The Monteregian Hills (french: Collines Montérégiennes) is a linear chain of isolated hills in
Montreal and
Montérégie
Montérégie () is an administrative region in the southwest part of Quebec. It includes the cities of Boucherville, Brossard, Châteauguay, Longueuil, Saint-Hyacinthe, Saint-Jean-sur-Richelieu, Salaberry-de-Valleyfield and Vaudreuil-Dorion.
Th ...
, between the
Laurentians and the
Appalachians
The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. They ...
.
Etymology
The first definition of the Monteregian Hills came about in 1903 when Montreal geologist
Frank Dawson Adams
Frank Dawson Adams (September 17, 1859 – December 26, 1942) was a Canadian geologist.
Early life and education
Frank Dawson Adams was born into a prosperous, middle-class family in Montreal, Quebec.
Adams attended the High School of Montr ...
began referring to
Mount Royal (
Latin, ''Mons Regius'') and hills of similar geology in the
Saint Lawrence Lowlands as the "Royal Mountains" (french: montagnes royales). Other hills in the chain included
Mont Saint-Bruno
Mont Saint-Bruno is part of the Monteregian Hills in southern Quebec, Canada. Its summit stands high and lies east of downtown Montreal.
This mountain has a ski resort, a natural area, and an apple orchard. Forests of beech, maple, oak, hickor ...
,
Mont Saint-Hilaire
Mont Saint-Hilaire (English: Mount Saint-Hilaire; abe, Wigwômadenizibo; see for other names) is an isolated hill, high, in the Montérégie region of southern Quebec. It is about thirty kilometres east of Montreal, and immediately east of the ...
,
Mont Saint-Grégoire,
Mont Rougemont,
Mont Yamaska,
Mont Shefford, and
Mont Brome.
It was only later that
Mont Mégantic, the Oka Hills, as well as the Saint-André and d'Iberville formations, were added to the list.
Geology
Each hill in the chain consists of an erosional remnant of
Cretaceous intrusive igneous rock
Rock most often refers to:
* Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids
* Rock music, a genre of popular music
Rock or Rocks may also refer to:
Places United Kingdom
* Rock, Caerphilly, a location in Wales ...
and associated
hornfels, which are more resistant to
weathering than the surrounding
sedimentary rock. All of the hills have dark-coloured
mafic rock such as
gabbro
Gabbro () is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is ch ...
and
essexite
Essexite (), also called nepheline monzogabbro (), is a dark gray or black holocrystalline plutonic igneous rock. Its name is derived from the type locality in Essex County, Massachusetts, in the United States.
Modern petrology identifies rock ...
; some also have large areas of
pulaskite,
syenite
Syenite is a coarse-grained intrusive igneous rock with a general composition similar to that of granite, but deficient in quartz, which, if present at all, occurs in relatively small concentrations (< 5%). Some syenites contain larger prop ...
, and other light-coloured rock.
The Monteregian Hills are part of the
Great Meteor hotspot track
The New England hotspot, also referred to as the Great Meteor hotspot and sometimes the Monteregian hotspot, is a volcanic hotspot in the North Atlantic Ocean. It created the Monteregian Hills intrusions in Montreal and Montérégie, the White ...
, formed as a result of the
North American Plate sliding westward over the long-lived
New England hotspot
The New England hotspot, also referred to as the Great Meteor hotspot and sometimes the Monteregian hotspot, is a volcanic hotspot in the North Atlantic Ocean. It created the Monteregian Hills intrusions in Montreal and Montérégie, the White ...
, and are the
eroded
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is disti ...
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,
[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 Retrieved on 2007-08-01] or as intrusives that never breached the surface in volcanic activity. 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
The Canadian Shield (french: Bouclier canadien ), also called the Laurentian Plateau, is a geologic shield, a large area of exposed Precambrian igneous and high-grade metamorphic rocks. It forms the North American Craton (or Laurentia), the anc ...
, 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
A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that.
Mantle may refer to:
*Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear
**Mantle (vesture), an Eastern Orthodox ve ...
velocity anomalies and
kimberlitic
Kimberlite is an igneous rock and a rare variant of peridotite. It is most commonly known to be the main host matrix for diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an diamond called the Star of So ...
volcanic features (e.g. the
Attawapiskat,
Kirkland Lake and
Lake Timiskaming kimberlite fields) that become older away from the Monteregian Hills.
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
In soil science, podzols are the typical soils of coniferous or boreal forests and also the typical soils of eucalypt forests and heathlands in southern Australia. In Western Europe, podzols develop on heathland, which is often a construct of huma ...
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.
[https://sis.agr.gc.ca/cansis/publications/surveys/pq/pq62/pq62_report.pdf Orchard Soils of the Province of Quebec]
Gallery
Monteregian Hills in the Fall.jpg, Four of the Monteregian Hills in the late fall
Mont Saint-Hilaire south.jpg, Mont Saint-Hilaire
Mont Saint-Hilaire (English: Mount Saint-Hilaire; abe, Wigwômadenizibo; see for other names) is an isolated hill, high, in the Montérégie region of southern Quebec. It is about thirty kilometres east of Montreal, and immediately east of the ...
from the south
MT YAMASKA.jpg, aerial view of Mont Yamaska
Panorama Mont Rougemont.jpg, Mont Rougemont as seen from Mt. Saint-Grégoire
Mont Mégantic.jpg, Mont Mégantic as seen from the Stoke Mountains
See also
*
Volcanism of Canada
*
Volcanism of Eastern Canada
External links
*
Les collines montérégiennesGeologic information about the chain
References
{{Mountains of Quebec
Mountain ranges of Quebec
Mountains of Quebec
Cretaceous volcanism
Igneous petrology of Quebec
Landforms of Montérégie