Termination of the Ganderian Cambrian–Ordovician Miramichi terrane in east-central Maine, northern Appalachian orogen, USA


  • Allan Ludman School of Earth and Environmental Sciences, Queens College (CUNY), Flushing, New York 11367, USA
  • Amber T.H. Whittaker Maine Geological Survey, 93 State House Station, Augusta, Maine E 04433, USA




The Ganderian Cambrian–Ordovician Miramichi terrane narrows in east-central Maine and terminates at the junction of faults that separate it from the mostly Silurian Central Maine/Aroostook–Matapedia basin (CMAM) to the northwest and Fredericton trough to the southeast. The terrane was emergent after Middle Ordovician recumbent folding and shed sediment to both adjacent depocenters. Its boundary faults are the youngest deformation events and play important roles in its termination, but do not by themselves explain it. The presence of distinctive CMAM strata southeast of the northwest boundary fault indicates that the first step in developing the current relationships was an episode of hitherto unrecognized late Silurian eastward thrusting. In the northern (Danforth) segment of the terrane, intermediate facies CMAM strata were thrust onto their Miramichi source rocks. The thrust sheet was deformed by Acadian upright folds, then dissected by dip-slip offset along boundary and internal faults prior to intrusion of the 409 ± 2 Ma Skiff Lake pluton. Subsequent erosion isolated a remnant of the thrust sheet as the Dill Hill klippe, its allochthonous CMAM strata isolated among Miramichi rocks. The southern (Greenfield) segment experienced similar events, but current relationships are different and timing of the late-stage faults is not well constrained. Allochthonous CMAM strata may have overridden the Miramichi terrane completely, so that a remnant of distinctive CMAM strata is now exposed east of the Miramichi terrane in fault contact with rocks of the Fredericton trough. The entire Greenfield segment is interpreted as a fault block exposed within the thrust sheet.


Ayuso, R. 1984. Field relations, crystallization, and petrology of reversely zoned granitic plutons in the Bottle Lake Complex, Maine. United States Geological Survey, Professional Paper 1320, 58 p. and 1:125 000 scale geologic map. https://doi.org/10.3133/pp1320

Ayuso, R., Arth, J., Sinha, A, Carlson, J., and Wones, J. 1984. Comparative geochronology in the reversely zoned plutons of the Bottle Lake complex, Maine: U–Pb on zircons and Rb–Sr on whole rocks. Contributions to Mineralogy and Petrology, 88, pp. 112–125. https://doi.org/10.1007/BF00371416

Bevier, M. and Whalen, J. 1990. U–Pb geochronology of Silurian granites, Miramichi terrane, New Brunswick. In Radiogenic age and isotopic studies, Report 3. Geological Survey of Canada, Paper 89-2, pp. 93–100. https://doi.org/10.4095/129075

Bradley, D., Tucker, R., Lux, D., Harris, A., and McGregor, D. 2000. Migration of the Acadian orogen and foreland basin across the Northern Appalachians of Maine and adjacent areas. United States Geological Survey, Professional Paper 1624, 51 p. https://doi.org/10.3133/pp1624

Cohen, K., Finney, S., Gibbard, P., and Fan, J.-X. 2013. The ICS International Chronostratigraphic Chart (updated 2022). Episodes 36, pp. 199–204. https://doi.org/10.18814/epiiugs/2013/v36i3/002

Dokken, R.J., Waldron, J.W.F., and Dufrane, S.A. 2018. Detrital zircon geochronology of the Fredericton trough, New Brunswick, Canada: Constraints on the Silurian closure of remnant Iapetus Ocean. American Journal of Science, 318, pp. 684–725. https://doi.org/10.2475/06.2018.03

Faul, H., Stern, T., Thomas, H., and Elmore, P. 1963. Ages of intrusion and metamorphism in the northern Appalachians. American Journal of Science, 261, pp. 1–19. https://doi.org/10.2475/ajs.261.1.1

Fyffe, L. 1995. Fredericton Belt. In Geology of the Appalachian–Caledonian orogen in Canada and Greenland. Edited by H. Williams. Geological Survey of Canada, Geology of Canada 6, Ch. 4, pp. 351–354.

Fyffe, L. 2001. Stratigraphy and geochemistry of Ordovician volcanic rocks of the Eel River area, west-central New Brunswick. Atlantic Geology, 37, pp. 81–101. https://doi.org/10.4138/1973

Fyffe, L. and Fricker, A. 1987. Tectonostratigraphic terrane analysis of New Brunswick. Maritime Sediments and Atlantic Geology, 23, pp. 113–122. https://doi.org/10.4138/1626

Fyffe, L., Johnson, S., and van Staal, C. 2011. Review of Proterozoic to Early Paleozoic lithotectonic terranes in the northeastern Appalachian orogen of New Brunswick, Canada, and their tectonic evolution during Penobscot, Taconic, Salinic, and Acadian orogenesis. Atlantic Geology 47, pp. 211–248. https://doi.org/10.4138/atlgeol.2011.010

Fyffe, L., Ludman, A., and McFarlane, C. 2023. Composition, age and tectonic significance of the Benton granite, Eel River area, west-central New Brunswick, Canada. Atlantic Geosciences 59, pp. 87–108. https://doi.org/10.4138/atlgeo.2023.004

Ghanem, H., Kunk, M., Ludman, A., Bish,D., and Wintsch, R. 2016. Dating slate belts using 40Ar/39Ar geochronology and zircon ages from crosscutting plutons: A case study from east-central Maine, USA. Journalof Structural Geology 93, p.51–66. https://doi.org/10.1016/j.jsg.2016.10.004

Hibbard, J., van Staal, C., Rankin, D., and Williams, H. 2006. Lithotectonic map of the Appalachian orogen, Canada–United States of America. Geological Survey of Canada, Map 2096A, Scale 1:1 500 000. https://doi.org/10.4095/221932

Hopeck, J. 1998. Stratigraphy and structural geology of the Wytopitlock and Springfield fifteen-minute quadrangles, eastern Maine. Unpublished PhD dissertation. City University of New York, New York. 160 p.

Hopeck, J. 2013. Transitional relationships in the Miramichi, Aroostook–Matapedia, and Central Maine belts. In Guidebook for field trips in north-central Maine. Edited by L. Hanson. New England Intercollegiate Geological Conference, Trip C-3, pp. 209–214.

Larrabee, D. and Spencer, C. 1963. Bedrock geology of the Danforth quadrangle, Maine. United States Geological Survey, Geologic Quadrangle 221, scale 1:62 500.

Larrabee, D., Spencer, C., and Swift, D. 1965. Bedrock geology of the Grand Lake area, Aroostook, Hancock, Penobscot, and Washington counties, Maine. United States Geological Survey, Bulletin 1201-E, 38 p.

Ludman, A. 1978. Stratigraphy and structure of Silurian and pre-Silurian rocks in the Brookton–Princeton area, eastern Maine. In Guidebook for trips in southeastern Maine and southwestern New Brunswick. Edited by A. Ludman. New England Intercollegiate Geological Conference, pp. 145–161.

Ludman, A. 1991. Stratigraphy of the Miramichi terrane in eastern Maine; In Geology of the Coastal Lithotectonic Belt and neighboring terranes, eastern Maine and southern New Brunswick. Edited by A. Ludman. New England Intercollegiate Geological Conference, Guidebook, pp.338–357.

Ludman, A. 2003. Bedrock Geology of the Dill Hill 7½’ quadrangle, Maine. Maine Geological Survey, Open File Report OF 03-93. 16 p. and map scale 1:24 000.

Ludman, A. 2020a. Bedrock geology of the Greenfield quadrangle, Maine. Maine Geological Survey, Open-File Report 20-10, 28 p. and map, scale 1:24 000.

Ludman, A. 2020b. Bedrock geology of the Lincoln Center quadrangle, Maine. Maine Geological Survey Open File Map 20-24, scale 1:24 000.

Ludman, A. 2023. Bedrock geology of the Greenfield quadrangle, Maine (revised). Maine Geological Survey, Open-File Report 23-1, 31 pp. and map, scale 1:24 000.

Ludman, A. and Berry, H. IV. 2003. Bedrock Geologic Map of the Calais 1:100 000-scale quadrangle, Maine. Maine Geological Survey, Open File Report, OF 03-97.

Ludman, A. and Hopeck, J. 2020. Bedrock Geology of the Springfield 15′ quadrangle, Maine. Maine Geological Survey, Open-File Report 20-22, 20 p. and 1:24 000 scale geologic maps of the Bowers Mountain, Springfield, Weir Pond, and Bottle Lake quadrangles.

Ludman, A., Hopeck, J., and Berry, H. 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, pp. 63–85. https://doi.org/10.4138/atlgeol.2017.003

Ludman, A., Aleinikoff, J., Berry, H., and Hopeck, 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. https://doi.org/10.4138/atlgeol.2018.012

Ludman, A., McFarlane, C., and Whittaker, A. 2021. Chemistry, age, and tectonic setting of Miramichi terrane volcanic rocks in eastern and east-central Maine. Atlantic Geology, 57, pp. 239–273. https://doi.org/10.4138/atlgeol.2021.012

New Brunswick Department of Natural Resources and Energy. 2008. Bedrock Geology of New Brunswick. Minerals and Energy Division, Map NR-1, scale 1:500 000.

New Brunswick Department of Natural Resources and Energy Development, 2022. New Brunswick Bedrock Lexicon. URL < https://dnr-mrn.gnb.ca/Lexicon/Lexicon/Lexicon_Search.aspx?lang=e&_gl=1*z7zslm*_ga*MjM3NzM5NTM3LjE2ODgyNTAwMzE.*_ga_F531P4D0XX*MTY4ODI1MDAzMC4xLjAuMTY4ODI1MDAzNi4wLjAuMA..p>, 6 January 2023.

Neuman, R. 1967. Bedrock geology of the Shin Pond and Stacyville quadrangles, Penobscot County, Maine. United States Geological Survey, Professional Paper 524-I. 37 p. https://doi.org/10.3133/pp524I

Olson, R. 1972. Bedrock geology of the southwest one sixth of the Saponac quadrangle, Penobscot and Hancock counties, Maine. Unpublished M.S. thesis. University of Maine, Orono, Maine, 60 p.

Osberg, P., Hussey, A., and Boone, G. 1985. Bedrock Geologic Map of Maine. Maine Geological Survey, Augusta, Maine, scale 1:500 000.

Pavlides, L. 1968. Stratigraphic and facies relationships of the Carys Mills formation of Ordovician and Silurian age, northeastern Maine. United States Geological Survey, Bulletin 1264, 44 p.

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 35, pp. 215–224. https://doi.org/10.4138/2035

Pollock, S. 2011. Bedrock geology of the Bangor quadrangle, Maine. Maine Geological Survey, Open File Report 11-57, scale 1:24 000.

Rickards, R. and Riva, J. 1981. "Glyptograptus? persculptus (Salter), its tectonic deformation, and its stratigraphic significance for the Carys Mills Formation of NE Maine, USA. Geological Journal, 16, pp. 219–235. https://doi.org/10.1002/gj.3350160402

Sayres, M. 1986. Stratigraphy, polydeformation, and tectonic setting of Ordovician volcanic rocks in the Danforth area, eastern Maine. Unpublished M.A. thesis. Queens College (City University of New York), Flushing, New York, 135 p.

Tucker, R., Osberg, P., and Berry H. 2001. The geology of a part of Acadia and the nature of the Acadian orogeny across central and eastern Maine. American Journal of Science, 301, pp. 205–260. https://doi.org/10.2475/ajs.301.3.205

van Staal, C., Wilson, R., Kamo, S., McClelland, W., and McNicoll, V. 2016. Evolution of the Early to Middle Ordovician Popelogan arc in New Brunswick, Canada and adjacent Maine, USA: Record of arc-trench migration and multiple phases of rifting. Geological Society of America, Bulletin, 128, pp. 122–146. https://doi.org/10.1130/B31253.1

Wang, C. and Ludman, A. 2001. Evidence for post-Acadian through Alleghanian deformation in eastern Maine: multiple brittle reactivation of the Norumbega Fault system. Atlantic Geology 38, pp. 37–52. https://doi.org/10.4138/1254

West, D. and Roden-Tyce, M. 2003. Late Cretaceous reactivation of the Norumbega fault zone, Maine: Evidence from apatite fission-track ages. Geology, 31, pp. 649–652. https://doi.org/10.1130/0091-7613(2003)031<0649:LCROTN>2.0.CO;2

West, D., Ludman, A., and Lux, D. 1992. Silurian age for the Pocomoonshine gabbro-diorite, southeastern Maine, and its tectonic implications. American Journal of Science, 292, pp. 253–273. https://doi.org/10.2475/ajs.292.4.253

West, D., Peterman, E., and Chen, J. 2021. Silurian–Devonian tectonic evolution of mid-coastal Maine, U.S.A. American Journal of Science, 321, pp. 458–489. https://doi.org/10.2475/04.2021.03

Winchester, J., van Staal, C., and Fyffe, L. 1992. Ordovician volcanic and hypabyssal rocks in the central and southern Miramichi Highlands: their tectonic setting and relationship to contemporary volcanic rocks in northern New Brunswick. Atlantic Geology, 28, pp. 171–179. https://doi.org/10.4138/1859



How to Cite

Ludman, A., & Whittaker, A. T. (2023). Termination of the Ganderian Cambrian–Ordovician Miramichi terrane in east-central Maine, northern Appalachian orogen, USA. Atlantic Geoscience, 59, 123–146. https://doi.org/10.4138/atlgeo.2023.006