Surficial geology of the Ellis Pond quadrangle, Maine
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S ervice Layer Credits: U S G S N ational Map 3DElevation P rog ram (3DEP)
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Surficial Geology
SURFICIAL GEOLOGY OF MAINE
S u rficial g eolog ic mapping of the Ellis P ond qu adrang le was condu cted by LindsayJ. S pig el during the 2019 and 2020 field seasons. G eolog y of remote orinaccessible areas was interpreted from aerial imag ery and/or lidar topog raphicdata.
SOURCES OF MAP INFORMATION
Ellis Pond Quadrangle, Maine
Open-File No. 21-82021
Digital cartography byLindsay J. Spigel State Geologist
Robert G. Marvinney Cartographic design byChristian H. Halsted
Surficial geologic mapping byLindsay J. Spigel
Address: 93 State House Station, Augusta, Maine 04333Telephone: 207-287-2801 E-mail: mgs@maine.govHome page: www.maine.gov/dacf/mgs/
Maine Geological Survey
1 0 10.5 Mile
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1000 0 1000 2000 3000 4000 5000 6000 7000FeetMaine
EastAndov er
Hou g hton
EllisP ond
P uzzleMountain
MetallakMtn.
Rumford
Roxbu ryAndov er
JacksonMountain
CO N T O U R IN T ERV AL 20 FEET
1:24,000S CALE Base map featu res from Maine O ffice of G IS - 1:24,000 U S G S contourlines, E911 roads, 1:24,000 N ational Hydrog raphy Dataset, U S G SG N IS placenames and 1:24,000 political bou ndaries. Map projectionU niversal T ransverse Mercator, N orth American Datum, 1927.T he use of indu stry, firm, or local g overnment names on this map is forlocation purposes only and does not impute responsibility for anypresent or potential effects on the natural resources.
Approximate MeanDeclination, 202015o 6' W (not to scale)
True North
Mag netic N orth
Funding for the preparation of this map was provided in part by the U.S. GeologicalSurvey STATEMAP Program, Cooperative Agreement No. G20AC00198.
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T his map shows approximate overbu rden (su rficial sediment) thickness modeled in ArcG IS frombedrock water well, seismic line, and other su bsu rface information. Data points shown as circles,modeled thickness as colored polyg ons. G ray areas have insu fficient data. Model used: IDW withpoints within qu adrang le and exterior 2,500 m bu ffer; 4-sector 2,500 m search radiu s with 140oazimuth. P ower optimized to minimize error (2.1144). RMS E = 20; model can be +/- this valu e.Model tends to overpredict shallow (< 25 ft) and underpredict thick overbu rden (> 25 ft). Model areaswith g reater point density are likely to be more accu rate.
Overburden Observations andModeled Thickness
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L)Schematic Cross Sections
S chematic cross sections with 10x vertical exag g eration for g eneral visu alization of the su bsu rface.Horizontal scale is 1:15,000. Depth to bedrock and the thickness of individu al su rficial g eolog y units areestimated and should not be used for other pu rposes without fu rther investig ation.
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Lidar sou rce: Maine O ffice of G IS , 2016 and 2018 1-meter data. Elevation color ramp depicts hig her elevations in red, g rading to lower elevations ing reen. Hig hest elevation ~3,460 ft (1,055 m); lowest elevation ~640 ft (195 m); averag e elevation ~1,265 ft (386 m).
___Continental glaciers like the ice sheet now covering Antarcticaprobably extended across Maine several times du ring the PleistoceneEpoch, between about 2.5 million and 11,700 years ag o. T he slow-moving ice superficially chang ed the landscape as it scraped overmountains and valleys (Figure 1), eroding and transporting bouldersand other rock debris for miles (Figure 2). T he sediments that covermu ch of Maine are larg ely the produ ct of g laciation. G lacial icedeposited some of these materials, while others washed into the sea oraccu mulated in meltwater streams and lakes as the ice receded. Earlierstream patterns were disrupted, creating hu ndreds of ponds and lakesacross the state. T he map at left shows the pattern of g lacial sedimentsin this qu adrangle.___T he most recent "Ice Ag e" in Maine beg an about 30,000 years ag o,when an ice sheet spread southward over N ew Eng land (S tone andBorns, 1986). During its peak, the ice was several thousand feet thickand covered the hig hest mountains in the state. T he weig ht of this hu g eg lacier actu ally cau sed the land su rface to sink hundreds of feet. Rockdebris frozen into the base of the g lacier abraded the bedrock su rfaceover which the ice flowed. T he g rooves and fine scratches (striations)resulting from this scraping process are often seen on freshly exposedbedrock, and they are important indicators of the direction of icemovement (Figure 3). Erosion and sediment deposition by the icesheet combined to g ive a streamlined shape to many hills, with theirlong dimension parallel to the direction of ice flow. S ome of these hills(drumlins) are composed of dense g lacial sediment (till) plasteredunder g reat pressu re beneath the ice (Figure 4).___A warming climate forced the ice sheet to start receding as early as21,000 years ag o, soon after it reached its southernmost position onLong Island (Ridg e, 2004). T he edg e of the g lacier withdrew from thecontinental shelf east of Long Island and reached the present positionof the Maine coast by about 16,000 years ag o (Borns and others, 2004).Even thou g h the weig ht of the ice was removed from the land su rface,the Earth's crust did not immediately spring back to its normal level. Asa result, the sea flooded mu ch of southern Maine as the g lacierretreated to the northwest. O cean waters extended far up the Kennebecand P enobscot valleys, reaching present elevations of up to 420 feet inthe central part of the state.___G reat qu antities of sediment washed out of the melting ice and intothe sea, which was in contact with the receding g lacier marg in. S andand g ravel accumulated as deltas and su bmarine fans where streamsdischarg ed along the ice front, while the finer silt and clay dispersedacross the ocean floor. T he shells of clams, mussels, and otherinvertebrates are fou nd in the g lacial-marine clay that blankets lowlandareas of southern Maine. Ag es of these fossils tell us that ocean waterscovered parts of Maine until about 13,000 years ag o. T he landrebou nded as the weig ht of the ice sheet was removed, forcing the seato retreat.___Meltwater streams deposited sand and g ravel in tunnels within theice. T hese deposits remained as ridg es (eskers) when the surrou ndingice disappeared. Maine's esker systems can be traced for up to 100miles, and are among the long est in the cou ntry.___O ther sand and g ravel deposits formed as mounds (kames) andterraces adjacent to melting ice, or as outwash in valleys in front of theglacier (Figure 5). Many of these water-laid deposits are well layered,in contrast to the chaotic mixtu re of boulders and sediment of all sizes(till) that was released from dirty ice without su bsequ ent reworking .
___Ridg es consisting of till or washed sediments (moraines) wereconstru cted along the ice marg in in places where the g lacier was stillactively flowing and conveying rock debris to its terminus. Moraineridg es are abundant in the zone of former marine su bmerg ence, wherethey are useful indicators of the pattern of ice retreat.___In recent years, a new type of topog raphic data called lidar (whichstands for lig ht detection and rang ing ) has helped g eolog ists to betteridentify and map g eolog y – especially landforms associated withsurficial g eolog y (T hompson, 2011). Lidar topog raphic data iscollected from airplanes that essentially scan the earth’s su rface withlasers. T hese data can be processed in a way that removes veg etationand bu ilding s, creating a final produ ct of hig h-resolution (1-meterscale) bare-earth topog raphy. In a heavily forested state like Maine,smaller featu res that were once hidden under a dense tree canopy havebeen revealed in stunning detail (Figure 6 and 7).___T he last remnants of g lacial ice were probably g one from Maine by12,000 years ag o. Larg e sand du nes accu mulated in late-g lacial time aswinds picked up outwash sand and blew it onto the east sides of rivervalleys, su ch as the Androscog g in and S aco V alleys. T he modernstream network became established soon after deg laciation, andorg anic deposits beg an to form in peat bog s, marshes, and swamps.T u ndra veg etation bordering the ice sheet was replaced by chang ingforest commu nities as the climate warmed (Davis and Jacobson, 1985).G eolog ic processes are by no means dormant today, however, sincerivers and wave action modify the land (Figure 8), and worldwide sealevel is g radu ally rising ag ainst Maine's coast.References
Borns, H.W ., Jr., Doner, L.A., Dorion, C.C., Jacobson, G .L., Jr.,Kaplan, M.R., Kreutz, K.J., Lowell, T.V ., T hompson, W .B., andW eddle, T.K., 2004, T he deg laciation of Maine, U .S .A.,in Ehlers, J.,and G ibbard, P.L., eds., Qu aternary G laciations – Extent andChronology, P art II: N orth America: Amsterdam, Elsevier, p. 89-109.
Davis, R.B., and Jacobson, G .L., Jr., 1985, Late-glacial and earlyHolocene landscapes in northern N ew England and adjacent areas ofCanada: Quaternary Research, v. 23, p. 341-368.Ridg e, J.C., 2004, T he Quaternary glaciation of western N ew Eng landwith correlations to su rrou nding areas,in Ehlers, J., and G ibbard, P.L.,eds., Qu aternary G laciations – Extent and Chronology, P art II: N orthAmerica: Amsterdam, Elsevier, p. 169-199.
S tone, B.D., and Borns, H.W ., Jr., 1986, Pleistocene g lacial andinterg lacial stratig raphy of N ew England, Long Island, and adjacentG eorg es Bank and G ulf of Maine,in S ibrava, V ., Bowen, D.Q., andRichmond, G .M., eds., Qu aternary glaciations in the northernhemisphere: Quaternary S cience Reviews, v. 5, p. 39-52.T hompson, W .B., 2011, Lidar imag ery reveals Maine's land su rface inunprecedented detail: Maine G eolog ical S u rvey, G eolog ic Facts andLocalities, Circular G FL-175, 13 p.
Figure 1: V iew of the Ellis P ond area looking north from RumfordW hitecap Mountain (East Andover qu adrang le). G lacial erosionscou red the basin in which Ellis P ond now sits, also creating an ideallocation for one of the first satellite commu nication stations: T heAndover Earth S tation became operational in 1962, but has beenreplaced by modern satellite dishes (white spot, mid-left).
Figure 2: T his boulder was moved a short distance to its cu rrentlocation by log g ing road constru ction, but it was first transported herethousands of years ag o by glacial ice that likely moved it several miles.As the boulder was drag g ed along in the base of the g lacier, frictionwith other rock debris planed it flat and left striations (g rooves) shownin this photo (same trend as red dashed line).
Figure 4: An exposu re of platy lodg ement till (also known as“hardpan”) along a log g ing road. G lacial ice plastered these sedimentsalong a southern ridg e of Dunham Hill.
Figure 3: G lacial striations in a bedrock exposu re on the Record Hillridg eline. Former g lacial ice flow was left to rig ht (compass for scale).
Figure 6: V iew to the northwest from the modern Ellis P ond shoreline.T his swampy area was once part of Ellis P ond du ring a slig htly hig herlake stag e earlier in the Holocene. Modern wave action reworked theold lake sediments to form a new lower sandy shoreline that extends tothe rig ht and left of this photo.
Figure 5: An exposure of g lacial outwash in the Black Brook V alleyshows mostly cobbles and small boulders that were sorted and rou ndedby flu vial action.
Figure 8: Flu vial processes dominate the modern Ellis P ondqu adrang le landscape. S everal waterfalls in the qu adrang le su ch asCoos Canyon (pictu red here), Ellis Falls, S ilver Ripple Cascade, andDevil’s Den may have been established by powerful glacial meltwaterflow, but they continu e to be shaped by modern streams and rivers.
Figure 7: Moss-covered cobbles and boulders mark a dry channel thatwas once the path of a glacial meltwater stream. Evidence of formerglacial meltwater channels is plentiful in the Ellis P ond qu adrang le,with many paths revealed by lidar topog raphic data.
Note: T he first letter of each map unit indicates the g eneral ag e of the unit:H= Holocene (post-glacial deposit; formed during the last 11,700 years).Q= Qu aternary (deposit of uncertain ag e; usu ally late-g lacial and/or post-glacial).P = Pleistocene (deposit formed du ring g lacial to late-g lacial time, prior to 11,700 yr B.P. [years beforepresent]).
Photo location- Locations of photos shown in sidebar.!(1
Boulder field/talus- Area of scattered boulders deposited by glacial ice or throu g h weatheringand mass wasting of steep bedrock exposu res. Areas may be more extensive than shown.
Meltwater channel - Channel eroded by a glacial meltwater stream. Arrow shows inferreddirection of water flow. Most channels were delineated from lidar topog raphic data.
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Axis of esker - S ymbol alig nment shows esker trend - chevrons point in direction of formerglacial meltwater flow.
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Ice-margin position - Approximate position of a g lacier marg in portion during ice retreatbased on the location of meltwater channels and/or g lacial deposits. Ice retreat to the northwestis assumed, so marg in positions become young er in this direction.
N o Data
Contact- Boundary between map units. Most contacts are approximately located and thereforeindicated by dashed lines.
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76-100 ft
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Wetland deposits - P eat, mu ck, silt, and clay in poorly drained areas. Map unit may overlieglacioflu vial or g laciolacu strine deposits and may also inclu de some allu vial sediments alongstream valleys.
Hw
Alluvial fan deposits - S and, g ravel, and silt deposited where hig her energ y hillside streamsmeet more su bdu ed topog raphy. Likely formed by the reworking and transport of till depositsby water flowing over a barren landscape in early post-glacial times.
Qf
Glacial lake delta deposits - S and, g ravel, and silt deposited by glacial meltwater streamswhere the ice marg in was in contact with a prog lacial lake. Delta surfaces denote approximateglacial lake water su rface elevations.
Pld
Glacial meltwater deposits - S and and g ravel of uncertain orig in; probably deposited byglacial meltwater streams.Pg
Esker deposits- S and and g ravel deposited by meltwater streams in subg lacial tunnels.Pge
Till - Loose to very compact, poorly sorted, massive to weakly stratified mixtu re of sand, silt,and g ravel-size rock debris deposited by glacial ice. May inclu de lenses of water-laid sand andg ravel. S cattered boulders on su rface are common.
Pt
Artificial fill - V ariable mixtu res of earth, rock, and/or human-made materials used as fill forroads or g raded areas for larg e developments.af
Fluted till - N arrow ridg e of till shaped by glacial ice flow. S ymbol indicates approximateleng th and direction of the ridg e crest, which is parallel to former ice flow direction. Mostridg es were delineated from lidar topog raphic data.
È
Glacially streamlined hill - S ymbol shows long axis of hill (drumlin) shaped by glacial iceflow, which is parallel to former ice flow direction.
Meltwater channel scarp - S teep slope created by meltwater stream erosion and incision ofg lacial deposits.
Landslide toe extent- S hows the approximate downslope extent of a landslide, also known asthe toe. In many cases, su bsequ ent stream erosion has removed toe material so cu rrent extent islikely less than orig inal extent. Delineated from lidar topog raphic data.
Moraine - Low relief (3-10 ft/1-3 m) ridg e comprised of poorly sorted sediments, orientedrou g hly perpendicular to former glacial ice flow and formed at or near the ice marg in du ringretreat. May have formed by ice marg in bulldozing of sediments du ring a short-lived advanceor from sediment dumping /melting out from the ice marg in. Delineated from lidar topog raphicdata.
Holocene lake deposits - S and, g ravel, and silt deposited in nearshore and/or lake bottomenvironments during slig htly hig her stag es of Ellis P ond sometime earlier in the Holocene(maximum of approximately 816-820 ft (249-250 m); modern stag e is approximately 812 ft(248 m)). Modern wave action has reworked these sediments to form noticeable beach bermson the north side of the lake.
Hl
Glacial lake deposits - S and, silt, and clay deposited in prog lacial lakes that were dammed bythe retreating ice marg in or remnant ice or debris. May be overlain by wetland deposits orallu viu m.
Pl
Bedrock outcrops/thin-drift areas - Ruled pattern indicates areas where bedrock outcrops arecommon and/or su rficial sediments are g enerally less than 10 ft (3 m) thick. Mapped from airphotos and g rou nd observations. Actu al thin-drift areas are probably more extensive thanshown.
Glacial striation locality - Arrow shows glacial ice flow direction(s) inferred from striationson bedrock. Dot marks point of observation. N u mber is azimuth (in deg rees) of flowdirection.
125
Landslide scarp - S teep slope that marks the upper bou ndary of a landslide, formed by thedownslope movement of earth materials. Barbs point downslope. Delineated from lidartopog raphic data.
USES OF SURFICIAL GEOLOGY MAPS___A su rficial g eolog y map shows all the loose materials su ch as till (commonly called hardpan), sandand g ravel, or clay, which overlie solid bedrock (ledg e). Areas of extensive and isolated bedrockoutcrops are shown on the map, but bedrock types are not disting u ished - these may be found on bedrockg eolog y maps of the area, if available. Most of the su rficial materials are deposits formed by glacial anddeg lacial processes during the last stag e of continental glaciation, which beg an about 30,000 years ag o.T he remainder of the surficial deposits, su ch as river floodplains, are the produ cts of post-glacialg eolog ic processes, or are attribu ted to human activity, su ch as fill or other land-modifying featu res.___S u rficial g eolog y maps show the areal distribution of different types of g lacial featu res, deposits, andlandforms as described in the map explanation. Featu res su ch as striations and moraines can be used toreconstru ct the movement and position of the g lacier and its marg in, especially as the ice sheet melted.O ther ancient featu res inclu de shorelines and deposits of g lacial lakes or the g lacial sea, now long g onefrom the state. T he g lacial g eolog ic history of the qu adrang le contributes to the larg er understanding ofpast earth climate, and how ou r reg ion of the world underwent recent g eolog ically sig nificant climaticand environmental chang es. W e may then be able to use this knowledg e in anticipation of fu tu re similarchang es for long -term planning efforts, su ch as coastal development or waste disposal.___For anyone wanting to know what lies beneath the land su rface, su rficial g eolog y maps are often bestused in conju nction with related maps such as su rficial materials maps or sig nificant sand and g ravelaqu ifer maps. For example, these maps may aid in the search for water supplies or economicallyimportant deposits, su ch as sand and g ravel for ag g reg ate or clay for bricks. Environmental issu es su chas the location of a su itable landfill site or the possible spread of g rou ndwater contaminants are directlyrelated to su rficial g eolog y. Constru ction projects su ch as locating new roads, excavating fou ndations, orsiting new homes may be better planned with g ood knowledg e of the area's su rficial g eolog y.
Large boulder - Location of larg e g lacially transported boulder with at least one axis g reaterthan 10 ft (3 m).X
0 - 25 ft
26 - 50 ft
Ice-contact deposits - Miscellaneous sand and g ravel deposited in contact with glacial ice orremnant g lacial ice. May include small esker seg ments.Pgi
Stream terraces - S and and g ravel deposits in the Ellis River, S wift River, Black Brook, andG arland Brook V alleys that were created by flu vial reworking of glacial deposits. S ome areasmay still be su bject to flooding , but most have been abandoned by modern stream processes.
Qst
Glacial outwash - S and and g ravel deposited by glacial meltwater flowing down the BlackBrook, Ellis River, and W est Branch Ellis River V alleys. May be underlain by silt and claydeposited in various short-lived prog lacial lakes that may have occu pied the valleys du ring iceretreat. May be overlain by wetland and modern allu viu m deposits.
Pgo
Bedrock - S ig nificant areas of exposed bedrock, su ch as in the S wift River and Black BrookV alleys.rk
Glacial lake elevation - Approximate elevation of a prog lacial lake water su rface inferredfrom related deposits or spillway locations. T ill below this elevation may be washed and/orinclu de isolated sand and fine-g rained deposits.Plby2: Lower stag e of G lacial Lake Byron atapproximately 1,380 ft (421 m) with spillway at Ding le Hill Road notch.Plel1: Hig hest stag eof G lacial Lake Ellis with spillway at approximately 1,000-1,020 ft (305-311 m).Plel2:Lowest stag e of G lacial Lake Ellis at about 860 ft (262 m), inferred from extent of relateddeposits.NOTE: A glacial lake delta deposit (unit P ld) in the P helps Brook V alley indicatesthat a lake was present in this area with a water su rface elevation of about 1,600 ft (488 m), butthe lake extent could not be determined from local deposits.
Foster, L.E., Lewis, E.B., N eil, C.D. (compilers), P rescott, G .C. (mapper), 2001, S ig nificant sand andg ravel aqu ifers in the Ellis P ond qu adrang le, Maine: Maine G eolog ical S u rvey, O pen-File Map 01-64,scale 1:24,000.
S pig el, L.J., 2021, S u rficial materials of the Ellis P ond 7.5' qu adrang le, Maine: Maine G eolog icalS u rvey, O pen-File Map 21-7, scale 1:24,000.
T hompson, W .B., 2015, S u rficial g eolog y handbook for southern Maine: Maine G eolog ical S u rvey,Bulletin 44, 97 p.T hompson, W .B., and Borns, H.W ., Jr., 1985, S urficial g eolog ic map of Maine: Maine G eolog icalS u rvey, scale 1:500,000.
All of the sou rces listed above and more can be viewed at or downloaded from the Maine G eolog icalS u rvey website: https://www.maine.g ov/dacf/mg s/.
SOURCES OF RELATED INFORMATION
Stream alluvium - S and, g ravel, and silt deposited on floodplains. May inclu de org anicwetland deposits, underlie some of the mapped wetland areas along streams, or overlieglacioflu vial and/or lacu strine deposits.
Ha
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