ABSTRACT The Laptev Sea Rift in the East Siberian continental margin plays an important role in the geodynamic models for the opening of the Eurasia Basin. The active Gakkel Ridge, which also represents the boundary between the North America and Eurasia plates, abruptly meets the continental margin of the Laptev Sea. On the continental shelf in the prolongation of the Gakkel Ridge, a rift developed since the Late Cretaceous/Early Cenozoic with the formation of five roughly north-south trending depocenters. To better understand the evolution of this rift, a basin modeling study was carried out with PetroMod® software. The modeled sections used in this study were developed on the basis of depth-converted reflection seismic sections. The sections cover the Anisin Basin in the north and the southeastern margin of the Ust´ Lena Rift in the south. The numerical simulations are supported by tectonic and sedimentological field data that were collected in outcrops during the CASE 13 expedition to the New Siberian Islands in 2011. For the Anisin Basin different scenarios were modeled with rift onsets between 110 Ma and 66 Ma. The results show that the present-day temperature field in the area of the Anisin Basin and at the southeastern margin of the Ust´ Lena Rift is characterized by horizontal, seafloor-parallel isotherms. Geohistory curves extracted from the 2D simulations indicate a twofold rift evolution with a stronger initial subsidence in the Late Cretaceous to Early Paleogene and a moderate subsidence in Late Paleogene and Neogene times. Based on the modeling results, an early rift onset around 110 Ma seems to be more realistic than a later one around 66 Ma.

ABSTRACT We apply zircon (U-Th)/He low-temperature thermochronology to metasedimentary sequences of the Southwestern Basement Province of Svalbard to investigate the shallow crustal tectonics of Svalbard and the High Arctic. We resolve Cretaceous through Paleogene time-temperature histories for four areas of the province: Sørkapp Land, Wedel Jarlsberg Land, Oscar II Land, and Prins Karls Forland. Results indicate peak Late Cretaceous temperatures of ~175–185 °C in the south (Sørkapp Land, Wedel Jarlsberg Land) and >200 °C in the north (Oscar II Land) as a consequence of maximum burial and an elevated geothermal gradient (>40 °C/km). Late Cretaceous cooling affected all areas during regional exhumation related to initial rifting in the Eurasian Basin to the north. A subsequent heating event (recorded at Wedel Jarlsberg Land and Oscar II Land) from ca. 53–47 Ma is interpreted to result from tectonic burial during Eurekan deformation and development of the West Spitsbergen Fold-and-Thrust Belt. Our thermal models reveal a subsequent cooling event (47–34 Ma) corresponding to a shift in tectonic regime from compression to dextral strike-slip kinematics during Eurekan deformation; exhumation of the West Spitsbergen Fold-and-Thrust Belt coincided with strike-slip tectonism. Throughout Eurekan deformation, Prins Karls Forland resided at temperatures >200 °C and records cooling during post-34 Ma extension. Our models indicate 2.5–3.5 km of unroofing in Wedel Jarlsberg Land and Oscar II Land, and >4 km of unroofing of Prins Karls Forland, which is a deeper structural level of the West Spitsbergen Fold-and-Thrust Belt than other exposures on Spitsbergen. The results of this study document elevated heat flow in the Late Cretaceous, extend spatial resolution of Late Cretaceous crustal cooling documented across Svalbard, and illustrate the temporal and thermal evolution of the West Spitsbergen Fold-and-Thrust Belt, which is necessary for an improved understanding of Arctic geodynamics.

ABSTRACT Eocene Eurekan deformation has proven to be an enigmatic sequence of tectonic episodes dominated by tectonic plate compression and translation in the circum-Arctic region. Prins Karls Forland on western Spitsbergen is composed of Neoproterozoic siliciclastic metasediments of Laurentian affinity regionally metamorphosed to greenschist facies conditions. A crustal-scale ductile to brittle deformation zone, here named the Bouréefjellet fault zone, contains the amphibolite facies Pinkiefjellet Unit exposed between the lower metamorphic grade, upper structural unit of the Grampianfjella Group and the Scotiafjellet Group in the footwall. A preliminary age for the amphibolite facies metamorphism (ca. 360–355 Ma) indicates Ellesmerian tectonism, unlike other higher-grade basement rocks on Svalbard. Ten metasedimentary rocks from within the fault zone were collected for multiple single-grain fusion 40 Ar/ 39 Ar geochronology, with up to ten muscovite crystals dated per sample. High strain in the rocks is evinced by mylonitic structure, mica fish, and C’ shear zones, and dynamically recrystallized quartz with significant grain bulging and subgrain rotation, indicative of >350 °C temperatures. There is notable dispersion in the 40 Ar/ 39 Ar ages between samples, with single muscovite dates ranging from ca. 300 Ma to as young as 42 Ma, reflecting recrystallization and resetting of the muscovite. Younger, reproducible ages were obtained from samples that possess chemically homogeneous muscovite, yielding dates of 55–44 Ma for the Eurekan deformation on Prins Karls Forland. We suggest that Ellesmerian structures on Prins Karls Forland were reactivated during the Eocene (commencing as early as 55 Ma) progressing under warm, yet brittle, conditions that continued to 44 Ma. These 40 Ar/ 39 Ar muscovite dates are the first documented Eurekan deformation ages from Svalbard and enable a better understanding of the stages of Eurekan deformation in the Eocene to improve correlations across the circum-Arctic region.

ABSTRACT Ellef Ringnes Island in the western Queen Elizabeth Islands near the Canadian Polar margin is characterized by intrusions of Cretaceous mafic sills and dikes related to the Canadian portion of the High Arctic Large Igneous Province (HALIP) and the presence of a unique network of NNE–SSW and WSW–ENE striking steep faults. The exposed dikes on northern Ellef Ringnes Island are mostly oriented parallel to the NNE–SSW faults according to the radiating dike swarm of the HALIP. The studied sills and dikes are geochemically very homogeneous and probably related to the same intrusion event at ca. 121 Ma. They share geochemical similarities with other tholeiitic basaltic rocks related to the first stage of the HALIP (ca. 130–120 Ma) that are exposed on Axel Heiberg and northern Ellesmere islands. All these suites were probably generated from a common large magmatic center related to a mantle plume. The NNE–SSW striking faults are characterized by dextral strike-slip kinematics active after ca. 100 Ma (after the intrusion of the Early Cretaceous sills and dykes and the deposition of the Christopher Formation) and before the deposition of the Neogene Arctic continental terrace wedge. However, they cannot be related to the dextral strike-slip regime parallel to the continental margin during stage 2 of the Eurekan deformation in the Late Eocene. Instead, the NNE–SSW dextral faults may represent dextral antithetic Riedel faults of a wide, NE–SW striking, anastomosing strike-slip fault zone along the northern continental margin of North America, which was possibly active during Eurekan stage 1 in the Early Eocene.

ABSTRACT The Central Tertiary Basin (CTB) of Svalbard provides a rare opportunity for studying the sedimentary response to the Cenozoic evolution of the Barents Sea area. Here we present a basin model based on low-temperature thermochronology data, vitrinite reflectance measurements, and clay mineralogy from two drill cores inside the CTB. Our model suggests a tight relationship between the basin history and the regional geodynamic evolution. Enhanced heat flow during the Paleocene implies an extensional or transtensional origin of the basin, prior to Eurekan deformation. The first, compressional stage of the Eurekan orogeny was associated with rapid basin subsidence and high deposition rates, causing the coalification of the CTB hard coals. The second, transpressional stage of the Eurekan triggered rapid basin erosion and was associated with a decreasing heat flow. Onset of erosion is placed at ~45 ± 5 Ma, suggesting cessation of CTB deposition already by the late Early Eocene. Rapid erosion stopped coevally or just prior to the change to an extensional setting at the end of Eurekan deformation. Between ~40 and 10 Ma, the CTB experienced continuous slow erosion. From the Late Miocene onwards, erosion again accelerated, maybe related to lithospheric processes associated with northward propagation of the Knipovich Ridge. Estimates from our best-fit model suggest that nearly ~4 km of overburden was removed from the CTB since the end of Early Eocene.

ABSTRACT Detrital zircon U-Pb and Hf isotopic data from Ordovician to Devonian–Carboniferous sedimentary rocks sampled from the Pearya terrane and adjacent areas, northern Ellesmere Island, record temporal variation in detrital zircon signature on the northeastern Arctic margin of Laurentia. Ordovician to Silurian clastic sediments deposited on the Pearya terrane record a provenance signal from before terrane accretion. This signal is dominated by Ordovician arc material and grains derived from recycling of Proterozoic metasedimentary and metaigneous basement. This pattern is similar to Neoproterozoic detrital zircon spectra from the Svalbard and East Greenland Caledonides, supporting the exotic nature of the Pearya terrane and links between Pearya and the Arctic Caledonides. Sedimentary rock deposited in the late Ordovician and early Silurian deep water basin of the Clements Markham fold belt likewise record a recycled source containing abundant early Neoproterozoic and Mesoproterozoic aged zircon. This contrasts with similarly aged units on Franklinian shelf, which contain much more abundant Paleoproterozoic zircon ages. The provenance of the late Devonian–Carboniferous(?) Okse Bay Formation is dominated by sediment reworked from the units exposed in Pearya or the East Greenland Caledonides, with new sources derived from Paleoproterozoic domains of the Canadian-Greenland shield and late Devonian igneous rocks documented in Ellesmere and Axel Heiberg Islands, and Arctic Alaska. In contrast, detrital zircon age spectra from Devonian sedimentary rocks in the western Ellesmerian Clastic Wedge and northern Cordilleran clastic wedge of the Mackenzie Mountains contain abundant zircon grains yielding ages characteristic of the Caledonian and Timanian Orogens. This contrast suggests that the northeastern and northwestern sectors of the Paleozoic Laurentian Arctic margin received sediments from different terranes, with the northeast being dominated by reworked Caledonide terrane and Laurentian craton detritus, and the northwest likely receiving sediment from elements of Arctic Alaska–Chukotka. These detrital zircon data indicate that the Pearya terrane was isolated from northern Laurentia until after the late Silurian. The accretion of the Pearya terrane is constrained between the late Silurian and middle Devonian by stratigraphy, detrital zircon provenance shifts indicating a Laurentian cratonic source by the early Carboniferous, metamorphism in the orthogneiss basement observed between ca. 395 and 372 Ma, and the emplacement of the Cape Woods post-tectonic pluton at 390 Ma.

ABSTRACT Within the Canadian High Arctic, Ellesmere Island represents a key region for improving our understanding of the plate tectonic configuration during the Paleogene times when Arctic Canada and Greenland represented two independently moving plates. Here, we present 4050 line kilometers of new high-resolution aeromagnetic data gathered across an area of 7000 km 2 in the Vendom Fiord region on southern Ellesmere Island. The survey was flown with a two-kilometer line spacing and covered sedimentary rocks of the Franklinian Basin and the partly ice-covered basement rocks of the Inglefield Uplift. Magnetic domains, major lineaments, and depths of magnetic sources as well as magnetic trend lines are detected from total field data. These data and additional ground-based magnetic susceptibility measurements are integrated with exposure information and structural data in order to distinguish whether or not the ca. NNE–SSW trending Vendom Fiord Fault Zone can be related to the Wegener Fault. In addition, high-resolution aeromagnetic data and digital enhancement provide support for early Eocene deformation in the Vendom Fiord region during “Eurekan stage 1,” which seems to be decoupled from Paleocene to early Eocene deformation along the Wegener Fault. A distinct NNE–SSW trending magnetic anomaly characterized by long wavelength is bordered by the Eurekan Fold-and-Thrust Belt in the western survey area. On a regional scale, this anomaly can be traced toward the NE where it represents the boundary between the deep water and shelf sequences of the Franklinian Basin along the Archer Fiord Fault Zone. Based on aeromagnetic anomaly data, the ice-covered boundary between sediments of the Franklinian Basin and the Precambrian basement is identified. High frequency anomalies east of this boundary characterize the basement rocks and show strong similarities to the Kane Basin region in the NE. The similarity of magnetic anomaly patterns in both regions indicates that the NNE–SSW trend of the fault zones in the study area west of the Inglefield Uplift turns continuously into an E–W trend north of the uplift in the Kane Basin region.

ABSTRACT North Yukon lies at the intersection of two major tectonic domains that define the western and northern edges of the North American continent—the northern Cordilleran mountain belt and the Arctic Ocean. The pre-Carboniferous geology in North Yukon includes the Neoproterozoic−lower Paleozoic North Slope subterrane of the Arctic Alaska terrane and, south of the Porcupine shear zone, Mesoproterozoic−Paleozoic rocks of the Yukon stable block. The North Slope subterrane was deformed prior to deposition of Carboniferous and younger strata, and its paleogeographic origins are debated. North Yukon was deformed again during Cretaceous−Cenozoic development of the northern Cordilleran−Brookian orogen. To help refine understanding of the geological evolution of the region, we present detrital zircon U-Pb and Hf isotopic data for 21 sandstone and conglomerate samples from Neoproterozoic to Cenozoic strata collected across North Yukon, between ~69°15′N and 67°11′N. Neoproterozoic−Cambrian strata in the British Mountains are characterized by a dominance of Paleoproterozoic zircons (peak at 1.7–1.8 Ga), whereas samples from the Barn Mountains to the south have abundant Mesoproterozoic grains (1.0–1.5 Ga), suggesting these rocks may have been deposited along different segments of the northern Laurentian margin. Regional geophysics suggest these domains could be separated by a fault. Northeastern Laurentian origins are indicated by distinct early Neoproterozoic and Ordovician−Silurian zircons in Upper Silurian−Lower Devonian immature sandstone and conglomerate of the Clarence River Group and provide the most compelling evidence for large-scale translation along northern Laurentia. Precambrian detrital zircons in Carboniferous and younger strata reflect mostly recycling of local older strata. Carboniferous conglomerates all show Late Devonian peaks (365–378 Ma) consistent with erosion of nearby granitoid plutons. Triassic to Paleocene samples yielded a range of Neoproterozoic−Paleozoic zircons recycled from nearby Devonian flysch. Most significantly, these samples also yielded juvenile zircons that are close to depositional age, but for which arc sources are only known in southern Yukon and Alaska, more than 700 km away. These source regions are distinct from NE Russian sources inferred for early Brookian (Early Cretaceous) foreland deposits in Alaska.

ABSTRACT We have identified 57 large-magnitude, sequence boundaries in the Phanerozoic succession of the Canadian High Arctic. The characteristics of the boundaries, which include angular unconformities and significant changes in depositional and tectonic regimes across the boundaries, indicate that they were primarily generated by tectonics rather than by eustasy. Boundary frequency averages 10 million years throughout the Phanerozoic and there is no notable variation in this frequency. It is interpreted that each boundary was generated during a tectonic episode that lasted two million years or less. Each episode began with uplift of the basin margins and pronounced regression. This was followed by a rapid subsidence and the flooding of the basin margins. Each tectonic episode was terminated by a return to slow, long-term subsidence related to basin forming mechanisms such as thermal decay. The tectonic episodes were separated by longer intervals of tectonic quiescence characterized by slow subsidence and basin filling. The tectonic episodes are interpreted to be the product of changes in lithospheric stress fields with uplift being related to increased, compressional horizontal stress and the following time of rapid subsidence reflecting a decrease in such stresses or an increase in tensional stresses. Conversely, the longer intervals of tectonic quiescence would reflect relatively stable, horizontal stress fields. The episodic changes in stress fields affecting the Canadian High Arctic throughout the Phanerozoic may be a product of intermittent, plate tectonic reorganizations that involved changes in the speed and directions of plate movements. The longer intervals of tectonic quiescence would occur during times of quasi-equilibrium in the plate tectonic mosaic. The tectonic episodes that generated the sequence boundaries were governed by nonlinear dynamics and chaotic behavior, and there is a one-in-10-million chance that a tectonic episode will be initiated in the Canadian High Arctic in any given year. Thus, the major transgression associated with each episode can be referred to as a “10-million-year flood.”

ABSTRACT The Tanquary High is a positive tectonic feature that was identified on the southern margin of the far northeastern portion of Sverdrup Basin. A sequence stratigraphic analysis of the Triassic succession of northern Ellesmere Island, involving 27 measured sections and one well section, has allowed the geometry and evolution of the high in the Triassic to be elucidated. The Triassic succession occurs within five second-order sequences, and each sequence boundary reflects the occurrence of a tectonic episode that included basin margin uplift and basinward movement of the shoreline. The Tanquary High was uplifted during these tectonic episodes, which occurred in the latest Permian, latest Early Triassic, latest Middle Triassic, latest Carnian, and latest Norian. Each sequence is truncated toward the crest of the high where Rhaetian strata now overlie Cambrian strata. Isopach and facies data for each sequence reveal that, at the times of maximum uplift of the Tanquary High, the subaerially exposed part of the high extended 100–150 km down its northwest-trending axis and up to 150–200 km down each flank. Rapid subsidence completed each tectonic episode and initiated the development of a new sequence. The Tanquary High was completely drowned at these times. It is hypothesized that the tectonic episodes were generated by changes in horizontal stress fields driven by plate tectonic reorganizations. The facies and isopach maps of the latest Triassic to early Early Jurassic (Rhaetian-Sinemurian) second-order sequence demonstrate that the Tanquary High ceased to exist following the first order, latest Norian sequence boundary. A complete reversal of source areas and the initiation of the Amerasia rift basin coincided with the demise of the Tanquary High.

ABSTRACT Vitrinite reflectance (R r ) data, combined with structural field evidence, allow insights into the thermal and tectonic history of North Greenland. During the tectonism at the Cretaceous–Paleocene boundary, the thermal imprint varies considerably, mostly controlled by active fault zones. The Upper Cretaceous sequences along the Harder Fjord Fault Zone show R r values between ~3.2% (Frigg Fjord area) and ~2.1% (Depotbugt area). Along the Trolle Land Fault Zone, R r varies between 1.3% and 2.9% in the Herlufsholm Strand area, and between 1.6% and 2.2% in the Kilen area. These maturity variations along regional fault zones are connected with varying deformation intensity and explained by unequal conductive heat flow. In the Kap Washington Group, the high coal rank attaining 5.4% R r is associated with ductile deformation, and is additionally influenced by magmatic activity, i.e., convective heat flow. The coalification is low in regions a greater distance away from active faults, e.g., in Lower Cretaceous sediments of Herluf Trolle Land with ~0.5% R r . The Paleogene Thyra Ø Formation was deposited following deformation and thermal imprint at the Cretaceous–Paleogene boundary. It remained undeformed and shows a reduced R r of ~0.55%, reflecting burial thermal imprint. A later thermal event (known from the literature) that affected Mesozoic sediments, and possibly also locally Paleogene sediments close to the continental margin, is assumed to be related to heat flow from the active plate boundary between northeast Greenland and Svalbard. Based on detailed geochemical and mineralogical studies, thin, yellowish jarosite-bearing, clayey horizons within the Thyra Ø Formation are interpreted to probably originate from volcanic ashes erupted during the first stage of the opening of the North Atlantic.

ABSTRACT The Neoproterozoic–Early Devonian platformal succession of the North Slope subterrane, northeastern Brooks Range, Alaska, represents a carbonate-dominated peri-Laurentian continental fragment within the composite Arctic Alaska–Chukotka microplate. The basal ca. 760–720 Ma Mount Weller Group consists of an ~400 m thick mixed siliciclastic and carbonate succession that records the onset of regional extensional tectonism associated with the separation of southeastern Siberia from northern Laurentia during the break-up of Rodinia. These strata are overlain by ca. 720 Ma continental flood basalts of the Kikiktat volcanic rocks, which provide a link between the northeast Brooks Range platformal succession and the ca. 723–717 Ma Franklin large igneous province (LIP) of northern Laurentia. The overlying Sturtian Hula Hula diamictite and Cryogenian–Ediacaran Katakturuk Dolomite record abbreviated thermal subsidence of the northeast Brooks Range platformal succession prior to renewed Ediacaran–early Cambrian extensional tectonism and deposition of the overlying lower Paleozoic Nanook Group (new name). Equivalent strata of the deep-water Cryogenian–lower Cambrian(?) Ikiakpuk Group (new name) are identified herein with new δ 13 C carb and 87 Sr/ 86 Sr isotopic data from the Fourth Range of the northeastern Brooks Range. The Nanook Group is formally divided herein into the Black Dog and Sunset Pass formations, which record isolated peri-Laurentian platformal carbonate sedimentation along the northern margin of Laurentia, in an analogous tectonic position to the modern Bahama Banks. A profound Late Ordovician(?)-Early Devonian unconformity within the platformal succession is marked by subaerial exposure, paleokarst development, and tilting of the northeast Brooks Range peri-Laurentian platformal fragment prior to deposition of the overlying Lower Devonian Mount Copleston Limestone.

ABSTRACT The Neoproterozoic–Early Devonian(?) northeast Brooks Range basinal succession of northern Alaska and Yukon represents a peri-Laurentian deep-marine carbonate and siliciclastic succession within the composite Arctic Alaska–Chukotka microplate. The basal Firth River Group consists of a mixed siliciclastic and carbonate succession that is divided into the informal Redwacke Creek, Malcolm River, and Fish Creek formations. New U-Pb detrital zircon geochronology and δ 13 C carb and 87 Sr/ 86 Sr isotopic data from these strata, in combination with previously reported and new trace fossil discoveries, suggest the Firth River Group is Cryogenian(?)–middle(?) Cambrian in age. These strata interfinger with or are depositionally overlain by the siliciclastic-dominated lower Cambrian–Middle Ordovician(?) Neruokpuk and Leffingwell (new name) formations, which potentially record a distal expression of Cambrian extension and condensed passive margin sedimentation along the northern margin of Laurentia. All of these units are unconformably overlain by the synorogenic Clarence River Group, which is divided into the informal Aichilik and Buckland Hills formations. New U-Pb detrital zircon geochronology and previous macrofossil collections suggest the Clarence River Group is Late Ordovician-Early Devonian(?) in age. Here, we present new sedimentological observations, stratigraphic subdivisions, detrital zircon U-Pb geochronology and Lu-Hf isotope geochemistry, detrital muscovite 40 Ar/ 39 Ar geochronology, and carbonate δ 13 C carb and 87 Sr/ 86 Sr isotope geochemistry from the basinal succession that revise previous tectono-stratigraphic models for this part of Arctic Alaska and support correlations with age-equivalent strata in the Franklinian basin of the Canadian Arctic Islands and Greenland.

ABSTRACT The North Slope subterrane of Arctic Alaska extends from the northeastern Brooks Range of Alaska into adjacent Yukon, Canada, and includes a pre-Mississippian deep-water sedimentary succession that has been historically correlated with units exposed in the Selwyn basin of northwestern Laurentia. Sedimentary provenance data, including Sm-Nd isotopes and major and trace element geochemistry, provide detailed geochemical characterization of the regional pre-Mississippian strata of the North Slope subterrane. Combined with paleontological and geochronological age constraints, these new data record a marked shift in provenance in the Ordovician–Devonian(?) Clarence River Group, evidently linked to an influx of juvenile, arc-derived material. The timing and nature of this provenance change are consistent with early Paleozoic tectonic reconstructions of the Arctic margin that restore the North Slope subterrane to northeastern Laurentia (present coordinates), proximal to the Appalachian-Caledonian orogenic belt. Such a restoration requires significant post-Early Devonian sinistral strike-slip displacement to later incorporate the North Slope subterrane into the composite Arctic Alaska terrane.

ABSTRACT Detrital zircon provenance studies of Precambrian metasedimentary rocks in Wedel Jarlsberg Land and Sørkapp Land, Svalbard’s Southwestern Caledonian Basement Province, were conducted to evaluate local stratigraphic correlations and the role of long-distance strike-slip displacements in assembling the basement of the Arctic Caledonides. The detrital zircon U-Pb age spectra of the late Mesoproterozoic to Neoproterozoic metasediments revealed mainly Mesoproterozoic to Paleoproterozoic age signatures characteristic for a Grenville–Sveconorwegian orogen provenance. These results confirmed a stratigraphic correlation between basement units of southern Sørkapp Land and the Isbjørnhamna Group of Wedel Jarlsberg Land and suggest relocation of the tectonic boundary between the Eimfjellet Complex and the Isbjørnhamna Group above the Eimfjellbreane Formation. Moreover, the results support the Vimsodden Kosibapasset Shear Zone (VKZ) as a major tectonic boundary and highlight the inhomogeneity in the Southwestern Caledonian Basement Province. The detrital zircon age signatures south of the VKZ bear similarities with coeval metasediments of the Northwestern Caledonian Basement Province of Svalbard and other localities in the Greenland and Scandinavian Caledonides. In contrast, the detrital zircon age spectra north of the VKZ are comparable with the high Arctic Neoproterozoic sediments of Baltican affinity. In conjunction with previous studies, the results suggest that the basement units may continue across the traditional boundaries of the Svalbard’s Caledonian basement provinces.

ABSTRACT Comprehensive understanding of the pre-Paleogene kinematic evolution of the North American Cordillera in the context of evolving global plate interactions must begin with an understanding of the complex Late Cretaceous–early Eocene structural geometry and evolution of the northwestern Cordillera of Alaska, United States, and Yukon, Canada. Here, I present a kinematic model of the region that shows how regional strike-slip fault systems, including plate-boundary transform faults, interacted with each other, and with north-striking oroclinal folds and fold-and-thrust belts, which formed progressively during coeval shortening between Eurasia and North America. These Late Cretaceous–early Eocene interactions are manifestations of the plate reorganizations in the Pacific and Atlantic-Arctic regions that took place at that time, and that led to rifting and seafloor spreading within the globe-encircling Eurasian–North American plate and to the formation of transform-dominant North American–Pacific (sensu lato) and possibly North American–Arctic plate boundaries.