Monteregian Hills

Monteregian Hills
Monteregian Hills
	Three of the central Monteregian Hills mountains (from left: Mont Saint-Hilaire, Mont Rougemont and Mont Yamaska) viewed from space.
Highest point
Peak	Mont Megantic
Elevation	1,105 m (3,625 ft)
Geography
Country	Canada
Province	Quebec
Range coordinates	45°28.7′N 73°2.4′W / 45.4783°N 73.0400°W
Geology
Age of rock	Early Cretaceous

The Monteregian Hills (French: Collines Montérégiennes) is a linear chain of isolated mountains in Montreal and Montérégie, between the Laurentians and the Appalachians.

Etymology

The first definition of the Monteregian Hills came about in 1903 when Montreal geologist Frank Dawson Adams began referring to Mount Royal (Latin, Mons Regius) and mountains of similar geology in the Saint Lawrence Lowlands as the "Royal Mountains" (French: montagnes royales).^[1] Other mountains in the chain included Mont Saint-Bruno, Mont Saint-Hilaire, Mont Saint-Grégoire, Mont Rougemont, Mont Yamaska, Mont Shefford, and Mont Brome.

It was only later that Mont Mégantic,^[2] the Oka Hills, as well as the Saint-André and d'Iberville formations, were added to the list.^[3]

Geology

Each mountain in the chain consists of an erosional remnant of Cretaceous intrusive igneous rock and associated hornfels, which are more resistant to weathering than the surrounding sedimentary rock. All of the mountains have dark-coloured mafic rock such as gabbro and essexite; some also have large areas of pulaskite, syenite, and other light-coloured rock.^{[citation needed]}

The Monteregian Hills are part of the Great Meteor hotspot track, formed as a result of the North American Plate sliding westward over the long-lived New England hotspot,^[4] and are the eroded remnants of intrusive stocks. These intrusive stocks have been variously interpreted as the feeder intrusions of long extinct volcanoes, which would have been active about 125 million years ago,^[5]^[6] or as intrusives that never breached the surface in volcanic activity.^[7] The lack of an obvious track west of the Monteregian Hills may be due either to failure of the plume to penetrate the Canadian Shield, to the lack of recognizable intrusions, or to strengthening of the plume when it approached the Monteregian Hills region. However, there is evidence the hotspot track extends northwestwards, including epeirogenic uplift, mantle velocity anomalies and kimberlitic volcanic features (e.g. the Attawapiskat, Kirkland Lake and Lake Timiskaming kimberlite fields) that become older away from the Monteregian Hills.^[8]

The shallow, rocky sandy loam soils of the summits are mostly covered in forest. Where the underlying rock is rich in olivine, as over large areas of Mont Saint-Bruno and Mont Rougemont, these soils are classed as dystric brunisol. Podzol tends to develop over rock which lacks olivine, although many of these podzols lack an eluvial (Ae) horizon. Lower slopes are covered with aprons of gravel or sand. The sandy soils are usually podzols with classic Ae development; they often have subsoil hardpan and are undesirable for agriculture. The free-draining gravels are preferred for apple orchards, which grow in thermal belts where cold air can drain to the valley floor.^[9]^[10]

Monteregian Hills
Name	Height	Age	Coordinates	Location
St. Andrews formation	130 metres (430 ft)	n/a	45°55"N, 74°31'W	Saint-André-d'Argenteuil
Oka Hills	249 metres (817 ft)^[11]	n/a	45°28'N, 74°5'W	Oka
Mount Royal	233 metres (764 ft)	118-138 myr	45°30'23"N, 73°35'20"W	Montreal
Mont Saint-Bruno	218 metres (715 ft)	118-136 myr	45°33'18"N, 73°18'36"W	Saint-Bruno-de-Montarville
Mont Saint-Hilaire	411 metres (1,348 ft)	135 myr	45°33'8"N, 73°9'50"W	Mont-Saint-Hilaire
Mont Saint-Grégoire	251 metres (823 ft)	119 myr	45°21'29"N, 73°9'8"W	Mont-Saint-Grégoire
Mont Rougemont	381 metres (1,250 ft)	137 myr	45°28'36"N, 73°3'17"W	Rougemont
Mont Yamaska	416 metres (1,365 ft)	120-140 myr	45°27'25"N, 72°52'19"W	Saint-Paul-d'Abbotsford
Mont Shefford	526 metres (1,726 ft)	120-130 myr	45°21'49"N, 72°37'33"W	Shefford
Mont Brome	553 metres (1,814 ft)	118-138 myr	45°16'59"N, 72°37'59"W	Bromont
Mont Mégantic	1,105 metres (3,625 ft)	128-133 myr	45°27'21"N, 71°9'8"W	Notre-Dame-des-Bois

Map all coordinates using OpenStreetMap

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Gallery

Four of the Monteregian Hills in the late fall
Mont Saint-Hilaire from the south
aerial view of Mont Yamaska
Mont Rougemont as seen from Mt. Saint-Grégoire
Mont Mégantic as seen from the Stoke Mountains

External links

(in French) Les collines montérégiennes Geologic information about the chain

References

^ "Banque de noms de lieux du Québec: Reference number 76975". toponymie.gouv.qc.ca (in French). Commission de toponymie du Québec.
^ Feininger, Tomas; Goodacre, Alan K. (2003). "The distribution of igneous rocks beneath Mont Mégantic (the easternmost Monteregian) as revealed by gravity". Canadian Journal of Earth Sciences. 40 (5): 765–773. Bibcode:2003CaJES..40..765F. doi:10.1139/e03-022.
^ Bédard, Pierre. "La province géologique montérégienne : l'état des connaissances" (PDF) (in French). Communauté métropolitaine de Montréal. p. 6. Retrieved 22 August 2014. Avec le progrès des connaissances géologiques, le mont Mégantic, les roches intrusives d'Iberville, d'Oka, et de Saint-André se sont progressivement ajoutés à la liste.
^ Eaton, David W.; Frederiksen, Andrew (2007). "Seismic evidence for convection-driven motion of the North American plate". Nature. 446 (7134): 428–431. Bibcode:2007Natur.446..428E. doi:10.1038/nature05675. PMID 17377580. S2CID 4420814.
^ A Hundred-Million Year History of the Corner Rise and New England Seamounts http://www.oceanexplorer.noaa.gov/explorations/05stepstones/background/geologic_history/geologic_history.html Archived 2013-07-08 at the Wayback Machine Retrieved on 2007-08-01
^ The Monteregian Hills: Igneous Intrusions, http://geoscape.nrcan.gc.ca/montreal/heritage_e.php#mont Archived 2009-04-26 at the Wayback Machine Natural Resources Canada, Geoscape Montreal, 2006-07-24
^ "Geology". Archived from the original on 2007-12-20. Retrieved 2007-12-16. Geology of Gault Nature Reserve, Mont St. Hilaire, McGill University
^ Darbyshire, Fione A.; Eaton, David W.; Frederiksen, Andrew W.; Ertolahti, Leila (2007). "New insights into the lithosphere beneath the Superior Province from Rayleigh wave dispersion and receiver function analysis". Geophysical Journal International. 169 (3): 4. Bibcode:2007GeoJI.169.1043D. doi:10.1111/j.1365-246X.2006.03259.x.
^ https://sis.agr.gc.ca/siscan/publications/surveys/pq/pq49b/pq49b_report.pdf Soil Survey of Rouville County (French)
^ https://sis.agr.gc.ca/cansis/publications/surveys/pq/pq62/pq62_report.pdf Orchard Soils of the Province of Quebec
^ "Mont Bleu". Peakbagger.com. Retrieved 20 August 2014.