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Geology of Ontario 8/5/2005
1
The Geology of Ontario
Gregory C. FinnDepartment of Earth Sciences
Brock University
Outline• Discuss the geologic make-up of Ontario• Examine four geologically significant
features in Ontario– The Sudbury Structure– The Thousand Islands– Niagara Falls– Oakridges Moraine
Geology of Ontario 8/5/2005
2
Ontario’s Geologic Legacy• Geologic history dates back to 3.25 billion
years• Rocks present represent
• ocean floor• deep crustal sections• remnants of ancient mountain chains• deep sea sediments• ancient and modern glacial deposits
• Rocks divided into 4 geologic provinces
Geologic Time ScaleEon Era
Phane
rozoic Mesozoic
Cenozoic
Paleozoic
Late
Middle
Early
Prot
eroz
oic
Late
Middle
Early
Arch
ean
Had
ean
Prec
ambr
ian
570
1,000
1,750
2,510
3,000
3,400
4,000
4,650
Age Era PeriodQuaternary
Tertiary
Ceno
zoic
Meso
zoic
Cretaceous
Jurassic
Triassic
Permian
Pennsylvanian
Mississippian
Devonian
Silurian
Cambrian
Paleo
zoic
Ordovician
Precambrian
Ca
rbo
nife
rou
s
570
505
438
408
360
320
286
245
208
144
65
Age Era Period Epoch
Holocene
Pleistocene
Pliocene
Miocene
Oligocene
Eocene
Paleocene
Qua
tern
ary
Te
rtia
ry
Ce
no
zo
ic
Cretaceous
66.4
57.8
36.6
23.7
5.3
1.6
0.01
Age
Ages in Millionsof Years3.25 billion years Oldest rock in Ontario
Geologic Provinces• Formed at different times - three (Superior,
Southern and Grenville) collectively form Ontario’s portion of the Canadian Shield, and form the bedrock in northern and central Ontario
• The fourth, consists of Paleozoic, Mesozoic and Cenozoic rocks, and occur as sediments which covers the ‘bedrock” in eastern, southwestern and extreme north of Ontario
Geology of Ontario 8/5/2005
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Geologic Provinces of
Ontario
(From ROCK ONtario1994)
Geologic Provinces (continued)
• Lithologies (rock types) present• e.g. volcanic
» basalt vs. andesite vs. rhyolite
• Age• based of geochronologic studies to determine the ages of the
lithologies present
• Structure and Metamorphism• intensity of deformation and degree of metamorphism
preserved/recorded
• Metallogeny• Types of mineral deposits present
Criteria for defining Geologic Provinces
Geology of Ontario 8/5/2005
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Superior Province• Oldest part and covers most of Northern Ontario• Can be further subdivided, based on rock type into
12 smaller subprovinces:• Granite-Greenstone - plutonic and volcanic
» Uchi, Wawa, Abitibi
• Sedimentary - range of sedimentary rock types» English River, Quetico
• Plutonic - mainly granite» Winnipeg River
• High Grade - deep crustal slice of a greenstone» Kapuskasing Zone
Superior ProvinceSubprovince Types
Bird River
MinnesotaRiver Valley
Winisk
Thompson Belt
N
0 250 Km
Hudson Bay
James Bay
Manito
baOntar
io
CanadaU.S.A.
Southern Province
GrenvilleProvince
Ontario
Quebec
Labrador Trough
Sugluk
CapeSmithBelt
Trans - Hudson Orogen
St. Catharines
Pikwitonei
Sachigo
Berens River
UchiEnglish River
Winnipeg RiverWabigoon
Wawa
Wawa
Quetico
Quetico
Kapu
skas
ing
Pontiac
AbitibiOpatica
Nemiscau R.
AshuanipiBienville
La Grande R.
Opinica R.
Minto
High Grade
Plutonic
Volcanic
Metasedimentary
Modified from Percival 1989
Geology of Ontario 8/5/2005
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Superior Province Highlights• Subprovinces separated from each other by
faults• Granite-Greenstone
• long narrow belts of volcanic rocks which were once island arcs - much like modern day Japan
• rocks formed on ancient sea floors, in ancient volcanoes
• host to world famous mines – e.g.
» gold at Hemlo,» copper, zinc, and silver at Kidd Creek
A portion of the Superior Province in NW Ontario. Greenstone belts (in green) are remnants of ancient volcanic rocks.
0 5 km
RichardsonArm
Rapson
StullRapson
Bay
StullLake
(From ROCK ONtario1994)
Sample Test Questions1. List three minerals that you would expect to find in each of the following rocks:
– Diorite Syenite Phyllite Marble
2. Define each of the following terms:– metamorphic rock texture euhedral Porphyroblast
3. Minerals are classified as belonging to either the silicate or non-silicate groups or classes. Provide the characteristics that define two non-silicate classes of minerals and give examples for each class:
– a) b)
4. Describe the three types of material produced as a result of volcanic eruptions:– a) b) c)
5. One identifiable group of metamorphic rocks are the foliated. What 2 processes result in the development of the foliation?
• a) b)
Ten questions, equal value, 60 minutes
Geology of Ontario 8/5/2005
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RECAP• Finished off Metamorphic rocks
– Index minerals, isograds– Prograde vs retrograde
• Metamorphic Environments– Thermal or contact– Dynamic– Dynamothermal
• Geology of Ontario– Geologic provinces
• Lithology, age, structure/metamorphism, metallogeny– Superior Province
The Southern Province
Geology of Ontario 8/5/2005
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North Channel
Cobalt Embayment
Sault Ste. Marie -Elliot Lake Area
Sudbury -Espanola Area
SUPERIOR PROVINCE
GRENVILLEPROVINCE
SudburyStructure
Southern Province• Rocks present range in age from 2.49 to 2.21 billion years • Consists mainly of sediments (3,000 to 15,000 m thick)
• conglomerate, sandstone, siltstone, mudstone
• Deposited by rivers, wind, glaciers etc. in an ancient ocean• comparable to the modern Atlantic Coast of North America
• Following deposition a period of mountain building occurred when Ontario collided with another continent
• preserved along the north shore of Lake Huron
• 1.11 billion years ago the the Earth’s crust of the Southern Province cracked forming a rift valley along which igneous rocks were formed
• volcanic rocks around Lake Superior• plutonic rocks around Lake Nipigon
Geology of Ontario 8/5/2005
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1.85 Billion Years Ago in the Southern Province
• Sudbury Event
Geologic Cross Section - Sudbury Area ~ 1.85 GaImpactor/Bolide~10 km diameter~ 25 km/sec
HuronianSedimentaryRocksN S
230 km
70 km
Mantle
Lower Crust
Archean Basement Rocks
Nipissing Magma Chamber
NipissingDiabase
CreightonGranite
Melt + Vapour
70 km
Archean
Huronian
Lower Crust
EjectaCurtain
Cratering FlowField
Time ~ 5 seconds
Geology of Ontario 8/5/2005
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70 km
Melt + Vapour
Archean
Huronian
Lower Crust Transient Cavity atMaximum Depth
Time: ~1 minute
Formation of Proto-Footwall Breccia and Sublayer,
Ejecta
70 km
Time: ~2 minutes
Transient Cavity at maximum diameterUplift of cavity floor and beginning of rim collapse
70 km
Time: minutes
Near completion of upliftand rim collapse
Formation of additional Sudbury Breccia, Footwall Breccia and Sublayer
Geology of Ontario 8/5/2005
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70 km
Time: minutes
Final Form Formation of SIC, BasalOnaping and Gray Member
Fall-back, CoolingLocal Readjustments
Formation of Black Onaping,Cooling and differentiation of SICIntrusion of Offset Dikes, Ores
SIC
70 km
Time: ~ Hours to 105 a
70 km
Time: 1.85 GaPresent Day
Penokean and Grenvillian
Geology of Ontario 8/5/2005
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The Sudbury Structure• The preserved remnant of this meteorite impact is
termed the Sudbury Structure composed of:• the Sudbury Basin• the Sudbury Igneous Complex
– World famous for:• its origin by
meteorite impact• Nickel deposits
Geology of Ontario 8/5/2005
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Subdury Mining History• Sudbury copper-nickel ores have been mined since 1883
• Early smelting took place out in the open - Copper Cliff
• Until WWII only copper was produced
• During WWII it was discovered that the addition of nickel served to strengthen steel - “armour plate”
• Ontario produces 2/3 of Canada’s nickel (2nd to Russia in terms of worldwide production)
• In 1993 17 operating mines produced 124 million kilograms of nickel worth of $835 million
• A total of 45 ore minerals are present at Sudbury, yielding in addition to Ni and Cu, Au, Ag, Co, Pt, Pd, Se
The Grenville Province
Geology of Ontario 8/5/2005
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LakeHuron
GeorgianBay
Sudbury
Pembroke
Kingston
Quebec
100 km
Central Metasedimentary Belt
Central Gneiss Belt
Tomiko
Algonquin
Nipissing
ParrySound
Boundary Zone
Frontenac
Shar
bot L
ake
Maz
imaw
Elzevir
BancroftBoundary Zone
(From ROCK ONtario1994)
Bancroft
The Grenville Province
Grenville Province• Consists of a patchwork of many different pieces of crust
or terranes, which collided to form a major mountain range.
• Rocks present range in age from 1.76 to 1.00 billion years • Rocks have been baked, squeezed, stretched and twisted
into metamorphic rocks by a series of mountain building events 1.18 to 1.00 billion years ago.
• Consists of two major belts:• Central Gneiss Belt• Central Metasedimentary Belt
• Complex history still being unraveled by geologists
Central Gneiss Belt• Oldest part of Grenville Province• Nipissing Terrane oldest
• metamorphosed sedimentary and igneous rocks
• Parry Sound Domain Youngest• volcanic island arc, formed at some locality far removed from Ontario
(Suspect Terrane)
• Consists of metamorphic rocks that have been subjected to intense heat (~800°C) and pressure (up to 10 kbars) due to burial during mountain building activity
• Central Gneiss Belt exposes deep sections of Earth’s crust the was buried to depths of 20 to 30 km
• Responsible for scenery in Algonquin Park
Geology of Ontario 8/5/2005
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Central Metasedimentary Belt• Largest section of Grenville Province• Consists of two sections
• A ‘Superterrane’ (Bancroft, Elzevir, Mazinaw, Sharbot Lake terranes)
– mixture of sedimentary and volcanic rocks formed ~1.30 billion years ago
– metamoprhosed 1.25 billion years ago when the four terranescollided and at the same time intrusions of granite ‘stitched’ together the terranes
• The Frontenac Terrane– lots of marble, quartzite and gneiss, but no volcanic rocks,
formed 1.28 billion years ago
• Story of erupting volcanoes, island arcs, erosion of sediments and mountain building ( = Himalayas)
• Volcanoes formed in a tropical environment, comparable to present-day Indonesia‘
Geology of Ontario 8/5/2005
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Phanerozoic Lithologies
Paleozoic (early life) and Mesozoic (middle life) Eras
Paleozoic Lithologies
• Occur in Southeastern Ontario, Southwestern Ontario and the Hudsons Bay and James Bay Lowlands
• Essentially flat lying sedimentary rocks• In general they get younger as you move
from east to west in Southern Ontario
Geology of Ontario 8/5/2005
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The Niagara Escarpment
• Is NOT a fault scarp• It is an erosional
feature• Extends from:
• up state New York through Ontario, along the Bruce Peninsula, into Michigan
• Represents a series of sediments deposited in an inland sea
Geology of Ontario 8/5/2005
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Niagara Falls
0 1 2 km
N
Niagara Falls(Ontario)
Niagara Falls(New York)
St. Davids Buried Gorge
Niagara Escarpment
Whirlpool State Park
WhirlpoolRapidsGorge
Whirlpool
Eddy Basin
Lyell/JohnsonRidge
NiagaraGlen
Queenston
Lewiston
PowerStations
PowerStations
AmericanFalls
Canadian orHoreshoe Falls
Niagar
a G
reat
Gor
ge
Niagara River
Geology of Ontario 8/5/2005
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From Tinkler 1993
0 1 2 km
N
St. Davids Buried Gorge
Niagara River
?
?
?
12500 BP
Lake Iroquois 0 1 2 km
N
Niagara RiverSt. Davids Buried Gorge
11500 BP
Recently Emerged
Now Dry
Submerged
Dry LandNewly Excavated Gorge
Exhumed Buried Gorge
Stages in the Recession of Niagara Falls
From Tinkler 1993
0 1 2 km
N
Niagara River
St. Davids Buried Gorge
NiagaraGlen
10500 BP
0 1 2 km
N
Niagara River
St. Davids Buried Gorge
NiagaraGlen
5500 BP
Recently Emerged
Now Dry
Submerged
Dry LandNewly Excavated Gorge
Exhumed Buried Gorge
Stages in the Recession of Niagara Falls
From Tinkler 1993
Geology of Ontario 8/5/2005
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0 1 2 km
N
St. Davids Buried Gorge
Sediment
Niagara River
Buried GorgeExhumed
4500+/-150 BP
LakeTonawanda
high
0 1 2 km
N
Niagara River
St. Davids Buried Gorge
Lyell-Johnson Ridge
4000-3500 BP
Recently Emerged
Now Dry
Submerged
Dry LandNewly Excavated Gorge
Exhumed Buried Gorge
Stages in the Recession of Niagara Falls
From Tinkler 1993
0 1 2 km
N
Niagara River
St. Davids Buried Gorge
LakeTonawanda
drained
Now
Recently Emerged
Now Dry
Submerged
Dry LandNewly Excavated Gorge
Exhumed Buried Gorge
Stages in the Recession of Niagara Falls
From Tinkler 1993
Distance Up River From Lewiston In Kilometres
14C
Age
for L
ocal
ities
2000
4000
6000
8000
10000
12000
1400016000
00 1 2 3 4 5 6 7 8 9 10 11 12
NiagaraGlen
Lewiston
PresetFalls
ExhumedGorge
Sediment slug to Lake Ontario
Whirlpool State parkAbove Gorge Walls
Recession Rate of Niagara Falls
From Tinkler 1993
Geology of Ontario 8/5/2005
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Historic Crest Position
Niagara Falls • Mean flow is ~ 5,760 m3s-1
• Since 1953 half of this is extracted for power generation
• At night in the summer and throughout the winter 3/4 of this is extracted from the river
• Effect is that the recession rate of 5 ft yr-1 from 19th Century is greatly reduced
The Oak Ridges Morraine
Geology of Ontario 8/5/2005
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Geomorphology of Toronto Region
From: Toronto Rocks, 1998
Digital Elevation Model wof Oak Ridges Moraine. Of particular note in this scene is the extremely linear character of the Oak Ridges Moraine across the
centre of the image. Major difference in terrain features north and south of the moraine can be recognized. North of the moraine the terrain is dissected by large valleys and has extensive drumlin uplands. South of the moraine the
elevation is lower, the topography smoother and there are fewer valleys and drumlins.
http://sts.gsc.nrcan.gc.ca/orm/landscapes.asp
Final Stages of Last Ice Age:Formation of Oak Ridges Moraine
From: Toronto Rocks, 1998
Geology of Ontario 8/5/2005
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Well stratified matrix-supported gravels (1) have been eroded and the resulting channel filled with a massive sand-silt diamicton (2). These deposits are part of the Paris Moraine, a thick accumulation of glacial fluvial deposits and illustrate the high energy associated with ice-front sedimentation.
http://sts.gsc.nrcan.gc.ca/orm/sediments.asp
These medium sands have well-developed planar laminations (1) resulting from deposition under high velocity flows commonly associated with glacial fluvial conditions. These planar laminated sands have been truncated by an erosional surface (2) which is overlain by a second phase of deposition (3). These types of deposits are common within the Oak Ridges Moraine, a regional glaciofluvial - glaciolacustrine complex http://sts.gsc.nrcan.gc.ca/orm/sediments.asp
Cross Section Oak Ridges Moraine:13,000 years ago
From: Toronto Rocks, 1998
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