Bedrock Geology of the Springfield 15′ Quadrangle, Maine

DEPARTMENT OF AGRICULTURE, CONSERVATION AND FORESTRY Maine Geological Survey Robert G. Marvinney, State Geologist

OPEN-FILE NO. 20-22

Title: Bedrock geology of the Springfield 15′ quadrangle, Maine

Allan Ludman and John T. Hopeck Date: October 2020

Contents: 20 p. report and 4 color maps

Recommended Citation: Ludman, Allan, and Hopeck, John T., 2020, Bedrock Geology of the Springfield 15′ quadrangle, Maine: Maine Geological Survey, Open-File Report 20-22, 20 p. report and 4 color maps, scale 1:24,000.

Bedrock geology of the Springfield 15′ quadrangle, Maine

TABLE OF CONTENTS Introduction ...... 1 Topography ...... 1 Access and Bedrock Exposure ...... 1 Geologic and Tectonic Settings ...... 2 Previous Work ...... 3 Stratigraphy ...... 3 Miramichi Terrane ...... 3 Baskahegan Lake Formation (Obl) ...... 4 Thickness ...... 5 Age ...... 5 Bowers Mountain Formation (Obm) ...... 5 Thickness ...... 5 Age ...... 5 Stetson Mountain Formation (Osm) ...... 6 Thickness ...... 7 Comparison with the Miramichi Terrane Greenfield Segment ...... 7 Age ...... 7 Central Maine/Aroostook-Matapedia Belt ...... 8 Facies Relationships...... 8 Proximal Facies ...... 8 Daggett Ridge Formation (SOd) ...... 8 Thickness ...... 9 Age ...... 9 Mill Priveledge Brook Formation (SOmp) ...... 9 Thickness ...... 10 Age ...... 10 Intermediate Facies ...... 10 Sam Rowe Ridge Formation (Ssr) ...... 10 Thickness ...... 10 Age ...... 10 Ellen Wood Ridge Formation (Sew) ...... 11 Thickness ...... 12 Age ...... 12 Distal facies...... 12 Carys Mills Formation (SOcm) ...... 12 Thickness ...... 12 Age ...... 12 Smyrna Mills Formation (Ssm) ...... 12 Thickness ...... 14 Age ...... 14 Bottle Lake Complex ...... 14 Age ...... 14 Deformation ...... 15

D1 Recumbent Folding ...... 15

D2 Thrusting ...... 16

D3 Upright Folding ...... 16 Age ...... 17

D4: Sinistral/reverse Oblique Slip Faulting ...... 17 Age ...... 17 Late-stage deformations ...... 17 References Cited ...... 19

Bedrock Geology of the Springfield 15′ Quadrangle, Maine

Allan Ludman1 and John T. Hopeck2 1School of Earth and Environmental Sciences, Queens College (CUNY), 65-30 Kissena Boulevard, Flushing, NY 11367; 2Maine Department of Environmental Protection, 17 State House Station, Augusta, ME 04333

deposits. The resulting topography consists of broad INTRODUCTION rolling hills that rise 300 to 500 feet above adjacent This report describes the geology of the Springfield lowlands and streams with only a few small ponds. 15′ quadrangle that today comprises the Springfield Economic activity consists mostly of forestry and (Plate 1), Bowers Mountain (Plate 2), Bottle Lake (Plate farming. Most local farms had historically raised 3), and Weir Pond (Plate 4) 7½′ quadrangles (Figure 1). potatoes, but some have switched recently to corn and The area of approximately 205 square miles is located hay. almost entirely in eastern Penobscot County, with a The southern half of the area is underlain mostly by small sliver of Washington County in the northeastern granitic rocks of the Bottle Lake Complex (Figure 1) corner. It is sparsely populated, with fewer than 1,000 and exhibits a very different topography with numerous permanent residents, most concentrated in the Spring- large lakes, swamps, and bogs, the largest of which is, field and Bowers Mountain quadrangles in Springfield appropriately, named 1,000 Acre Heath. The contact (409) and Prentiss (214) townships and Carroll Planta- aureole and northern margin of the complex support tion (144). rugged topography with greater relief than the northern half of the area, including the three highest elevations – Topography Bowers (1195′), Almanac (1070′+), and Getchell (1020′ The northern Springfield and Bowers Mountain +) mountains – and several unnamed rounded hills over quadrangles are characterized by lower relief than the 800′ high. Weir Pond and Bottle lake quadrangles to the south. Access and Bedrock Exposure The northern part of the area is underlain largely by weakly metamorphosed Late Ordovician to Late Maine Route 6 traverses the central part of the area Silurian sedimentary rocks of the eastern Central Maine/ east-west, and Routes 169 and 170 provide north-south Aroostook-Matapedia (CMAM) basin and Cambro- access in the northern part. In addition, an extensive Ordovician sedimentary and volcanic rocks of the network of paved and unpaved county, town, farm, Miramichi terrane (Figure 1) blanketed by glacial recreational, and lumber roads extends throughout the

Figure 1. Location and lithotectonic setting.

Allan Ludman and John T. Hopeck study area. In an area with less than 1% outcrop, these unfortunately, poison ivy) with limestone and hay with roads also provide a large percentage of the bedrock turbiditic sandstone-shale belts. exposures on which this report is based, including a few Geologic and Tectonic Settings relatively large three-dimensional outcrops on Route 6, smaller exposures along the secondary roads, and The Paleozoic history of the Northern Appalachians numerous pavement outcrops from which glacial involved the progressive closing of the Iapetus Ocean deposits have been scraped. during accretion of three microplates of the Gondwanan The thickness of glacial cover varies widely. Thick realm (Figure 2A) to ancestral North America, causing till and outwash deposits in the Bottle Lake and Weir the orogenic events outlined in Figure 2B. Maine is Pond quadrangles result in poor bedrock control in the underlain largely by remnants of the Ordovician Bottle Lake Complex, particularly in the southern two Ganderian microplates separated by Late Ordovician to thirds of those quadrangles where there are few out- Early Devonian cover rocks (Figure 3). The older rocks crops, even on the highest hills. Hornfels holds up represent the basements and volcanic rocks of Ganderi- rugged hills in the contact area, however, so that the an island arcs deformed during mid-Ordovician accre- pluton/host rock contact can be traced with confidence. tion to North America (“Taconian” orogeny), and the In contrast, glacial cover is typically thinner in the younger rocks are thick basin sediments eroded from Springfield and Bowers Mountain quadrangles where post-Taconian highlands (Ludman et al., 2017). several large farms are located. As a result, their crops The Springfield 15′ quadrangle straddles the commonly reflect the nature of the underlying bedrock boundary between the Cambrian-Middle Ordovician with strong correlation of potatoes and corn (and, Miramichi terrane and adjacent, largely Silurian, cover

B Age Orogenic Event Plate Tectonic Explanation Permian Alleghanian Accretion of Gondwana to previously amalgamated plates Late Devonian “Neoacadian” Accretion of Meguma to previously amalgamated plates Early Devonian Acadian Accretion of Avalon to previously amalgamated plates Closure of remnant back-arc basin and amalgamation of Late Silurian Salinic Ganderia with Laurentia Mid-Ordovician Accretion of leading edge of Ganderian composite plate to “Taconian” (Caradocian) Laurentia Amalgamation of Ganderian microplates within the Cambro-Ordovician Penobscot Iapetus Ocean Latest Rifting of Rodinian supercontinent, opening of Iapetus

Neoproterozoic Ocean Late Neoproterozoic Grenville Assembly of Rodinian supercontinent (~1Ga)

Figure 2. Tectonic setting. (A) Tectonic framework of the Northern Appalachian orogen (after Hibbard et al., 2006). (B) Tecton- ic evolution of the Northern Appalachians. Shading indicates the time spanned by rocks and structures in the study area.

2 Bedrock geology of the Springfield 15′ quadrangle, Maine Lake complex, interpreted its emplacement and petro- logic evolution, and constrained its age to around 380 Ma (Ayuso et al., 1984) The complex was evaluated by the Maine Geological Survey in the 1980s as a possible national repository for high-level nuclear waste. Structural analyses based on our mapping, gravity modeling (Doll and Potts, 1990), and a seismic reflection transect (Doll et al., 1996; Costain et al., 1996) revealed that the complex is lens-shaped, shallow, and locally highly fractured, ruling it out its use as a repository. Our work in the Springfield 15′ quadrangle spans more than 30 years, beginning in the early 1980s with Ludman’s reconnaissance mapping for the Maine bedrock map (Ludman, 1985; Osberg et al., 1985) and Hopeck’s initial studies in the Springfield and Wytopit- lock 15′ quadrangles (reported in Hopeck, 1998). Improvements in understanding stratigraphy and structure have been reported in several Maine Geologi- Figure 3. Lithostratigraphic framework of Maine. Springfield cal Survey open file reports (Hopeck, 1990; Ludman, 15′ quadrangle shown in black 1985) and guidebooks of the New England Intercolle- giate Geological Conference (Ludman, 1991, 2003, rocks of the CMAM belt, and contains important 2013; Hopeck, 1991, 1994, 2013). Local Miramichi evidence for the sedimentologic and tectonic evolution stratigraphy was established in the adjacent Dill Hill of their relationships following the Taconian orogeny. 7½′ (Ludman, 2003) and Calais 1:100,000 quadrangles Eastern and northeastern Maine experienced only (Ludman and Berry, 2003). These studies set the weak regional metamorphism (chlorite and sub-chlorite) stratigraphic and structural framework for the Spring- despite its complex, multi-episodic deformation history field 15′ and adjacent quadrangles and played a major (Ludman, 2017). As a result, primary sedimentary role in recent interpretations of post-Middle Ordovician structures and textures are generally preserved, although lithofacies relationships and reconstructions of post- they are masked and, in some places, obliterated by Taconian, pre-Acadian paleogeography and sediment- transposed layering associated with folding and faulting. source relationships (Ludman et al., 2017). More intense metamorphism is recorded only in contact aureoles of granitic and mafic plutons. Extensive STRATIGRAPHY magmatism occurred in two pulses following accretion- Rocks of the Miramichi and CMAM belts record ary events. Igneous rocks of the earliest event, associat- two different segments of Early Paleozoic time (Figure ed with Salinic (early Acadian) deformation at around 4). No fossils have been found in the Springfield study 420 Ma, are not found in the study area. Granitic rocks area but graptolites and trace fossils in neighboring of the Bottle Lake igneous complex represent the later quadrangles and New Brunswick indicate a Cambrian pulse that followed the main Acadian deformation at through Middle Ordovician range for the Miramichi around 380 Ma. section. U-Pb ages of detrital and volcanic zircons Previous Work discussed below confirm the ages of the three Mira- michi units (Ludman et al., 2018). Ages of the CMAM The first modern geologic map that included the rocks are based on correlation with similar but fossilif- study area was a 1:250,000 compilation based on USGS erous rocks of the Meduxnekeag Group near Houlton reconnaissance mapping between 1956 and 1962 (Pavlides, 1974). A single brachiopod valve yielded a (Larrabee et al., 1965). That study distinguished the two “Silurian” age for the Daggett Ridge Formation in the stratigraphic suites here called the Miramichi and proximal facies of the CMAM belt (Larrabee et al., CMAM basin strata and postulated a fault contact 1965). between them; correlated the Miramichi terrane with Cambro-Ordovician belts in northern Maine; and Miramichi Terrane delineated the contact between the Bottle Lake complex The Miramichi terrane is a prominent component of and its host rocks far more accurately than the previous Ganderia, generally interpreted as the sedimentary Maine bedrock map (Keith, 1933). foundation and volcanic carapace of Ordovician island Ayuso (1984) conducted comprehensive field, arcs and back-arc basins (Fyffe et al., 2011). It extends petrographic, and geochemical studies of the Bottle

Allan Ludman and John T. Hopeck

Figure 4. Stratigraphic framework for the Springfield 15′ quadrangle. Italics indicate units not present in the quadrangle but included for completeness. more than 300 kilometers (km) from northern New mudstone/slate. Graded bedding, load casts, ball-and- Brunswick into Maine, where the Bottle Lake complex pillow, and flame structures are common. A distinctive separates it into the Danforth segment north of the close-spaced “bread-slicer” anastomosing solution complex (including rocks of the study area) and the cleavage recognizable at chlorite through andalusite smaller Greenfield segment to the south. The belt in the metamorphic grades is characteristic of most thick- Danforth segment appears to be continuous, with bedded arenites and wackes. conformable contacts between formations. The Baskahegan Lake Formation is divided into Baskahegan Lake Formation (Obl) upper (green or gray) and lower (maroon to pale pink) members, whose relative ages are indicated by graded The Baskahegan Lake Formation is the dominant beds at gradational contacts in three places in the unit in the Danforth segment and is named for extensive Farrow Mountain quadrangle. Both members have outcrops on the east and south shores of that lake in the similar bedding styles, lithic proportions, and varied Brookton 7½′ quadrangle. It crops out in a broad band clast/matrix proportions; the difference is a greater that narrows to the southwest through the Dill Hill proportion of hematite in the lower member and of quadrangle and crops out in the study area only on chlorite in the upper. Almanac Mountain in the Bottle Lake quadrangle. Outcrops at Almanac Mountain are close to the The Baskahegan Lake Formation consists mostly of contact with the Passadumkeag River pluton and are thick bedded quartzose and quartzofeldspathic arenites unusually rusty weathering, probably because of sulfide and wackes (~70%) intercalated with abundant but introduced by hydrothermal fluids from the pluton. The subordinate (30%) slates and mudstones. Feldspathic rocks are thermally metamorphosed to biotite-cordierite wackes and arenites typically develop a pale gray to grade. Wackes are converted to dense biotite-rich white clay-rich weathering rind as much as 2 centime- hornfels containing large spherical cordierite porphy- ters (cm) thick, whereas the quartzose rocks have a thin roblasts, arenites to massive quartzofeldspathic hornfels, (millimeters) gray outer weathered rind. Several and pelitic rocks to biotite and cordierite-rich hornfels. bedding styles are observed, including massive sand- Lacking the color differences characteristic of low- stone beds more than 2 meters thick, nearly complete grade outcrops, these outcrops are assigned the upper Bouma sequences of similar thickness, and 5–7.5 cm member because of their proximity to the overlying horizons of rhythmically interlayered sandstone and Bowers Mountain Formation. 4 Bedrock geology of the Springfield 15′ quadrangle, Maine Thickness Zones of euxinic and non-euxinic pelite tens of meters The thickness of the Baskahegan Lake Formation thick are typically homogeneous (Figure 5A), with cannot be determined, partly because its base is no- bedding revealed only by beds and laminae of quartzose where exposed in Maine or New Brunswick, and partly siltstone a few millimeters (mm) to 2 cm thick. Massive because it has been folded at least twice. The width of beds of quartz arenite 15–40 cm thick occur throughout its outcrop belt and regional continuity suggest a the formation but appear to be more abundant in the minimum thickness on the order of 1–2 kilometers. lower part, close to the contact with the Baskahegan Lake Formation (Figure 5B). Age Lithologic variations from the base to the top of the The presence of the trace fossil Oldhamia in the Bowers Mountain Formation record a transition from lower member of the Baskahegan Lake Formation in highly euxinic to more oxidizing conditions. Sooty New Brunswick indicates a Late Cambrian to earliest black pyritiferous shales occur throughout the formation Ordovician (Tremadocian) age for that part of the but are most abundant near its base, decrease upward, formation (Pickerill and Fyffe, 1999). Its maximum age and are rare near the top where they are nearly com- is constrained, albeit not tightly, by the earliest Cambri- pletely replaced by zones of gray shales and thinly an to late Neoproterozoic ages of its youngest detrital intercalated shale and siltstone with little or no pyrite. zircons: 532 Ma in the lower member, 555 Ma in the Thickness upper member (Ludman et al., 2018). The Bowers Mountain Formation is sandwiched Bowers Mountain Formation (Obm) between the older Baskahegan Lake and younger The Bowers Mountain Formation is named for Stetson Mountain formations and is the only Miramichi extensive outcrops on that eponymous elongate ridge in unit in Maine for which both upper and lower contacts the Bowers Mountain and Dill Hill quadrangles. Its are preserved. Nevertheless, multiple generations of conformable contact with the Stetson Mountain For- folding combined with local (?) shearing in black shales mation can be traced through tight folds from the and larger offsets in the Stetson Mountain and related northwest slope of Bowers Mountain in the southeast faults preclude precise thickness estimates. Outcrop corner of the Bowers Mountain quadrangle northward to width and inferred deformation style in the type locality Getchell Brook, Brown Hill and the unnamed adjacent suggest a tentative thickness of approximately 200–350 hill to the north, and then north-northeastward across meters. Route 6 to where it is truncated by the Stetson Mountain Age fault zone in the northeast corner of the quadrangle. A (brittle) fault contact with the Sam Rowe Ridge For- Detrital zircons were collected from the sandstones mation is exposed in the northern part of the Bottle Lake shown in Figure 5B in an attempt to constrain the quadrangle, south of South Springfield. maximum age of the Bowers Mountain Formation. The The Bowers Mountain Formation is a distinctive, 485 Ma age of the youngest zircons (the Cambrian- dominantly pelitic unit containing rusty- and sooty- Ordovician boundary) is consistent with the formation’s weathering sulfidic black shales and non-sulfidic to position conformably above the Late Cambrian to sparsely sulfidic gray weathering shales, with subordi- Tremadocian Baskahegan Lake Formation and con- nate shale-siltstone couplets and sulfidic quartz arenites. formably below the Stetson Mountain Formation

A B

Figure 5. Bowers Mountain Formation (A) Strongly cleaved pyritiferous black shales; (B) sulfidic quartz arenite interbedded with biotite-grade black shales (Dill Hill quadrangle).

Allan Ludman and John T. Hopeck (Middle Ordovician; see below). In view of the eruptive the eastern margin of the Miramichi terrane in the age of the overlying volcanic rocks, the Bowers Moun- Farrow Mountain quadrangle are not exposed in the tain Formation is assigned a late Early to early Middle study area. Chemical analyses reported by Sayres Ordovician age (Floian to Dapingian). (1986) and Ludman (2003) indicate that the Stetson Stetson Mountain Formation (Osm) Mountain rocks are calc-alkaline with volcanic arc affinities, consistent with the interpretation that the The Stetson Mountain Formation is named for Miramichi terrane represents one or more Ordovician extensive outcrops of volcanic and volcaniclastic rock island arcs (Wilson et al., 2016; Fyffe et al., 2011). on the prominent NNE-trending ridge of that name in A wide variety of eruptive rock types is present in the Stetson Mountain and Dill Hill quadrangles. It can the Stetson Mountain Formation (Figure 6). Cryptocrys- be traced continuously from the type locality into the talline to very fine grained ashfall tuffs are abundant northeastern corner of the Bowers Mountain quadran- and typically weather pale gray to chalky white (Figure gle, and thence to the south and southwest where it 6A). Some occur in thin (2–8 cm) beds with homogene- occupies the keel of a large synform that underlies the ous grain sizes, others in massive layers 1–3 meters (m) southeastern part of the quadrangle and closes in the thick, and some in thick layers ranging from cryptocrys- Bottle Lake quadrangle to the south. A second narrow talline, almost glassy, to fine grained with 0.5 to 5 mm outcrop band crops out east of Sheepskin Ridge, where microphenocrysts. Most of these tuffs have devitrified it is separated by the Stetson Mountain fault from the completely but a few well-preserved shards have been Sam Rowe Ridge Formation. Although the volcanic recognized in thin section. rocks locally support steep ridges and hills, they also Slightly coarser porphyritic and microporphyritic underlie areas of low relief, such as the lowland occu- ashflow tuffs are also common, some displaying a weak pied by Lindsey and Barker brooks. flow foliation (Figure 6B). Coarse crystal, lithic, and The Stetson Mountain Formation contains a variety crystal-lithic ashflow tuffs (Figure 6C) are also abun- of volcanic and volcaniclastic rocks ranging chemically dant, in flow units ranging from 10 cm to well over 3 m from rhyolites and rhyodacites to dacites and andesites thick. Lithic fragments 1 cm to 1 m long appear to be (Sayres, 1986) with very subordinate black shale, intraformational, including several types of ashfall and manganiferous mudstone, and thinly interbedded ashflow tuffs and sedimentary rocks similar to those siltstone and gray shale. Phenocrysts and micropheno- interbedded with the volcanic rocks (Figure 6D) as crysts are typically subhedral to euhedral feldspars or described below. The crystals are quartz and feldspars anhedral quartz that exhibit resorption relationships with and, as in the finer grained rocks, are commonly partly a surrounding cryptocrystalline matrix. Original ferro- resorbed by a cryptocrystalline matrix. Lapilli tuffs and magnesian phenocrysts are rare and, when present are tuffs containing flattened pumice fragments are relative- nearly completely chloritized, as are large parts of the ly rare. matrix in the andesitic rocks. Mafic volcanic rocks near Sedimentary rocks constitute less than 10% of the Stetson Mountain Formation. The most abundant are A thinly interbedded pale gray weathering siltstone and medium gray mudstone, probably eroded from eruptive centers, and interlayered with the volcanic rocks (Figure 6E). Black, carbonaceous shales form discontinuous

Figure 6. Stetson Mountain Formation volcanic rocks. See text for explanation.

6 Bedrock geology of the Springfield 15′ quadrangle, Maine

C D

E F

Figure 6 (continued). Stetson Mountain Formation volcanic rocks. See text for explanation. layers and lenses up to several meters thick but unmap- (Ludman, 2020). The most significant difference is the pable at 1:24,000. Unique manganiferous mudstone and absence of the basal Baskahegan Lake Formation from siltstone layers present on Stetson Mountain are interca- the Greenfield section. lated in some instances with siltstone-shale couplets and Modern island arc settings like that interpreted for in others with fine- to medium-grained tuffs (Figure the Stetson Mountain Formation typically comprise 6F). These have not been observed in the Springfield subaerial volcanic centers spaced 75–100 km apart, each study area. spewing ash and lava into shallow and deep marine Thickness waters at the same time that erosion adds a fringing apron of sedimentary and volcaniclastic debris to the Challenges to estimating thickness of the Stetson eruptive piles. There are several significant differences Mountain formation include the lack of an overlying between the Greenfield and Danforth segments unit, complex mid-Ordovician and Acadian folding and (Ludman, 2020), suggesting that simple “layer cake” faulting, and post-Acadian deformation associated with stratigraphy should not be expected. emplacement of the Bottle Lake complex. The formation is estimated to be on the order of a few thousand Age meters thick. “Middle Ordovician” graptolites (Climacograptus Comparison with the Miramichi Terrane Green- sp. and Orthograptus sp.) were reported from a carbona- field Segment ceous shale horizon in the Danforth quadrangle now mapped as part of the Stetson Mountain Formation The upper parts of the Danforth and Greenfield (Larrabee et al., 1965), suggesting a Middle Ordovician segments have similar stratigraphies (Ludman, 2020), age for the formation. Attempts were made to recollect with a thick, young volcanic pile underlain by an at least at this site, but the outcrop has deteriorated and no partly euxinic sedimentary section. The range of additional fossils were found. A 469.3 ±4.6 Ma U-Pb chemical compositions of volcanic rocks is nearly age for zircon from the correlative Olamon Stream identical from the two segments, with sparse basalts and volcanic rocks in the Miramichi Greenfield segment is more abundant andesites, dacites, and rhyolites 7

Allan Ludman and John T. Hopeck consistent with the fossil data, suggesting a possible grained versions of those in the Daggett Ridge and in latest Early Ordovician to earliest Middle Ordovician many instances contain the same lithic clasts, indicating range (Ludman et al., 2018). the same Miramichi source. The Mill Priveledge Brook, Sam Rowe Ridge, and Central Maine/Aroostook-Matapedia (CMAM) Belt Ellen Wood Ridge formations define a continuous Larrabee et al. (1965) recognized the difference upright sequence but their relationship to the Daggett between the Miramichi and CMAM suites but assigned Ridge Formation is less certain. The Mill Priveledge some units incorrectly to both. Ludman (1985) suggest- Brook may locally interfinger with and in some places ed the name Prentiss Group for rocks eroded from the lie beneath the Daggett Ridge and it is possible that Miramichi terrane and distinguished these from lime- Daggett Ridge deposition was coeval with at least some stone and pelites to the west (now the Carys Mills and of the other formations. To the west and south, the Mill Smyrna Mills formations of the Meduxnekeag Group). Priveledge Brook and Carys Mills formations appear to Hopeck (1998) confirmed the Miramichi provenance for interfinger with one another and it is difficult to distin- the Prentiss Group, demonstrated proximal through guish them in this transition zone. The Carys Mills intermediate facies relationships within the Prentiss passes gradually upward into the Smyrna Mills For- Group, and showed that the Carys Mills and Smyrna mation, a thick pile of pelite-rich turbidites very similar Mills formations represent a more distal facies of the to those of the Sam Rowe Ridge and Ellen Wood Ridge same basin. Today, rocks in the study area west of the formations. Miramichi terrane are interpreted as proximal, interme- Proximal Facies diate, and distal facies deposited in the eastern part of a single broad depocenter (Figure 4; Ludman et al., 2017). Daggett Ridge Formation (SOd) This basin contains what had previously been described The Daggett Ridge Formation was named by as separate Central Maine and Aroostook-Matapedia Larrabee et al., (1965) for massive conglomerates on belts and extends from western Maine through the study that ridge and on Jimmey Mountain in the Jimmey area into southwestern New Brunswick. Mountain quadrangle (Figure 1). It extends southward Facies Relationships to the Stetson Mountain and westward into the Potter Hill quadrangle but is not exposed in the study area. The Relationships among the four formations of the formation consists mostly of massively bedded coarse Prentiss Group appear to be conformable and, in many polymictic conglomerates (Figure 7) with rare interbed- cases, gradational, both vertically and laterally. Coarse ded grits and pelite. boulder, cobble, and pebble conglomerates of the Clasts are angular to sub-rounded, equidimensional Daggett Ridge and Mill Priveledge Brook formations to strongly elongated, and typically range in size from crop out near the contact with the Miramichi terrane and cobbles to pebbles but boulders up to two to three pass westward into finer grained and thinner bedded meters across are found in several localities. Local clast turbidites of the Sam Rowe Ridge and Ellen Wood imbrication and field relationships suggest deposition as Ridge formations that contain large amounts of mud- a series of debris flows. Most clasts are lithic fragments stone and slate. Intraformational conglomerates in the and the most common are fine- to medium-grained Sam Rowe Ridge and Ellen Wood Ridge are finer quartzofeldspathic sandstones whose texture, mineralo-

A B

Figure 7. Daggett Ridge Formation conglomerates. (A) Polymict matrix-supported conglomerate with quartz-feldspar sandstone and volcanic clasts. (B) Large rounded tuffaceous clasts.

8 Bedrock geology of the Springfield 15′ quadrangle, Maine gy, and bedding features suggest derivation from the erosion and deposition of the conglomerate. Coral and Baskahegan Lake Formation. All volcanic components crinoidal debris are not age-diagnostic, but a single of the Stetson Mountain Formation are also present as brachiopod valve was described by Boucot as clasts, including the unique manganiferous iron for- “Silurian” (in Larrabee et al., 1965). The Daggett Ridge mation, as well as pyritiferous black shale possibly Formation is assigned a late Middle Ordovician through derived from the Bowers Mountain Formation. Middle Silurian range based on the age of the The conglomerate matrix is poorly sorted and (unconformably) underlying Stetson Mountain For- ranges from granule to sand-sized lithic fragments, mation and inferred ages of the intermediate and identical to those of the larger clasts, to silt-sized quartz Prentiss Group distal facies. and feldspar, to fine grained mudstone. The matrix is Mill Priveledge Brook Formation (SOmp) typically calcareous and locally contains abundant The Mill Priveledge Brook Formation was named fragments of shallow- water fossils including crinoid after extensive exposures in and near that brook in the columnar segments, brachiopods, and corals, but similar north-central part of the Potter Hill and south-central fossils also occur in cobble-sized clasts, suggesting that part of the Wytopitlock quadrangle (Hopeck, 1998). It these were not living in the area at the time that the consists mostly (80%) of nearly equal amounts of rusty- conglomerates were deposited. weathering dark gray to black shale and quartzofeld- Thickness spathic siltstone in typically well graded beds (Figures The unconformable nature of its contact with the 8A, B), granule to pebble conglomerate and sooty black Miramichi terrane and the lack of an overlying unit shale in graded beds 2.5 to 5.0 cm thick, with subordi- would make it difficult under the best conditions to nate (10%) cobble conglomerate in thicker horizons (30 estimate the minimum thickness of the Daggett Ridge cm–1 m), calcareous wackes and pelites, and felsic Formation. The conditions are, however, far from tuffs. optimal. It is impossible to estimate the degree to which All lithologies are sulfidic to some extent, with the formation has been affected by folding because of pyrite cubes as large as 0.5 cm in some pelites. The difficulty in recognizing bedding, the absence of facing calcareous wackes also contain smaller grains (1–2 mm) indicators, and the lack of mappable horizons or of ankerite that resemble more widespread similar members. The formation’s lateral extent and the nature lithologies in the overlying Sam Rowe Ridge For- of folding in the rest of the Prentiss Group suggest a mation. Pelites interbedded with the calcareous wackes thickness of at least several hundred meters. become progressively more calcareous near the transi- Age tion to the micritic limestones of the Carys Mills Formation, making it difficult to distinguish the two The Daggett Ridge Formation contains fragments formations. of the three formations described above and is therefore Coarse conglomerates contain clasts up to 25 cm younger than the entire Miramichi section, i.e. post across similar to those in the Daggett Ridge Formation. Floian-Dapingian. In addition, the large lithic clasts Most appear to have been derived from the Baskahegan contain cleavages, randomly oriented quartz veins, and Lake Formation, with significant contributions from the strain fabrics not observed in the matrix, indicating that Stetson Mountain volcanics. In contrast to the Daggett the Miramichi source rocks were deformed prior to

A B

Figure 8. Mill Priveledge Brook Formation. (A) Interbedded black shale and subordinate sulfidic sandstone and siltstone. (B) Closeup showing thin siltstone layers in dominant rusty weathering sulfidic black shale (Wytopitlock quadrangle)

Allan Ludman and John T. Hopeck Ridge, however, most clasts in the Mill Priveledge weathering siltstone and darker mudstone (Figure 9A). Brook are well rounded, suggesting greater transport. Rhythmic and continuous bedding is characteristic of Thickness many exposures (Figure 9A) but many show a greater variety of thickness and/or wacke beds that pinch out The Mill Priveledge Brook Formation is estimated (Figure 9B). Equal proportions of wacke and mudstone to be several hundred to 1,000 meters thick. are most common but can vary from 1:4 to 4:1 in a Age single large outcrop. Diagenetic 1–2 mm ankerite Derivation of lithic clasts in the Mill Priveledge rhombs and pyrite cubes are abundant in wackes and Brook Formation from the Miramichi suite requires the mudstones (Figure 9B) and weather to a pale orange- formation to be younger than Middle Caradocian, and brown color characteristic of deeply weathered Sam its interfingering with the Carys Mills Formation Rowe Ridge exposures. suggests an Ashgillian to Llandoverian range. It is older Conglomerates with a sandy matrix make up than the (structurally) overlying Sam Rowe Ridge perhaps as much as 5% of the Sam Rowe Ridge For- Formation, for which there is neither fossil nor detrital mation. Most clasts are similar to those in the Mill zircon age control. Priveledge Brook (i.e. derived from the Miramichi Intermediate Facies terrane) but in some areas intraformational clasts are also observed. Gray argillaceous micrite is associated Sam Rowe Ridge Formation (Ssr) with calcareous wacke at a few outcrops in the north- The Sam Rowe Ridge Formation underlies a large eastern corner of the Bowers Mountain quadrangle, part of the Bowers Mountain quadrangle, with numer- notably in Tar Ridge Road east of North Road, and in ous exposures on Sam Rowe, Tar, and Sheepskin ridges, Baskahegan Stream. Fine-grained felsic ashfall tuff Weatherbee Hill, and unnamed hills east of Thompson’s horizons have also been observed as well as a single Corner. It also crops out in Bog Brook and adjacent hills coarser grained mafic crystal tuff. These subordinate in the southeast corner of the Springfield quadrangle, rock types appear to be distributed randomly in the and west of South Springfield in the northwest corner of formation. the Weir Pond quadrangle where it is in fault contact Thickness with the Bowers Mountain Formation. Many outcrops The Sam Rowe Ridge Formation is in fault contact have bedding styles reminiscent of the Mill Priveledge with underlying units so that its base is not exposed, Brook Formation, but Sam Rowe Ridge rocks are making it impossible to estimate its thickness accurate- lighter colored, finer grained, thinner bedded, and ly. Based on its areal extent and deformation, a mini- contain less pyrite and carbon than the more euxinic mum thickness of 1,000 m is suggested. Mill Priveledge Brook. The formation consists mostly of non-sulfidic, non- Age carbonaceous thin- to medium-bedded (2.5–12 cm), Fossils have not been found in the Sam Rowe well graded sand-silt and sand-silt-mud turbidites Ridge Formation, but several lines of evidence suggest (Figure 9). Bases of the graded sets are fine- to medium- an Early to Middle Silurian age: (1) Baskahegan Lake grained quartzofeldspathic wackes that weather pale and Stetson Mountain Formation clasts in Sam Rowe gray to white and pass upward into medium gray Ridge conglomerates indicate that the Sam Rowe Ridge

A B

Figure 9. Sam Rowe Ridge bedding styles. (A) Millimeter and centimeter scale graded beds of siltstone and slate. (B) Slate dominant section with weathered ankerite crystals (dark spots) in siltstone.

10 Bedrock geology of the Springfield 15′ quadrangle, Maine is younger than its Miramichi source rocks. (2) The Sam common in the upper part of the formation. Flute casts Rowe Ridge apparently lacks the mid-Ordovician and flame structures are locally well developed (Figure folding that affected the Miramichi terrane (see below) 10C) and is therefore post-Caradocian. (3) The Sam Rowe The Ellen Wood Ridge is distinguished from the Ridge appears to interfinger to the west with the lower Sam Rowe Ridge by the (mostly) green and greenish part of the mid-Llandovery through Wenlock Smyrna gray color of its wackes and pelites, sparse ankerite and Mills Formation; (4) In the Lincoln area, the Smyrna pyrite, and a greater abundance of volcanic and volcani- Mills grades upward into sandstones correlated with the clastic rocks, particularly in the upper part of the Mayflower Hill Formation of central Maine, indicating formation. Typical Sam Rowe Ridge wacke and pelite correlation with the Waterville Formation in central are gray on both weathered and fresh surfaces, but the Maine which has been dated as Llandovery (Orr and uppermost horizons weather greenish-gray even though Pickerill, 1995) and Wenlock (Ruedemann, in Perkins the fresh surface remains gray. These pass upward into and Smith, 1925) . the Ellen Wood Ridge Formation, the contact drawn Ellen Wood Ridge Formation (Sew) where green-weathering wacke and pelite are also green on fresh surfaces. The distinctive light green color is The Ellen Wood Ridge Formation lies conformably caused by abundant small chlorite flakes but varies and gradationally above the Sam Rowe Ridge For- locally to grayish maroon as in Figure 10C. mation, with which it shares very similar lithology and Most of the Ellen Wood Ridge volcanic component bedding styles. It consists mostly of thin to medium crops out north of the Springfield 15′ quadrangle. It bedded (a few millimeters to several centimeters) fine- consists of massive felsic rhyolitic breccias, ash flows grained sandstone, siltstone, and pelite, usually in well and tuffs locally interbedded with feldspathic wackes graded beds (Figure 10). Conglomerate lenses occur and pelite. Clasts in the breccias include angular and throughout the formation and felsic volcanic rocks are subangular cobbles and pebbles of greenish pelites and

A B

C D

Figure 10. Ellen Wood Ridge Formation bedding. (A) Millimeter to centimeter scale graded silt (light) and siltstone/mudstone (dark). (B) Centimeter scale silt-mud turbidite bedding. (C) Thick-bedded maroon silt-mud turbidites showing well-developed graded beds . (D) Flute casts.

Allan Ludman and John T. Hopeck wackes interpreted as intraformational, fine-grained Carys Mills Formation (SOcm) felsic tuffs, with cobbles and pebbles of pumiceous The Carys Mills Formation in the Springfield 15′ debris. Clasts definitely attributable to the Baskahegan quadrangle consists mostly of medium to dark gray Lake Formation are rare but are present. Feldspathic micrite and dolomicrite interlayered with argillaceous wackes interbedded with these volcanic rocks are white micrite and calcareous slates and phyllites, calcareous on weathered surfaces but deep forest-green when fresh. wackes, and very subordinate non-calcareous slate and Thickness phyllite. Weathering in unmetamorphosed outcrops As with the Sam Rowe Ridge, a complete section produces a ribbed appearance in which thin (1–2 mm) through the Ellen Wood Ridge Formation is not ex- knife-sharp pelitic laminae stand above the dominant posed. The base can be located in several places, but carbonates. Dark gray weathering of the micrite and nowhere has a contact with an overlying unit been slightly rusty weathering of dolomicrite reveal bedding observed. A minimum thickness of 800–1,000 m is (Figure 11A), but only at a few rare places. One or more suggested. generations of transposed layering obscure or completely obliterate bedding at most outcrops (Figures 11B, C), Age making it difficult to interpret both stratigraphy and the The age of the Ellen Wood Formation is most style, number, and sequence of deformation events. probably Middle Silurian. It is clearly younger than the Metamorphism in the Bottle Lake complex contact Sam Rowe Ridge and appears to be equivalent to the aureole brings about a profound change, coarsening the upper part of the Smyrna Mills Formation, suggesting a Carys Mills and producing distinctive layers of white to Late Wenlock to Early Ludlow age. greenish-white marble/calc-silicate granofels and dark Distal Facies purplish-gray biotite-rich hornfelsed pelite that further The distal facies of the CMAM belt underlies part mask original bedding (Figure 11C, D). of the Weir Pond quadrangle, most of the Springfield, Thickness East Winn, and Lee 7½′ quadrangles to the west and the The base of the Carys Mills Formation is not Potter Hill quadrangle to the north. It consists of broad exposed in the Springfield area so that only a portion of outcrop bands of a dominantly carbonate unit (micritic the formation is visible. Multiple folding events (see limestone and dolomicrite) and a dominantly pelitic unit below) coupled with difficulties distinguishing bedding (mudstone thinly interbedded with subordinate silt- from secondary layering further obstruct thickness stone). These have been correlated with the Carys Mills estimates. Broad outcrop bands in the Springfield 15′ and Smyrna Mills formations, respectively, near and quadrangles adjacent to the west and north suggest Houlton (Pavlides, 1974) and those names have been that thickness is on the order of several hundred to adopted in the Lincoln—Springfield area (Ludman et thousands of meters. al., 2017). A thick-bedded, variably calcareous, Age quartzofeldspathic sandstone caps the Carys Mills- Smyrna Mills belt just west of the Springfield 15′ Fossils in the Houlton area indicate that the Carys quadrangle and in several places south of Houlton in the Mills Formation ranges from latest Ordovician Danforth 1:100,000 quadrangle (Ludman et al., 2017). (Ashgillian) to earliest Silurian (Llandoverian; Pavlides, 1974). Relationships with adjacent units suggest that

A B

Figure 11. Bedding (S0) and transposed layering (S1) in the Carys Mills Formation. (A) S0 cut by S1 but still visible. (B) Bedding (S0) obscured by two generations of secondary layering: S1 transposed layering parallel to cleavage; S1+x younger carbonate veins. 12 Bedrock geology of the Springfield 15′ quadrangle, Maine

C D

Figure 11 (continued). Thinly (C) and thickly (D) banded Carys Mills calc-silicate. Dark = biotite-rich granofels; White=calcite ± actinolite. this range is also appropriate in the Springfield area. Gray and greenish-gray slate and pale gray siltstone Smyrna Mills Formation (Ssm) make up the bulk of the formation, but one of two dramatic changes characterize the transition to the The Smyrna Mills Formation consists almost overlying Mayflower Hill Formation north and west of entirely of thinly interbedded medium to dark gray the Springfield 15′ quadrangle. In some instances, the slates and lighter gray siltstones (Figure 12), with some uppermost horizons are alternating green and pale fine sandstone and color variations related to strati- grayish-red to deep maroon slates with white- graphic position. As with the Carys Mills Formation, weathering, pale gray siltstones. In others, the pelites primary layering is often obscured by a transposed are pyritiferous, sooty, highly carbonaceous slates with structural fabric (described in detail below). There few siltstone interbeds. appear to be gradational contacts with the underlying Contact metamorphism near the Passadumkeag Carys Mills Formation (similar to that reported in the River pluton accentuates primary and transposed Houlton area by Pavlides, 1974), and with the overlying compositional layering (Figure 12). Gray siltstone Mayflower Hill Formation west of the study area. layers recrystallize to tough, dense quartzofeldspathic Smyrna Mills slate-siltstone couplets are typically granofels with abundant red-brown biotite. Lower grade around 5 cm thick, with slate:siltstone proportions averaging 60:40. Graded beds are not uncommon but many siltstone beds have sharp upper and lower contacts with adjacent slate. The siltstones lack internal lamination seen in the Sam Rowe Ridge and Ellen Wood Ridge formations, and locally show pinch-and- swell structures. Some exposures contain minor amounts of ankerite, but pyrite is very rare. The lower part of the Smyrna Mills Formation consists of pale gray, locally calcareous siltstone and medium gray pelite that can be difficult to distinguish from deeply weathered Carys Mills outcrops. Lenses of blue-gray calcareous siltstone and dark gray argillaceous limestone 8–10 m thick are similar to the upper horizons of the Carys Mills Formation and are found only in the lower part of the Smyrna Mills. Bedding above the transition zone is similar but the limestones Figure 12. Cordierite-grade Smyrna Mills Formation hornfels. disappear, and siltstone and slate are chalky weathering Pale gray layers are metamorphosed siltstone, darker layers rather than gray, indicating increased feldspar (ash?) pelite. Small circular pits in both layers are weathered cordier- content, and many outcrops have a pale greenish tinge. ite crystals.

Allan Ludman and John T. Hopeck pelitic hornfelses are biotite-muscovite rich and at higher grade develop equant 1–4 mm cordierite porphy- roblasts. These tend to weather more rapidly than the matrix, producing a characteristic pitted appearance. Thickness Difficulties distinguishing bedding from transposed layering and the lack of marker horizons hinder structural interpretation for the Smyrna Mills Formation and estimates of its thickness. Its broad outcrop bands in the Springfield, Lee, and East Winn quadrangles suggest a thickness on the order of at least two kilometers. Age Interfingering relationships with the Ellen Wood Ridge and Sam Rowe Ridge formations to the east indicate that Smyrna Mills deposition spanned those of Figure 13. Extent and zonation of the Bottle Lake complex those units. Fossils have not been found in the Smyrna (after Ayuso, 1984). Dpr = Passadumkeag River pluton; Mills in the study area, although as this is written Dwc=Whitney Cove pluton. [c=core; r-rim facies] specimens are being processed for microfossils. A mid- Silurian age is inferred, based on fossils reported by detail by Ayuso (1984) and will be summarized only Pavlides (1971) in the Houlton area. briefly here. Most of the pluton is leucocratic, generally containing less than 5% biotite ± hornblende; Figure BOTTLE LAKE COMPLEX 14A, B), although these ferromagnesian minerals are The Bottle Lake complex occupies approxi- more abundant locally (Figure 14C). Biotite and mately 1,100 km2 in east-central and eastern Maine and hornblende are typically finer grained and interstitial was divided by Ayuso (1984) into the Passadumkeag within a framework of coarser quartz and feldspar River and Whitney Cove granitic plutons (Figure 13). crystals. Most of the pluton is quartz monzonite with The Passadumkeag River pluton underlies ~75% of the potassic feldspar more abundant than plagioclase, and Weir Pond and 85% of the Bottle Lake quadrangle but quartz making up less than 20% of the volume. A few is well exposed only near its northern margin. (Plates 1– outcrops have more quartz and less plagioclase and 4). Ayuso’s (1984) map projects the Whitney Cove approach granitic composition. pluton into the southeastern corner of the Bottle Lake Most of the rocks are coarse grained, with quartz quadrangle, but in an area lacking outcrop. Although and feldspar crystals 5 mm to 2.5 cm long (Figure 14A), his map shows both rim and core facies in the southern but porphyritic varieties are abundant in which euhedral half of the Springfield map area, most exposures are gray, white, or pink potassic feldspar phenocrysts up to from the rim facies. Both plutons are reversely zoned, 7.5 cm long are set in a finer grained (5 mm – 1 cm) with more mafic core and felsic rim facies. groundmass (Figure 14B). Rapakivi textures are rare The mineralogy, textures, and chemistry of the and foliation has only been observed in a few places. Passadumkeag River pluton were described in great

A B

Figure 14. Variation within the Passadumkeag River pluton.

14 Bedrock geology of the Springfield 15′ quadrangle, Maine

C D

Figure 14 (continued). Variation within the Passadumkeag River pluton.

Age DEFORMATION The Passadumkeag River pluton must be younger A complex deformation history involving episodes than the youngest rocks that it intrudes, in this case the of folding, thrusting, and high-angle faulting is recorded Late Silurian Mayflower Hill Formation west of the in the study area despite the low intensity of regional study area at Rollins Mountain in the Lee and East metamorphism (Figure 15). The timing of events is Winn quadrangles. It also truncates Acadian folds and based on known and inferred ages of the affected rocks, the Stetson Mountain fault, helping to determine the radiometric dating of plutons that intrude or are affected timing of the ductile and brittle events that produced by deformation, and by structural relationships among those structures. the Springfield area formations in nearby quadrangles. The pluton was dated directly as Middle to Upper Insofar as most stratigraphic age assignments are not Devonian (Givetian-Frasnian) by Ayuso et al. (1984), precisely defined by faunal or radiometric means, the based on nearly identical 381 ±4 Ma whole-rock Rb-Sr timeline should be considered tentative at this time. isochron and 381 ±3 Ma U-Pb zircon Concordia Temporal boundaries between series and stages in the intercept ages. The cooling history of the pluton was following discussion are from the 2017 International reported in a 40Ar/39Ar study that tracked the times of Chronostratigraphic Chart, v. 2017/02 (Cohen et al., cooling through the closure temperatures of amphibole, 2013, modified in 2020). biotite, and potassic feldspar (Ghanem, 2015). Results D Recumbent Folding indicate rapid cooling at shallow crustal depths, con- 1 sistent with the low regional metamorphic grade and the The earliest tectonic event (D1) was an episode of emplacement age from Ayuso et al., (1984). large-scale recumbent folding observed only in the

Figure 15. Deformation timeline for Springfield 15′ quadrangle.

Allan Ludman and John T. Hopeck

Miramichi terrane. No small-scale recumbent folds have D2 Thrusting been observed in the study area, but the Bowers Moun- A tectonically quiet interval followed D , during tain Formation lies structurally above younger Stetson 1 which the Prentiss Group and Meduxnekeag Group Mountain volcanic rocks southeast of Gates Hill were deposited unconformably on the folded Miramichi (Bowers Mountain quadrangle), indicating that these lie belt (Figure 16A). Deformation of these cover rocks on the inverted limb of large D fold. Several smaller- 1 began with eastward thrusting of intermediate facies scale inverted anticlines and synclines in have been rocks of the Prentiss Group over their Miramichi source observed in the Dill Hill and Stetson Mountain quadran- area (Figure 16B). A klippe in the Dill Hill quadrangle gles involving all three formations of the Miramichi was isolated from the thrust sheet during subsequent belt. evolution of the Stetson Mountain fault (Figures 16C, Based on the stratigraphic ages discussed above, D 1 D, E). occurred between the inferred 469 Ma age of the The timing of D thrusting is bracketed in the study Stetson Mountain Formation and the Late Ordovician to 2 area between deposition and lithification of the Early Silurian (~453–438 Ma) age of the Carys Mills Wenlockian (~433–427 Ma) Sam Rowe Ridge For- Formation, the oldest rocks not affected by those events. mation and its displacement by the Stetson Mountain Support for this timing comes from a well-developed fault which is intruded by the 381 Ma Passadumkeag early cleavage (S ) found in large Miramichi clasts in 1 River pluton in the Weir Pond quadrangle. In the the Daggett Ridge and Mill Priveledge Brook for- Danforth quadrangle, the thrust is deformed by D mations but not in those formations themselves where 3 folding and cut by D faulting, both of which are older the dominant structural fabric is related to D . Mid- 5 3 than the Early Devonian Pokiok plutonic complex (402– Ordovician deformation in Maine and New Brunswick 415 Ma). is attributed to the accretion of Ganderia to ancestral North America and is commonly referred to as the D3 Upright Folding Taconian orogeny. In this report, that event will be D folding affected all stratified rocks in the study described as “Taconian” in view of the distance of the 3 area and is expressed as numerous outcrop- and smaller- study area from the classic Taconian orogen in New scale, northeast to north-northeast-trending upright folds York and Massachusetts – without disputing the plate that typically plunge gently to either the northeast or tectonic cause of this orogeny. southwest. Large-scale folds are hard to identify

Figure 16. Evolution of the Stetson Mountain fault zone .

16 Bedrock geology of the Springfield 15′ quadrangle, Maine

A B

Figure 17. Small-scale D3 upright folds in (A) Carys Mills limestone and (B) Smyrna Mills silt/mud turbidites. Yellow arrows point to transposed layering axial planar to D3 hinge surfaces. because of a lack of marker horizons within the broad ed by Miramichi strata in the Dill Hill and Stetson outcrop bands shown in Plates 1–4. Fold style varies Mountain quadrangles is now interpreted as a klippe, depending on lithology, generally broadest in thick- isolated by late stage movement on later faults. bedded Baskahegan Lake and Stetson Mountain Cataclasite at the contact between the two belts is formations, but tight to isoclinal in thinner bedded visible in two places, demonstrating the brittle nature of Smyrna Mills, Carys Mills, Sam Rowe Ridge, and Ellen faulting. Fine-grained cataclasite derived from Stetson Wood formations (Figure 17). Mountain volcanic and Sam Rowe Ridge sedimentary A prominent close-spaced cleavage is characteristic rocks is exposed on the west side of Stetson Mountain of D3 folding in thin-bedded carbonate and pelitic rocks in the Dill Hill quadrangle. Cataclasite at the contact and is commonly paralleled by transposed layering between juxtaposed Bowers Mountain and Sam Rowe shown in Figure 17A and B. Although bedding is still Ridge strata is visible on a camp road southwest of recognizable in Figure 17B, in many outcrops it is South Springfield in the Bottle Lake quadrangle. uncertain whether the dominant layering is primary or Two lines of evidence indicate the strike-slip tectonic. It is particularly difficult to determine whether component of the fault: (1) sinistral shear bands in Sam layering folded during D5 shearing is primary or Rowe Ridge and Bowers Mountain cataclasite juxta- secondary. posed at the latter exposure mentioned above (Figure Age 18A) and (2) steeply plunging minor folds that deform thin layering interpreted as D transposed layering The timing of D is bracketed between the ages of 3 3 (Figure 18B). the youngest rocks affected and the oldest plutons that Outcrops of Carys Mills limestone on Route 6 just intrude its folds. The youngest rock is the Mayflower west of Springfield contain a NNE trending, moderately Hill Formation (Ludlow-Pridoli; see Ludman et al., to steeply west-dipping spaced cleavage parallel to the 2018) in the East Winn and Lincoln Center quadrangles. Stetson Mountain fault zone and observed thus far only The Passadumkeag River pluton cuts D folds and 3 near that structure (Figure 19). This cleavage cuts metamorphoses transposed layering in the Bottle Lake bedding, cleavage and transposed layering associated and Weir Pond quadrangles so that D3 must be older with D3 folding and is interpreted as a D4 fabric. than ~381 Ma. D3 folds also appear to be intruded in the Danforth quadrangle by the Skiff Lake component of Age the Pokiok pluton dated at 409 ±2 Ma (U-Pb zircon; Fabrics and structures associated with the Stetson Bevier and Whalen, 1990) and 389 ±20 (Rb-Sr whole- Mountain fault zone are intruded and metamorphosed rock; McCutcheon et al., 1981). D3 is therefore consid- by the Passadumkeag River pluton in the study area and ered to be an early Acadian event. by the Pokiok pluton in the Danforth quadrangle. The last stage of reverse oblique faulting is thus older than D4: Sinistral/Reverse Oblique Slip Faulting 389–409 Ma. The final step in evolution of the Stetson Mountain Late-stage Deformations fault zone that today separates the Miramichi and CMAM belts was an episode of moderate to high angle The Bottle Lake pluton intrudes most, but not all oblique faulting attributed to D4 (Figure 16). Figure 16 structural features, but is itself sheared locally at Rand shows that an area of Sam Rowe Ridge rocks surround- Hill (D5) and hydrothermally altered. Passadumkeag

Allan Ludman and John T. Hopeck

A B

Figure 18. Indicators of sinistral oblique nature in the Stetson Mountain fault zone. Sinistral shear bands in Sam Rowe Ridge (A) and drag folds in Bowers Mountain (B) formations, Bottle Lake quadrangle SW of South Springfield. (C) Steeply plunging folds deforming initially near-vertical D3 transposed layering. River pluton coarse granitic rock is brittlely fractured in this shear zone and its feldspars altered to white clay minerals. The brittle nature of deformation suggests some degree of cooling of the pluton, whereas the extensive hydrothermal alteration, not observed else- where in the study area, suggests interaction with late- stage hydrothermal fluids from the pluton. An age slightly younger than the ~381 Ma emplacement age is suggested. Small-scale WNW-trending asymmetric (sinistral) folds with steep plunges are found throughout the study area and much of eastern and central Maine. These are attributed to a late-stage (D6) event that appears to deform all other structures in the region. D6 appears to have been caused by a stress field different from those of the older NE-SW trending structures but there is little evidence for its age in the study area.

Figure 19. Moderately west-dipping spaced cleavage attributed to D4 cutting D3 folds, cleavage, and transposed layering in Carys Mills limestone, Springfield quadrangle.

18 Bedrock geology of the Springfield 15′ quadrangle, Maine high-level nuclear waste sites in Maine; Maine REFERENCES CITED Geological Survey Open File Report 90-25b, 7 p. Ayuso, R., 1984, Field relations, crystallization, and and map. petrology of reversely zoned granitic plutons in the Hopeck, J., 1991, Post-Caradocian stratigraphy of the Bottle Lake Complex, Maine; U.S. Geological CMAM and Miramichi lithotectonic belts in Survey Professional Paper 1320, 58 pp and Maine; In Ludman, A., (editor), Geology of the 1:125,000 scale geologic map Coastal Lithotectonic block and neighboring Ayuso, R., Arth, G., Sinha, A., Carlson, J., and Wones, terranes, eastern Maine and southern New Bruns- D., 1984, Comparative geochronology in the wick; New England Intercollegiate Geological reversely zoned plutons of the Bottle Lake Com- Conference, Princeton, ME; p. 157–168 plex, Maine: U-Pb on zircons and Rb-Sr on whole Hopeck, J., 1994, Post-Caradocian strata of the Mira- rocks; Contributions to Mineralogy and Petrology, michi anticlinorium and their relation to the 88, pp. 113–125). CMAM belt; In Hanson, L. (editor), Guidebook to Bevier, M., and Whalen, J., 1990, U-Pb geochronology field trips in north-central Maine; New England of Silurian granites, Miramichi terrane, New Intercollegiate Geological Conference, Millinocket, Brunswick. In Radiogenic age and isotopic studies, ME; p.43–59. Report 3. Geological Survey of Canada, Paper 89– Hopeck, J., 2013, Transitional relationships in the 2, p. 93–100. Miramichi, CMAM , and Central Maine belts; In Cohen, K., Finney, S., Gibbard, P., and Fan, J-K, 2013, Hanson, L. (editor), 2013 Guidebook for field trips The International Chronostratigraphic Chart, in north-central Maine; New England Intercolle- Episodes v. 36, p. 199–204 (2017 modification). giate Geological Conference, Millinocket, ME; p. 209–214. Costain, J., Domoracki, W., and Coruh, C. 1989. Processing and preliminary interpretation of the Keith, A., 1933, Preliminary bedrock geologic map of Bottle Lake seismic reflection data. Final report. Maine; Maine Geological Survey, Augusta, ME. Maine Geological Survey Open File report, 28 pp. Scale 1:1,000,000 Doll, W., Domoracki, W., Costain, J., Coruh, C., Larrabee, D., Spencer, C., and Swift, J., 1965, Bedrock Ludman, A., and Hopeck, J., 1996. Seismic geology of the Grand Lake area, Aroostook, reflection evidence for the evolution of a transcur- Hancock, Penobscot, and Washington counties, rent fault zone: the Norumbega Fault Zone, Maine; Maine; USGS Bulletin 1201-E, 38 pp and Geology, v. 24, No. 3, pp. 251–254. 1:250,000 geologic map. Doll, W., and Potts, S., 1990. Gravity study of the Ludman, A., 1985, Pre-Silurian rocks of eastern and Bottle Lake Complex. In Special geological studies southeastern Maine; Maine Geological Survey in the Department of Energy’s proposed high-level Open File Report 85–78, 29 pp. nuclear waste sites in Maine; Maine Geological Ludman, A., 1991, Stratigraphy of the Miramichi Survey, Open File Report 90-25c, 45 pp. and map. terrane in eastern Maine; in A. Ludman, editor, Fyffe, L., Johnson, S., and van Staal, C. 2011. A review Geology of the Coastal Lithotectonic Belt and of Proterozoic to Early Paleozoic lithotectonic neighboring terranes, eastern Maine and southern terranes in the northeastern Appalachian orogen of New Brunswick; New England Intercollegiate New Brunswick, Canada, and their tectonic Geological Conference Guidebook, p. 338–357. evolution during Penobscot, Taconic, Salinic, and Ludman, A., 2003, Bedrock geology of the Dill Hill 7½′ Acadian orogenesis. Atlantic Geology v. 47, pp. quadrangle, Maine; Maine Geological Survey Open 211–248. File Map 03-93. Ghanem, H., 2015 Thermal and tectonic history of east- Ludman, A., 2013 Closing the gap: Relationships of the central Maine: Insights from 40Ar/30Ar geochro- Waterville and CMAM belts; in Hanson, L., ed., nology; PhD thesis, Indiana University, Blooming- Guidebook for field trips in north-central Maine; ton, IN, 340 pp. New England Intercollegiate Geological Confer- Hibbard, J., van Staal, C., Rankin, D., and Williams, H., ence, Trip A-1, p. 1–14. 2006. Lithotectonic map of the Appalachian Ludman, A., 2017, Multiple deformation of chlorite- orogeny, Canada-United States of America. grade late Ordovician to early Devonian strata in Geological Survey of Canada, Map 2096, scale 1:1 eastern Maine; Geological Society of Ameri- 500,000. ca Abstracts with Programs. Vol. 49, No. 2. doi: Hopeck, J., 1990, Tectonic fabrics of the Passadumkeag 10.1130/abs/2017NE-290457 River pluton, Bottle Lake complex, Springfield and Ludman, A., 2020, Bedrock geology of the Greenfield Scraggly Lake 15′ quadrangles. In Special geologi- quadrangle, Maine: Maine Geological Survey, cal studies in the Department of Energy’s proposed

Allan Ludman and John T. Hopeck Open-File Report 20-10, 28 p. report and color map, scale 1:24,000. Ludman, A., and Berry, H. N. IV, 2003, Bedrock geology of the Calais 1:100,000 quadrangle, Maine; Maine Geological Survey Open File Report 03-97. Ludman, A., Hopeck, J., and Berry, H. N. IV, 2017. Provenance and paleogeography of post-Middle Ordovician pre-Devonian sedimentary basins on the Gander composite terrane, eastern and east-central Maine: implications for Silurian tectonics in the northern Appalachians. Atlantic Geology, 53, p. 63 –85. Ludman, A., Aleinikoff, J., Berry, H.N. IV, and Ho- peck, J., 2018, SHRIMP U-Pb zircon evidence for age, provenance, and tectonic history of early Paleozoic Ganderian rocks, east-central Maine. Atlantic Geology 54, pp 335–387. McCutcheon, S., Lutes, G., Gauthier, G., and Brooks, C., 1981, The Pokiok batholith, a contaminated Acadian intrusion with an anomalous Rb-Sr age. Canadian Journal of Earth Sciences, 18, pp. 910– 918. Orr, P., and Pickerill, R., 1995, Trace fossils from Early Silurian flysch of the Waterville Formation, Maine, U.S.A. Northeastern Geology and Environmental Sciences, 17, 4, p. 394–414. Osberg, P., Hussey, A., and Boone, G., 1985, Bedrock geologic map of Maine; Maine Geological Survey, Augusta, ME. Scale: 1:500,000 Pavlides, L., 1974, General bedrock geology of northeastern Maine, in Osberg, P., editor, Geology of east-central and north-central Maine, New England Intercollegiate Geological Conference guidebook, p. 61–84. Perkins, E., and Smith, E., 1925, Contributions to the geology of Maine, No. 1. A geological section from the Kennebec River to Penobscot Bay (citing fossil identification by Ruedemann). American Journal of Science 9, 204–225. Pickerill, R., and Fyffe, L., 1999, The stratigraphic significance of trace fossils from the Lower Paleozoic Baskahegan Lake Formation near Woodstock, west-central New Brunswick; Atlantic Geology v. 35, p. 205–214. Sayres, M., 1986, Stratigraphy, polydeformation, and tectonic setting of Ordovician volcanic rocks in the Danforth area, eastern Maine; Unpublished Masters thesis, Queens College, Flushing, NY, 135 pp. Wilson, R., Van Staal, C., and McClelland, W., 2015, Synaccretionary sedimentary and volcanic rocks in the Ordovician Tetagouche backarc basin, New Brunswick, Canada: evidence for a transition from foredeep to forearc basin sedimentation. American Journal of Science, v. 315, p. 958–1001.

20 68°15'00"W 68°12'30"W 68°10'00"W 68°7'30"W Bedrock Geology of the 5 59000mE 60 61 62 63 64 65 66 67 568000mE 45°29'60"N 45°29'60"N Springfield Quadrangle, Maine

attago M d S u s tr Bedrock geologic mapping and compilation by ea m 88 Mattag

h o S c dus tr

n e John T. Hopeck and Allan Ludman  a a 50 000 K m 38 mN r

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r t k s

l e 50 000 a W 38 mN n Digital cartography by Geologic editing by Cartographic design by d G o rd on Ssm Susan S. Tolman Henry N. Berry IV Christian H. Halsted Broo k R 86 id  g Amber T. H. Whittaker e

75 P r e n

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W T SOcm w e b p State Geologist s T t 70 e  7 r 37 P R

l 3 t 37 N 0 0  72 B 5 0  P Funding for the field work and preparation of this map was provided by the Maine Geological Survey. 0

0 4 P 0 40 5  0 68 72  81

31   73  L Open-File No. 20-22 i Ssm  81 t tl  Maine Geological Survey e G 4 o 0 r 0 d 2020 o n B ro Address: 93 State House Station, Augusta, Maine 04333 o 36 k Telephone: 207-287-2801 E-mail: [email protected] Plate 1 36 Home page: www.maine.gov/dacf/mgs/ This map supersedes a portion of  MGS Open File No. 90-25b. Ssm SOcm

EXPLANATION OF UNITS 86

66 Rd STRATIFIED ROCKS

 ge 35 id  R r e k Note about term inology. S tratified rock s in this quadrangle are in the lower greenschist facies of regional m etam orphism . Because sedim entary  c 35 u T 69 400 features are widely preserved at such a low m etam orphic grade, sedim entary rock nam es are used in the unit descriptions to em phasize their 84 depositional character with the understanding that all stratified rock s have been m etam orphosed. SOcm Aroostook-Matapedia Basin Aroostook-Matapedia Basin Distal facies Intermediate facies Silurian [S] Silurian [S]

Smyrna Mills Formation. T hinly interbedded p Sam Rowe Ridge Formation. T hinly bedded to

u  Ssm Ssr

 (com m only 2–7 centim eters) silt-m ud turbidites o m edium -bedded (5–20 centim eters) turbidites with r  G

34 ty pically in well-graded couplets. Mudstone/slate nearly equal proportions of pale gray or chalk y buff 81 e s 45°27'30"N 45°27'30"N s g m ak es up about 65% of form ation overall but i weathering, variably calcareous siltstone to fine-

74 34 t d i proportions vary within and between outcrops. n grained sandstone and dark gray, strongly cleaved rook R e ry B r ra

t  Mudstones are ty pically m edium to dark gray, P non-calcareous m udstone. 1–3 m illim eter lim onite on p

C u siltstones m edium gray but weathered siltstone spots weathered from py rite and/or ank erite are locally o  Ssm

r surfaces are pale buff. Bedding is com m only obscured characteristic of both siltstone and m udstone. G

P   ic 80 k g or obliterated by transposed lay ering parallel to axial l e a

R T  e 79 i o planes of upright folds. Ssm d

 k  w g

e e 69 e

r R  n R d

d x   Silurian-Ordovician [SO]

r u

e 83 d

 e k Carys Mills Formation. Interbedded dark gray 33 84 0  0 73 5 c 5 0 M SOcm 0 79 e u 33 m icrite and lighter gray dolom icrite with subordinate g  T

d calcareous and non-calcareous phy llite and sparse  i d Cole 69 n R calcareous wack e. Bedding com m only obscured or Ssm o P ond P e C obliterated by transposed lay ering. W hen visible, beds r r  n a  ne 65 e a t Ri range from 5 to 15 centim eters; transposed lay ers are r d s 35 ge B b C r e thinner (m illim eter to centim eter scale). W ell exposed o 0 o 0 k W 5 SOcm in road cuts on Route 6 west of S pringfield near the  intersection of Ham Drive. 81 W  84  orsterRd  77 32 W  e 0 40 32 b W s t i e n r n P 400 4 l 0

t 0 INTERPRETIVE STRATIGRAPHIC RELATIONSHIPS

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

4 ! Plt 00 ! ster ! W eb SOcm ! ld 400 ! ingfie !

r SOcm T ucke ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! p W rR ! S i 4 dg 0 0 e Ssm 0 40 R d Ssr

31 3 00 

400 31 SOcm

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

 !

 !

! !

 !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! 84 85 W inn Ssm

80 Lee   0 40 Ssm 84

30 S p 81 r  EXPLANATION OF SYMBOLS i 30 n L 73 g  e f e i e SOcm 400 l d 70 Note: S tructural sy m bols are drawn parallel to strik e or trend of m easured structural feature. Barb or tick indicates direction of dip, if k nown. Annotation d R

 tory 87 S tarch F8ac3  4 0 gives dip or plunge angle, if k nown. For planar features, sy m bol is centered at observation point. For linear features, tail of sy m bol is at observation

0 point. Multiple m easurem ents at a site are represented by com bined sy m bols. S y m bols on the m ap are graphical representations of inform ation stored in

 169  a bedrock database at the Maine Geological S urvey. T he database m ay contain additional inform ation that is not display ed on this m ap.

 «¬170 45°25'00"N   tream 45°25'00"N 88 87 keunk S  S p tta Outcrop of m apped unit. ring ran a fiel t B ch M  d s   Rd Ea   U 20 Bedding, tops unk nown (inclined, vertical). 29   400 D

k 29  o

ro 20 Bedding, tops up (inclined). B  e s

r 70 a t Be l  u 20 T ransposed lay ering (inclined). a   SOcm f   20 Cleavage (inclined, vertical). c1 = First cleavage, in outcrop with m ultiple cleavages. Rd 80 inn 78   M Old W 82 ax  well 20 Intersection lineation (plunging). Rd 74    74 0x1 = Intersection of bedding (S 0) with first cleavage (S 1). 1x2 = Intersection of first cleavage (S 1) with second cleavage (S 2). Rd

Coffin  28 20 Axial plane of fold (inclined).  t  f 28 81 o r 20 T c o  Fold axis (plunging).

w Clark rook n G n 400 B

o L t t i  B SOcm n  B e 83 r o R o 0 81 d 19 Photo location. Num bers refer to figure num bers in the report. k 0

4 R

d 82 

84 0

d 4 h SOcm e R H t idg Ssm o 3  4 ea R r 0 0 P m 0 0 e o 84 H s d t

R a Ne  m a

79 w d o D  b L S pringfield x SOcm r 

27 O n GEOLOGIC TIME SCALE

  ¬6 86 Bunn  « y Ln 12 1x2 70 27 Geologic Age Absolute Age*  80  65 0x1 0 0

6 0

84 0 Cenozoic Era () 0-66

 66c1 7

  EXPLANATION OF LINES Mesozoic Era ()  19  Gott Brook 80  K

84 ___Cretaceous Period ( ) 66-145

83 79 ___J urassic Period (J) 145-201

87  Ssr  

78 Contact between rock units, of stratigraphic origin. ___T riassic Period () 201-252 m  Paleozoic Era () a 75 Location is constrained by bedrock outcrops indicated by sy m bols on the m ap. re t 79

S 89 P

l ___Perm ian Period ( ) 252-299

l    i  T he location of som e contacts is not well constrained. 6 M C

«¬ 81 S 82 ___Carboniferous Period ( ) 299-359

s h

t e h  37 0x1 p d  D 26 g ___Devonian Period ( ) 359-419 R R i 11 r  U 400 W 61 d

a d ___S ilurian Period (S) 419-444 e R  26

r l

t l G i S H D

h O d l ___Ordovician Period ( ) 444-485

o il s a t e

M 60 0x1 High-angle fault (approxim atel y located).

R SOcm

D d  ___Cam brian Period () 485-541 0 d 0 R  U D 3 83 60 T he sense of inferred relative m otion is indicated by = up and = down.  e p u Precam brian tim e ( ) Older than 541 r  T 82 Arrows indicate sense of strik e-slip m otion. 88 * In m illions of y ears before present. (W alk er, J .D.,

 27

74

e  Geissm an, J .W ., Bowring, S .A., and Babcock , L.E., com pilers,

g  B 

u Ssr 68 c d 77  2012 Geologic T im e S cale v. 4.0: Geological S ociety of

k i  75 s

hSOcm 0 R B 74

o 0 50 o  Am erica, doi: 10.1130/2012.CT S 004R3C.) 6 0 g

n  Bro 50

R 80 67  U ok 600

d a 

H D  75 

 78 72 50 000 400 o 0 m 

0 0  4 0 78 600

25 mN l 7 h 79 86 t s  

86 d 76 P u R 50 000

odge 62 80 25 mN t L 

0 o C rcu 0 lea 72 4 C  n

d 0 0 0 5  Ssm 0 84 7 45°22'30"N 45°22'30"N 5 59000mE 60 61 62 63 64 65 66 67 568000mE REFERENCES 68°15'00"W 68°12'30"W 68°10'00"W 68°7'30"W Hopeck , J ohn T ., 1990, T ectonic fabrics of the Passadum k eag River pluton, Bottle Lak e com plex, S pringfield and S craggly Lak e 15-m inute quadrangles: Maine Geological S urvey , Open-File Report 90-25b, 7 p. report, 4 figs., m ap, scale 1:62,500. Hopeck , J ohn T hom as, 1998, S tratigraphy and structural geology of the W y topitlock and S pringfield fifteen-m inute quadrangles, eastern Maine: Ph.D. g a n e ¼ a

k  Base m ap features from Maine Office of GIS - 1:24,000 U S GS contour

SOURCES OF GEOLOGIC INFORMATION 1:24,000 T S CALE M m

m dissertation, City College (CU NY ), New Y ork , 160 p. a Potter r g a u w a n g e lines, E911 roads, 1:24,000 National Hy drography Dataset, U S GS GNIS t i t Hill 1 0.5 0 1 Mile n N a

K e Ludm an, Allan, 2013, Closing the gap: correlation of the W aterville and Aroostook -Matapedia stratigraphic sequences: in Hanson, Lindley S . (editor), M

Field work by Allan Ludm an, 1981–2017. t o i placenam es and 1:24,000 political boundaries. Map projection U niversal c r d t n

N h i s

e Guidebook to field trips in north central Maine: New England Intercollegiate Geological Conference, 105th Annual Meeting, October 11-13, r a Field work by J.T . Hopeck , 1986–1998. i o t f e T ransverse Mercator, North Am erican Datum , 1927. 1000 0 1000 2000 3000 4000 5000 6000 7000 Feet r n East g t w

u h Maine n o i

o 2013, Millinock et Lak e, p. 1-14. W inn r B p M S Ludm an, Allan, Hopeck , J ohn T ., and Brock , Pam ela Chase, 1993, Nature of the Acadian orogeny in eastern Maine: in Roy , David C., and S k ehan, 1 0.5 0 1 Kilom eter Approxim ate Mean T he use of industry, firm , or local governm ent nam es on this m ap is for W eir Bottle location purposes only and does not im pute responsibility for any present J am es W . (editors), T he Acadian orogeny ; recent studies in New England, Maritim e Canada, and the autochthonous foreland: Geological Lee Declination, 2017 Pond Lak e 17o W or potential effects on the natural resources. S ociety of Am erica, S pecial Paper 275, p. 67-84. CONT OU R INT ERVAL 10 FEET Ludm an, Allan, Hopeck , J ohn, and Berry , Henry N., IV, 2017, Provenance and paleogeography of post-Middle Ordovician, pre-Devonian sedim entary basins on the Gander com posite terrane, eastern and east-central Maine: im plications for S ilurian tectonics in the northern Appalachians: Atlantic Geology , v. 53, p. 63-85. doi: 10.4138/atlgeol.2017.003. 68°7'30"W 68°5'00"W 68°2'30"W 68°00'00"W Bedrock Geology of the 569000mE 70 71 72 73 74 75 76 77 578000mE 45°30'00"N 45°30'00"N R 4 a W

00 d i P s A h E S

L L N Bowers Mountain Quadrangle, Maine n H il a S O c I 40  a B N 0 L U D  169 n m S G 0 «¬ Bedrock geologic mapping and compilation by 0 C T  6 

F R SOmp O

O Ssr r

e o T 82 N e Sew

d w 171 C Allan Ludman and John T. Hopeck o C «¬ m e 

  O O 0

R8 84 0 0 7 50 00 W 0 P 0  i  38 mN a d r y e 6 Mud g 0 Brook n 81 n 0 Digital cartography by Geologic editing by Cartographic design by L e t  i 50 000 vy s T 38 mN I s S 86 8  u T

n   R Susan S. Tolman Henry N. Berry IV Christian H. Halsted

P w f SOcm rentiss l  o 3

p w n  v  N e rLily H  T r e Ln Amber T. H. Whittaker at d B D W o 7 73 o r P ew R s P  o Ssr 3  R 84  N 84  B Ashlee Ln M P

oos eb  P Robert G. Marvinney

 erry   Ln M 

  d  ap 84

y R le  a State Geologist  s   W

88 a Dr 81 d r o

o o 40 88 w r

0 ld  u i

A Ssr  W   37 

  81

SOcm  71 37 Funding for the field work and preparation of this map was provided by the Maine Geological Survey. SOcm 

 n

77  L m m W  a edo a R ain h Fre y 10B y R rn 74 87 d u  74  ib

  V

 80  

  

 is79 Open-File No. 20-22 V 81   y  ok rr Maine Geological Survey Bro e Ssr ves b  a w le ra C S t 2020 87 79    Address: 93 State House Station, Augusta, Maine 04333 Mu   nson  Plate 2 Ln  Telephone: 207-287-2801 E-mail: [email protected]

36 

   Home page: www.maine.gov/dacf/mgs/ 87   This map supersedes a portion of

 36

79 SOcm

ll S t  Sm MGS Open File No. 90-25b. i  M ith 84 17 4 Brook  

00  

170 77  72 75 «¬    662  00 4 77 00      Obm 80 EXPLANATION OF UNITS

Ssm 169   

t «¬ 

l e  55e 

u g   70e  Osm a M  70 f d

 Ssr i INTRUSIVE ROCKS

Presco o 65

tt Br s  ook R  71 s   81 Ssr r 80 86 R dg

35 88 a

84 e Middle Devonian [D] SOcm T D 0

T k  a  x rR 0 0 U i 8 0 a 87 dg 35 e e 7  t R l S d

 L 79 Passadumkeag River pluton. 6 p

b 0 o 0

c e a l J  0 m 0

6 t o

t  t f Rim facies. Coarse-grained hornblende-biotite granite. S omewhat lower color index and higher ratio of biotite to

P o B C o r   a Dbpr

s B r k e  84 ahe hornblende than rocks in the core facies of the pluton. n  c g a t n

i n s S s t a r W T  ea 88 m B w e STRATIFIED ROCKS b p

s T t e 7 r

P R  l Note about terminology. S tratified rocks in this quadrangle are in the lower greenschist facies of regional metamorphism. Because sedimentary 3 t

N  features are widely preserved at such a low metamorphic grade, sedimentary rock names are used in the unit descriptions to emphasize their

45°27'30"N B 45°27'30"N P ve  34 sA  P ras depositional character with the understanding that all stratified rocks have been metamorphosed. lueg  B  34 P 83 6 BP 00 3 N h 7 R Aroostook-Matapedia Basin Aroostook-Matapedia Basin t  p T r Tw t ntiss lt l o re ll P Distal facies Intermediate facies P Carro u N fa N

o rt

74 h   R  d  600 Silurian [S] Silurian [S]  

  5 78 00  74 Smyrna Mills Formation. Thinly interbedded Ellen Wood Ridge Formation. Thinly to moderately

Ssr SOcm Obm 74 d Ssm Sew

R Sew  (commonly 2–7 centimeters) silt-mud turbidites bedded (5–20 centimeters) silt-mud and fine-grained

d l   6 e 0 i  0

f typically in well-graded couplets. Mudstone/slate sand-mud turbidites with nearly equal proportions of g SOcm 82 80 n

i r Osm p makes up about 65% of formation overall but mudstone and coarser clastic rocks. V ery similar to 33  

S 

SOcm  80 W 0 proportions vary within and between outcrops. S am R owe R idge but typically pale green on both 0

 86 86 33

6 60  

17 Mudstones are typically medium to dark gray, fresh and weathered surfaces. Minor tuffaceous  80   400    7 75 73 68 0 siltstones medium gray but weathered siltstone horizons. Load and flute casts abundant locally.  0   69     surfaces are pale buff. Bedding is commonly obscured

Plt 169 84 84 p

ebster «¬

W d 170  u or obliterated by transposed layering parallel to ax ial Sam Rowe Ridge Formation. Thinly bedded to el 

gfi ¬ o rin « 86 p Ssr p r S  medium-bedded (5–20 centimeters) turbidites with  80 planes of upright folds. u G o

Obm  r nearly equal proportions of pale gray or chalky buff

Ssr g a G

e weathering, variably calcareous siltstone to fine-

82  s  k e 68 s  81 i

v e

 k t A roo grained sandstone and dark gray, strongly cleaved ter Tolman B n

a 87 n 6 T  0 x

80 7 e 0 00   non-calcareous mudstone. 1–3 millimeter limonite u  r

32 169 d

 P  

170 72

«¬     D e spots weathered from pyrite and/or ankerite are locally d 76  32  M R  U  characteristic of both siltstone and mudstone.

d  0

m o a 0

o 79  8 e pruc

tr g  S e Brook

S s

us Co

od O  ff 89 

ag  in  Silurian-Ordovician [SO] Silurian-Ordovician [SO] tt B 0

a r 0 87  o   M ok 9

 Tolman71

86 Carys Mills Formation. Interbedded dark gray

45 77 Mill Priveledge Brook. R usty-weathering, black, 83  Hill SOcm

 micrite and lighter gray dolomicrite with subordinate SOmp pyritiferous, highly carbonaceous mudstone and shale  SOcm 83 80 13  calcareous and non-calcareous phyllite and sparse

9A,B 78   71 interbedded with lithic sandstones, granule  83

U 86    calcareous wacke. Bedding commonly obscured or D  86  conglomerates, and quartzofeldspathic sandstones.

82  66  79 obliterated by transposed layering. W hen visible, beds 68  82 

31 range from 5 to 15 centimeters; transposed layers are N

4  e 0 o 0 63 9 r

 6 

0 71 g t thinner (millimeter to centimeter scale). 0  h 31

d R     i

79 d Osm  

77 R 81 R d

k 

Broo 76 pruce   Miramichi terrane    S 76  82  n 7  tL 0 es  0 r   Fo Late Early Ordovician - early Middle Ordovician [O] Osm 84 

d arm Stetson Mountain Formation. Chalky white weathering felsic to intermediate, fine-grained to very fine grained ashfall tuffs and fine- 6 d R 88 F o  0 sgo y 00   O 6 0 it Osm Ssr c i grained to medium-grained crystal and lithic ashflow tuffs. S ubordinate discontinuous horizons of thinly interbedded dark gray 84 l e n F

80 i mudstone, feldspathic siltstone, and manganese-rich mudstone.

k 87 D   a 78 s n  f 30 p  o r e t

in h  80  Bowers Mountain Formation. S ulfidic, black, carbonaceous shale with subordinate beds 10–30 centimeters thick of quartzose

 e a R SOcm h t d 86 30 Obm n 83  600 S u  sandstone passes upward in the formation into alternating zones of black (carbonaceous) and dark gray (non-carbonaceous) shale thinly

S o 69 O h 70 interbedded with quartzose and quartz-feldspar siltstone. In the contact aureole of Passadumkeag R iver pluton, shales are converted to e M 

s e g

s o

k 80 cordierite-biotite-muscovite hornfels; sandstones to dense quartzose hornfels. d Obm 89  i

SOcm n  R 

 d   R 84  d d Lin seyB 81 r   o o 45°25'00"N   k 45°25'00"N   0 8176 66 0 EXPLANATION OF SYMBOLS  7

d  00 Carroll 6 R   in 0

ff 70

o Note: S tructural symbols are drawn parallel to strike or trend of measured structural feature. Barb or tick indicates direction of dip, if known. Annotation C 

29 82  6C,F gives dip or plunge angle, if known. For planar features, symbol is centered at observation point. For linear features, tail of symbol is at observation

7  66  8 0 0 point. Multiple measurements at a site are represented by combined symbols. S ymbols on the map are graphical representations of information stored in 0 0  29  51   61 a bedrock database at the Maine Geological S urvey. T he database may contain additional information that is not displayed on this map.

0  0  0  1 O 6B  l  i v  e 6 r d Outcrop of mapped unit. 20 Transposed layering (inclined). «¬ R R

d n   t B

 r M o  w 79 Gates rs   0 n e R ock chips from drilled well. Cleavage (inclined, vertical). e = early.  0 20 R w 6 Ssr o Osm 

d Hill B

20 

    70  Float presumed to represent underlying bedrock. Lineation, unspecified (plunging).

28 74 00 76 73  10 20 20

  Fold ax ial plane (inclined); fold ax is, plunging

81 77 80      28 20 Quartz vein (inclined, strike only). 20

Weatherbee    (unknown rotation, sinistral rotation sense).

0 0 69

 80 7 

Hill  

 86 66 83    Bedding, inclined (tops unknown, tops known,   Phyllonitic foliation or foliation in brittle shear zone

 82 og 77

 Obm  B 20 20 20 20

71 sey  72 overturned); vertical (tops unknown, tops known). (inclined, strike only). 84 S C   KossarR d d  n

p  a 58 69 Li  81

r r 71 67  i r  n 

o     g l  76    l 50  Flow fabric in volcanic ash flow (inclined). J oint or joint set (inclined, vertical). f 73 66 20 20

i P  e 69 l 22 l

t 0

1 0

  1 0

0 0 1 0 9 75   n 85 70 1 Photo location. Numbers refer to figure numbers

27 s   in the report. t   

69 0  e 67 0 t 49

7 27

74 S 

 0 73  GEOLOGIC TIME SCALE 0 86

icker R d 8  71 D 75 Obm

   Geologic Age Absolute Age*

 900 Cenozoic Era () 0-66

 

  EXPLANATION OF LINES 

 Mesozoic Era () Osm 77 d 00  8 R71  19 K n 84 ___Cretaceous Period ( ) 66-145 w  82 o R d 83 r ose 80 B Mo ___J urassic Period (J) 145-201  79 0

0 ___Triassic Period () 201-252

 8 Contact between rock units, of stratigraphic or intrusive origin. 78     81 in Paleozoic Era () 6 Location is constrained by bedrock outcrops indicated by symbols on the map. 0 ta 0 0 0 26 D  n 1 ___Permian Period (P) 252-299 U u 1 The location of some contacts is not well constrained. o C Osm M 26 ___Carboniferous Period ( ) 299-359

s  B r

o F e Dbpr ___Devonian Period (D) 359-419 t la  t

le nd w

L er o Ssr 8 s  S

ak 00 R B ___S ilurian Period ( ) 419-444 e d 84  600

72 0 U R 0 00 d 0 1 ___Ordovician Period (O) 444-485 8  0

ro 00 D B 0 87 8 ___Cambrian Period () 485-541

0 

o g 7 B  84 0 High-angle fault (well located, approx imately located).

 0 Precambrian time (p) Older than 541

74 7

62 3 79

0 82

0 U D  

  The sense of inferred relative motion is indicated by = up and = down.

8 68  82

  

76  71 0 G Obm    0  R d e * In millions of years before present. (W alker, J .D.,  nt 7 tc 65 oi  he k Arrows indicate sense of strike-slip motion.

72  84 P ll Broo 78

68 R ocky  Geissman, J .W ., Bowring, S .A., and Babcock, L.E., compilers,

0 88 Obm 0  Lo  6  72 well 71 Dbpr 800 2012 Geologic Time S cale v. 4.0: Geological S ociety of 67 6 50 000 0  d 0 70 25 mN Lake Ba 0 R rke America, doi: 10.1130/2012.CTS 004R 3C.) s R d k r B en c tev ro 60 50 S u ok 0 000 0 25 m B N 0 0 0 6 7 allace Brook 45°22'30"N W 45°22'30"N 569000mE 70 71 72 73  74 75 76 77 578000mE 68°7'30"W 68°5'00"W 68°2'30"W 68°00'00"W REFERENCES

Ayuso, R obert A., 1984, Field relations, crystallization, and petrology of reversely zoned granitic plutons in the Bottle Lake Complex , Maine: U. S . Geological S urvey, Professional Paper 1320, 58 p. report, map, scale 1:125,000. n n

i ¼ n a  Base map features from Maine Office of GIS - 1:24,000 US GS contour a Hopeck, J ohn T., 1990, Tectonic fabrics of the Passadumkeag R iver pluton, Bottle Lake complex , S pringfield and S craggly Lake 15-minute T

SOURCES OF GEOLOGIC INFORMATION o t 1:24,000 S CALE M m s r Potter n t g a u u e n g e t lines, E911 roads, 1:24,000 National Hydrography Dataset, US GS GNIS o i quadrangles: Maine Geological S urvey, Open-File R eport 90-25b, 7 p. report, 4 figs., map, scale 1:62,500. Hill 1 0.5 0 1 Mile n S N

K e M

Field work by Allan Ludman, 1979–2014. t o i placenames and 1:24,000 political boundaries. Map projection Universal c r d t

l Hopeck, J ohn Thomas, 1998, S tratigraphy and structural geology of the W ytopitlock and S pringfield fifteen-minute quadrangles, eastern Maine: Ph.D.

N h i s e r i

Field work by J.T. Hopeck, 1986–1998. a o f t e Transverse Mercator, North American Datum, 1927. 1000 0 1000 2000 3000 4000 5000 6000 7000 Feet r g n Dill t w dissertation, City College (CUNY ), New Y ork, 160 p.

n h Maine u i Published mapping by R .A. Ayuso, 1984. o o r Hill B p M

S Ludman, Allan, Hopeck, J ohn T., and Brock, Pamela Chase, 1993, Nature of the Acadian orogeny in eastern Maine: in R oy, David C., and S kehan, 1 0.5 0 1 Kilometer The use of industry, firm, or local government names on this map is for y Approx imate Mean l e g J ames W . (editors), The Acadian orogeny; recent studies in New England, Maritime Canada, and the autochthonous foreland: Geological k W eir Bottle g Declination, 2017 location purposes only and does not impute responsibility for any present a a

r o L Pond Lake c 17 W S ociety of America, S pecial Paper 275, p. 67-84. S or potential effects on the natural resources. CONTOUR INTER V AL 20 FEET Ludman, Allan, Hopeck, J ohn, and Berry, Henry N., IV , 2017, Provenance and paleogeography of post-Middle Ordovician, pre-Devonian sedimentary basins on the Gander composite terrane, eastern and east-central Maine: implications for S ilurian tectonics in the northern Appalachians: Atlantic Geology, v. 53, p. 63-85. doi: 10.4138/atlgeol.2017.003. 68°7'30"W 68°5'00"W 68°2'30"W 68°00'00"W Bedrock Geology of the

5 000 70 71 72 73 74 75 76 77 5 000 69 mE  78 mE

45°22' 30"N C 45°22'30"N S

 y 6 p a a  00

r r W

 Obm 74 i r s k r  n o e 88 o

76 7 dn ro 00 g l r B Bottle Lake Quadrangle, Maine a  l ce f G lla 700 0 a

i P 84 68 5 0 W e B 00 6 l u

l t c

d d k  77 R R  v   d  n R d Bedrock geologic mapping and compilation by

n Obm  ntai 00  Mou w  ll H 7 e

0 83 h F Ssr o 74  tc 0 e i r G r l  6 14B i  e

l B T d Lowel n 7 l Osm

d Allan Ludman and John T. Hopeck o

0 R 0 78  s

p 80 e

0 ac t  h 8 P l  i 

R Lake p  L d u Vinegar

1 n

8 Getche a 6 ll 80 0 0

0 0 0 f  0

 0 0 0 0  0 9

7  Hill

 Digital cartography by Geologic editing by Cartographic design by

50 000 Mtn 800  73 

24 mN 78 87

0 R d v

0 7 owell 76  L v  84 86

S outh     50 000 Susan S. Tolman Henry N. Berry IV Christian H. Halsted

d 7  Dbpr 00 24 mN

71 R S pringfield h 6    0

c  R T 0

r B  Amber T. H. Whittaker 80 i i o

o c a

B t k a d

t e   l R

e r u

 R n 66 L

700   a d R

66 k 70 Dbpr d R d 21 80 

Moores e R d  y 

R alit 60 R e    d 69 lt   oll P P Robert G. Marvinney 83 arr  a C g v e lle  s evi 4 k R 0 18B La S 0 Osm v  d ha w R State Geologist id g e

Ch 

ase D  R d

R d U    S  85  ha

23 5 La Funding for the field work and preparation of this map was provided by the Maine Geological Survey.  00 70 k 74   e R n i i dg 23 6 e a 0 Ssr t D 0 uc  n k

ld u 41 L

gfie 60 a prin o ke S 86  53 R lle d evi M 5 Lak 00   Dbpr R Open-File No. 20-22 a b b Maine Geological Survey 7 it M 0  0 R a eA u

c ly n c

n M k 2020 a 60 r  L il

e l H l o P

w r i o 70 Obm iv l Address: 93 State House Station, Augusta, Maine 04333 T 0 e i  5  l l L le 00 Spauld n l ow g

ing ell B e Plate 3  o rook R Telephone: 207-287-2801 E-mail: [email protected] Pond s B d t ro Spa k o ul oo e k d Home page: www.maine.gov/dacf/mgs/ ding Br t R R E d s r Dbp This map supersedes a portion of 22 S b 65 n b ie S pa o s uld H R ing lR d MGS Open File No. 90-25b. P B  el G o  Gow d e 22 n e tc d a h B

r e irch R d c ll Hill

GapR d e Bro R d

R  ok

d   B Penobscot   a rke T r B o R ro w o Plt v n o k roll Bald n ar 7 t c C 0 k p 0 H y T w 6 EXPLANATION OF UNITS M kon Mtn 0  a R Puka 0

ll d 5

d  R 0 4 r Obl d 00 0   Dbpr 5 a 900  00 INTRUSIVE ROCKS b W m eym Mill Privilege 10 o o E Almanac0 u n 0 th L a 76 Br Middle Devonian [D] L g ook e Lake l R d s e  nt Mtn i o 800 900 Long Po 21  R 700 R i d 90 g 6 Passadumkeag River pluton. Coarse-grained biotite-hornblende granodiorite. Locally porphyritic with larger alkali feldspar 0 e 00 R  Duck Lake 21 Dbp 8 d 00 B phenocrysts up to 5 centimeters in a coarse-grained matrix . Mafic enclaves (x enoliths of Ayuso, 1984) are common. o 5 t e D 00 t i l l e k l x  V  L v

a a ll a e e l Rim facies. Coarse-grained hornblende-biotite granite. S omewhat lower color index and higher ratio of biotite to y k 

R e L p

  d Junior Dbpr S R p d e hornblende than rocks in the core facies of the pluton. Patterned area near the margin of the pluton north of Duck Lake

a l

ul m

d t i  Mtn n o g P 500 t o Pi contains abundant leucocratic dikes. n n o d C

R e n 400 d C L  D on B ill Broo e on  v k T r Lo Dbpr k R d Dbpr l Whitney Cove pluton. Medium-grained to coarse-grained biotite granite. Mapped in the southeast corner of the quadrangle based on Broo Lombard mouth Dbw Lake  W ey v ex posures to the south and east (Ayuso, 1984). Ln 45°2 0'00"N ce 45°20'00"N an h Lom  C bar L M 20 d R d o u v  n w g i P n  o R STRATIFIED ROCKS

 in d 20 t  R d D e e r Note about terminology. S tratified rocks in this quadrangle are in the lower greenschist facies of regional metamorphism. Because sedimentary s Dbp r R h u  S n features are widely preserved at such a low metamorphic grade, sedimentary rock names are used in the unit descriptions to emphasize their e l  l i

v  e depositional character with the understanding that all stratified rocks have been metamorphosed. k

a  D L 90 0 il  M H l e a R m r 80 v o v Aroostook-Matapedia Basin 0 id r e y  y U 7 g pp 00  Ln v e e R rP

u 6 d g 00 H V Silurian [S]

R i ist l avi d l ew t R d o  p 80 s

0 R Sam Rowe Ridge Formation. Thinly bedded to medium-bedded (5–20 centimeters) turbidites with nearly equal proportions of pale s

p d 19  Junior Lake i Ssr t Keg Lake u gray or chalky buff weathering, variably calcareous siltstone to fine-grained sandstone and dark gray, strongly cleaved non-calcareous o Upper n r 4 e 00 19 r mudstone. 1–3 millimeter limonite spots weathered from pyrite and/or ankerite are locally characteristic of both siltstone and G

Dbpr L P a k mudstone.

B e F Pug v

Ln o i

s i r e t l k l e

a t e

L  l f r e 00 ou l 6 F S y h L Miramichi terrane r L a s k n Lake  e R P K u d g e Late Early Ordovician - early Middle Ordovician [O] Dbpr  g L a L k  n e s R d Dbp Stetson Mountain Formation. Chalky white weathering felsic to intermediate, fine-grained to very fine grained ashfall tuffs and fine-

500 Osm

T grained to medium-grained crystal and lithic ashflow tuffs. S ubordinate discontinuous horizons of thinly interbedded dark gray 4  00 lc U L p n mudstone, feldspathic siltstone, and manganese-rich mudstone. p 18 e

r P  D u L

v g e p a L 18 Bowers Mountain Formation. S ulfidic, black, carbonaceous shale with subordinate beds 10–30 centimeters thick of quartzose o k S d e a t k 00 R v Obm tr 5 R il e P e O d le v Dbpr sandstone passes upward in the formation into alternating zones of black (carbonaceous) and dark gray (non-carbonaceous) shale thinly

ic a ld S il m n

k T h le 5 e o o

00 r w t r S

e e l s C r i l R o h interbedded with quartzose and quartz-feldspar siltstone. The upper part of the formation is ex posed in and southeast of S outh P d d r

oin m y s t a R d W

 H S pringfield. In the contact aureole of Passadumkeag R iver pluton, shales are converted to cordierite-biotite-muscovite hornfels; a Bottle Lake y  sandstones to dense quartzose hornfels.  Lower Dbp Early Ordovician - Cambrian [O] 60 0 W

Pug Lake 7 i 40 Bam 00 nd 0 aR

y S d S horesR h Baskahegan Lake Formation. The typical rock type, ex posed in adjacent quadrangles, consists of thick-bedded (up to 2.5 meters)   d o e b T Obl L o r o d x a quartzofeldspathic wackes and quartz arenites in massive beds and in graded turbidite sequences with siltstone and shale (Ludman and

p w R L Dbpr d e  B p

r n s e e R 17 R e a B Dbp k  r d a Bear Mounta r L in s nt others, 1993; Ludman and Berry, 2003). In the Bottle Lake quadrangle, the Baskahegan Lake is mapped only on Almanac Mountain 30  Pug M o oi P P a o t r P u t n t r r 17 near the contact with the Passadumkeag R iver pluton, where it is hornfels. The hornfels is unusually rusty weathering, attributed to t i iv 700 a r l d a in e g t D e e R d r P interaction with fluids from the pluton. W ackes are intensely recrystallized to medium to thick bedded (20–50 centimeters) quartz- d a ro ll R pe 5 r 0 a u ty 0 E M n L feldspar granofels with abundant biotite and sparse cordierite. S ubordinate pelitic hornfels is a coarse-grained metamorphic a n

t S assemblage of cordierite + biotite + muscovite.  h L

70 o a v  0 r e k R e d B

a B y o EXPLANATION OF PATTERNS v v Q y i c u e e a w R C i 5 l ed 00 Pin o S R e R v y s d Ln d Stream e R egion with abundant leucocratic dikes. R M R d o d o se Dbp R u 16 n R d P u 16 L k a EXPLANATION OF SYMBOLS a k k d o e R n v Upper t

i o T n l p L Dbp l w e e Note: S tructural symbols are drawn parallel to strike or trend of measured structural feature. Barb or tick indicates direction of dip, if known. Annotation

Sysladobsi y s Lake d D t i p Junior Lake

n R e gives dip or plunge angle, if known. For planar features, symbol is centered at observation point. For linear features, tail of symbol is at observation r 45°17'30"N e am 45°17'30"N S re W ildernessW ay S t point. Multiple measurements at a site are represented by combined symbols. S ymbols on the map are graphical representations of information stored in

400 W a bedrock database at the Maine Geological S urvey. T he database may contain additional information that is not displayed on this map. i t y c a h W H U p t o per a b D bc b o l Outcrop of mapped unit (small ex posure, large area of ex posure). bs o e isR B d R  d d 15 R 500 S e a dl Outcrop of massive rock having no foliation. Up lm Sysladob id per o T sis Lake  S n all M 15 ys R Pi la d neT d r o l   b Dbp s Leucocratic dike (inclined, vertical). v = variable dip; a = aplite; g = granite. T i  r s R 20a o u S ed t tre R d am P  in 

e  Bedding, tops unknown (inclined, vertical).

R 20 d 

S   h C e Inclined bedding, tops known (upright, overturned). o i 20 l y a o D te v r  Trl   20 Cleavage (inclined, vertical). D d epot R    Foliation (inclined, vertical). v = variable dip. 14 400 20

 14  v Foliation in brittle shear zone (inclined).  20 80 Dbpr  F 20  o  x  Fold ax is (plunging).  R Po v un ss  um W 50 ay  0    20 J oint or joint set (inclined, vertical). v = variable dip. W

ilso n    g D r a  C ra 4 n 00  d 4 Photo location. Numbers refer to figure numbers in the report. be s R 0 1 rr w 0 y C a o 5 Br rr 0 o r a  o a v 0 N k w E Dbpr

fi a

sh  st S  Dbp L   h 4 n o C 00 re 6 h  0 a  R 13 0 m 18 d GEOLOGIC TIME SCALE be  rla  13 in  Geologic Age Absolute Age* R  500 id  Cenozoic Era () 0-66

d Mesozoic Era () R  EXPLANATION OF LINES Dbpr Ch t amb o K erla p 400 Dbp ___Cretaceous Period ( ) 66-145 in e  R i d D ge ___J urassic Period (J) 145-201 R d  400 ___Triassic Period () 201-252 H o Contact between rock units, of stratigraphic or intrusive origin. r se Paleozoic Era ()  sh o Location is constrained by bedrock outcrops indicated by symbols on the map. e P C ___Permian Period ( ) 252-299 o v The location of some contacts is not well constrained. e Dbw ___Carboniferous Period (C) 299-359 R 12 d ___Devonian Period (D) 359-419 U 12 ___S ilurian Period (S) 419-444 le D O Lakevil ___Ordovician Period ( ) 444-485 S t T wp High-angle fault (well located, approx imately located). ebb OT CO S akom ___Cambrian Period () 485-541 ins OBS C  R d PEN CO The sense of inferred relative motion is indicated by U = up and D = down. NGT ON Precambrian time (p) Older than 541 Sysladobsis Lake W AS HI Dbpr

Dbp d * In millions of years before present. (W alker, J .D.,

e Geissman, J .W ., Bowring, S .A., and Babcock, L.E., compilers,

h Dbp S 2012 Geologic Time S cale v. 4.0: Geological S ociety of CO E Dbw BS COT America, doi: 10.1130/2012.CTS 004R 3C.) PENO O ille COCK C 50 000 Lakev HAN 11 mN Taylor Brook  iton T wp Oq 50 000 REFERENCES 45°15'00"N 11 mN 45°15'00"N 569000mE 70 71 72 73 74 75 76 77 578000mE 68°7'30"W 68°5'00"W 68°2'30"W 68°00'00"W Ayuso, R obert A., 1984, Field relations, crystallization, and petrology of reversely zoned granitic plutons in the Bottle Lake Complex , Maine: U . S . Geological S urvey, Professional Paper 1320, 58 p. report, map, scale 1:125,000. Hopeck, J ohn T., 1990, Tectonic fabrics of the Passadumkeag R iver pluton, Bottle Lake complex , S pringfield and S craggly Lake 15-minute quadrangles: Maine Geological S urvey, Open-File R eport 90-25b, 7 p. report, 4 figs., map, scale 1:62,500. d l n i s

e ¼

r  Base map features from Maine Office of GIS - 1:24,000 U S GS contour i a Hopeck, J ohn Thomas, 1998, S tratigraphy and structural geology of the W ytopitlock and S pringfield fifteen-minute quadrangles, eastern Maine: Ph.D. SOURCES OF GEOLOGIC INFORMATION T t

f 1:24,000

e S CALE M r n g Dill w a u u n i o g e lines, E911 roads, 1:24,000 National Hydrography Dataset, U S GS GNIS o

r dissertation, City College (CU NY ), New Y ork, 160 p. Hill 1 0.5 0 1 Mile n

B N

p e M S

Field work by Allan Ludman, 1979–2014. t o i placenames and 1:24,000 political boundaries. Map projection U niversal c r

t Ludman, Allan, and Berry, Henry N., IV , 2003, Bedrock geology of the Calais 1:100,000 quadrangle, Maine: Maine Geological S urvey, Open-File Map

y N h Field work by J.T. Hopeck, 1986–1998. l e g o Transverse Mercator, North American Datum, 1927.

k 1000 0 1000 2000 3000 4000 5000 6000 7000 Feet r W eir Bottle g t a a 03-97, color map, scale 1:100,000. Maine h r

Published mapping by R .A. Ayuso, 1984. L

Pond Lake c S Ludman, Allan, Hopeck, J ohn T., and Brock, Pamela Chase, 1993, Nature of the Acadian orogeny in eastern Maine: in R oy, David C., and S kehan,

e 1 0.5 0 1 Kilometer The use of industry, firm, or local government names on this map is for n v i Approx imate Mean o a

t J ames W . (editors), The Acadian orogeny; recent studies in New England, Maritime Canada, and the autochthonous foreland: Geological C

S pring n Duck Declination, 2017 location purposes only and does not impute responsibility for any present u k o r Lake Lake o a 17 W S ociety of America, S pecial Paper 275, p. 67-84.

M or potential effects on the natural resources. D CONTOU R INTER V AL 20 FEET Ludman, Allan, Hopeck, J ohn, and Berry, Henry N., IV , 2017, Provenance and paleogeography of post-Middle Ordovician, pre-Devonian sedimentary basins on the Gander composite terrane, eastern and east-central Maine: implications for S ilurian tectonics in the northern Appalachians: Atlantic Geology, v. 53, p. 63-85. doi: 10.4138/atlgeol.2017.003. 68°15'00"W 68°12'30"W 68°10'00"W 68°7'30"W Bedrock Geology of the

559000mE 60 61 62 63 64 65 66 67 568000mE

45°22'30"N  45°22'30"N

81  73

d  700 68  U

R D

t s  W 0 Weir Pond Quadrangle, Maine

o 0 35 7 h 87  r 00 M  7 i

«¬6 G g 0 i h 0  l 0 400 0 74 l t 6 5 s H SOcm

e M Bedrock geologic mapping and compilation by 0 i  18 l i

0 SOcm l

g l 5 d l

R R 71 d R S  e d rue  g d 6  id i 78 68  T 0 t 0 R Ssm 0 r e Ssm 0 m an 82 Allan Ludman and John T. Hopeck h a 0 4 us R C 7 0  m 0 7 83 n 0 Ssr a Drak e Place 5024000mN SOcm m d  (historical) 0 R 40 h e Digital cartography by Geologic editing by Cartographic design by

dg 50 000

s Lo 79 24 mN u ut  arc C Cle Susan S. Tolman Henry N. Berry IV Christian H. Halsted 7 B 00 B a R e r t

a Amber T. H. Whittaker l i e n

Ssm  v t g

e t

r R 6 68 R 0 D  80  # B d d t 0 r l a o 71 k g u

 e R R Buxton a SOcm R f d d d t Robert G. Marvinney

 71 f

d o R r y  Ginle  67 # Egg Mc c 500 77 State Geologist  n Pond a

G 00 6 B

h o C D  h s i rty G 67 h as t lo e  ve R t R  R d d 23 r d 88 81 5 o S 0 0 0 p 0 Funding for the field work and preparation of this map was provided by the Maine Geological Survey. N d 6 23 r l R i il S n  23 H L SOcm p g   Obm a e ll # f e u e dw M i rea l e 0 T d 0 i i

l 71 72 6  l n d G l

d g R H 5 Ssr  

0 0 r i B 0 e 0 l

7 a l r

g o

d n o i R 74 i d k

R t R

40 e d  t 500 k

u S o Open-File No. 20-22 17A c pau o  i Ssm ld r t  i 73 ng B c Maine Geological Survey e 4 n 0 n 77 0 o 2020 C 0 73 70 R Tredwell id Address: 93 State House Station, Augusta, Maine 04333 tlett Stream g Plate 4 Bar Hill e Telephone: 207-287-2801 E-mail: [email protected] 22 R e id it ge Home page: www.maine.gov/dacf/mgs/  n Rd This map supersedes a portion of 70 a 84 0 r 22 G  MGS Open File No. 90-25b. 0  0 0 5 0 Ssm 600 7

  SOcm  11 D 70 SOcm Dbpr W 76  e 88 g 17B e id i r R 

 P t o u n ic Dbpr 60 d t EXPLANATION OF UNITS  c R e d n 0

n 0

o 6 d C  Ced R arDr l S il p INTRUSIVE ROCKS  a 6

00 H L u

ll ld d  e o i fiel w n ring d Oa T m g S p a k M oz v Middle Devonian [D] 21 re oun ie P lle ta r b o e85vi T inR L

Lak d n a n Lombard 6 d 0  0  r 21 R 80 6 d d d 0 Mtn800 e n Passadumkeag River pluton. Coarse-grained biotite-hornblende granodiorite. Locally porphy ritic with larger alk ali feldspar 0 700 L k B

 x Dbp a 7 a e

n 0 600 phenocry sts up to 5 centim eters in a coarse-grained m atrix. Mafic enclaves (xenoliths of Ay uso, 1984) are com m on. 0 l r Weir 6 8 k o 00 0 L  0 p h e e s y O ak e o Dbpr

w Pond l o r  m

T t M o Rim facies. Coarse-grained hornblende-biotite granite. S om ewhat lower color index and higher ratio of biotite to d Mountain t n 900 o  o Dbpr Round P C hornblende than rock s in the core facies of the pluton.

4 B B 0 5 6 0 u 0 0 0 d  0 d 0 R v 0 g d 6 e r ba F m a o r L m 0 e d Le 0 P R R  5 STRATIFIED ROCKS NBP s d  R1 bsi T 3 Do  er 45°20'00"N pp  4 U 5°20'00"N Note about term inology. S tratified rock s in this quadrangle are in the lower greenschist facies of regional m etam orphism . Because sedim entary 20 5

0 d features are widely preserved at such a low m etam orphic grade, sedim entary rock nam es are used in the unit descriptions to em phasize their R 20 lf

wo er depositional character with the understanding that all stratified rock s have been m etam orphosed.  b d im R T Car n ib N i ou a R t u Aroostook-Matapedia Basin Aroostook-Matapedia Basin n n u  o 6 Distal facies Intermediate facies 500 M 0 0 k T a h u O rl ow Silurian [S] Silurian [S] B r Dbp ook r 0 Dbpr p

0 B

6 Smyrna Mills Formation. T hinly interbedded u Sam Rowe Ridge Formation. T hinly bedded to   r e t o S Ssm Ssr s r u (com m only 2–7 centim eters) silt-m ud turbidites m edium -bedded (5–20 centim eters) turbidites with T 4 i B T rl 00 m ees G  tr be m ttle a i ty pically in well-graded couplets. Mudstone/slate s nearly equal proportions of pale gray or chalk y buff 19 rw L o D s

l i 00 f R t 6 d m ak es up about 65% of form ation overall but weathering, variably calcareous siltstone to fine-  19 n v proportions vary within and between outcrops. e grained sandstone and dark gray, strongly cleaved

 r B  P v r ru e in P Mudstones are ty pically m edium to dark gray, non-calcareous m udstone. 1–3 m illim eter lim onite iv at  5 U h R 0 p S 0 p g e  a a p 700 siltstones m edium gray but weathered siltstone spots weathered from py rite and/or ank erite are locally e r Dbpr l D i k n o  g m b B  surfaces are pale buff. Bedding is com m only obscured characteristic of both siltstone and m udstone. u s

d i r Pas s p

Branch sa a st du s R 00 We  6 m s u k d or obliterated by transposed lay ering parallel to axial 300 eagR a  o

No 3 i P

v h

r c

e  

r n planes of upright folds. Adjacent to the pluton, contact a

G Pond r

 B v

g m etam orphism has produced quartzofeldspathic

s INTERPRETIVE STRATIGRAPHIC

Dbp a a

E 70 Lower PugS e granofels with red-brown biotite and cordierite- tre am k RELATIONSHIPS e m bearing m ica-rich hornfels with a pitted appearance a n e 18 r

t x ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !  S due to weathering of the cordierite. u rd  18 d ba om e 4 L Silurian-Ordovician [SO] 0 0 M Ssm Ssr D 0 00 0 a 4  5 m  Carys Mills Formation. Interbedded dark gray 5 6 0 SOcm ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! R 0 ! Rand Hill 0 ! i 0 S m icrite and lighter gray dolom icrite with subordinate ! d y ! v s g ! Pa R e s ! s d 5 calcareous and non-calcareous phy llite and sparse a 0 ! d 0  ! u

! m 4 calcareous wack e. Bedding com m only obscured or ke 0 ! 0 agR ! iv obliterated by transposed lay ering. W hen visible, beds ! E e ! r ! n SOcm g ! s t range from 5 to 15 centim eters; transposed lay ers are ! r ! o ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! m R thinner (m illim eter to centim eter scale). Adjacent to d 43 Upper 17 Sysladobsis Lake the pluton, the rock has recry stallized during contact  17 m etam orphism to banded greenish-white calc-silicate

U pp  hornfels and dark purple-gray biotite-rich hornfels.  e rD ob si d sR Farm R d rry Miramichi terrane Ca

Dbp

300 Rand Br Late Early Ordovician - early Middle Ordovician [O] ook   v d L nd Brook R Ra it   Bowers Mountain Formation. S ulfidic, black , carbonaceous shale with subordinate beds 10–30 cm thick of quartzose sandstone t Obm

le passes upward in the form ation into alternating zones of black (carbonaceous) and dark gray (non-carbonaceous) shale thinly

3 U n

4 0 Dbpr 0 0 p L T 0 p  er interbedded with quartzose and quartz-feldspar siltstone. In the contact aureole of Passadum k eag River pluton, shales are converted to w D x ob n 16 o si y  s L m Rd cordierite-biotite-m uscovite hornfels; sandstones to dense quartzose hornfels. b 16 ly

R id EXPLANATION OF SYMBOLS g e

C a Note: S tructural sy m bols are drawn parallel to strik e or trend of m easured structural feature. Barb or tick indicates direction of dip, if k nown. Annotation r 300 r y 6 45°17'30"N 0 5 45°17'30"N 4 0 Dbp 0 Fa 0 gives dip or plunge angle, if k nown. For planar features, sy m bol is centered at observation point. For linear features, tail of sy m bol is at observation 0 rm 0 300 Rd  4

0  point. Multiple m easurem ents at a site are represented by com bined sy m bols. S y m bols on the m ap are graphical representations of inform ation stored in 0 Dbp  a bedrock database at the Maine Geological S urvey. T he database m ay contain additional inform ation that is not display ed on this m ap.

d 15 R m Outcrop of m apped unit. o r t s 15  g n T E 3 L

a R Outcrop of m assive rock having no foliation. k

1  e

v N i l B l e P Float presum ed to represent underly ing bedrock . Brown  B o P r ok    Leucocratic dik e (inclined, vertical). v = variable dip. 20

Dbp d R  k  o Bedding, tops unk nown (inclined, vertical). o 20 r B r lo y Patterson   300 a T 20 Cleavage (inclined, vertical). 14 B

 og

14  Feldspar alignm ent in plutonic rock (vertical).  20

 Fold axis (plunging). Dbp 400  Chamberlain   Cataclastic surface (vertical). P Raidge v tt Dbp er so   n 20 J oint or joint set (inclined, vertical). v = variable dip. 85 B o ok g ro R 3  00 B d aylo r 5 Photo location. Num bers refer to figure num bers in the report. ttle T 0 1 Li 0

13 rkl Tu oin Brook 13

EXPLANATION OF LINES GEOLOGIC TIME SCALE 85  Geologic Age Absolute Age*

T Cenozoic Era () 0-66 a d y R lo e Mesozoic Era () r g 40 d B 0 i R Contact between rock units, of stratigraphic or intrusive origin. r K o n ___Cretaceous Period ( ) 66-145 o 00 ai k 5 l Location is constrained by bedrock outcrops indicated by sy m bols on the m ap. er H R b ___J urassic Period (J) 145-201 d T am A h T he location of som e contacts is not well constrained. E C ___T riassic Period () 201-252 H

 E Paleozoic Era () 12 R 30 C d 0 ___Perm ian Period (P) 252-299 300 A R 12 0 0 U ___Carboniferous Period (C) 299-359 0 300 1 e ___Devonian Period (D) 359-419 W v D hee o ler B r ro G ___S ilurian Period (S) 419-444

o High-angle fault (well located, approxim ately located). k e l

p a Tay U D ___Ordovician Period (O) 444-485 lor Br T he sense of inferred relative m otion is indicated by = up and = down. Dbp M ook Arrows indicate sense of strik e-slip m otion. ___Cam brian Period () 485-541 Precam brian tim e (p) Older than 541 Dbp * In m illions of y ears before present. (W alk er, J .D., # # Geissm an, J .W ., Bowring, S .A., and Babcock , L.E., com pilers,

5011000mN T hrust fault. 2012 Geologic T im e S cale v. 4.0: Geological S ociety of

00 50 Am erica, doi: 10.1130/2012.CT S 004R3C.) 3 11000mN T eeth on upper plate.

45°15'00"N 45°15'00"N 559000mE 60 61 62 63 64 65 66 67 568000mE 68°15'00"W 68°12'30"W 68°10'00"W 68°7'30"W REFERENCES

Ay uso, Robert A., 1984, Field relations, cry stallization, and petrology of reversely zoned granitic plutons in the Bottle Lak e Com plex, Maine: U . S . Geological S urvey , Professional Paper 1320, 58 p. report, m ap, scale 1:125,000. d l n i s

e ¼

r  Base m ap features from Maine Office of GIS - 1:24,000 U S GS contour i a Hopeck , J ohn T ., 1990, T ectonic fabrics of the Passadum k eag River pluton, Bottle Lak e com plex, S pringfield and S craggly Lak e 15-m inute SOURCES OF GEOLOGIC INFORMATION T t

f 1:24,000

e S CALE M r n East g w a u u n i o g e lines, E911 roads, 1:24,000 National Hy drography Dataset, U S GS GNIS o

r quadrangles: Maine Geological S urvey , Open-File Report 90-25b, 7 p. report, 4 figs., m ap, scale 1:62,500. W inn 1 0.5 0 1 Mile n B N

p e M S

Field work by Allan Ludm an, 1979–2014. t o i placenam es and 1:24,000 political boundaries. Map projection U niversal c r

t Hopeck , J ohn T hom as, 1998, S tratigraphy and structural geology of the W y topitlock and S pringfield fifteen-m inute quadrangles, eastern Maine: Ph.D.

Field work by J.T . Hopeck , 1986–1998. N h o T ransverse Mercator, North Am erican Datum , 1927. W eir Bottle 1000 0 1000 2000 3000 4000 5000 6000 7000 Feet r t dissertation, City College (CU NY ), New Y ork , 160 p. Published m apping by R.A. Ay uso, 1984. Maine Lee h Pond Lak e Ludm an, Allan, Hopeck , J ohn T ., and Brock , Pam ela Chase, 1993, Nature of the Acadian orogeny in eastern Maine: in Roy , David C., and S k ehan, 1 0.5 0 1 Kilom eter T he use of industry, firm , or local governm ent nam es on this m ap is for

c Approxim ate Mean a J am es W . (editors), T he Acadian orogeny ; recent studies in New England, Maritim e Canada, and the autochthonous foreland: Geological n S pring o Duck Declination, 2017 location purposes only and does not im pute responsibility for any present

p o a Lak e Lak e 17 W S ociety of Am erica, S pecial Paper 275, p. 67-84. S or potential effects on the natural resources. CONT OU R INT ERVAL 20 FEET Ludm an, Allan, Hopeck , J ohn, and Berry , Henry N., IV, 2017, Provenance and paleogeography of post-Middle Ordovician, pre-Devonian sedim entary basins on the Gander com posite terrane, eastern and east-central Maine: im plications for S ilurian tectonics in the northern Appalachians: Atlantic Geology , v. 53, p. 63-85. doi: 10.4138/atlgeol.2017.003.