Surficial Geology of the Waterford Flat 7.5' Quadrangle, Maine

DEPART MENT OF CONSER VA TION Maine Geo logi cal Sur vey Rob ert G. Marv in ney, State Ge olo gist

OPEN- FILE NO. 00-136

Ti tle: Surficial Geology of the Water ford Flat 7.5-minute Quadran gle, Ox ford and Cum ber land Counties, Maine

Author: Woodrow B. Thompson

Date: 2000

Fi nan cial Sup port: Funding for the prepara tion of this report was provided in part by the U.S. Geo logi cal Sur vey STATE MAP Pro gram, Co op era tive Agree ment No. 99HQAG0119.

As so ci ated Maps: Sur fic ial ge ol ogy of the Wa ter ford Flat quad ran gle, Open- File 00-133 Sur fic ial ma te ri als of the Wa ter ford Flat quad ran gle, Open- File 00-134

Con tents: 8 p. report Maine Geo logi cal Sur vey Open- File 00- 136

Surficial Geology of the Water ford Flat 7.5-minute Quadran gle, Ox ford and Cum ber land Coun ties, Maine

Woodrow B. Thompson Maine Geo logi cal Sur vey State House Stati on 22 Augusta, ME 04333-0022

IN TRO DUC TION

This re port de scribes the sur fic ial ge ol ogy and Qua ter nary Sweden in Oxford County, and Har rison and Bridgton in Cum - history of the Water ford Flat 7.5-m inute quadran gle in south- berland County. The neighbor ing village s of Water ford Flat and west ern Maine. Sur fic ial earth ma te ri als in clude un con soli dated South Water ford are the only popula ti on center s in the quad- sedi ments (sand, gravel, etc.) of gla cial and nongla cia l ori gin. rangle. Most of these de posit s formed during and after the latest episode The Crooked River is by far the larg est stream in the Water - of gla cia tion in Maine, within the last 25,000 years. Surfic ial ford Flat quadran gle. The Bear River is also signifi cant, and sev - sedi ments cover the bedrock over most of the quadran gle and are eral brooks drain the rem ain der of the map area. Lakes and subject to many uses and envi ron m ental consid era ti ons. These ponds in the quadran gle provide attra cti ve scenery and rec rea- in clude sand and gravel ex trac tion, de vel op ment and pro tec tion tion for sum mer camps and tourist s. The topog ra phy is hilly of ground-wate r suppli es, siting of waste disposal facil iti es, and across much of the area. Eleva ti ons range from about 310 ft (94 ag ri cul ture. m) above sea level on Crystal Lake to 1328 ft (405 m) on the The field work for this study was carrie d out in 1999 for the summit of Rice Hill. STATE MAP co op era tive be tween the Maine Geo logi cal Sur vey Bed rock ge ol ogy. Qua ter nary sedi ments cover the bed - (MGS) and the U. S. Geologi cal Survey (USGS). Two maps are rock over much of the Water ford Flat quadran gle, but bedrock as so ci ated with this re port. The geo logic map (Thompson, outcrops are com mon on the hills. The map area is under lai n by 2000) shows the dis tri buti on of sedi mentar y units, and indi cat es granit e of Carbon if er ous age, which is part of an exten sive gran- their age, com posi ti on, and known or inferred origin. It also in- ite body called the Sebago pluton (Osber g and others, 1985). cludes infor m ati on on the geologi c his tory of the quadran gle, Veins of gran ite peg matite occur lo cally. such as features in di cating the flow di rec tion of gla cial ice. This map provides the ba sis for the discus sion of glacia l and postgla - PREVIOUS WORK cial history presented here. The ma te ri als map (Locke and Thompson, 2000) shows Stone (1899) conducte d a recon nais sance of south west ern specif ic data used to help construc t the geologi c map. These data Maine during his USGS study of Maine's gla cial grav els. He include obser va ti ons from gravel pits, shovel and auger holes, was in trigued by the di ver gence of gla cial drainage routes just construc tion sites, and natural expo sures along stream banks. west of the study area, in North Water ford. At this lo cati on a The mate ri als map also shows boring logs. Sand and gravel aq- major es ker sys tem leaves the Crooked River valley and con - uifer studies by the USGS provided addi ti onal data on the type tinues southwest into the Kezar River basin, while a sec ond se- and thickness of surfic ial sedi ments in the quadran gle (Prescott , ries of gla cial sand and gravel depos it s extends eastward along 1979, 1980). the Crooked Valley and into the Waterford Flat quadran gle. Geo graphic set ting. The Water ford Flat quadran gle is lo- Stone’s dis cussion of these deposit s (p. 252-254) include s the cated on the approxi m ate border betwee n the White Mountai n memo ra ble re mark that “I have long since learned that gla cial foothil ls (a.k.a. Oxford Hills) and the coastal lowland of south- riv ers bear care ful watch ing. Their de ceitful ness is well ex hib - west ern Maine. The map area ex tends in lati tude from 44o07'30" ited at North Wa ter ford.” to 44o15'00" N, and in longi tude from 70o37'30" to 70o45'00" W. Thompson (1977a) conducted reconnaissance-level It encom passes parts of the towns of Water ford, Norway , and surficial geologic mapping of part of the study area for the Maine

1 W. B. Thompson

Geological Survey and Greater Portland Council of cover is thin on the tops of many hills, where bedrock is likely to Governments. Prescott (1979, 1980) compiled well and test hole be exposed. A ruled line pat tern on the geologi c map shows ar- data, and carried out preliminary surficial and gravel aquifer eas where bedrock out crops are common and/or the till thickness mapping. Thompson compiled an aquifer map that included the is inferred to be less than 10 ft (3 m). Waterford Flat quadrangle as part of the Significant Sand and Till depos it s probably rest direct ly upon bedrock over most Gravel Aquifer Project sponsored by the MGS, USGS, and of the quadran gle. However , pits on the south sides of Deer Hill Maine Department of Environmental Protection (Williams and and Rice Hill show till overly ing gravel and sand (see photos on others, 1987). Neil and Locke (1998) com piled a more detai led geologi c map). A similar rela ti onship has been noted at several aqui fer map of the quadran gle for the Maine Geologi cal Sur- other local iti es in the uplands of southwest ern Maine. In all vey’s Signifi cant Sand and Gravel Aqui fer Project . The U. S. known exam ples the bur ied gravel occurs on the south Depart ment of Agriculture ’s soil survey of Oxford County (downgla cier) sides of bedrock-cored hills. The stra tigraphic re- (Wilk in son, 1995) pro vided use ful ma terials in for ma tion for lati onships and high de gree of com pacti on of these gravels sug- sev eral sites that the pres ent author did not visit in the field. gest they were de posit ed in front of the advanc ing late Thompson (in press) sum mariz es the late- glacial history of Wisconsi nan ice sheet and then overrid den by the glacie r western Maine. (Thomp son, 1994). The texture and structure of till depos it s vary depend ing on their source and how they were formed. In the Water ford Flat DESCRIP TION OF GEOLOGIC MAP UNITS quad ran gle, till may in clude a small per cent age of clay, but it has a dominantl y sandy or silty-sandy matri x as a conse quence of The sur fic ial de pos its rep re sented on the geo logic map having been eroded from coarse-grai ned bedrock. Till has littl e have been classi fie d on the ba sis of their age and ori gin. Map or no obvi ous stratifi ca ti on in some places. Elsewhere it is units are des ig nated by let ter sym bols, such as “Pt”. The first let- crudely stratifie d, with discon ti nuous lenses and laminae of silt, ter in di cates the age of the unit: sand, and gravel result ing from sorting by melt water during depo si tion. “P”-Pleis to cene (Ice Age); Stones are abundant in this unit, and boul ders scat tered “H”-Holo cene (postgla cia l, i.e. formed during the last across the ground surface often indi cat e the presence of till. Till 10,000 years); stones in the quadran gle chiefly consis t of coarse-grai ned igne - “Q”-Qua ter nary (en com passes both the Pleis to cene ous and meta morphic rocks, espe cia lly granit ic rocks de rived and Holocene epochs) from local bedrock sources. Most till stones are more-or -les s an- gular , and some have smooth, flat, stri ated surface s due to sub- The Qua ter nary age is assigne d to units which overlap the gla cial abra sion. These fac eted sur faces are best de vel oped on Pleistocene-Holoc ene boundary , or whose ages are uncer tai n. dense, fine-grai ned rocks such as basal t (ba salt occurs as dikes The other letter s in the map sym bol indi cat e the origin and/or as- cutti ng other rock types in southwest ern Maine). signed name of the unit, e.g. “t” for gla cial till and “goc” for gla- Varie ties of till formed be neath a gla cial ice sheet in clude cial out wash de posit ed in the Crooked River val ley. Surfic ial lodgem ent and basal melt-out tills. Lodgem ent till was depos - map units in the Water ford Flat quadran gle are descri bed below , ited un der great pres sure beneath the ice sheet. It may be very starting with the older depos it s that formed in contac t with gla- compact and dif fi cult to ex cavate (“hardpan”), with a platy cial ice. struc ture (fissil ity) evident in the upper , weathered zone (see photo on geo logic map). Ba sal melt- out till is diffi cult to iden tify Till (unit Pt) with cer tainty, but typi cally shows a crude stratifi ca tion in her - ited from debris bands in the lower part of the glacie r. Abla ti on Till (Pt) is a gla cially de pos ited sedi ment con sist ing of a till formed during the melt ing of the ice and tends to be loose- more-or -les s random mixture of sand, silt, and gravel-siz e rock textured and stony, with num erous lenses of washed sedi ment. debris. In southern Maine it typical ly include s num erous boul- More than one of these till varieties may oc cur at a sin gle lo cal ity. ders. Till blankets much of the upland por tions of the quadran - For exam ple, a thin veneer of stony abla ti on till com monly over- gle, where it is the prin ci pal sur fic ial mate rial; and it commonly lies lodge ment till. under li es younger depos it s in the val leys. Some of the till in Field evi dence in southern Maine and elsewhere in New Maine probably was de rived from glacia l erosion of older surfic - England (e.g. Kotef f and Pessl, 1985; Thompson and Borns, ial sediments (ei ther gla cial or non- glacial), while the re mainder 1985; Weddle and others, 1989), suggest s that till depos it s of was freshly eroded from nearby bedrock sources during the lat- two glacia tions are present in the region. The “upper till” is est gla cia tion. clearly the prod uct of the most re cent, late Wisconsi nan glacia - Expo sures in the Water ford Flat quadran gle show up to at tion, which covered southern Maine betwee n about 25,000 and least 20 ft (6 m) of till, and well logs indicate the thick ness locally 13,000 years ago. Expo sures of upper till can be seen in many is as much as 88 ft (27 m) (Locke and Thompson, 2000). The till shal low pits, road cuts, and tem porary exca va ti ons. It is not

2 Surficial Geology of the Waterford Flat Quadrangle, Maine weathered (ex cept in the near- surface zone of mod ern soil for - cusing the deposi ti on of gla cial sedim ents in front of an ice mati on) and is usuall y light olive-gray in color. Lodgem ent and tongue as it retre ated northwest ward up the Crooked Valley . abla ti on facie s of the upper till have been recog nize d in the Wa- ter ford Flat quad rangle (see mate ri als map by Locke and Hummocky Moraine (unit Phm) Thomp son, 2000). The “lower till” con sists of compact, silty- sandy lodge - An area of hum mocky morai ne (Phm) was mapped in the ment de posit s. In southwest ern Maine, as in other parts of New Crooked River val ley, adja cent to the end morai nes de scribed England, it is likely to be found in drum lins and other smooth, above. These depos it s are disti nguishe d in the field by their gla cially streamlined hills where a con sid er able thick ness of till knobby topog ra phy (see photo on geologi c map), and large boul- has ac cu mu lated. These thick de pos its of ten oc cur as “ramps” ders are very abundant. The lack of bedrock out crops, togethe r on the gentl e northwest slopes of hills, while bedrock is exposed with the topographi c reli ef, suggest s that the thickness of this on the steeper, gla cially plucked southeas t slopes. The lower till unit may be tens of feet. Sec tions exposed during pipeli ne con- is disti nguishe d by its thick weather ing profil e, which may ex - struc tion in 1998 re vealed dia micton (till) with lenses of gravel. tend to a depth of 10 ft (3 m) or more. Within this weathered In southwest ern Maine, hum mocky morai ne usuall y is zone, the till is oxi dized and has an olive-gray to dark olive-gray concen tra ted in lowlands , but it occurs at higher eleva ti ons than or dark grayish-brown color. Dark-brown iron/manga nese ox - nearby water laid glacia l depos it s consis ting of sand and gravel ide staining coats the surface s of stones and joints (Thompson, (e.g. unit Pgoc in present study area). Holland (1986) observe d 1986). This till is be lieved to have been depos it ed during an ear- that the loca ti on, com posi ti on, and topog ra phy of unit Phm sug- lier glacia tion in Il li noian time, prior to 130,000 years ago (Wed- gest that it formed during the melt ing of stagnant debris-ric h ice dle and others, 1989). in a late stage of degla cia tion. The asso cia tion with end mo - The author has not seen any ex posures of lower till in the raines in the Crooked River valley im plies deposi ti on during re - Water ford Flat quadran gle, perhaps be cause borrow pits are rare treat of a valley ice tongue. in this hard-to- exca vate sedi ment. The consid er able till thickness in some of the stream lined hills in the quadran gle suggest s that the lower till may be pres ent at depth. An ex tremely dense Es ker De pos its (unit Pge) lodge ment till occurs beneath gla cial fan gravel and a late Wis- conin san lodgem ent till in the Norway town pit, locat ed in the A short ridge in the area of sand and gravel northwest of Pa- nearby West Paris quadran gle (Thompson and others, 2000). poose Pond may be an es ker. It was noted on aerial photo graphs, The strati graphic posi ti on and pres ence of rotten stones in this but has not been field-chec ked. If the ridge is an es ker, it would buried unit suggest that it is proba bly equiva lent to the lower till have been depos it ed in a subgla cia l ice tunnel. Alter nati vely, it seen else where. may be some other type of ice-channe l fill ing or part of the Crooked River out wash system (unit Pgoc).

End Moraines (unit Pem) Glacial Lake Se bago Depos it s (unit Pls) End morai nes (Pem) are ridges of sedim ent de posit ed at the mar gins of glacie rs. They may form in many dif ferent ways, but The Bear River and Crystal Lake basins contai n depos it s of gen er ally are sedi ment ac cu mu la tions de rived from the ad ja cent sand, silt, and gravel (Pls). There are few di agnos ti c expo sures gla cial ice (or shaped by gla cial pro cesses at the ice mar gin). from which to deter mine the ori gin of these sedi ments. How- Mo raine ridges lo cated above the zone of late-gla cial marine ever, the fine-grai ned sand observed in many places suggest s subm er gence in southwest ern Maine com monly are strewn with that much of unit Pls formed in a quiet-wate r glacial-lake envi - boulders on the surface . Their inte ri ors are sel dom well exposed, ronm ent. Varved clay-sil t was form erly ex posed in a borrow pit but surface indi ca ti ons and shallow pits suggest that most end on the east side of the Bear River, near the south edge of the morai nes are com prised largely of till with local ly abundant quadran gle (W. B. Thompson, 1976 field notes). Flat-topped de - lenses of sand and gravel. posit s of sand and gravel in the highest porti ons of the unit, at ele - True end moraines (which are use ful mark ers of ice- margin vati ons of about 400 ft, proba bly are at least partly deltai c. positi ons) may be dif ficult to disti nguish from areas of hum - Mapping by C. T. Hil dreth (1997a,b; 2000) and Thompson mocky morai ne (q.v.), which also occur in the Water ford Flat (1977b) in quadran gles to the south has shown that a dis conti nu - quadran gle. Till ridges that are thought to be end morai nes oc cur ous se ries of similar gla cio lacus trine de pos its can be traced from in the Crooked River val ley in the eastern part of the quadran gle. the Crystal Lake-Bea r River area southward down the Long The ridge close to the river is lit tered with many large boulders. Lake val ley to Se bago Lake. All of these depos its are attrib uted These moraines are lo cated in a to pographically low area. This is to a former lake (glacial Lake Se bago) that in cluded and ex - probably the result of melt water and debris-flow proces ses fo - tended north from the Sebago Lake basin. The pres ent eleva -

3 W. B. Thompson tions of Pls depos it s rise to the north due to postgla cia l crustal Ta lus De pos its (unit Qta) up lift and tilt. Large boulders have fallen from the cliff on the west side of Glacial Lake Keoka Depos it s (unit Plkd) Bear Mountain, form ing a prominent talus pile (Qta) along the northeas t shore of Bear Pond. Similar talus accu m ula ti ons may Much of the village of Water ford Flat is locat ed on a flat de - be found at the base of steep bedrock slopes else where in the posit of sand and gravel (Plkd) at the mouth of the Kedar Brook quadran gle. They could have been ini ti ated by glacia l plucking val ley, on the west side of Keoka Lake. This fea ture is a delta of the cliff faces, but the ta lus piles probably have grown during that was built into the lake when it stood at a slightly higher level postgla cia l time as frost acti on causes blocks of bedrock to break than today . The mate ri als map (Locke and Thompson, 2000) loose along fracture surface s and fall to the bottom of the slopes. shows that 33 ft (10 m) of gravell y sand and silt overly ing bedrock were encoun ter ed in a test boring through the delta. The sedim ent com prising the delta probably came from Eo lian De pos its (unit Qe) gla cial streams, rather than the small brooks that pres ently en ter the lake ba sin. Meltwa ter chan nels south west of Rice Hill in di - Small areas of eoli an (windblown) sand were mapped in cate the former course of gla cial drain age, which flowed from three places along the side of the Crooked River val ley. These the ice mar gin down the Kedar Brook val ley and into the lake depos it s (Qe) re sulted from wind erosion of out wash sand in the (see geo logic map). Glacial Lake Keoka was dammed at an ele - val ley. They proba bly formed in late- glacial time, when vege ta- vati on of about 500 ft by the till depos it s at the out let of the lake tion cover was sparse (McKeon, 1989). Eoli an sand is alm ost (head of Mill Brook). Post glacia l erosion of this out let eventu - certai nly more exten sive than shown on the geologi c map. Thin ally low ered Lake Keoka to its pres ent level. patchy de posit s are eas ily overlooked in wooded areas , and may not be obvi ous where they rest upon water-lai d sand. For exam - Ice- contact De pos its (unit Pgi) ple, a small eo lian de posit that had drifted up against the till slope at the east edge of the Crooked River out wash plain was recog - A very small deposit of gravell y sand (Pgi) was mapped on nized only becaus e a borrow pit had been opened in it. the southwest side of the Crooked River val ley in Water ford, at an eleva ti on slightly higher than the adja cent glacia l out wash Shore line De pos its (unit Hls) plain (Pgoc). Unit Pgi is pre sumed to have formed in contac t with melting gla cial ice as this part of the val ley was de gla ci ated. Beach depos it s (Hls) have formed at the south end of McWain Pond and at the north end of Bear Pond. They re sulted Crooked River Out wash (unit Pgoc) from the erosion and transport of glacia l sedim ents by wave and current acti on. Other beach depos it s likely occur in the quadran - The Crooked River valley contai ns exten sive depos it s of gle, es pe cially where eas ily eroded sand and gravel de pos its sand and gravel emplaced by glacial meltwa ter streams (Pgoc). form the shoreli nes of modern lakes. These outwash de posit s under li e a disconti nuous flat surface at elevati ons higher than the modern river flood plain. Sedi ments Wet land De pos its (unit Hw) comprising unit Pgoc are usuall y well-rounded gravel or grav - elly sand at the surface . The thickness of the out wash excee ds 25 Unit Hw consis ts of fine-grai ned and organic-ric h sedi - ft (8 m) in places, but its maxim um thickness is not known. A ments depos it ed in low, flat, poorly drained areas . In the Water - well log indi cat es 105 ft (32 m) of sand overly ing 7 ft (2 m) of till ford Flat quadran gle this unit occurs mostly in valley s and small southeas t of Pa poose Pond (Locke and Thompson, 2000). The upland ba sins. The bounda ries of unit Hw were mapped pri mar- upper part of this sand is probably outwash, but its great thick- ily from aerial photo graphs. These boundarie s are approxi - ness sug gests that the deeper sand is a gla cio lacus trine del taic mately locat ed and should not be used rigor ously for land-use deposit . A glacia l lake may have been dammed by the bedrock zoning. There is littl e infor m ation on the thickness of wetland threshold and end-m oraine where the valley narrows in the east- deposit s in the quadran gle. A report by Cam eron and others ern part of the quad ran gle. If so, it was later filled by del taic sedi - (1984) descri bing peat depos it s in southwest ern Maine notes ments that were in turned capped by the outwash. that they usuall y aver age less than 20 ft (6 m) thick. Expo sures of unit Pgoc were seen in num erous borrow pits (many of them inac ti ve) along the Crooked River valley . Stream Al lu vium (unit Ha) Cross-bed ding at these lo cali ties clearly in di cates gla cial stream flow down the val ley. Trenches exca vate d for pipe line construc - Unit Ha consis ts of allu vial sand, gravel, silt, and or ganic tion in 1998 showed many fine expo sures of the outwash, in mate ria l depos it ed by modern streams. In the Water ford Flat some cases includ ing the contac t betwee n the sand and gravel quad rangle, sig nifi cant al lu vial de posits oc cur mostly along the and un der ly ing till. Crooked River and a few smaller streams. There is no infor m a-

4 Surficial Geology of the Waterford Flat Quadrangle, Maine tion on the thickness of this unit, but it proba bly is less than 10 ft was de gla ciated by this time. How ever, iso lated masses of stag - (3 m) in most places. nant ice may have lingered in val leys. The nearby Saco Valley was certai nly ice-free by 12,000 years ago, judging from dated plant rem ains in Fryebur g (Thompson, 1999). GLACIAL AND POST GLACIAL GEOLOGIC In coastal Maine it is pos si ble to trace the re treat of the gla - HISTORY cier mar gin in detai l becaus e there are hundreds of end-m oraine ridges, subm arine fans, and deltas that were de posit ed at the edge The following reconstruction of the Quaternary history of of the ice during its re ces sion in a marine envi ron m ent. End mo - the Waterford Flat quadrangle and surrounding area is based on raines are rare in the Water ford Flat quad ran gle, making it more the interpretations of surficial earth materials described in this dif fi cult to re con struct the pat tern of de gla cia tion. How ever, the report, together with published information from surrounding ori en ta tions of melt wa ter chan nels show that ice re ces sion pro- areas of New England. It is uncertain how many episodes of ceeded in a gener all y north to northwest ward di recti on. glaciation have affected the study area during the Pleistocene Ice Some of the rock de bris in the ice sheet was de posit ed di- Age. Till deposits in western Maine clearly record the most rectly from the gla cier as variou s types of till, includ ing end recent (late Wisconsinan) glaciation, and probably one earlier moraines and hum mocky morai ne (units Pt, Pem, and Phm). The event. The deeply weathered lower till found elsewhere in re mainder was washed out of the ice by meltwa ter streams issu - central and southern New England has also been recognized in ing from the glacie r mar gin and de posit ed in valley s during de- this part of the state (Thompson and Borns, 1985; Weddle and glacia tion of the Water ford Flat quadran gle. The oldest others, 1989). Although it is not well-dated, the lower till was meltwa ter de pos its in the quad ran gle (unit Pls) are del taic and deposited during the penultimate glaciation, of probable lake-bott om sedi ments depos it ed in glacia l Lake Se bago (Crys- Illinoian age. tal Lake and Bear Pond ar eas). This lake formed when a gla - Data publi shed by Stone and Borns (1986) indi cat e that the ciomarine delta com plex at the south end of Se bago Lake late Wisconsi nan Lauren ti de Ice Sheet expanded out of Canada im pounded a large body of fresh wa ter that extende d from the and spread into Maine approxi m ately 25,000 radio car bon years Sebago basin northward up the Long Lake valley (Hil dreth, ago. As the gla cier flowed across the state for thousands of 1997a,b,c,d) and into the pres ent study area. years, it shaped the surface of the land by eroding, transport ing, As the glacie r mar gin re treated northward from the quad - and de pos it ing tre men dous quan ti ties of sedi ment and rock de- ran gle, a small delta (unit Plkd) was de pos ited in gla cial Lake bris. The com bined ef fects of erosion and deposi ti on have given Keoka, and a cluster of end morai nes and hum mocky morai ne some hills a streamlined shape, with their long axes par al lel to formed in the Crooked River val ley. The youngest glacial the south-southe astward flow of the ice. Prominent stream lining meltwater deposit in the quadran gle is the outwash (unit Pgoc) in is seen on many till-covere d hills in the Water ford Flat quadran - the Crooked River valley . These sedim ents conti nued to wash gle, such as in the area east and south of Keoka Lake. Gla cial down the valley from the ice mar gin when the glacie r had re- plucking on the lee sides of some hills create d steep south-faci ng ceded northwest from the map area. The prolonged influx of bedrock slopes. A good exam ple is on Hawk Mountai n in Water - sand and gravel probably filled in a gla cial lake dammed behind ford (see photo on geologi c map). the constri cti on of the valley in the eastern part of the quadran - Abrasion by rock debris dragged at the base of the gla cier gle. polishe d and striate d the bedrock surface . Striati ons are not easy Mi nor deposit s of eoli an sand (unit Qe) formed on the sides to find in the Water ford Flat quadrangl e becaus e in many places of the Crooked River val ley in late- glacial to post gla cial time. they are ei ther con cealed be neath sur fic ial sedim ents or have Wetlands (Hw) and flood plains (Ha) began to de velop soon af- been de stroyed by weather ing at the ground surface . The geo - ter degla cia tion, and conti nue to accum ulate sedim ents to the logic map shows sites where stria tion trends have been re corded. pres ent day. Good exam ples of striati ons and glacially pol ished ledges are exposed along the jeep trail that climbs the north side of Hawk ECO NOMIC GE OL OGY Moun tain. All known stria tion lo cali ties in di cate gla cial flow to - ward the southeas t or south-southe ast. This flow presum ably oc- Sand and gravel suppli es are plenti ful in several valley s in curred dur ing the maxim um phase of late Wisconsi nan the Water ford Flat quadran gle, espe cia lly along the Crooked gla cia tion, when the gla cially streamlined hills were sculpted River val ley (Pgoc) and in the vicini ty of Bear Pond and Crystal with the same ori en ta tion. Lake (Pls). Num erous borrow pits have already been opened in The minim um age of gla cial retreat from the Water ford Flat these depos it s. Gravel is most abundant in the upper part of the quadrangl e can be es ti mated from radiocar bon dating of or ganic Crooked River out wash plain, while sand or gravell y sand may ma te rial in lake- bottom sedi ments de pos ited soon af ter de gla cia - occur at depth. The out wash is gener all y coarsest (more grav- tion. Thompson and others (1996) obtained an age of 13,200 ra- elly, with larger stones) in the west ern part of the quadran gle, diocar bon years from Cushm an Pond in Lovell , locat ed in the which was closer to the ice mar gin during the fi nal pe riod of adja cent North Water ford quadran gle, so the study area probably depo si tion.

5 W. B. Thompson

Small pits have been opened in glacia l till depos it s. The Stone, B. D., and Borns, H. W., Jr., 1986, Pleisto cene glacial and inter glacial sandy till in this area packs well and is of ten well- suited for fill. stra tigraphy of New England, Long Is land, and adja cent Georges Bank and the Gulf of Maine, in Sibrava , V., Bowen, D. Q., and Richm ond, G. It may also provide favor able sites for septi c tank absorp ti on M. (editors), Qua ternary gla ciations in the North ern Hemi sphere - IGCP fields. Project 24: Per gam on Press, Ox ford, Eng land, p. 39-53. Stone, G. H., 1899, The glacial gravels of Maine and their asso ci ated de posits: U. S. Geo logical Survey, Monograph 34, 499 p. Thomp son, W. B., 1977a, Recon nais sance surfic ial ge ology of the Norway REF ER ENCES quadran gle, Maine: Maine Geologi cal Survey, Open- File Map 77- 34, scale 1:62,500. Cameron, C. C., Mul len, M. K., Lepage, C. A., and An der son, W. A., 1984, Peat Thomp son, W. B., 1977b, Recon nais sance surfic ial ge ology of the Sebago Lake resource s of Maine - Volum e 4: southern and west ern Maine: Maine quad ran gle, Maine: Augusta, Maine Geo logi cal Sur vey, Open- File Map Geo logi cal Sur vey, Bul le tin 31, 123 p. 77-45, scale 1:62,500. Hildret h, C. T., 1997a, Surfic ial geologic map of the Naples quadran gle, Maine: Thomp son, W. B., 1986, Glacial geol ogy of the White Mountain foot hills, south- Maine Geologi cal Survey, Open- File Map 97- 50. west ern Maine, in Newberg, D. W. (editor) , Guidebook for field trips in Hildret h, C. T., 1997b, Sur ficial geologic map of the Sebago Lake quadran gle, south west ern Maine: New Eng land In ter col le giate Geo logi cal Con fer- Maine: Maine Geologi cal Survey, Open- File Map 97- 53. ence, 78th annual meeting, Bates Col lege, Lewiston, Maine, Trip C-1, p. Hildret h, C. T., 1997c, Surfic ial ge ology of the Naples 7.5- minute quad rangle, 275- 288. Cum berland County, Maine: Maine Geologi cal Survey, Open- File Thomp son, W. B., 1994, Glacial fan depos its overrid den by the late Wisconsi nan Report 97-65, 9 p. ice sheet, south west ern Maine: Geo logi cal So ci ety of America, Ab - Hildret h, C. T., 1997d, Sur ficial ge ology of the Sebago Lake 7.5- minute quad - stracts with Program s, v. 26, no. 3, p. 76. rangle, Cum berland County, Maine: Maine Geologi cal Survey, Open- Thomp son, W. B., 1999, Surfic ial ge ology of the Fryeburg 7.5- minute quad ran- File Report 97-68, 7 p. gle, Oxford County, Maine: Maine, Maine Geologi cal Survey, Open- Hildret h, C. T., 2000, Sur ficial geo logic map of the Bridgton quadran gle, Maine: File Report 99-8, 20 p. Maine Geologi cal Survey, Open- File Map 00- 138. Thomp son, W. B., 2000, Surfic ial geology of the Wa ter ford Flat quadran gle, Holland, W. R., 1986, Feature s asso ci ated with the degla cia tion of the upper Maine: Maine Geologi cal Survey, Open- File Map 00- 133. Saco and Ossipee River basins, northern York and south ern Ox ford Thomp son, W. B., in press., De glacia tion of western Maine, in Wed dle, T. K., Coun ties, Maine, in Newberg, D. W. (editor) , Guidebook for field trips in and Re telle, M. J. (edi tors), De gla cia tion his tory and rela tive sea- level south west ern Maine: New Eng land In ter col le giate Geo logi cal Con fer- changes, northern New Eng land and adja cent Canada. ence, 78th annual meeting, Bates Col lege, Lewiston, Maine, Trip B-1, p. Thomp son, W. B., and Borns, H. W., Jr., 1985, Till stratigr aphy and late Wis- 98- 123. consinan degla cia tion of southern Maine: A re view: Geogra phie phy - Ko teff, C., and Pessl, F., Jr., 1985, Till stra tigra phy in New Hampshire : Cor re la - sique et Quater naire, v. 39, no. 2, p. 199-214. tions with ad ja cent New Eng land and Que bec, in Borns, H. W., Jr., La - Thomp son, W. B., Fowler, B. K., Flana gan, S. M., and Do rion, C. C., 1996, Re - Salle, P., and Thompson, W. B. (edi tors), Late Pleisto cene history of cession of the late Wisconsi nan ice sheet from the northwest ern White north east ern New Eng land and ad ja cent Que bec: Geo logi cal So ci ety of Moun tains, New Hampshire, in Van Baalen, M. R. (editor) , Guidebook America, Spe cial Pa per 197, p. 1- 12. to field trips in north ern New Hamp shire and adja cent regions of Maine Locke, D. B., and Thompson, W. B., 2000, Surfic ial mate ri als map of the Water - and Ver mont: New Eng land In ter col le giate Geo logi cal Con fer ence, 88th ford Flat quad ran gle, Maine: Maine Geo logi cal Sur vey, Open- File Map annual meeting, Harvard Univer sity , Cam bridge, Trip B-4, p. 203-234. 00- 134. Thomp son, W. B., Locke, D. B., Neil, C. D., and Raw cliffe, R. J., 2000, In ves ti - McKeon, J. B., 1989, Late- glacial dunes, venti facts, and wind di rec tion in west- gation of sub- till glacial fan grav els in west ern Maine us ing ground- central Maine, in Tucker, R. D., and Marv in ney, R. G. (edi tors), Stud ies penetrating radar (abstract): Geo logi cal So ci ety of Amer ica, Ab stracts in Maine geol ogy - Volum e 6: Qua ter nary geol ogy: Maine Geologi cal with program s, v. 32, no. 1, p. A78- A79. Survey, p. 89-101. Wed dle, T. K., Stone, B. D., Thomp son, W. B., Re telle, M. J., Cald well, D. W., Neil, C. D., and Locke, D. B., 1998, Signifi cant sand and gravel aqui fers map of and Clinch, J. M., 1989, Il linoian and late Wisconsi nan tills in eastern the Wa terford Flat quad ran gle, Maine: Maine Geo logi cal Sur vey, New Eng land: A tran sect from north east ern Mas sa chu setts to west- Open- File Map 98- 214. central Maine, in Berry, A. W., Jr. (edi tor), Guide book for field trips in Os berg, P. H., Hussey, A. M., II, and Boone, G. M. (edi tors), 1985, Bed rock geo - south ern and west-cen tral Maine: New Eng land In tercol le giate Geo logi - logic map of Maine: Maine Geologi cal Survey, 1:500,000- scale map. cal Con ference, 81st annual meeting, Univer sity of Maine at Farm ington, Prescott, G. C., Jr., 1979, Royal, upper Presum pscot, and upper Saco River ba - Farm ington, Maine, Trip A-2, p. 25-85. sins (Maine) area: U. S. Geo logi cal Sur vey, Maine Hydrologic-Data Re - Wilkin son, D. E. (editor) , 1995, Soil sur vey of Oxford County, Maine: U. S. De- port No. 10, Ground-Wat er Serie s, 53 p. part ment of Agri cul ture - Soil Conser va tion Service, 296 p. and maps. Prescott, G. C., Jr., 1980, Ground- water availabil ity and surfic ial ge ology of the Wil liams, J. S., Tep per, D. H., Tol man, A. L., and Thomp son, W. B., 1987, Hy- Royal, upper Presum pscot, and upper Saco River ba sins, Maine: U. S. droge ol ogy and water quality of signifi cant sand and gravel aq uifers in Geo logi cal Sur vey, Water- Resources In ves ti ga tions 79- 1287, 3 maps. parts of Androscog gin, Cum berland, Oxford, and York Counties , Maine: Maine Geologi cal Survey, Open- File Report 87- 1a, 121 p. and maps.

6 Surficial Geology of the Waterford Flat Quadrangle, Maine

AP PEN DIX A

GLOS SARY OF TERMS USED ON MAINE GEOLOGI CAL SURVEY SURFIC IAL GEOLOGI C MAPS

compi led by John Gosse and Woodrow Thompson

Note: Terms shown in ital ics are de fined elsewher e in the glos sary.

Ab la tion till: till formed by re lease of sedim en tary de bris Eo lian: formed by wind acti on, such as a sand dune. from melting gla cial ice, accom pa nied by vari able amounts of slumping and melt water acti on. May be loose and stony, and Es ker: a ridge of sand and gravel depos it ed at least partly contai ns lenses of washed sand and gravel. by meltwa ter flow ing in a tun nel within or be neath gla cial ice. Many ridges mapped as eskers include vari able amounts of sedi- Ba sal melt- out till: till result ing from melt ing of debris- ment de posit ed in narrow open channels or at the mouths of ice rich ice in the bottom part of a glacie r. Gener all y shows crude tun nels. strati fica ti on due to include d sand and gravel lenses. Flu vial: Formed by running wa ter, for exam ple by melt - Clast: pebble- , cobble- , or boulder -siz e fragm ent of rock wa ter streams dischar g ing from a glacier . or other mate rial in a finer- grained ma trix. Often re fers to stones in gla cial till or gravel. Gla cio la cus trine: re fers to sedi ments or proces ses involv - ing a lake which re ceived meltwa ter from gla cial ice. Clast- supported: re fers to sedi ment that con sists mostly or en tirely of clasts, gener all y with more than 40% clasts. Usu- Gla cioma rine: re fers to sedi ments and pro cesses re lated ally the clasts are in con tact with each other. For ex am ple, a to en vi ron ments where marine wa ter and glacial ice were in con - well- sorted cob ble gravel. tact.

Delta: a body of sand and gravel depos it ed where a stream Head of outwash : same as out wash head. en ters a lake or ocean and drops its sedim ent load. Gla cially deposit ed del tas in Maine usuall y con sist of two parts: (1) coarse, Holo cene: term for the time peri od from 10,000 years ago horizon tal , often gravell y topset beds de posit ed in stream chan- to the pres ent. It is often used synony m ously with “post glacia l” nels on the flat delta top, and (2) under ly ing, finer-grai ned, in - be cause most of New Eng land has been free of gla cial ice since clined foreset beds de posit ed on the advanc ing delta front. that time.

De posit: gen eral term for any ac cu mu lation of sedi ment, Ice age: see Pleis to cene. rocks, or other earth mate ri als. Ice- contact: re fers to any sedi mentar y deposit or other Dia mic ton: any poorly-sorte d sedi ment contai ning a wide fea ture that formed ad ja cent to gla cial ice. Many such de pos its range of par ticle sizes, e.g. glacial till. show irregu lar topog ra phy due to melt ing of the ice against which they were laid down, and re sult ing col lapse. Drum lin: an elongate oval- shaped hill, often com posed of gla cial sedim ents, that has been shaped by the flow of gla cial ice, Ket tle: a de pression on the ground surface , ranging in out- such that its long axis is par al lel to the di rec tion of ice flow. line from circu lar to very ir regu lar, left by the melting of a mass of gla cial ice that had been surrounded by glacia l sedim ents. End moraine : a ridge of sedi ment de posit ed at the mar gin Many kettl es now contai n ponds or wet lands. of a glacie r. Usuall y con sists of till and/or sand and gravel in vari ous pro por tions. Ket tle hole: same as ket tle.

En gla cial: occur ring or formed within glacia l ice. La cus trine: per tain ing to a lake.

7 W. B. Thompson

Late- glacial: re fers to the time when the most recent gla - Out wash head: the end of an out wash deposit that was cial ice sheet was re ced ing from Maine, ap proxi mately 15,000- clos est to the gla cier mar gin from which it originated . Ice- 10,000 years ago. contact outwash heads typi cally show steep slopes, ket tles and hum mocks, and/or boul ders dumped off the ice. These fea tures Late Wis consi nan: the most re cent part of Pleis to cene help de fine former posi ti ons of a re treating glacie r mar gin, espe - time, dur ing which the lat est con tinen tal ice sheet cov ered all or cially where end moraine s are ab sent. porti ons of New England (approx. 25,000-10,000 years ago). Pleis to cene: term for the time pe ri od be tween 2-3 million Lodge ment till: very dense va riety of till, depos it ed be- years ago and 10,000 years ago, during which there were several neath flowing glacia l ice. May be known local ly as “hardpan.” gla ciations. Also called the “Ice Age.”

Ma trix: the fine- grained mate rial, gen er ally silt and sand, Pro gla cial: occur ring or formed in front of a glacie r. which com prises the bulk of many sedim ents and may contai n clasts. Qua ter nary: term for the era be tween 2-3 mil lion years ago and the pres ent. Include s both the Pleis to cene and Holo- Matrix- supported: re fers to any sedi ment that con sists cene. mostly or enti rely of a fine-grai ned com ponent such as silt or sand. Gener all y con tains less than 20-30% clasts, which are not Stria tion: a narrow scratch on bedrock or a stone, pro- in contac t with one another . For exam ple, a fine sand with scat- duced by the abrasive ac tion of debris- laden gla cial ice. Plu ral tered pebbles . form sometim es given as “striae.”

Mo raine: Gen eral term for gla cially depos ited sedi ment, Subaque ous fan: a somewhat fan-shape d deposit of sand but often used as short form of “end moraine .” and gravel that was formed by meltwa ter streams enter ing a lake or ocean at the mar gin of a gla cier. Similar to a delta, but was not Mor phose quence: a group of water-lai d glacia l depos it s built up to the water surface . (often consis ting of sand and gravel) that were de posit ed more- or- less at the same time by meltwa ter streams issu ing from a par - Sub gla cial: occur ring or formed beneat h a gla cier. ticular posi ti on of a glacie r mar gin. The depo si ti onal patter n of each morphose quence was usuall y control led by a local base Till: a het ero ge ne ous, usu ally non- stratified sedi ment de- level, such as a lake level, to which the sedim ents were trans - pos ited di rectly from glacial ice. Par ticle size may range from ported. clay through silt, sand, and gravel to large boulders.

Out wash: sedi ment de rived from melt ing gla cial ice and Topset/fore set con tact: the more-or -les s horizon tal de pos ited by meltwa ter streams in front of a gla cier. boundary betwee n topset and foreset beds in a delta. This boundary closely approxi m ates the water level of the lake or ocean into which the delta was built.