, .July 28, 1976.

(11 dirll Netrearch, Inc., 1977, Instruction matluals for Orion Lonalyzer speci; ic d all el pi: trodes,

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!(-7nri, 1.1 I*,, Grt!enFrerg, A.K , end T~TUS,M.J. (eds.), 1975, Standard ~nethorls 1-\,i (.lit. examinat ~OIIor tJntsi. and waste water, fourteenth edition : d\lri~ilitigloil~D.C., her ican Public Health Assoc. 1193 p.

Ky ,,!iea~ko, HUN,, 1967, De t mina nation of hydrolysis of sodium sil icate and cal- rlil ant. iorl ot disso~iariun constante of orthosilicic acid at elevated u:c*nper.ht.trres. Gesc'tnemitd tiy International, 4, 99-107, Trans. from Gt.ok'kimiya, No, 2, 161- 169.

:i,.,/ ,t &I, 'l'.M, , ICB74, 7a.r.errnination of the first ionization constant of silicic I~JIIti-tun~ quartz r_iol~ni-,tii ey in borate buffer solutions to 35Q°C: ~;uot.ilLm. ct C:ntsatocli iit~. ;ic ta, v 38, p. 1651-1664,

,:i,i,~j,.rtad, M.W. , Fi 61irasucl, M,.T, , Fr iedman, L.C. , Erdmann, 11.E. , and nunc~.n,

!; S, (ecl~cr, 1, 197?, MeLhsd~for determination of irrorganic substarlces irn water ard fluv iel. bedimerat&: I!.:;. Gcol. Survey Techniques of Wutcr. lilt -,nurces I.nv. , bt-rcsic 5, chap. Al., 526 p.

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.- , ! 4/65, Clawniz.~l analysis of sample from Bell lsland Hot Sprirrgs: 1, ,>i, Get12 , !!~i<~t:yCent fa1 T,aborakory, Denver, Colorado, Water Qualiiry .Ill .lysic Pi 13, iarth ID 216:lG(Cp xecoi-d 24821.

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Llright, F.E. anrl Wright, C.W., 1908, The Ketchikan and Wrangell mining districts, Alaska: U.S, Geol. Survey Rull. 347, 210 p., 12 pls., 2'3 t i :i, s nPPENDTX A: ABBREVIATIONS, UNIT SYMBOLS, AND CONVERSION FACTORS

A 1,I: C: S - Alaska UivPsion of GeologicaL and Geophysical Surveys X (:I\ P - Znduct.Lvcly coupled argon plasma tt ,ti . -- not deterrn.t.ned srd dev - standard deviation 1J:;ft'S - IJni ted States Forest Servjce ilSi;S .- llni trd Statde Geological Survey

2, .Ilrii t symbols

degrees Cel sius reiltimeter joule ki logram kilometer liter llter per mlnute meter rul 1ligraul ~ni.r:ro#ra~n rnfcrogrilm per liter rriillime ter million years parts per million

3 , Zlrrrverslon----- factors - 5/9 "Fahrenheit - 32 - S/9 'P-32 /0.621 mile - 0,394 inches - 0.035 ounce - 0,239 calorie (cal) -- 9.480 x II)"-'+ British thermal unit (Btu) 10j5 ~tu1 quad 2,2 05 pounds -. 0.621 rnilc .- 0,264 galloti - 0,260 gal Sons per minute - 3,781 Feet- - 0,039inch APPENDIX R. PRECISLON OF WATER ANALYSES (from Skougstad and others 1979).

KeLntS. ve dtbviat Lon Constituent Mean (mg/l) ------,. (~ercent) Si02 ill i I :% 1-71 *.. ' r~l

. ., ui iJ .LJ :G '.U L': C, m cU !--I ,.I :.I C.( ro -a; r-i "CI ,4 cu I.-: c:) ;< >! ..-I o 111 tin 7.1 Ld 0 a, F-I v.1 ,Q 1.7 (2 cs p) Ul t3 ;: ;s ,,a ,- cn (v 4 ,-. v-4 , -2 d 12. i"L1 CI El *"I tu rci e m 8 .$ 03 % c, ,$ 2, :?J L:l ,.a ,I [r] .,-I ! 3 ~(-1 "q t\4 a' c,

I..)f.7 !j .'.I LJ 0 ,?d '4-1 ci F.8 !..I

n r-i