University of New Hampshire University of New Hampshire Scholars' Repository New England Intercollegiate Geological NEIGC Trips Excursion Conference Collection 1-1-1989 The Chain Lakes Massif and its Contact With a Cambrian Ophiolite and a Caradocian Granite Boudette, Eugene L. Boone, Gary M. Goldsmith, Richard Follow this and additional works at: https://scholars.unh.edu/neigc_trips Recommended Citation Boudette, Eugene L.; Boone, Gary M.; and Goldsmith, Richard, "The Chain Lakes Massif and its Contact With a Cambrian Ophiolite and a Caradocian Granite" (1989). NEIGC Trips. 455. https://scholars.unh.edu/neigc_trips/455 This Text is brought to you for free and open access by the New England Intercollegiate Geological Excursion Conference Collection at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in NEIGC Trips by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. THE CHAIN LAKES MASSIF AND ITS CONTACT WITH A CAMBRIAN OPHIOLITE AND A CARADOCIAN GRANITE Eugene L. Boudette Gary M. Boone^, and Richard Goldsmith ^ 1 State Geologist, New Hampshire Geological Survey; ^Department of Geology, Syracuse University; ^U.S. Geological Survey (Ret.) INTRODUCTION The Boundary Mountains along the Maine — Quebec border form the height of land and watershed between drainage northward to the St. Lawrence River and southeastward to the New England part of the Atlantic coast. Along this part of the international boundary the highest peaks attain elevations of 3500 to 4000 feet (-1070-1220 m), and are held up by resistant rocks of the Chain Lakes Massif and the western part of the Boil Mountain ophiolitic complex (Boudette, 1982). The Boundary Mountains constitute the massif and the principal exposure of this distinctive basement, but exotic blocks of Chain Lakes granofels are found in the St. Daniel melange in southeastern Quebec and in its equivalent, the Melange ophiolitique du Ruisseau Nadeau, in the southeastern part of Gaspe peninsula (de Broucker, 1987), as detailed in Boone and Boudette (1989), and references therein. Inasmuch as the type locality of the Chain Lakes granofelsic basement is in the Boundary Mountains, we have termed the tectonic terrane underlain by sialic basement that is bounded by the two ophiolite and melange belts — the St. Daniel, along the Baie Verte Brompton line, and the Hurricane Mountain belt to the southeast — the Boundary Mountains terrane (fig. 1). The Boundary Mountains terrane was progressively covered by forearc turbiditic flysch of Late Cambrian to Early Ordovician age, followed by Mid- to Late Ordovician felsic and mafic volcanics and an unconformable northwest-transgressive shoreline-shelf, cyclic turbidite succession beginning in the Silurian. These rocks range in age up to Lower Devonian, immediately preceding the Acadian orogeny. Rocks of the Boundary Mountains terrane are intruded by calc-alkalic granitic rocks. Their ages range from Late Ordovician to Middle Devonian (fig. 2; table 1). The principal purpose of this trip is, first, to examine several lithologic and structural variants of Precambrian metamorphosed diamictite constituting perhaps the major rock type as seen in outcrops of the Chain Lakes Massif (Boudette and Boone, 1976), and second, to examine a part of the Hurricane Mountain Belt, where (1) the Boil Mountain ophiolitic complex is combined within a tectonostratigraphic succession with (2) metamorphosed volcanics and volcanogenic metasedimentary rocks (Jim Pond Fm.) and melange (Hurricane Mountain sequence), both probably of Middle to Late Cambrian age (table 1), and (3) a forearc basin flysch sequence (Dead River Fm.) of Late Cambrian to Early Ordovician age, which overlies the melange. The volcanics - melange - flysch succession is almost entirely unfossiliferous. The Hurricane Mountain melange is separated from the Chain Lakes Massif (CLM) by the Boil Mountain complex (Boudette, 1982). The Boil Mountain ophiolite lies in tectonic contact with the Chain Lakes Massif. The fault pattern (figs. 2a and 2b) is complicated by numerous normal and transverse faults, but the initial juxtaposition is best interpreted as 98 CLM FIGURE 1. Index map showing the accretionary configuration of major lithotectonic terranes in the northern Appalachian orogen. CLM, Chain Lakes massif; TPF, Thrasher Peaks fault. Modified from Boone and Boudette (1988, Fig. 4A). 99 © o in rt n Oo <D C 03 <DE 00 0> £ 03 u . G o0) G G 0300 <D > P4 c/3<d O O s u . CX<u CX G 0) o cx 03 £ O ’Eb <Do a cd <S w eti D a pu 100 • • V • % = \ ' = II - v ' \ \ v ^ v r » • \ \ v \ V - \' A\ \ - \ XX A >V • i \ ' ' ,v L \ v \\N \\v » ' % » ™ • * .. •••■ •• ■'..••••A v ■ - • .* " - ' S ''.'* ':> - \ \ \ V^ V VX \v // V <D --------------------------A • * * • a C * - ' * - . • . • • • • . •' . * > . •• ' » * ; \ ' \v\ • • ^ 0 • m' • # % . • * ' 4 X * • * . \* S'* • •• • * - S’ * > • * * * a v - - ' «*. i * ^ 'v\xV : ' A A UT. V —« ru; .• .v- - * • S i % • •% ■ % • • V* * *■ • ft . x * : * * v. %*» V \ E * » ” * . % •• > • • • <D • % A I - V \ % ■ V 9 * • % \\ % • * • • • • • c/5 f a I • • • 0 ) ; - -X- - •*- ' • - • • ' * y . .* - , A .. • • • -v ' . % * •’ "i • • • X .. X • , . » ^ I • X v . 4 , X - • • 1 • 4 I • \ •/ • /• 1 ^ •' • ^ .X • ' » - _ - • r . ' . • ••••/ X , • - • , • ' , * X * « Jr . *«■*•• • » / ) i •* > X\\V A ^ - •' ^ .•« •’; ; ;• •'• s } . :^y '*r'?/ \ C3 V - v u- ' % • • X / . ' • » . - .* . ■ A I A \ C I .• . •• .i * / 1 . * ♦ V ' y •; ^ .«\a 4 • • \ a-) o \ - \ 1 1 \ i W /•. • • • v W v / •• • • % U\/ \v I * • •• V. ■/ a v \ • % * • 9 Jf' - M * * \ • • \ \ % [ ^ ^ C /3 * • V f • ■ • V * A O r - V\ \ --v > v O > . ' \y - / ♦ • • C /3 V . ^ 1 • • • • • • • * % • • • • \ . % * • ‘V V t a « • • • o - 1 • : ' . .............. • 'I*'**. * 1 .* • • • • • \ v •• i •. V. *’ - % - \ <D • • • • U . r . i * <* 4 \ W v - V v v , w u. i n X ft A • \ O '* .*.*4 . *v .*■ •..• . * . * V # • » » 1, .• • .a •-'A • 4 * 1 * • \ • • ^ * % • ' ' ' " * * ■ •• • a A -' % • • • . • *. ..• . - M ’ • • • ft • • • • • » 3 VO V 7 r « • ft" . / _ • » : -- •* j . * •• J • • .ft • • • I • « . •» ' . v j» - v\ - JO * • / • a O ft % V * - • \ * l ft «ft • a • • *ft U • ft • • N \ aa L% • ft • ft ^ • - • . ‘ - a * ft 4 a* + m 0 m. ;\ • 1 - • a • a . • a • s % • A ■ - a a • o * - • ■ • • • ft \ v. ‘ y-\ V: <*Md I a • <l\r • ft • ft * • • 1 • ft • ft • a ft ft o Ml v l •- (U • • C /3 * • aft ft • ft W * V ' I #* % ft c ft- ft ft • ft • a ft ft ft • I Sfc • % ft Uh • ft • * • \ • # • • * .•a * • • V.y/v.- / '-/--'•/ - A . /■U ..H- ft V.. .\ • ' * .* ' • «ft^ r* II S’ II 'h / ■ ir '-y r S • • . • - . I - . • • . j r " ! ' - 1 ' / IB' - A: 'Tsi rr a • *kv''D® '!•■•* / • c . • • • • • •. r~* i1 -J % */. II v' r. • • <■ A c • I J : : / V 2 -i * •- * " • • • o • • d a • • I a1 o *5- r- » 0 // /. Du > ^ 1 // ft • c C3 • ^ / a — ed / A < % • O' ' » a f i _ -5- u O 'A \ \ • - s\ CO V ll ft ft o • V / .•U o <u - ^ VN - • • / /• a V' /, 1/ * • I * \ \ ^ #i *# *o \\ i # — / a *. CN A\% • - \ ft> ^ \ N - M % \ \ % • t a • • • • • - Vs o i •5- ' • • I' *- 41 V D n f I V c* a • \N a » • \ ' - • • tL. • • • 0 • • • • \ \ O - J • • • ft • ft ft * % ft ft • . • o 101 EXPLANATION METAMORPHOSED SEDIMENTARY ROCKS, VOLCANIC ROCKS, AND INTRUSIVE ROCKS :-----O * ll vV *\t § Calc-alkalic (magnetite-type) gabbro, § 2 diorite, granodiorite, and granite D o *8 - DEVONIAN Clastic and chemical sediments of shelf and shoreline environments, with minor c/) T33 O• .J bimodal volcanic rocks grading up into cyclic turbidite of deeper regimes I Unconformity 3 1 W\>V'-N\ • * • S. \ • ^ • V ' 3 > > > .i A y ,. v =34 ) ’gO .■s 6 Calc-alkalic (magnetite-type) O granodiorite, granite, granophyre, and quartz porphyry undivided Dead River Formation c (Flysch carapace of oceanic layer 1) o0) Oi)<D W 4—» OC Sandy, calcareous member o6 Pelitic member a o- oE Hurricane Mountain Formation Magnesitc-quartz-chromium muscovite Clinochrysotile serpentinite, talc, (Trench melange of an accrectionary prism — oceanic layer 1) -chromite rock (virginite) and blackwall (Emplacement as cold diapirs) Carbonaceous, sulfidic scaly pelitic and greywacke charged with blocks and rafts of Boil Mountain Ophiolite autoclaslic and exotic rocks •c (Oceanic layer 3) -O cc Jim Pond Formation U < (Boil Mountain ophiolitc of oceanic layer 2 grading up into keratophyric and CJ silicic rocks succeeded by a clastic melange-olistostromal sequence of oceanic Trondhjemitc (plagiogranite) D layer 1) 2 j j *o • ■ • • • 2 Quartzwacke and • * • greywacke with Scaly pelite and rafts of greenstone greywacke charged with Pyroxenitc, gabbro, epidioritc, and epidiorite breccia, Siliceous iron formation (mostly layered) blocks and rafts of and laminated chert clastic and exotic rocks Felsic flows and epiclastic Tholeiitic Greenstone a * 'A A A rocks with vent facies A ▲ A J /^ /■* 'N Antigorite serpentinite (altered har/burgite, websterite, chromitic cumulate dunite, and troctolitic) Pillowed Epiclastic and pillowed Obduction /()nc Chain Lakes Massif Major Faults * • * a • z Aquagene bimodal 'J2 < Early gravity or Unclassified Thrust or reverse JJ volcanic rocks grading up c* "o slide blocks (sawteeth on upper plate) I into arkosic sandstone Massive, locally gneissic, £ granofels (diamictite) ^ (barbs on downthrown side) charged with exotic rock UJu 7 clasts, locally a polycyclic a: breccia, sillimanite schist a. and mcladioritc I Field Stops 102 Table 1. Chronology of tectonometamorphic events in the