the cordilleran foreland thrust and fold belt in southern canada
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THE CORDILLERAN FORELAND THRUST AND FOLD BELT IN SOUTHERN CANADA: PLATE TECTONICS, MANTLE FLOW, GRAVITATIONAL SPREADING, AND TECTONIC HEREDITY Raymond A. Price, Dept. of Geological Sciences and Geological Engineering Queen’s University, Kingston, Ontario
Transcript of the cordilleran foreland thrust and fold belt in southern canada
THE CORDILLERAN FORELAND THRUST AND FOLD BELT IN SOUTHERN CANADA:
PLATE TECTONICS, MANTLE FLOW,
GRAVITATIONAL SPREADING, AND TECTONIC HEREDITY
Raymond A. Price, Dept. of Geological Sciences and Geological Engineering
Queen’s University, Kingston, Ontario
INTERIOR PLATEAU
COLUMBIA PLATEAU
THE SOUTHERN CANADIAN CORDILLERA
(AN EARLY MESOZOIC TECTONIC SUTURE
SEPARATING UNDERLYING NORTH AMERICAN
ROCKS FROM OVERLYING SLIDE MTN. &
QUESNEL TERRANES)
THE SOUTHERN CANADIAN CORDILLERA
BC AB
THE FORELAND THRUST & FOLD BELT
Lewis Thrust
Lewis Thrust BC AB Crowsnest Mtn.
The Lewis Thrust at Crowsnest Mountain
UPPER DEVONIAN
UPPER CRETACEOUS
Lewis Thrust
Crowsnest Mountain
THE FORELAND THRUST & FOLD BELT
Lewis Thrust
Bow River.
N. Sask. River.
Athabasca River
(AN EARLY MESOZOIC TECTONIC SUTURE
SEPARATING UNDERLYING NORTH AMERICAN
ROCKS FROM OVERLYING SLIDE MTN. &
QUESNEL TERRANES)
THE SOUTHERN CANADIAN CORDILLERA
TOTAL RESIDUAL MAGNETIC FIELD
WITH ALL FAULTS
Magnetic field data from Geological Survey of Canada
Tectonic domains in
Paleoproterozoic
basement after G.M.
Ross et al., 1991,
CJES v28, n 4.
RETROGRADE BACK-ARC FORELAND THRUST AND FOLD BELTS ARE A BASIC FEATURE OF THE ARCHETYPAL CONTINENTAL-MARGIN OROGENS
THE NORTH AMERICAN CORDILLERA AND THE SOUTH AMERICAN CORDILLERA ARE BOTH BIVERGENT AND ASYMMETRICAL
THE TECTONICALLY ACTIVE ANDEAN FORELAND THRUST AND FOLD BELT PROVIDES AN ACTUALISTIC MODEL FOR THE ORIGIN OF THE NORTH AMERICAN CORDILLERA FORELAND THRUST AND FOLD BELT
VOLCANOES - RED
EARTHQUAKES BLACK – SHALLOW GREY – INTERMEDIATE WHITE – DEEP
THE AGE OF THE THE EARTH’S CRUST UNDER THE OCEANS (from magnetic anomaly maps and the magnetic polarity reversal scale
THE AGE OF THE THE EARTH’S CRUST UNDER THE OCEANS (from magnetic anomaly maps and the magnetic polarity reversal scale
Late Cretaceous Early Cretaceous Jurassic
Pal. Eocene Miocene Olig. M L E
(AN EARLY MESOZOIC TECTONIC SUTURE
SEPARATING UNDERLYING NORTH AMERICAN
ROCKS FROM OVERLYING SLIDE MTN. &
QUESNEL TERRANES)
200 Ma – 180 Ma
ACCRETIONARY COMPLEX
BACK-ARC BASIN
TECTONIC WEDGING AND DELAMINATION
OCCURS AT ALL SCALES FROM MICROSCOPIC TO LITHOSPHERIC
Photo courtesy of M.E. McMechan
0 5 1 2 3 4 cm
TECTONIC WEDGING AND DELAMINATION
OCCURS AT ALL SCALES FROM MICROSCOPIC TO LITHOSPHERIC
Photo courtesy of M.E. McMechan
5 0 1 4 3 2 cm
TECTONIC WEDGING AND DELAMINATION
OCCURS AT ALL SCALES FROM MICROSCOPIC TO LITHOSPHERIC
Photo courtesy of M.E. McMechan
0 5 1 2 3 4 cm
LATERAL GRAVITATIONAL SPREADING WITHIN THICK HOT DUCTILE CONTINENTAL CRUST
ROYDEN, BURCHFIEL & VAN DER HILST, SCIENCE, 2008
LATERAL GRAVITATIONAL SPREADING - THE CONCEPTUAL MODEL
CONCURRENT SIDE-BY-SIDE EXTENDING FLOW AND COMPRESSING FLOW
From Price, 1972, Proc. 24th IGC (after Bucher, 1956, GSA Bulletin v.67, n.10 -- GSA presidential address)
EXTENSION IN THE DIRECTION OF FLOW
COMPRESSION IN THE DIRECTION OF FLOW
EXTENDING FLOW EXTENSION (STRETCHING) IN THE DIRECTION OF FLOW FLOW LINES CONVERGE IN THE DIRECTION OF FLOW DISPLACEMENT INCREASES IN THE DIRECTION OF FLOW
From Price: -
EXTENDING FLOW BOUDINAGE WITH EXCISION OF AMPHIBOLITE LAYERS IN MIGMATITIC PARAGNEISS – Shuswap Metamorphic Complex,
Three Valley Lake, B.C.
COMPRESSING FLOW COMPRESSSION (SHORTENING) IN THE DIRECTION OF FLOW DISPLACEMENT DECREASES IN THE DIRECTION OF FLOW FLOW LINES DIVERGE IN THE DIRECTION OF FLOW
From Price: -
COMPRESSING FLOW -- ALL THRUSTS DIE OUT ALONG STRIKE. DISPLACEMENT (SLIP) WAS DISTRIBUTED AMONG A MYRIAD ARRAY OF DISCRETE DISPLACEMENT DISCONTINUITIES ALL OF WHICH ARE EMBEDDED WITHIN A
COHERENT ROCK MASS THAT HAS FLOWED NORTHEASTWARD.
Bow River.
Boudins were exhumed from depths of 25 – 35 km within Paleocene continental crust that was > 60 km thick
EOCENE DEXTRAL TRANSTENSION AND CRUSTAL BOUDINAGE
LITHOPROBE SOUTHERN CORDILLERA TRANSECT
LITHOPROBE SOUTHERN CORDILLERA SIMPLIFIED COMPOSITE SECTION
LITHOPROBE SOUTHERN CORDILLERA TRANSECT
LOCATION OF CRUSTAL SECTION
Reciprocal Stretching of Upper and Lower Crust --- Boudins exhumed from 25 - 35 km
Ductile Boudinage of the Lower Crust
Exhumed
40 48 32 km
LITHOPROBE Depth to the Moho (Seismic refraction)
EOCENE DEXTRAL TRANSTENSION AND CRUSTAL BOUDINAGE
BOUGUER GRAVITY ANOMALIES
AND
GEOLOGICAL SURVEY OF CANADA
Currie & Hyndman, 2006, JGR v. 111.
VARIATIONS IN
HEAT FLOW
CASCADE SUBDUCTION
ZONE
RMT –- Rocky Mountain Trench
-- volcano
VARIATIONS IN HEAT FLOW
CENTRAL ANDES
Currie & Hyndman, 2006, JGR v. 111
Cordillera
Hyndman et al., 2005, GSAToday, v. 15
Hyndman et al., 2005, GSAToday, v. 15
Currie & Hyndman, 2006, JGR v. 111
INTERIOR PLATEAU
COLUMBIA PLATEAU
THE SOUTHERN CANADIAN CORDILLERA
LOCATION OF RESTORED BALANCED STRUCTURE SECTION
LINE OF SECTION
Section after Price and Fermor, 1985, Geological Survey of Canada Paper 84-14
BALANCED (RETRO-DEFORMABLE)
STRUCTURE SECTION AND CORRESPONDING
PALINSPASTICALLY RESTORED SECTION
PALEOPROTEROZOIC BASEMENT
CAMBRIAN TO MIDDLE DEVONIAN
UPPER DEVONIAN TO TRIASSIC
JURASSIC TO PALEOCENE
WINDERMERE AND PURCELL
MIOGEOCLINE AND CRATONIC PLATFORM FORELAND BASIN PROTEROZOIC RIFT BASINS
A BALANCED (RETRO-DEFORMABLE) STRUCTURE SECTION Whatever occurs on one side of a fault has matching counterpart on the other side
COMPRESSING FLOW
HORIZONTAL SHORTENING AND VERTICAL THICKENING
DURING DETACHMENT AND SOUTHWEST TO NORTHEAST
DISPLACEMENT OF SUPRACRUSTAL ROCKS
SW NE LOCAL TECTONIC WEDGING
(= INTRUSIVE COMPRESSING FLOW)
PALEOPROTEROZOIC BASEMENT
CAMBRIAN TO MIDDLE DEVONIAN
UPPER DEVONIAN TO TRIASSIC
JURASSIC TO PALEOCENE
WINDERMERE AND PURCELL
MIOGEOCLINE AND CRATONIC PLATFORM FORELAND BASIN PROTEROZOIC RIFT BASINS
BALANCED (RETRO-DEFORMABLE) STRUCTURE SECTION
Price and Fermor, 1985, Geological Survey of Canada Paper 84-14
LOCAL TECTONIC WEDGING (= BACK-FOLDING)
ABOVE A DETACHMENT THRUST
LOCAL TECTONIC WEDGING (= INTRUSIVE COMPRESSING FLOW)
Belt-Purcell -- Paleoproterozoic ( 1400 - 1500 Ma)
Windermere Supergroup -- Neoproterozoic (750 - 542 Ma)
Superposition of the Windermere Basin over part of the Belt Purcell Basin
Superposition of the Cordilleran Miogeocline over the Windermere & Belt Purcell Basins
Tectonostratigraphic Domains before Palinspastic Reconstruction
Location of restored balanced structure section
LINE OF SECTION
Section after Price and Fermor, 1985, Geological Survey of Canada Paper 84-14
BALANCED (RETRO-DEFORMABLE)
STRUCTURE SECTION AND CORRESPONDING
PALINSPASTICALLY RESTORED SECTION
Whatever occurs on one side of a fault
must have a compatible counterpart on the other side
TOTAL RESIDUAL MAGNETIC FIELD
from Geological Survey of Canada
Tectonic domains in
Paleoproterozoic basement
after G.M. Ross et al.,1991
CJES, v 28, n 4.
Fernie Map-Area
116
116
114
114
49 49
FERNIE MAP-AREA
AB
BC
MONTANA
AB BC
Paleozoic Miogeocline Basin
THE END
(FOR NOW)
