U.S. DEPARTMENT OF THE INTERIOR Prepared in cooperation with the U.S. GEOLOGICAL SURVEY STATE OF VERMONT, VERMONT AGENCY OF NATURAL RESOURCES, MARCIA K. McNUTT, DIRECTOR VERMONT GEOLOGICAL SURVEY LAURENCE R. BECKER, STATE GEOLOGIST CORRELATION OF MAP UNITS (Some lesser units listed in the Description of Map Units may not be shown here. Asterisk indicates U-Pb zircon age.) NEW HAMPSHIRE PLUTONIC SUITE OTHER DEVONIAN GRANITES STAGE FRENCH STAGE Brandon Lignite GRANITE BLACK AND PLUTONS DIKES MOUNTAIN POND AGE UNCERTAIN GRANITE Tmb Lower GRANITE TERTIARY Dg Dfpg Miocene *364 Ma 365* Ma *365 Ma 365 Ma 24 Ma 365 Ma Dbmg BARRE EAST BETHEL PLUTONS break in scale PLUTONS DERBY *368 Ma PLUTON Dbbg Dbqm WHITE MOUNTAIN IGNEOUS SUITE Ddbg FAMENNIAN FAMENNIAN (consisting of plutons and dike swarms Ddrz of Jurassic to Early Cretaceous age) VICTORY (Dbg) Upper Devonian Upper Devonian PLUTON (Dqm) WILLOUGHBY PLUTON CUTTINGSVILLE STOCK (Ddg) Dwmz DIKES 100 Ma Dvbg (Dg) Dwwz 375 Ma Kqs 375 Ma Kns (Debg) Dwhz NIAN NIAN FRAS- FRAS- Kes Kab (Dedg) (Degr) 382 Ma Kpd Kmd (Dwdg) 382 Ma BARBER HILL ASCUTNEY MOUNTAIN IGNEOUS COMPLEX CONNECTICUT VALLEY TROUGH TIAN TIAN GIVE- GIVE- STOCK Kag Kgd Lower CRETACEOUS Kas Kahg 387 Ma Kbh 387 Ma Kfd Khf Kav BRONSON HILL AREA CHESTER DOME NULHEGAN GRANITE PLUTON Middle Devonian EIFELIAN EIFELIAN 144 Ma SOUTH- CENTRAL- NORTH- SAWYER Middle Devonian Dg Dnqm (See DMU for Upper SHAW MOUNTAIN, NORTHFIELD, WAITS RIVER EASTERN EASTERN EASTERN MOUNTAIN *392 Ma unlisted symbols) MONADNOCK AND GILE MOUNTAIN FORMATIONS VERMONT VERMONT VERMONT BELT MOUNTAIN 159 Ma Littleton Formation 394 Ma PLUTON JURASSIC Dga Dcoa 394 Ma DEVONIAN DEVONIAN Jmg Middle Jd Dl Jmsy Dgqs Dgqs Dgqs Dco Dga Littleton EMSIAN EMSIAN Jme BETHLEHEM GNEISS AND Formation Dgmr Dih KINSMAN QUARTZ MONZONITE Dir Dlr Dla Dlr break in scale Dgr 407 Ma * *407 Ma *409 Ma Dgm Di *407 Ma Dih Di Dir FAIRLEE QUARTZ Dkq 409 Ma Dbgn 409 Ma MONZONITE Dgmc Dia Dfqm Dga Dgq *410 Ma Dr Dga Dm PRAGIAN PRAGIAN 412,414* Ma Lower Devonian Lower Devonian DSw 413.5 Ma Dl 413.5 Ma DSwi Dga (DSwb) DSwac Dgq DSws Dga LOCHKOVIAN LOCHKOVIAN DSnl DSwv FITCH- DSwc DSwa Sf LITTLETON DSn Dga DSfra LAKE MEMPHREMAGOG INTRUSIVE SUITE AREA 418 Ma DSwq DSw 418 Ma Ss DSwgs NEWPORT BRAINTREE ˆ INTRUSIVE INTRUSIVE COMERFORD Sf ˆ DSwc Sv PRÍDOLÍ PRÍDOLÍ DSwb COMPLEX COMPLEX INTRUSIVE COMPLEX Scv Snd Sbg Sbd Scm 419 Ma Sng Scd Scg 419 Ma DSwb DSwqc Ssm * * * * Srr DSnq 425 Ma 421 Ma 419 Ma 419 Ma DSfr LUDLOW LUDLOW Upper Silurian Upper Silurian PIERMONT SILURIAN Svf AND OTHER SILURIAN WENLOCK WENLOCK ALLOCHTHONS Clough Quartzite 428 Ma Sr 428 Ma Sc Sc LAURENTIAN MARGIN Src TRANSITIONAL MARGIN ROCKS EARLY TO LATE TACONIAN ACCRETED TERRANE HIGHLAND- Partridge Formation Sg LLANDOVERY LLANDOVERY CORE ROCKS CROFT Lower Silurian Lower Silurian Partridge Formation OF THE PLUTONIC AMMONOOSUC VOLCANICS VERNON DOME SUITE OF BILLINGS (1935) 441 Ma 441 Ma Ol Obqd 442-444* Ma Opr Op RICHMONDIAN RICHMONDIAN ADIRONDACK LOWLANDS AND VERMONT VALLEY SEQUENCE AND Opa ASHGILLIAN ASHGILLIAN LAKE CHAMPLAIN LOWLANDS MIDDLEBURY SYNCLINORIUM OLIVERIAN PLUTONIC SUITE Oha TACONIC ALLOCHTHON (syn- and post-emplacement) Whipstock Breccia Oogt Oobg Oohg 449 Ma 449 Ma of the Walloomsac Ohi MAYSVILLIAN Formation 450* Ma MAYSVILLIAN CINCINNATIAN CINCINNATIAN Oi FORBES (largely tectonic) Basalt at Op Oh Oib Oh HILL East Hoosick ? ? ? Oaa CONGLOMERATE Owwu Ofh Oag Ofh Ow AND TACONIC ALLOCHTHON (GIDDINGS BROOK, Owbl Obvb EDENIAN EDENIAN Oarq SUNSET LAKE, AND SUDBURY SLICES) AND BRECCIA Oww Ochd Oilc ROCKS OF THE BENNINGTON AREA Ofh Ow Upper Ordovician Osp Upper Ordovician after Potter (1972) Opr Oat Ohc Austin Glen Graywacke Ohc Oam Oac Owbl Omm CARADOCIAN CARADOCIAN Ohl TRENTON TRENTON Owl Ogf Ogf Ogf Ohl Oil Oaa 453 Ma Opaw 453 Ma Oar Oaa MOHAWKIAN Oa MOHAWKIAN Obr Otl Oar Owc Oo Oo Oir ? BLACK RIVER BLACK RIVER COVER ROCKS EAST COVER ROCKS OF GREEN Otl OF GREEN MOUNTAIN MASSIF MOUNTAIN ANTICLINORIUM Oarq 458 Ma 458 Ma Ov West Bridgewater ORDOVICIAN Formation ORDOVICIAN Omi Oaa Ocgu Ocp Owb Omi unconformities CHAZY CHAZY ST. ALBANS AREA Oarq Odp CRAM HILL FORMATION JOSLIN TURN OF THE NEWPORT CENTER AREA PLUTON LLANVIRNIAN LLANVIRNIAN 464 Ma 464 Ma Ocbe Ochsb Ows WHITEROCKIAN Ocw West Bridgewater VOLCANIC ARC INTRUSIVE AND VOLCANIC WHITEROCKIAN Middle Ordovician Opi Ocbrp Oj Oaa Middle Ordovician Ofcrp Ofcpi Oml Formation Ochcv ROCKS OF THE NORTH RIVER IGNEOUS SUITE (Ocbrp) OF THE ROWE–HAWLEY ZONE 469* Ma Ocbu Owb Ochp Oap Ofcs Oam Ob Ochcv Ochuc INTRUSIVE 470 Ma Ofcw BRANCH BROOK 470 Ma unconformity ? ROCKS unconformity DIKE AND SILL COMPLEX 471* Ma Opo ROWE – HAWLEY ZONE Cram Hill Formation Ob Ob Ochfs LAYERED FELSIC Ontw Cram Hill Formation Ochic AND MAFIC ROCKS, Moretown Formation IN PART VOLCANIC ARENIGIAN ARENIGIAN Ofa Ocha Ochu Ochs Ochq Ohg Ocha Och Ochu Oal Ochfg Ocha Onbw Ochfv Ochfv IBEXIAN IBEXIAN Ochq Ochv Onb Lower Ordovician Ochpq Lower Ordovician Ochq * Oalm Ocu unconformity ? 483 Ma Oalp Oali 485 Ma Obku Ocu Ochfg Ochic Oma Ochfg Ochv * 485 Ma Ogml 486 Ma Onr Onbm Onbwm Ogm Ocu Omb Omq Ont Zu Och Os Osk Os Omw Omwhb Omp Omp Ogmw Ombq Onbs Omfv Beekmantown Group Os Oma Omfgc TREMADOCIAN TREMADOCIAN *492 Ma Omfv Oma Omhb Omwhb 495 Ma Omwh 495 Ma Owl ? * Omwhv 496 Ma Ow Oma Omfs Omwhg Onnt Og * Osw Oma 502 Ma CROIXIAN sp sp Osw sp Ombq CROIXIAN wcu hh ti Ottauquechee Formation Omc Oma Oma TREMPEALEAUAN TREMPEALEAUAN Upper Cambrian Stowe Formation Omfv Omp Upper Cambrian pt Oskl eb Omq Oals Omp Omq Omc Omc ls o Omb d d Omfq d Osks psh opw Omfs Ombb Omgt FRANCONIAN FRANCONIAN psc w p w w Zsd ocf ROWE SCHIST pq pdo Zsa (many units fault bounded) om ULTRAMAFIC ROCKS higher structural level (tectonically intercalated) pq m m Eastern flank of the Green Mountain massif wc Zra CAMBRIAN m CAMBRIAN Middle Cambrian and eastern domes Middle Cambrian pdo psc Zsws DRESBACH DRESBACH wcbb Zs oa Zsgt wcnb DORSET MOUNTAIN AND MOUNT EQUINOX AREA obq pc Zrfb Plymouth MOUNT EQUINOX AND Formation Cooper Hill Zu ARLINGTON AREA Member du du du du du ls DORSET MOUNTAIN AREA Zrc Zrs pd cb SOUTHERN GREEN co oa of STRUCTURAL COMPLEXES Zrgs MOUNTAINS d Zbms Zutc c c c c d Tillotson Peak Belvidere Mountain c Zswa Zrch Zsp Zbp Znq Zj Complex Complex lower structural level ca ca Dalton Formation (serpentinite) ls Zsbg Zra Znq oq Ztm Zbu Zrr Zra Zdb Zsg Zmpq Zjg Zd ? Zbq Ztp Zbc Zrs Lower Cambrian Zdq Lower Cambrian pfq Hazens Notch and Pinney Hollow Zra Fayston Formations Zn Ztagn Hoosac Formation Fairfield Pond Underhill Formation Zbf Zra Zd Monastery Zmf Formation Formation Zbg Zds Formation Zmq Zngs Zap Zrrgt Zrr Tibbit Hill Zhn Zbb Zzh Zdfq Zmp Za Zsa Zbs Zdb Tyson Formation Zmmt Zun Formation (Znb) 544 Ma Zbagn 544 Ma Zhs ? Zfqz (Zsg) Zdm Ztbs Ztq Zfp Zungs Znw units completely Zdph Zmt Zfd Zsa fault bounded Zdq Ztrg Ztab Zfq Zunql Zfs Zfc Znab ? Zfb Zfco Zphw Zwb Zhnn Zunw Ztg Zfq Zbmg Zd Ztq Zhng Netop Formation Zds Zhgab Ztc Zhbs Znw ? Zswa Zdc Zpva Zh Ztd Zps Zphq Zbk Zngq Zdc Zfw Zhq Ztgr ? Zsa Zhd Zpc Zpvc Zph Zbm Zngq (Zsg) Zpw Zpwd Zngq Zfa (Znm) Zngs Ztc Zpw Zpvf Zth Zhab Zpc Zung Zpha Znr Zhtm Ztc Zf Bull Formation and Nassau Zpc Zphb ADIRONDACKS IN VERMONT AND IN THE WHITEHALL, N.Y., AREA Zphw Zhrab unconfomity Zhcgt INTRUSIVE ROCKS Zps ? Zpv Z Zhtm Z Znr ? ? Zbv Neoproterozoic Zhgt Zpu Neoproterozoic Pinnacle Formation Zhs ? Zpha Zhtm Zdi * Zd Zhq 571 Ma 571 Ma Zphf 571 Ma Zhab ? Zhc ? ? ? Zhabc Zhc Rocks at Devils Den (age problematic) ? INTRUSIVE ROCKS OF THE GREEN MOUNTAIN AND LINCOLN MOUNTAIN 900 Ma MASSIFS AND EASTERN DOMES 900 Ma Y3C Y3C Y3Cp CARDINAL BROOK INTRUSIVE SUITE 3C Y3Ccbsa Y bsa 945,* 3C 3C Y p 962* Ma Y cbhr 955 Ma 965* Ma Y3Ccbs Y3Ccbbh Subdivisions and symbology of the Mesoproterozoic on this map follow the time scale used by Tony Davidson Y3Ccbsr GREEN MOUNTAIN MASSIF on the 1998 geologic map of the Grenville province (Geological Survey of Canada Map 1947A, scale AND EASTERN DOMES: 1:2,000,000). Because late orogenic activity of the Grenville orogeny is younger than 1,000 Ma we adopt 1000 Ma MOUNT HOLLY COMPLEX the much more functional boundary between Neoproterozoic and Mesoproterozoic of 900 Ma following the 1000 Ma usage of Davidson (1998) rather than that of Plumb (1991). Chronostratigraphic subdivisions in the Ordovi- cian are after Fortey (2000). 3B Y p Y3Bg 1037* Ma PRECAMBRIAN PRECAMBRIAN Y3B Y3B Late Late Mesoproterozoic Mesoproterozoic Cavendish Formation (age problematic) Early Mesoproterozoic or 1100 Ma Neoproterozoic in part CHITTENDEN INTRUSIVE SUITE 1100 Ma ? Y3Ama 3A 3A 3A 3A Y mb 3A 3A Y gb Y la * Y pg * Y gg Y ma Y3Ag 1149 Ma Y3Abga Y3Afg 1121 Ma,1119 Ma Y3A Y3A Y3Agb Y3Agd 3A Y phg ? STRATTON MOUNTAIN IGNEOUS SUITE 1200 Ma 1200 Ma * 1221 Ma 2 2 Y ch 2 Y gg Y2lg Y ap * ? 1244 Ma Y2 Y2 Middle Middle SOUTH LONDONDERRY IGNEOUS SUITE ? Mesoproterozoic Green Mountain massif Mesoproterozoic * 1300 Ma 2 2 1309 Ma 1300 Ma Y rgt Y lq 2 2 2 2 Y2wxd Y mig 2 Y phg 2 Y ba Y wg 2 Y lgg Y bt 2 1,2 Y q Y2pha * 2 Y wxs Y be * 1321 Ma PARAGNEISS Y rs 2 1326 Ma 2 2 Y hg Y lga Y2cp Y wxq Y1,2bg 2 2 2 2 2 2 2 Y rss 2 2 Y a Y dm 2 Y bv Y cs 2 2 Y cs Y bmg Y wxg Y bgt 2 Y cs 2 Y hgn Y qz 2 Y m Y myu 1348 Ma Y2bpg Y wxcs 1342* Ma Y1rta Y1,2bg * 1 Chester and Athens domes 1 ? Y rt 1350 Ma Y cg Y cms 1350 Ma Y1tg Y1fg 1,2 ? 1 * Y be 1 ? 1367 Ma Y q Y a 1 ? Y q 1370 Ma 1 1 Y cfs Y mfs * Y fga Y1 Y rs 1 Y?dm * Y1 Y cs 1372 Ma Early 1? ? Early ? ? Y cm 1 ? 1 Y bm Y dg 1 * Y bmp ? * 1383 Ma Mesoproterozoic 1393 Ma Mesoproterozoic ? 1400 Ma 1400 Ma DESCRIPTION OF MAP UNITS Predominantly mafic and intermediate dikes of diabase, <1 m to 3 m thick, consisting cline with Carlsbad twinning (in granite), plagioclase, and euhedral biotite Ofcs Sciota Limestone Member (Middle and Lower Ordovician)—Light-gray, fine- [Minerals are listed in order of increasing and approximate abundance.