Résumés
Abstract
The Benton pluton, located in the Eel River area of west-central New Brunswick, Canada, consists of two components—the Caldwell Brook quartz monzonite and Dugan Road monzogranite. Field relations suggest that the two are essentially coeval, the Dugan Road being slightly younger. The Benton pluton intrudes Cambrian to Early Ordovician sedimentary rocks of the Woodstock Group and overlying Early to Middle Ordovician calc-alkaline rhyolitic, andesitic, dacitic, and basaltic rocks of the lower Meductic Group. A new U–Pb (LA-ICP-MS) zircon age of 467 ± 2. Ma indicates that the Dugan Road monzogranite component of the Benton pluton was emplaced during the Middle Ordovician (late Dapingian to early Darriwilian). The Dugan Road monzogranite is ca. 7 million years younger than the nearby arc-related Connell Mountain tonalite and Gibson granodiorite, and ca. 13 million years younger than arc- related volcanic rocks of the Porten Road Formation, the oldest unit of the Meductic Group. The Benton pluton is interpreted to have been emplaced in an active extensional arc setting, coinciding with a shift in the focus of subduction-related volcanism from the Eel River area of New Brunswick to the Greenfield area of adjacent Maine, USA.
Résumé
Le pluton de Benton, situé dans le secteur d’Eel River dans le centre-ouest du Nouveau-Brunswick, au Canada, est constitué de deux éléments : la monzonite de quartz du ruisseau Caldwell et le monzogranite du chemin Dugan. Leurs rapports sur le terrain laissent supposer que les deux éléments sont essentiellement du même âge, celui du chemin Dugan étant légèrement plus récent. Le pluton de Benton pénètre des roches sédimentaires du Cambrien à l’Ordovicien précoce du groupe de Woodstock ainsi que des roches sus-jacentes calco-alcalines rhyolitiques, andésitiques, dacitiques et basaltiques de l’Ordovicien précoce à moyen de la partie inférieure du groupe de Meductic. Une nouvelle datation U–Pb (LA-ICP-MS) sur zircon de 467 ± 2 Ma révèle que l’élément de monzogranite du chemin Dugan du pluton de Benton s’est mis en place durant la période de l’Ordovicien moyen (du Dapingien tardif au Darriwilien précoce). Le monzogranite du chemin Dugan est plus récent d’environ sept millions d’années que la granodiorite de Gibson et la tonalite du mont Connell apparentées à un arc voisines, et plus récent d’environ 13 millions d’années que les roches volcaniques d’un arc de la Formation de Porten Road, l’unité la plus ancienne du groupe de Meductic. Le pluton de Benton est interprété comme un élément s’étant mis en place dans le cadre d’un arc d’extension active coïncidant avec un déplacement du foyer du volcanisme lié à une subduction depuis le secteur d’Eel River au Nouveau-Brunswick au secteur de Greenfield dans l’État voisin du Maine, aux États-Unis.
Parties annexes
Bibliography
- Anderson, F.D. 1968. Woodstock, Millville and Coldstream map areas, Carleton and York counties, New Brunswick. Geological Survey of Canada, Memoir 353, 69 p, and three 1:63 360 scale map sheets. https://doi.org/10.4095/101485
- Bevier, M.L. 1989. Preliminary U–Pb geochronologic results for igneous and metamorphic rocks, New Brunswick. In Project Summaries for 1989, Fourteenth Annual Review of Activities, Edited by S.A. Abbott. New Brunswick Department of Natural Resources and Energy, Minerals and Energy Division, Information Circular 89-2, pp. 208–212.
- 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
- Crocco, P. 1975. A summary report on the granitic rocks of New Brunswick. New Brunswick Department of Natural Resources, Mineral Resources Branch, Topical Report 75-6, 150 p.
- Dostal, J. 1989. Geochemistry of Ordovician volcanic rocks of the Tetagouche Group of southwestern New Brunswick. Atlantic Geology, 25, pp. 199–209. https://doi.org/10.4138/1684
- Fyffe, L.R. 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.R. and Fricker, A. 1987. Tectonostratigraphic terrane analysis of New Brunswick. Maritime Sediments and Atlantic Geology, 23, pp. 113–123. https://doi.org/10.4138/1626
- Fyffe, L.R and Wilson, R. 2012. An ancient volcanic environment in the Benton–Meductic area of West-Central New Brunswick, Canada. New Brunswick Department of Natural Resources, Geological Surveys Branch, Field Guide No. 5, 31 p.
- Fyffe, L.R., Pajari, G.E., and Cherry, M.E. 1981. The Acadian plutonic rocks of New Brunswick. Maritime Sediments and Atlantic Geology, 17, pp. 23–36. https://doi.org/10.4138/1373
- Fyffe, L.R., Forbes, W.H., and Riva, J. 1983. Graptolites from the Benton area of west-central New Brunswick and their regional significance. Maritime Sediments and Atlantic Geology, 19, pp. 117–125. https://doi.org/10.4138/1570
- Fyffe, L.R., Barr, S.M., Johnson, S.C., McLeod, M.J., McNicoll, V.J., Valverde-Vaquero, P., van Staal, C.R., and White, C.E. 2009. Detrital zircon ages from Neoproterozoic and early Paleozoic conglomerate and sandstone units of New Brunswick and coastal Maine: implications for the tectonic evolution of Ganderia. Atlantic Geology, 45, pp. 110–144. https://doi.org/10.4138/atlgeol.2009.006
- Fyffe, L.R., Johnson, S.C., and van Staal, C.R. 2011. A 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.R., van Staal, C.R., Wilson, R.A., and Johnson, S.C. 2023. An overview of Early Paleozoic arc systems in New Brunswick, Canada, and eastern Maine, USA. Atlantic Geoscience, 59, pp. 1–28. https://doi.org/10.4138/atlgeo.2023.001
- Johnson, S., West, D., Jr., and Peterman, E. 2022. Petrology, age, and geochemistry of the Yarmouth Island Formation, Casco Bay, Maine: Insights into the Paleozoic tectonic evolution of mid-coastal Maine. Geological Society of America, Abstracts with Programs, 54, no. 5.
- Kramers, J. and Tolstikhin, I. 1997. Two terrestrial lead isotope paradoxes, forward transport modeling, core formation and the history of the continental crust. Chemical Geology, 139, pp. 75–110. https://doi.org/10.1016/S0009-2541(97)00027-2
- 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 Allan Ludman. New England Intercollegiate Geological Conference Guidebook, pp. 338–357.
- Ludman, A. 2020. Bedrock geology of the Greenfield quadrangle, Maine. Maine Geological Survey, Open File Report 20-10, 43 p.
- Ludman A. 2023. Bedrock geology of the Greenfield quadrangle, Maine. Maine Geological Survey, Open File Report 23-1, 31 p.
- Ludman, A. and Berry, H. 2003. Bedrock Geologic Map of the Calais 1:100 000 quadrangle. Maine Geological Survey, Open File Report, OF 03-97.
- 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.T.H. 2021. Age, chemistry, and tectonic setting of Miramichi terrane (Early Paleozoic) volcanic rocks, eastern and east-central Maine, USA. Atlantic Geology, 57, pp 239–273. https://doi.org/10.4138/atlgeol.2021.012
- Ludwig, K.R. 2003. Isoplot 3.75: A Geochronological Toolkit for Microsoft Excel. Special publication/Berkeley Geochronology Center, No. 4, 74 p. URL 10 June 2022.
- Ludwig, K.R., 2012. Isoplot 4.15: A Geochronological Toolkit for Microsoft Excel. Berkeley Geochronological Center. URL 10 June 2022
- Martin, R. 1966. Chemical and petrographic study of the granitic rocks of New Brunswick, Canada. M.Sc. thesis, Pennsylvanian State University, State College, Pennsylvania, 120 p.
- McClenaghan, S., Lentz, D., and Fyffe, L. 2006. Chemostratigraphy of volcanic rocks hosting massive sulfide clasts within the Meductic Group, west-central New Brunswick. Exploration and Mining Geology, 15, pp. 241–261. https://doi.org/10.2113/gsemg.15.3-4.241
- McNicoll, V., Whalen, J., and Stern, R. 2003. U–Pb geochronology of Ordovician plutonism, Bathurst Mining Camp, New Brunswick. Massive Sulfide Deposits of the Bathurst Mining Camp, New Brunswick. Economic Geology Monograph 11, pp. 203–218.
- Mohammadi, N., Fyffe, L., McFarlane, C., Wilson, R., and Lentz, D. 2019. U–Pb zircon and monazite geochronology of volcanic and plutonic rocks in southwestern, central, and northeastern New Brunswick. Geological Survey of Canada, Open File 8581, 46 p. https://doi.org/10.4095/314824
- Osberg, P., Hussey, A., and Boone, G. 1985. Bedrock Geology of Maine. Maine Geological Survey, scale 1:500 000.
- Paces, J. and Miller, J. 1993. Precise U–Pb ages of Duluth Complex and related mafic intrusions, northeastern Minnesota. Geochronological insights to physical, petrogenetic, paleomagnetic, and tectonomagmatic processes associated with the 1.1 Ga Midcontinent Rift System. Journal of Geophysical Research: Solid Earth, 98, pp. 13997–14013. https://doi.org/10.1029/93JB01159
- Pearce, J., Harris, N., and Tindle, A. 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. Journal of Petrology, 25, pp. 956–983. https://doi.org/10.1093/petrology/25.4.956
- Petrus, J. and Kamber, B. 2012. Vizual age: a novel approach to Laser Ablation ICP-MS U–Pb geochronology data reduction: Geostandards and Geoanalytical Research, 36, pp. 247–270. https://doi.org/10.1111/j.1751-908X.2012.00158.x
- 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. 205–214. https://doi.org/10.4138/2035
- Poole, W. and Neuman, R. 2002. Arenig volcanic and sedimentary strata, central New Brunswick and eastern Maine. Atlantic Geology, 38, pp. 109–134. https://doi.org/10.4138/1257
- 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.
- Sláma, J., Košlera J., Condond, D.J., Crowley, J.L., Gerdes, A., Hanchar J.M., Horstwood, M.S.A., Morris, G.A., Nasdala, L., Norberg, N., Schaltegger, U., Schoene, B., Tubrett. M. N., and Whitehouse, M.J. 2008. Plešovice zircon-A new natural reference material for U–Pb and Hf isotopic microanalysis. Chemical Geology, 249, pp. 1–35. https://doi.org/10.1016/j.chemgeo.2007.11.005
- van Staal, C.R. and de Roo, J. 1995. Mid-Paleozoic tectonic evolution of the Appalachian Central Mobile Belt in northern New Brunswick, Canada: Collision, extensional collapse and dextral transpression. In Current Perspectives in the Appalachian–Caledonian Orogen. Edited by J.P. Hibbard, C.R. van Staal, and P.A. Cawood. Geological Association of Canada, Special Paper, 41, pp. 367–389.
- van Staal, C.R. and Fyffe, L. 1995. Dunnage zone, New Brunswick; Chapter 3. In Geology of the Appalachian–Caledonian Orogen in Canada and Greenland. Edited by H. Williams. Geological Society of America, The Geology of North America, v. F-1, pp. 166–178.
- van Staal, C.R., Winchester, J., and Bédard, J. 1991. Geochemical variations in Middle Ordovician volcanic rocks of the northern Miramichi Highlands and their tectonic significance. Canadian Journal of Earth Sciences, 28, pp. 1031–1049. https://doi.org/10.1139/e91-094
- van Staal, C.R., Dewey, J., McNicoll, C., and McKerrow, W.S. 1998. The Cambrian–Silurian tectonic evolution of the northern Appalachians and British Caledonides: History of a complex west and southwest Pacific-type segment of Iapetus. In Lyell: The Past Is the Key to the Present. Edited by D.J. Blundell and A.C. Scott. Geological Society of London, Special Publication 143, pp. 199–242. https://doi.org/10.1144/GSL.SP.1998.143.01.17
- van Staal, C.R., Wilson, R.A., Rogers, N., Fyffe, L., Langton, J., McCutcheon, S., McNicoll, V., and Ravenhurst, C. 2003. Geology and tectonic history of the Bathurst Supergroup, Bathurst Mining Camp and its relationship to coeval rocks in southwestern New Brunswick and adjacent Maine. Economic Geology, Monograph 11, pp. 37–40. https://doi.org/10.5382/Mono.11.03
- van Staal, C.R., Wilson, R.A., Kamo, S.L., McClelland, W.C., 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
- Venugopal, D. 1978. Geology of Benton–Kirkland, Upper Eel River Bend map-area G-22. New Brunswick Department of Natural Resources, Geological Surveys Branch, Map Report 78-3, 16 p.
- Venugopal, D. 1979. Geology of Debec Junction–Gibson Millstream–Temperance Vale– Meductic region, map-areas G-21, H-21, I-21, and H-22 (Parts of 21 J/3, 21 J/4, 21 G/13, 21 G/ 14). New Brunswick Department of Natural Resources, Geological Surveys Branch, Map Report 79-5, 36 p.
- West, D., Jr., Coish, R., and Tomascak, P. 2004. Tectonic setting and regional correlation of Ordovician metavolcanic rocks of the Casco Bay Group, Maine: Evidence from trace element and isotope geochemistry. Geological Magazine, 141, pp. 125–140. https://doi.org/10.1017/S0016756803008562
- Whalen, J. 1993. Geology, petrography and geochemistry of Appalachian granites in New Brunswick and Gaspésie, Québec. Geological Survey of Canada, Bulletin 436, 124 p. https://doi.org/10.4095/183907
- Whalen, J., Rogers, N., van Staal, C., Longstaffe, F., Jenner, G., and Winchester, J. 1998. Geochemical and isotopic (Nd, O) data from Ordovician felsic plutonic and volcanic rocks of the Miramichi Highlands: petrogenetic and metallogenic implications for the Bathurst Mining Camp. Canadian Journal of Earth Sciences, 35, pp. 237–252. https://doi.org/10.1139/e97-102
- Wilson, R.A. 1993. Geology of Heath Steele–Halfmile Lakes area; Northumberland County, New Brunswick (Part of NTS 21 O/8). New Brunswick Department of Natural Resources and Energy, Mineral Resources, Report of Investigation 25, 98 p.
- Wilson, R.A. and Fyffe, L. 1996. Geologic setting of mineralization in the Big Bald Mountain area (NTS 21 O/1), Bathurst camp, New Brunswick. In Current Research 1995. Edited by B.M.W. Carroll. New Brunswick Department of Natural Resources and Energy, Mineral Resources Report 96-1. pp. 179–217.
- Winchester, J., van Staal, C.R., 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