Abstract The Canadian Beaufort-Mackenzie Basin lies on the continental margin of the Arctic Ocean and contains 14–16 km of Late Cretaceous to Recent sediment, the bulk of which is Tertiary in age. It has rifted basin margins although the southeastern margin has been overprinted by compressional structures that are contemporaneous with deposition and are part of the Cordilleran foldbelt that extends along west North America. The combination of post-rift subsidence and tectonic loading explains the thick accumulation of Late Cretaceous to Recent sediments. These sediments have been divided into several large transgressive-regressive sequences, each one dominated by the formation of delta complexes and their lateral equivalents. Sediment was supplied mostly from the rising orogenic belt on the southwestern margin of the basin. Several phases of tectonism have been recognized, each terminated by a major basin-scale unconformity. The first phase extended from the Late Cretaceous to about the Middle Eocene, the second from Middle Eocene to the Late Miocene, and the third from the Late Miocene to the present. The first two phases are dominated by compressional tectonics, although listric faults and some translational faults also formed. The third phase is characterized by the lack of any significant deformation. The basin has significant reserves of oil and gas and its potential of additional resources is high. Exploration in the basin started in the 1960s but has undergone several periods of exploration slow-down. At present there is renewed activity and undoubtedly this basin will be a major source of hydrocarbons in the future.

Abstract This chapter is concerned with the southern portion of the craton, the southern craton margin, and its geological relationship with the Ouachita Orogeny. The southern continental margin was shaped by extensional and transform faulting, during the breakup of Rodinia, and includes the Oklahoma Basin, a basin formed by transtensional faulting. Carbonate reef systems flourished along the entire continental margin from Texas to Newfoundland during the Early Paleozoic. Shallow-water, carbonate, and siliciclastic sedimentation continued in the Oklahoma Basin from Middle Ordovician through Earliest Mississippian time. The ocean that lay south of the North American Plate through much of the Paleozoic was closed by collision with Gondwana, starting in the Mid-Mississippian. Northwesterly directed contractional stress generated a regionally distinctive style of transpressive fault and block-uplift deformation across the Southwestern United States. Mild warping of the Texas–Oklahoma area during this period accentuated existing differentiation of the continent into a series of basins (including the Delaware and Midland basins) and intervening uplifts (Diablo Platform, Central Basin Platform, Eastern Shelf, Llano Uplift, Ozark Uplift). That portion of this basin and uplift system located within Texas now constitutes the classic Permian Basin. The carbonate platform and basin configuration of the Permian Basin is similar in topography and scale to that of the Cretaceous to modern Bahamas Platform. The basin is probably best known for the distinctive “clinoform” stratigraphy of the Capitan Reef, one of the first places where the lateral facies transition from back reef, through reef crest, foreef slope to basin floor was mapped and described in detail, based on superb outcrops in the Guadalupe Mountains. Sediments of the Absaroka Sequence (Uppermost Mississippian to Lower Jurassic) are widely distributed across the continental interior. For much of the Carboniferous to Permian, the Earth was under the influence of repeated, high frequency glacioeustatic sea-level changes. These caused transgressions and regressions that shifted shorelines and depositional systems back and forth hundreds to thousands of kilometers across low-relief continental interiors. The classic Pennsylvanian cyclothems of the southern US Midcontinent are the most characteristic and well-known products of this process. Crustal loading of the continental margin by colliding Gondwana terranes commencing in the Mid-Pennsylvanian generated typical foreland-type basins which now constitute the Ouachita system, and including such foreland basins as the Forth Worth, Arkoma, and Black Warrior basins. In the Ouachita Mountains of Oklahoma and Arkansas some 3,500 m of structurally disturbed Late Cambrian to Mississippian pre-orogenic strata have been mapped. They consist mainly of shales and sandstones, the latter representing a variety of sediment-gravity flow mechanisms.

During the final assembly of Pangea, the Maritimes Basin of Atlantic Canada was tectonically active for ∼120 Myr from the Mid-Devonian to the Early Permian, following terrane accretion and ocean closure in the region. The basin's history records a prolonged period of convergence that post-dated the collision of Gondwana and Laurussia. The 12 km of basin fill was laid down in suites of periodically connected depocenters, and parts of the region experienced a polycyclic basin history, with repeated subsidence and inversion of fault-bounded depocenters, many associated with strike-slip faults. During two periods in the basin history, sedimentation overstepped fault zones under a regime of thermal subsidence to blanket much of the region. The basin fills are largely continental but include one open-marine interval with evaporite accumulation (Mississippian), as well as restricted-marine intervals, reflecting progressive loss of oceanic connection. Basinal architecture testifies to rapid subsidence against a backdrop of glacioeustatic influence in a paleoequatorial setting. Volcanics and intrusions were especially prominent during Devonian to Mississippian convergence, and halokinesis greatly influenced later basin development.

The Appalachian Basin is a composite, retroarc foreland basin that in many ways is the “type” foreland basin and the “type area” for the Wilson cycle. Our understanding of the basin, and others like it worldwide, is largely the legacy of a single observation by James Hall in 1857, an observation that also effectively established the framework for the later plate-tectonic paradigm, not to mention major framework developments in structure, tectonics, isostasy, flexural modeling, stratigraphy, sedimentation, paleoclimate and paleogeography. As preserved today, the basin is about 2,050 km long with an area of nearly 536,000 km2, extending from southern Quebec in Canada to northern Alabama in the U.S., and reflects the structural influence of earlier Grenvillian convergence and Rodinian dispersal, as well as the paleoclimatic, paleogeographic, eustatic and tectonic history of eastern Laurentia/Laurussia from latest Precambrian to Early Mesozoic time. During latest Precambrian to Early Ordovician time, the recently formed, southern to southeastern, Appalachian margin of Laurentia experienced mainly synrift and postrift, passive-margin sedimentation, largely controlled by local structure, regional climate and eustasy. However, by Cambrian time on some of the more distal, outboard parts of the Laurentian margin, the initial tectonic reorganization that would ultimately produce the Appalachian foreland basin had already begun. Major development of the Appalachian foreland basin began with the advent of the Taconian orogeny at about 472 Ma near the Early–Middle Ordovician transition and continued for nearly 200 Ma during four nearly continuous orogenies that reflect closure of the Iapetus and Rheic oceans and growth of Pangea. Tectonic dynamics controlled the extent and shape of the basin during various orogenies, and the resulting deformational loading is largely thought to have generated the accommodation space in which Appalachian sediments accumulated. Sediment thicknesses up to 13,700 m accumulated in 13, third-order (106–107 years), unconformity-bound, cycles that are clearly related to Appalachian tectophases, distinct phases of tectonism controlled by sequential convergence with continental promontories during orogeny. Tectophase cycles during the Taconian and Salinic orogenies and during the succeeding Acadian and Alleghanian orogenies form the larger, second-order (107–108 years), Caledonian and Variscan–Hercynian orogenic supercycles, which generally reflect closure of the Iapetus and Rheic oceans, respectively. These supercycles are separated by the brief, Siluro-Devonian, Helderberg interval, which in the foreland basin is represented by a thin, widespread, shallow-water, clastic and carbonate succession with poorly developed tectophase cycles. In contrast to the relative tectonic quiescence apparent in the foreland basin, evidence from more outboard parts of the orogen indicates that the Helderberg interval appears to represent a transitional period of uplift, magmatism and successor-basin formation during Taconian–Salinic orogen collapse and change to collision-related, strike-slip and transpressional regimes in succeeding orogenies. The first 11 cycles in the foreland basin mainly reflect subduction-type orogenies and typically consist of basal, dark, marine shales succeeded in ascending order by flysch-like and molasse-like units, all of which track the progress of orogeny in time and space. The last two Alleghanian cycles, in contrast, reflect collision-type orogeny and are largely composed of clastic-dominated, terrestrial or marginal-marine sediments with a strong eustatic overprint related to Gondwanan glaciation. Although Alleghanian tectonism probably continued through Late Permian time, no foreland-basin sediments younger than Early Permian age are preserved. By Late Triassic time, thermo-tectonic thickening and uplift in the Alleghanian orogen caused orogen collapse and extension, ending the Iapetan or Appalachian Wilson cycle and initiating Pangean dispersal and the current Atlantic Wilson cycle. The importance of the Appalachian Basin lies not only in its “type” status as a basis for our understanding of geomorphological, structural, stratigraphic and sedimentary parts of the plate-tectonic paradigm, but also in the fact that it contains the relatively well-preserved, 545 Ma, stratigraphic and sedimentary record of one complete Wilson cycle and parts of others. The larger foreland-basin/orogen area clearly shows the orogen collapse and extension phase of the previous Laurentian or Grenvillian Wilson cycle during dispersal of the Rodinia supercontinent, as well as late-synrift, passive-margin, active-margin and orogen collapse phases of the Iapetan or Appalachian cycle during accretion and dispersal of the Pangean supercontinent. The foreland-basin area itself shows evidence for all the phases except orogen collapse. Nonetheless, what is particularly apparent throughout the basin's entire history is the fact that the zigzag shape of the old Iapetan margin and the basement structural framework remaining at the end of the previous Laurentian cycle, combined with a series of probably global tectonic events, essentially controlled development and infill of the Appalachian foreland basin. This is apparent in the timing and distribution of the 13 sedimentary cycles that largely comprise its sedimentary infill. Even so, every cycle in the basin differs, reflecting the indelible overprint of changing climatic, geographic and eustatic regimes.

Abstract The Western Interior Basin extends north–south over about 35° of latitude, from Texas to the Northwest Territories, a distance of more than 3,000 km. The basin developed as a result of crustal loading during the western migration of the North American Plate and the subduction of Panthalassa. Initiation of the Western Interior Basin as a distinctive geodynamic and stratigraphic province is traditionally associated with the deposition of the Upper Jurassic (Oxfordian–Tithonian) Morrison Formation in the United States, and the Fernie and Kootenay Formations in Canada. Crustal loading occurred as a series of pulses, as successive terranes arrived at and were obducted onto the western Laurentian margin. These events are represented in the basin as a series of clastic wedges. Westerly sediment sources associated with contractional tectonism appeared for the first time in the Late Jurassic, including the Mesocordilleran Geanticline of Nevada. The first major clastic wedge, constituting the Morrison and Kootenay formations, continued into the Berriasian, but much of the Berriasian to Barremian (Neocomian) interval is represented by a regional unconformity throughout the Western Interior Basin. This period corresponds to a “magmatic lull” in the Cordillera. The base of the Cretaceous section, of Late Berriasian or Aptian age, typically consists of a sheet of coarse, fluvial gravels, throughout much of the Western Interior Basin. Provenance studies of the foreland-basin strata indicated that following the regional Mid-Cretaceous episode of tectonic quiescence, erosion tapped into oceanic-arc and related rocks, and syndepositional continental magmatic rocks of Quesnellia, far to the west of the orogenic front. Examination of the ages of conglomerates deposited at this time, and reconstruction of the subsidence histories suggest that a new phase of flexural loading and subsidence commenced shortly after deposition, initiating a new “constructive” phase of development of the Cordilleran orogen. At least two Cretaceous cycles of transgression occurred in northern Canada, but marine waters did not extend southward into the Western Interior Basin until the Aptian. During the Aptian–earliest Albian interval, most of the Western Interior Basin was occupied by fluvial and estuarine systems assigned to such units as the Mannville Group in Alberta–Saskatchewan, and the Kootenai Formation of Montana. The Upper Cretaceous stratigraphy of the Western Interior Basin is characterized by the deposits of several major marine transgressions. Gaps in the stratigraphic record are numerous; some represent millions of years, although most are less than one million years in duration. Eustatic sea-level changes were probably partly responsible for this stratigraphic architecture, but regional and local tectonic processes were also important. During the Turonian the sea reached an all-time high, calculated to be at least 300 m higher than at present. Shallow seas may have extended over much of the Canadian Shield, with a connection through Hudson Bay to the north Atlantic Ocean. High-frequency sequence cyclicity in some parts of the basin suggest a control by orbitally forced eustasy, which caused sea-level changes in the range of 10 m over time scales in the range of 10–125 ka. Termination of the Western Interior Seaway and foreland basin began during the Late Campanian or Maastrichtian throughout much of the United States, as shallow subduction of the Farallon Plate on the western margin of the continent led to the Laramide Orogeny and to the break-up of the basin.

Abstract The western margin of the Paleozoic Laurentian continental margin is now largely buried beneath the accreted terranes and fold-thrust belt of the Cordilleran Orogen. An extensional continental margin developed from Mexico to Yukon during the breakup of Rodinia about 900–800 Ma, commencing with a series of Precambrian rift basins, followed by the development of a wedge of Paleozoic continental margin (“miogeoclinal”) sediments up to 6 km thick. Shallow-water carbonate and clastic sediments characterize most of the preserved sediment pile. Slope and deep-basin sedimentary rocks are rarely preserved. An arc collided with this continental margin from southeastern California to central Idaho between the latest Devonian or Early Mississippian generating the Antler Orogeny and the emplacement of the Roberts Mountains Allochthon on the continental margin, above a thrust belt. Most of the Canadian portion of the margin remained an extensional margin until the Nicola Arc was thrust eastward over the margin during the Jurassic. The Canadian Margin may have developed by simple-shear extension during the Paleozoic, that portion lying south of the 60th parallel forming the upper-plate margin and the margin north of the 60th parallel constituting the lower-plate margin, with the Liard Line functioning as a transfer fault across which the shear polarity reversed direction.

Abstract The Atlantic margin of North America represents the classic “Atlantic-type” continental margin, notably the margin off the east coast of the United States, which was the site of five deep offshore stratigraphic test holes wells (the Continental Offshore Stratigraphic Test, or COST series) drilled in 1976–1979 on the Georges Bank, the Baltimore Canyon Trough, and the Southeast Georgia Embayment. Data from these holes were used in the development of what have become standard backstripping methods and subsidence models for extensional continental margins. Development of the margin began with the initial rifting of Pangea in the Triassic. Sea-floor spreading began in the central Atlantic Ocean during the early Middle Jurassic, and extended northward past Newfoundland beginning in the Late Jurassic. Active sea-floor spreading generated the Labrador Sea and Baffin Bay between the Cenomanian and the end of the Oligocene. Structural styles vary along the Atlantic margin. Off the southern U.S. margin, the edge of the continental margin was affected by magmatic underplating and extensive volcanism during the Jurassic. The Newfoundland continental margin developed by the processes of crustal thinning and crustal detachment. The Grand Banks area was affected by two distinct phases of rifting and flexural subsidence as extension occurred in the central Atlantic, to the south, from Late Triassic to Early Jurassic, and in the North Atlantic, to the northeast of the bank, from Late Jurassic to Mid-Cretaceous. The thickness of Jurassic-Recent sedimentary deposits on the continental margin locally reaches 25 km. Transects across the margin show a series of largely non-marine rift basins, capped by a breakup unconformity, above which is a seaward-thickening wedge of prograding shallow- to deep-water marine deposits. Evaporites are widespread at the base of this section from the Grand Banks to the Bahamas. Carbonates dominate the remaining deposits in the south, notably in the Bahamas area, but as the North American continent drifted northwestward through the Mesozoic, carbonate sedimentation gradually became less important in more northerly parts of the continental margin. On Georges Bank, carbonate sedimentation ended in the Mid-Cretaceous, whereas on the Grand Banks it had essentially come to an end by the close of the Jurassic. Shallow-marine and deltaic clastics comprise much the remaining succession throughout the length of the Atlantic margin. The discovery of major petroleum resources beneath the Grand Banks in 1979 led to extensive seismic and offshore exploration work there, and additional oil and gas resources have been discovered and developed. Gas reserves have been developed off Nova Scotia, and undeveloped gas reserves are located on the Labrador shelf, but no commercial discoveries have been made in the U.S. portion of the Atlantic margin.

Abstract Many of the developments in basin analysis originated in North America, including ideas about isostasy and about geosynclines. The first comprehensive application of plate-tectonic concepts to interpretations of continental geology took place in Newfoundland, and served as a confirmation of Wilson's revolutionary idea that the Atlantic Ocean “closed and then re-opened.” Later developments regarding foreland basins and controversies about thick-skinned versus thin-skinned tectonism were also resolved from North American data, particularly following the advent of the deep-crustal reflection-seismic methods of COCORP and Lithoprobe. Sequence stratigraphy was also developed initially in North America, stimulated by the recognition of widespread packages of strata separated by unconformities that did not correlate to the standard, largely European, chronostratigraphic framework. The major problems of North American Phanerozoic geology have now been largely solved, but significant issues remain, particularly regarding the local and regional histories of terrane amalgamation in the Appalachian and Cordilleran orogens.

Abstract Although the term craton is often taken as synonomous with tectonic quiescence, the North American craton is not simply an unchanging, stable platform accumulating strata and influenced only by changes in global sea-level. Rather, viewed on a timescale of tens to hundreds of millions of years at least, it is a dynamic tectonic environment influenced by various plate tectonic, mantle, denudational and depositional processes. The Sloss cratonic sequences record the history of this dynamic tectonic environment, in the form of episodes of transgression, regression and erosion and non-deposition, generated on a timescale of tens of millions of years. These sequences occur across the craton, on areas of platform, as well as in the four main intracratonic basins, yet their origins remain relatively poorly understood. Long-term eustatic oscillations must certainly have contributed to development of the transgressive and regressive sequence elements, but basic observations of tilted strata and angular sequence-bounding unconformities show eustasy cannot have been the only responsible mechanism. Variations in dynamic topography generated by subducting lithospheric slabs, and by thermal insulation of mantle beneath supercontinents, can explain much of the large-scale sequence architecture but more detailed plate tectonic reconstructions and associated mantle convection models are necessary to further test and develop these explanations. Intraplate stress also seems likely to have played a large role in generating the cratonic sequences by reactivating pre-existing structures and driving subsidence and uplift. Variations in intraplate stress through time can be related, to some degree at least, to tectonic events occurring on the cratonic margins and on other adjacent plate margins. Given present available evidence and theory, the North American intracratonic basins seem most likely to be due to a combination of mantle downwelling and focused intraplate stress variations, in some cases with an element of long-wavelength tilting due to subduction-induced dynamic topography, and in some cases with an initial trigger by lithospheric stretching. Although taken together all these mechanisms provide a plausible explanation for the development of the North American cratonic sequences, they are certainly not definitive, conclusive explanations. Much work remains to be done to test, and to confirm or refute these ideas.

Abstract The Sverdrup Basin is located in the Canadian Arctic Islands. It is 1,000 km by 350 km and is filled with up to 13 km of Carboniferous to Paleogene strata. The basin initially developed in Early Carboniferous as a rift basin upon highly deformed Early Paleozoic strata of the Ellesmerian Orogenic Belt. The development of the basin can be broken into eight phases, each being characterized by a distinctive combination of tectonic, depositional and climatic regimes and separated by episodes of widespread uplift and basin reorganization. The Upper Paleozoic strata are up to 5 km thick and are characterized by a distinct shelf to deep basin topography. Carbonate strata dominated the shelf until Middle Permian and were supplanted by siliciclastics and chert in Middle and Late Permian when the climate cooled. Triassic siliciclastics are up to 4 km thick and they filled the deep, central basin by Late Triassic. From latest Triassic to earliest Cretaceous the basin was occupied by shallow siliciclastics shelves and up to 2 km of strata accumulated. Renewed rifting in Early Cretaceous resulted in a thick succession (2 km) of Early Cretaceous non-marine to shallow marine strata with units of basalts in the northeast. Widespread diabase sill and dyke intrusion, likely related to the Alpha Ridge Plume and the opening of the Amerasia Ocean Basin, occurred at this time. Following an interval of low subsidence and low sediment supply in the Late Cretaceous, the basin began to be deformed in earliest Paleocene by the Eurekan Orogeny driven by the counterclockwise rotation of Greenland. Local foreland basins developed and contain up to 3 km of Paleocene–Eocene strata. In Late Eocene the basin was uplifted and deformed by faulting and folding with deformation decreasing southwestwards. Eighteen oil and gas fields have been discovered in Eurekan anticlines and potential prospects include traps associated with Eurekan structures, salt domes, reefs and prominent unconformities. Widespread petroleum source rocks are documented in Middle and Upper Triassic strata and likely occur with other stratigraphic intervals from Carboniferous to Lower Cretaceous.