Abstract The Canadian sector of the Cordilleran Orogen encompasses an area of over 1.6 x 106 km 2 and extends from the base of the continental slope on the west to the western limit of undeformed strata underlying the Interior Plains. Its northern boundary is the Beaufort Sea and its southern boundary, 2000 km to the south, is the International Boundary, for the most part at 49°N (Map 1701 A, in pocket). The great diversity in the geology of the region is reflected in its varied physiography. Spectacular exposures of layered sedimentary strata characterize the British, Richardson, Ogilvie, Wernecke, Mackenzie and Rocky mountains of the Foreland Belt in the eastern part of the Cordillera. To the west equivalent rocks have been intensely folded, metamorphosed and intruded by granitic rocks to form the rugged Selwyn, Kaska and Columbia mountains of the Omineca Belt (Morphogeological Belt map - inside front cover). Transecting the Omineca Belt in the Yukon Territory and separating the Foreland and Omineca belts in British Columbia is one of the world's most remarkable lineaments represented by the Tintina, Northern Rocky Mountain and Southern Rocky Mountain trenches. The straight valleys of the Tintina and Northern Rocky Mountain trenches coincide with the traces of dextral transcurrent faults, whereas the three arc-like segments of the Southern Rocky Mountain Trench, although everywhere associated with faults, are not known to be the loci of transcurrent displacements. The Intermontane Belt of central British Columbia and south-central Yukon Territory is underlain by a wide variety of

Abstract The first part of this chapter deals with the concepts of morphogeological belts, tectonic assemblages and terranes. These concepts are fundamental to the understanding of Canadian Cordilleran evolution and play an important role in the organization of the volume. Part B is mainly devoted to recent paleontological studies and their significance relative to the characterization of Cordilleran terranes. No attempt is made to synthesize the full scope of paleontology in the context of Cordilleran geology, a subject beyond the purview of this volume, but the importance of this discipline will be apparent in the chapters on stratigraphy. Part C presents a synthesis of crustal geophysical surveys including refraction and reflection seismology, seismicity, heat flow, geomagnetism, gravity, isostasy and magnetotellurics. Although many of these studies are in their infant stages they have already provided a wealth of data on the nature of the deep crust and processes contributing to its evolution.

Abstract Paleomagnetic studies in the Canadian Cordillera began in the late 1950s. During the past two decades efforts to determine displacements and rotations have concentrated largely on the terranes of the Intermontane and Insular belts, and, to a lesser extent, on Proterozoic and Cretaceous strata of the Foreland Belt. Results obtained from Neogene rocks confirm the average dipolar nature of the ancient geomagnetic field and indicate that since the mid-Tertiary, except for the Queen Charlotte Islands, no paleomagnetically detectable tilting, rotations or horizontal motions relative to the craton haveoccurred throughout most of the Cordillera. Paleogene rocks commonly show significant rotations but no detectable latitudinal displacements. Cretaceous paleopoles from the western Cordillera mostly are clustered in the North Atlantic whereas those from the craton occur northwest of Alaska. Many paleopoles have been determined from well-dated older rocks in the accreted terranes, all from overprints of probable mid- Cretaceous age. These data, when applied to Pacific plate motion reconstructions, suggest that the Intermontane and Insular superterranes may have been one coherent crustalfragment ("Baja British Columbia") by mid-Cretaceous time and located along the eastern edge of the Kula Plate some 2000 km south of its present position. Northward motion between mid-Cretaceous and Eocene time, together with clockwise rotation, terminated with the accretion of BajaBritish Columbia to ancestral North America when the Kula Plate ceased to exist as a separate plate and when the approximate position of the present Pacific-America plate boundary was established. Results from Cretaceous rocks of the Foreland

Abstract The metamorphic and plutonic rocks upon which the miogeocline was developed are considered to be the basement rocks of the Canadian Cordillera. They are recognized by an unconformable relationship with Proterozoic or younger bedded rocks and/or on the basis of reliable geochronological data. According to these criteria, basement rocks in the Cordillera are exposed only in fold and thrust nappes of the Omineca Belt, and, at one locality, unconformably beneath the Windermere Supergroup in the Foreland Belt. Basement rocks sampled in diatremes and drill holes provide additional geochronological data. drill holes provide additional geochronological data. The principal basement exposures comprise mainly granitic paragneiss and orthogneiss, with minoramphibolite and metasedimentary rocks. U-Pb zircon dating provides the most reliable age assignment. These age determinations suggest that most Precambrian crystalline rocks of the Cordillera fall into three groups, 1.85-2.1 Ga, 1.1-1.2 Ga, and 0.7-0.8 Ga; the first and third of these categories are probably represented throughout the full length of the Canadian Cordillera. Relationships with the structurally or stratigraphically associated Windermere Supergroup suggest but do not prove that all of these rocks are part of the North American craton. The earlier Proterozoic ages (1.85-2.1 Ga) probably represent those of one or more Proterozoic tectonic provinces of the western Canadian Shield. Granitic rocks from a diatreme in the Mackenzie Mountains (1.1-1.2 Ga) may be associated with a Middle Proterozoic orogenic event in the northern Cordillera. The latest Proterozoic rocks may be related to magmatism caused by pre-Windermere rifting, eventually resulting in the

Abstract The ages of formations and larger groupings of Precambrian stratified rocks in the Cordillera are, in general, poorly constrained. Only two useful macrofossil assemblages are known: an Ediacaran, non-skeletal fauna found only in the youngest formations, and an older, Chuaria-Tawuia associationwhose duration of several hundred million years provides age control little more constrained than that provided by the few available radiometric dates. Stromatolite biostratigraphy to date has failed to provide useful chronocorrelation with the Riphean of the U.S.S.R. Only the youngest formations have been characterized palynologically. Few reliable radiometric dates have been published, but bracketing dates and structural relationships permit the assignment of most major successions of Cordilleran Proterozoic strata to one or other of the sequences recognized by G.M. Young and co-workers: Sequence A: =1.7 to =1.2 Ga Sequence B: =1.2 to =0.78 Ga Sequence C: =0.78 to =0.57 Ga These sequences, of which A and B are the subject of this chapter, provide a useful, though imprecise, framework for discussion. Sequence C nconformably overlies Sequence B and is discussed in Chapter 6. Sequence A (Purcell-Wernecke, Cap Mountain-Hornby Bay, Muskwa assemblages) conspicuously lacks the longitudinal Cordillera continuity of Upper Proterozoic strata (Sequence C) and is exemplified by the classical Purcell (Belt) Supergroup of southeastern British Columbia, southwestern Alberta, Montana and Idaho. Its patterns of sedimentary facies and thickness (up to 20 km) have generally been interpreted as those of a continental-marginsuccession, but for the Belt-Purcell Basin at least, work in the northwestern United

Abstract Sequences of Upper Proterozoic, dominantly clastic, sedimentary rocks, generally assigned to the Windermere Supergroup, are commonly more than 2000 m thick and are exposed almost continuously throughout the length of the eastern Cordillera (Fig. 6.1, 6.2). In the Purcell and Mackenzie mountains the supergroup unconformably overlies strata of the Purcell and Mackenzie Mountains supergroups, respectively. In and near the Omineca Belt the rocks unconformably overlie basement of granitic gneiss ranging in age from 728 Ma to more than 2 Ga (see Chapter 4). Elsewhere, the lower contact of the supergroup is not exposed. In many places the supergroup is overlain unconformably by clastic rocks, commonly sandstone, of Early Cambrian age, but in more western areas, whereLower Cambrian rocks may be fine grained, an unconformable relationship is difficult to demonstrate. Characteristically, in the central and southern Cordillera, the lower part of the Windermere Supergroup comprises thick, monotonous sequences of gritty, feldspathic sandstone, siltstone and shale, variably metamorphosed from low greenschist to upper amphibolite facies. The upper part of the Windermere is more calcareous and much more variable in lithology. One or more carbonate formations are of regional significance although correlationsbetween regions are dubious. Conspicuous maroon, purple and green shale occurs in the uppermost formation of the group in the Selwyn, northern Rocky, Cassiar, Omineca and Cariboo mountains. In the Selwyn Mountains the varicoloured shales overlie thick successions of gritty sandstone that are younger than most grits assigned to the Windermere Supergroup elsewhere. Diamictite, at least locally reflecting glacial

Abstract Lower Cambrian to Middle Devonian miogeoclinal strata were deposited along a passive margin of western Ancestral North America which formed as a result of rifting in Late Proterozoic time. Local anomalous thicknesses and facies of sedimentary rocks and the presence, in all systems, of minor volcanic rocks suggest repeated episodes of extension. The miogeoclinal sedimentary prism thickens markedly west of hinge lines which vary slightly in position for different rock units. Farther west thick carbonate sequences grade abruptly into much thinner argillaceous strata which, perhaps, reflect deposition on significantly attenuated continental crust. Thus, the main characteristics of the Lower Cambrian to Middle Devonian rocks in themiogeocline may be attributed to a complex interplay of continental rifting, attenuation, drifting, thermal subsidence and flexuring along the western margin of the continent. Rocks of similar ages, in part volcanogenic, mainly in the Alexander Terrane and forming minor components of several other terranes seem to have had both volcanicisland arc and possibly miogeoclinal affinities. The Cambrian System of the Cordillera can be subdivided into four series, the Lower Cambrian Placentian and Waucoban Series, Middle Cambrian, and Upper Cambrian. The Placentian Series is strikingly different from the other three in its predominance of clastic sediments. Various water depths are indicated, but no major carbonate body was deposited, which suggests deposition in relatively cool waters. Placentian basinal shale and siltstone were probably deposited in British-Barn Basin and are present in much of Selwyn Basin. Between the two basins was the ancestral Yukon Platform, which

Abstract The pre-Late Devonian Cordilleran miogeocline consisted of extensive shallow-water platforms upon which carbonate-clastic deposits accumulated. They were flanked to the west by deep-water environments where shale and carbonate accumulated (Rocky Mountains Assemblage). Clastic sediments were largely craton-derived. During the Late Devonian sedimentation patterns changed dramatically as turbiditic, chert-rich clastics, derived from the west and north, flooded the northern Cordillera (Earn and Imperial assemblages). Shale (Besa River Assemblage) was deposited far out onto the miogeocline and InteriorPlatform; the carbonate front of the Rundle Assemblage retreated far to the east and south of its Middle Devonian position. By mid-Mississippian time the clastic influx waned and normal marine shelf carbonate and clastic sedimentation resumed, once again with clastics derived from the craton. Devono-Mississippian plutonism occurred only in northernmost Yukon Territory, and volcanism was restricted to central Yukon and south-central British Columbia.Pre-Late Mississippian folding occurred in northern Yukon but elsewhere deformation is expressed only by local high-angle faults and disconformities. Devono-Mississippian tectonism in the northern Yukon involved uplift and granitic intrusion in Frasnian to Early Mississippian time, resulting in an upward shoaling and southward-prograding clastic wedge. The sequence consists of shale at the base, flyschoid sediments near the middle, and partly fluvial-deltaic strata at the top. Deformation migrated southward from the area of uplift until the clastics themselves were folded prior to the mid-Carboniferous. The source of Devono-Mississippian sediments in the central Cordillera was uppermost Precambrian quartzose clastics and lower Paleozoic chert from the western miogeocline. Western coarse clastics are typified

Abstract The Upper Jurassic (Oxfordian) to Paleogene (Oligocene) assemblages record the effects of Mesozoic and early Cenozoic terrane amalgamations and collisions which, with consequent orogenesis and sedimentation, created the modern framework of the Canadian Cordillera. During this interval the five geological belts were established, more or less, but not entirely concordantly with major terrane boundaries. The sedimentary basins which developed as a result of and subsequent to terrane accretion reflect the full range of continental and oceanic plate interactions including orthogonal, oblique and transform motions. The assemblages are important hosts to several episodic suites of copper, copper-molybdenum and molybdenum porphyry deposits as well as all of the economic coal deposits of the Cordillera. Additionally, Cretaceous strata in the Foothills of the Foreland Belt serve as reservoirs for many hydrocarbon accumulations. The tectonic setting within which the assemblages developed was dominated by the accretion of large, composite crustal fragments to the continental margin. The Intermontane Superterrane, comprising the amalgamated components of Stikinia, Quesnellia, the Slide Mountain and Cache Creek terranes probably collided with and subsequently was thrust over the pericratonic terranes at the western edge of North America in Early to Middle Jurassic time. Likewise, the Insular Superterrane, composed of Wrangellia and the Alexander Terrane, together with several smaller terranes in the Coast Belt, accreted to the Intermontane Superterrane no later than mid-Cretaceous time and possibly as early as latest Jurassic to earliest Cretaceous time. The great width of the Canadian Cordillera is a reflection of the dimensions of the successively

Abstract By the beginning of Neogene time, some 24 Ma ago, the Kula Plate had disappeared and the Pacific-Farallon spreading ridge had collided with the western margin of North America north of Queen Charlotte Islands. During the early Neogene the Pacific-North America-Farallon triple junction migrated southeastward to a position adjacent to the northern end of Vancouver Island where it has remained relatively fixed for the past 10 Ma. The early Neogene shift in the position of the triple junction was accompanied by a rapid decrease in the size of the easterlysubducting Farallon Plate. The present small remnants of the Farallon Plate have been renamed the Juan de Fuca and Explorer plates, and the active spreading centre (Farallon-Pacific spreading ridge) which bounds them on the west has been renamed the Juan de Fuca Ridge system. Motion vectors relative to the absolute (hotspot) framework indicate that the western Canadian part of the North American Plate moved southwestward at about 22 mm per year for most of Neogene time. Dextral transcurrent faulting, which dominated the early Tertiary tectonics of the Intermontane Belt, was greatly reduced during the Neogene, and confined to faults at or near the continental margin. Movement on the Totschunda and Border Ranges fault systems accompanied profound Neogene uplift, folding and northeasterly directed thrusting in the Saint Elias Mountains. During this time the Intermontane Belt remained relatively stable whereas the axis of the Coast Belt was greatly uplifted and deeply dissected. throughout the offshore regions of the Insular Belt, on parts

Abstract The geomorphic development of the Canadian Cordillera is here considered as starting from Middle or Late Jurassic time when ancestral North America collided with the Intermontane Superterrane along its western margin. This, and a similar event later in the Mesozoic, produced two metamorphic and plutonic complexes, each of which are loci of high-grade metamorphism, rapid uplift, and vigorous erosion. These complexes, the Omineca Belt in the east and the Coast Belt to the west, constitute two of the five morphogeological belts in the Cordillera. Development of the Foreland Belt was an additional outcome of plate collision. With the growth of this belt in mid-Mesozoic to earliest Cenozoic time, a trellis drainage pattern developed, simulating that in the present Cordillera. Individual river courses of that time, however, bear little or no relationship to present drainage. The early erosion-products, together with material from the Omineca Belt to the west, contributed to an almost continuous apron of alluvial fans and associated deltaic deposits in the foredeep, east of the rising orogen. Widespread Early Cretaceous pediplanation, recorded by pre-Hauterivian to Albian erosion surfaces, coincided with a lull in magmatic activity throughout the Cordillera. Contemporaneous uplift and volcanism in the western Cordillera provided sources for rapid degradation and alluvial sedimentation in and adjacent to contemporaneous narrow seaways. Although transcurrent faulting and arc (Andean?) magmatism prevailed in part of the western Cordillera erosional and depositional activity west of the Foreland Belt subsided in Late Cretaceous and Paleocene time only to become vigorously rejuvenated in Early

Abstract The Quaternary Period, encompassing the last two million years of geological time, is noteworthy for major climatic perturbations that resulted in episodic growth and decay of continental ice sheets in middle latitudes of the Northern Hemisphere. One such ice sheet and smaller independent satellite glaciers repeatedly enveloped most of the Canadian Cordillera with the exception of the northern Yukon and parts of the western District of Mackenzie. Global cooling at the beginning of each glaciation led to the expansion of cirque and valley glaciers in the high mountains of western Canada. As climate deteriorated, glaciers advanced and coalesced to form piedmont complexes and mountain ice sheets. Eventually, glaciers from separate mountain ranges joined to cover most of British Columbia, southern Yukon, and parts of westernmost Alberta, Alaska, and the northwestern conterminous United States. During most Quaternary glaciations, the Cordilleran Ice Sheet was continuously nourished from source areas in high mountain ranges, and ice flow was controlled mainly by topography. However, at the climaxes of a few glaciations, ice in the interior of British Columbia became sufficently thick for one or more ice domes to develop with surface flow radially away from their centres. Glaciations ended with rapid climatic amelioration. Deglaciation occurred by complex frontal retreat and by downwasting accompanied by widespread stagnation. In areas of moderate relief, uplands appeared through the ice sheet first, dividing it into a series of tongues that decayed in response to local conditions. Glaciers existed in the Canadian Cordillera during late Tertiary and early

Abstract The western margin of the Cordillera and adjacent offshore areas of western Canada exhibit pronounced tectonic activity through a variety of plate tectonic interactions, includingocean-ridge spreading, transform faulting, and subduction. Interactions occur among three principal plates or plate systems: the Pacific Plate, the America Plate and the intervening small Juan de Fuca Plate system. The en échelon Juan de Fuca spreading ridge system is the accretionary boundary between the Pacific and Juan de Fuca plates. The ridge system spreads at rates of between 40 and 60 mm/a and is fragmented and complex. Detailed surveys show that the ridge morphology and tectonics are extremely variable. The Juan de Fuca Plate system east of the ridge is equally complex and has apparently responded to varying resistance at the subduction zone along the continental margin by plate breakup, ridge jumping and re-orientation. The Pacific-America interaction, which extends along the continental margin northwards from Queen Charlotte Sound, is predominantly right-lateral transform at a rate of 50 to 60 mm/a. However, there is evidence for a small component of convergence along the Queen Charlotte Islands that causes underthrusting. To the north, off Dixon Entrance, there appears to be pure transcurrent motion. Farther north in southeast Alaska and the western Yukon, the plate boundary becomes more complex and through studies of seismicity, it seems likely that several faults in the region transfer strike-slip motion along the Fairweather system into thrust motion in the Chugach-Saint Elias system and the Aleutian Trench. Convergence beneath the western margin

Abstract Volcanic rocks are found in most of the major rock assemblages in the western Cordillera. In-situ models of their origin (Souther, 1977) have been superseded by tectonic models based on evidence that the Cordillera is a collage of separate, once distant terranes that have been accreted to the continental margin. This concept is the basis for the three-fold subdivision of volcanic regimes in this chapter: (1) volcanic rocks of the miogeocline, (2) volcanism in the accreted terranes, (3) post-accretionary volcanism. Following the separation of ancestral North America from a Precambrian continental mass in mid-Proterozoic time the deposition of a prograded terrace wedge along the western continental margin was accompanied by episodes of crustal extension and minor igneous activity. Tectonism about 1.2 Ga produced a widespread unconformity in the northern Cordillera between the Wernecke and Mackenzie Mountains supergroups and was accompanied by local effusions of alkali-tholeiite lavas and the emplacement of diabase dyke swarms and sills throughout the entire western half of North America. A second tectonic event about 780 Ma initiated deposition of the Windermere Supergroup in a relatively narrow rift depression that truncated the older terrace wedge deposits. Rifting was accompanied by widespread eruption of mafic volcanic rocks and, at least locally, by the explosive eruption of intermediate to salic magma. Deposition of the Windermere Supergroup was followed by a relatively stable regime that lasted through the early Paleozoic. Deposits of quartzite and carbonate reefs on the continental shelf and thick deep-water shale deposits on the outer slope

Abstract The greatest concentrations of plutonic rocks in the Canadian Cordillera are in the Coast and Omineca belts but significant amounts also occur in adjacent belts. Most Cordilleran plutons are Late Triassic to Paleogene in age, and are coeval and comagmatic with volcanic rock suites. Proterozoic and Paleozoic plutons of ancestral North America consist of Early and Middle Proterozoic granodiorite, Late Proterozoic alkalic plutons, early Paleozoic alkalic to carbonatitic suites, and Proterozoic and Paleozoic mafic sills and diatremes. The pericratonic Kootenay Terrane contains granite to quartz diorite intrusions of mainly Ordovician to Mississippian age. The Monashee Terrane has Proterozoic and Paleozoic(?) alkaline intrusions. The Slide Mountain Terrane contains a variety of Paleozoic plutons, mostly diorite, quartz porphyry, and tonalite. The Alexander Terrane includes Ordovician to Early Silurian calc-alkaline plutons; mid- to Late Silurian sodic plutons emplaced during the Klakas orogeny; and, in the Saint Elias Mountains, late Paleozoic calc-alkaline stocks and batholiths. Wrangellia has small mafic to ultramafic plutons in the Saint Elias Mountains and Devonian quartz-feldspar porphyry in southwestern British Columbia. Late Triassic plutons are largely restricted to small, Alaskan-type ultramafic bodies in Quesnellia and Stikinia, and to a belt of tholeiitic to calc-alkaline granitoid rocks that intrude Stikinia along the Stikine Arch. Both suites are spatially and probably genetically related and are associated with Middle to Upper Triassic volcanic rocks. In the Early Jurassic, plutonic activity occurred in Quesnellia, Stikinia, and Wrangellia. Calc-alkaline batholiths in Quesnellia and alkaline bodies there and in Stikinia show close spatial and temporal

Abstract All pre-Miocene rocks in the Canadian Cordillera have been regionally metamorphosed. The highest grade rocks, reflecting deep burial and high temperatures, form core zones in the Coast and Omineca belts whereas lower grade rocks, suggestive of burial metamorphism, characterize most of the Insular, Intermontane, and Foreland belts. Regional metamorphism reached its peak in the Omineca Belt in Middle Jurassic time and in the Coast Belt in Late Cretaceous time. Both episodes correlate with periods of intense crustal contraction and thickening and were followed by great and rapid uplift. Except for metamorphic culminations in the Deserters Range east of the Northern Rocky Mountain Trench and a local area east of the Southern Rocky Mountain Trench most of the regional metamorphism in the Foreland Belt is of low-grade burial type. Precambrian rocks are commonly in greenschist facies, Paleozoic and some Mesozoic strata are mainly in prehnite-pumpellyite facies, and most Mesozoic strata are in zeolite facies. Although there is a general westward increase in coal rank with increasing stratigraphic burial, several east- to northeasttrending belts of anomalous organic maturation parallel present geothermal gradients. These belts may be related to faults in the Precambrian basement. Rocks in the Omineca Belt received their main metamorphic imprint in Middle Jurassic time, presumably as a result of collision between ancestral North America and the Intermontane Superterrane. Locally, there is evidence for Precambrian metamorphism in the Monashee Complex, pre-Late Mississippian metamorphism in the Kootenay Arc, Late Permian(?) high-pressure and lowtemperature metamorphism in accreted terranes in the southern

Abstract The dominant elements of structural style in the Canadian Cordillera are related to the Insular, Coast, Intermontane, Omineca, and Foreland morphogeological belts, of which the Coast and Omineca belts represent greatly uplifted granitic and metamorphic orogenic core zones. Structures commonly verge outward from the core zones so that, in cross-section, the Cordilleran orogen contains two symmetrical suborogens (Fig. 17.1, in pocket). The first to develop was the Omineca Belt wherein Mesozoic deformation is attributed to the collision of the Intermontane Superterrane with ancestral North America. Orogenesis in the Coast Belt is attributed to the long-lived development of a volcanic-plutonic arc perhaps coupled with collision of the Insular and Intermontane superterranes beginning in Jurassic time. Subsequent dextral strike-slip faulting greatly modified the distribution of components of the amalgamated terranes. Mesozoic and Cenozoic structures in the Insular Belt comprise two main elements: 1) contractional, subduction or accretion related faults and folds in the Saint Elias Mountains and Vancouver Island and 2) dextral strikeslip faults and transpressive folds in the Queen Charlotte Islands. In the Saint Elias Mountains contractional structures are cut by Late Jurassic and Early Cretaceous plutons, and, in the southern Insular Belt, both extension and contraction structures are associated with hypabyssal, felsic dykes, sills and small plutons. On Vancouver Island northwest-trending anticlinoria and northerly trending Early and Middle Jurassic plutons dominate the structural grain; on the Queen Charlotte Islands, similar plutons are of Late Jurassic age. The structurally symmetrical Coast Belt consists of a western part with westward verging

Abstract The geological architecture of the Cordilleran Orogen in Canada is the product of a long-lived evolution through a variety of tectonic processes acting upon and adjacent to the ancient continental margin. From its rift inception during the Middle Proterozoic until the present, the continental margin discontinuously moved oceanward through sediment progradation and as a result of convergence and transform-related processes involving the accretion of island arc and oceanic assemblages of distant and disparate origin. Throughout much of this time (1.44 Ga), the miogeocline of ancestral western North America evolved in a passive margin setting. One or more Precambrian folding events, accompanied by low-grade regional metamorphism, occurred in the northern and southern parts of the Cordillera but their timing and extent are poorly documented. Following Late Proterozoic to Early Cambrian rifting, broad carbonate platforms developed on a westerly sloping shelf, the edge of which was irregularly indented by numerous embayments and basins which received terrigenous clastics from the craton and intra-platform ridges and shoals. Local, episodic volcanism and graben development reflect rifting in the outer part of the miogeocline in early Paleozoic time. The northern part of the Cordillera was flooded by an Upper Devonian and Mississippian westerly derived clastic wedge succeeded by Mississippian and Pennsylvanian clastics whose source lay to the north, presumably in the Innuitian Orogen. Since the Middle Jurassic Epoch, as a consequence of collision and incorporation of the large exotic superterranes, intense metamorphism, plutonism and uplift took place in the Omineca Belt, and the miogeocline was

Abstract The Canadian Cordillera is a region of great geological and metallogenic diversity. Just as each Cordilleran terrane preserves a stratigraphic record different from those of neighbouring terranes, characteristic suites of mineral deposits, as integral parts of their host terranes, reflect fundamental differences in their depositional environments. The miogeocline and displaced equivalents in the eastern Cordillera, as well as each of the terranes comprising the accreted collage of the western Cordillera, possess unique lithotectonic characteristics that are reflected in the types of mineral deposits they contain. Predominantly stratiform deposits of Zn, Pb, Cu, Ba, and Fe and skarn deposits of W, Zn, Pb, Mo, and Sn are hosted by layered sedimentary strata of the ancestral North American miogeocline. The similar types of mineral deposits of displaced (Cassiar) and/or deformed (Kootenay, Nisling) continental margin terranes support their cratonal linkage. Stikinia and Quesnellia, which together constitute the bulk of the Intermontane Superterrane, host a suite of mineral deposits typical of their predominantly calc-alkalic volcanic-arc composition: abundant porphyry Cu,Mo deposits, Cu, Zn volcanogenic massive sulphides, Cu and Au skarns, and Au,Ag veins. On the other hand, the ophiolitic Cache Creek and Slide Mountain terranes of the Intermontane Superterrane display distinctive kinds of mineral deposits typical of their oceanic origin: magmatic Cu,Ni, volcanogenic Cu,Zn and mesothermal Au veins, in addition to ultramafic pluton-related asbestos, jade, Cr and platinum group element (PGE) deposits. The dominantly arc volcanic character of the diverse terranes of the Coast Belt is reflected in their metallogeny: volcanogenic Cu,Zn, porphyry Cu,Mo,

Abstract Petroleum resources of the Canadian Cordillera are mainly confined to the Foreland Belt where structural traps dominated by thrust faults and folds in Mesozoic and Paleozoic rocks form the main reservoirs. In the Insular Belt hydrocarbons have yet to be found, however, potential reservoirs are associated with rocks of mainly Tertiary age within structures which have arisen from interplate processes along an active continental margin. In the Foreland Belt established initial recoverable reserves of gas amount to 375 x 109 m 3 ; two oil fields together contain an estimated recoverable reserve of 65 x 106 m 3 . In the Insular Belt estimates of potential recoverable reserves at an "average expectation" (34% level of probability) are: 265 x 10 9 m 3 for gas and 38.5 x 106 m 3 for oil. Vast resources of bituminous and sub-bituminous coal and lignite occur in the Cordillera within strata of Jurassic, Cretaceous and Tertiary age. Upper Jurassic and Cretaceous coal deposits are part of regionally extensive clastic wedges that accumulated in the Foreland, Intermontane and Insular belts in response to tectonism, partly associated with accretion of suspect terranes. The most significant deposits and the only ones presently being mined are bituminous coals in the Foreland Belt. In the Intermontane Belt Jurassic and Lower Cretaceous(?) coal measures occur in the Whitehorse Trough, Bowser Basin and on the north flank of the Skeena Arch. The Whitehorse Trough and Groundhog coal measures of the Bowser Basin contain the only significant deposits of anthracite in the Cordillera. In the Insular Belt