Fieldwork in the summer of 2015 was carried out at various localities in the southern half of Axel Heiberg Island, and focused on volcanic successsions and sub-volcanic intrusive complexes of the High Arctic Large Igneous Province (HALIP). The ~ 950 m thick sequence of basalts of the Strand Fiord Formation occurring east of Plateau Lake represents a world-class exposure of continental flood basalts consisting of thick units of basalt flows that display well-developed colonnades and entablatures. The intrusive complex at Middle Fiord exhibits intrusions with complex geometries, cross-cutting relationships and lithological variability rarely exposed in Large Igneous Provinces (LIPs) of Mesozoic age. Highlights of fieldwork also include field observations and sampling of the Surprise Fiord dyke swarm and the documentation of showings of massive sulphide mineralization in the Expedition Fiord area. Follow-up mapping, geochemistry, mineralogy and U-Pb geochronology will fill critical knowledge gaps on the magmatic history and Ni-Cu-PGE prospectivity of the Canadian portion of the HALIP. Intrusive complexes in the Middle Fiord area, in particular, will provide a unique opportunity to elucidate the architecture and chemical variability of rarely-exposed volcanic feeder systems associated with LIPs.

Ellef Ringnes Island lies in the western Queen Elizabeth Islands, Nunavut, Canada (parts of NTS 69-C, -D, -E, -F, -G and 79-D, -E, -H). The bedrock consists mainly of Jurassic to latest Cretaceous sedimentary rocks of the Sverdrup Basin, and a thin veneer of Neogene sediments in the far north, adjacent to the Arctic Ocean. Strata are intruded by Cretaceous mafic sills and dykes, disrupted by several evaporite diapirs, and folded by northwest-trending folds associated with Eurekan (Paleogene) deformation. The majority of sills are concentrated close to the contact between Deer Bay and Isachsen formations (late Valanginian), but range as high as the lower Hassel Formation (late Albian). In the central and southern island, steeply dipping extensional faults occur in patterns radial to the evaporite domes. In the northern half of the island, steep faults and associated minor folds trend north-northeast, with the addition of east trending normal faults in the far north.

In north-central British Columbia, the contact between the Lower to Middle Jurassic Hazelton Group and the Middle Jurassic to Cretaceous Bowser Lake Group is an upward gradational change from fine-grained, commonly tuffaceous sedimentary lithofacies to commonly coarser and more heterogeneous lithofacies assemblages that include abundant chert clasts and generally lack distinct tuff beds. Paleontologic dating reveals that the lowest Bowser Lake Group is generally older (Bajocian) in north-most exposures and younger (Early Oxfordian) to the southwest toward the centre of the Bowser Basin. Interpretation of stratigraphic changes relies upon age data from ammonites, and to a lesser extent marine bivalves; a new bivalve species with biostratigraphic significance, Myophorella richardsi n. sp., is named herein.In many places the contact between the Hazelton and Bowser Lake groups is younger than previously understood. Earlier treatments of this boundary over-emphasized paleontologic content and time correlations rather than lithologic criteria. The diachroneity of the base of the Bowser Lake Group resulted from: southwestward migration of the initial front of coarse, chert-bearing, clastic detritus derived from the Cache Creek terrane, which started in the Bajocian; and subsequent northward migration of coarse facies containing volcanic clasts shed from a volcanic highland near the south margin of Bowser Basin. Although volcanic activity in the immediate vicinity of the Bowser Basin diminished significantly in the Bajocian, volcanism continued to the south of the basin into the latest Jurassic. This southern volcanism was likely the source for tuff beds in the uppermost Hazelton Group in the immediate vicinity of Bowser Basin. Continued southern volcanism and input of ash to the Bowser Lake Group is recorded by U-Pb ages of detrital zircons that are coeval with depositional ages inferred from fossils. The large volume of clastic detritus in the Bowser depositional systems, however, diluted the influx of ash and prevented the accumulation of distinct tuff beds within the Bowser Basin proper.

Summary Backstripping calculations performed on a stratigraphic section near Tsatia Mountain, north-central British Columbia, indicate that the northwestern edge of the Bowser Basin and Hazelton Trough was characterized by two phases of enhanced subsidence. An initial episode of rapid subsidence of the Hazelton Trough occurred in the Pliensbachian, during which bimodal volcanic flows and associated sedimentary rocks were deposited in a shallow-marine environment. This episode corresponds to the end of a rifting event in the Stikine arc when most of the accommodation space was generated by extensional faulting of the predominantly igneous basement. Slower subsidence took place in Toarcian to Bajocian time along with deposition of a condensed section in a deep-water basin. This part of the history is consistent with thermal subsidence following the end of volcanism. An increase of subsidence rates in the Bathonian-Callovian interval was accompanied by increased sediment supply, marking the start of deposition of the Bowser Lake Group. This second pulse of rapid subsidence can be explained by sediment loading alone; it does not require, but neither does it negate, tectonic loading of the basin floor. The Early to Middle Jurassic subsidence history observed at Tsatia Mountain is consistent with a simple extensional model defined by a rifting episode, followed by thermal contraction of the crust, sediment loading, and possibly flexural subsidence.

The Bow ser Ba sin is a sed i men tary ba sin lo cated over the Stikine Terrane in the Intermontane Belt of northwestern Brit ish Co lum bia (Fig 1). In this area, the Stikine Terrane is over lain by Early Ju ras sic sed i men tary rocks of the up per Hazelton Group (Troy Ridge fa cies of the Salmon River For ma tion in An der son [1993]; Spatsizi For ma tion in Thomson et al. [1986]) and then by a thick suc ces sion (ap prox i mately 6 km) of Mid dle Ju ras sic to Early Cre ta ceous sed i men tary rocks mainly as signed to the Bow ser Lake Group (Evenchick and Thorkelson, 2005). The fill of the Bow ser Ba sin was de pos ited over the arc vol ca nic rocks and as so ci ated volcaniclastic rocks of the lower Hazelton Group. A broad va ri ety of sed i men tary en vi ron ments char ac ter ized the Bow ser Ba sin, rang ing from ba sin-floor turbidites at the base through mar ginal-ma rine clastic rocks to nonmarine redbeds in the uppermost parts of the succession.

The owners of Tatogga Lake Resort informed geologists of persistent flammable natural gasseepage into Tatogga Lake, British Columbia.. The gas seep was sampled from anomalously unfrozen, openings (UTM zone 440378/6396983, NAD27) when the ice cover was generally 15 to 20 cm thick. Samples-of this gas are compose&of methane:(98.2 %) and carbon dioxide (1.8 %). The stable carbon isotopic composition of both gases is consistent with biogenic- generation and possibly slight- microbial oxidation. The biogenic origin of this natural petroleum seepage suggests that the gas is not associated. with crude oil stains and. thermogenic petroleum systems in the Bowser Basin and underlying rocks. The seepage source strata and economic potential remain unidentified and obscured by its underwater occurrence.