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The Montney tight siltstone reservoir is a multi-stacked play, which covers a total area of 130,000 km2 along the Alberta–British Columbia border in Western Canada. Since the late 1990s, different fracturing methods and fluids have been tested in 4000-plus Montney wells to find the optimal fracturing method and fluid. The previous studies reviewing the performance of fracturing methods in Montney do not represent a holistic evaluation of these methods, owing to some limitations, including: (1) using a small sample size, (2) having a limited scope by focusing on a specific aspect of fracturing (method/fluid), (3) relying on data analytics approaches that offer limited subsurface insight, and (4) generating misleading results (e.g., on optimum fracturing method/fluid) through using disparate data that are unstructured and untrustworthy as a result of significant regional variations in true vertical depth (TVD), geological properties, fluid windows, completed lateral length, fracturing method/fluid/date, and drawdown rate management and choke size strategy. The present study eliminates these limitations by rigorously clustering 4000-plus Montney wells based on the TVD, fluid window, completed lateral length, fracturing method/fluid/date, and drawdown rate strategy to isolate the effect of each fracturing method by comparing each well's production to that of its offsets, which use different fracturing methods but possess similar geology, fluid window, and TVD. With similar TVD, fracturing fluid, and completion date, wells completed with pinpoint fracturing method outperform their offsets completed with ball-and-seat and plug-and-perforate (PnP) fracturing methods. However, wells completed with ball-and-seat and PnP methods that outperform their offset pinpoint wells have either: (1) been fractured one to four years earlier than the pinpoint wells and/or (2) used energized oil-based fluid, hybrid fluid, and energized slickwater versus slickwater used in the pinpoint offsets. This suggests that the water-phase trapping is more severe in these pinpoint wells attributable to the use of slickwater. Previous studies often favored one specific fracturing method or fluid without highlighting these complex interplays between the type of fracturing method, fracturing fluid, completion date (regional depletion or well vintage), and the reservoir properties and hydrodynamics. [ABSTRACT FROM AUTHOR]

In 1989, TMP 89.127.3, a basal ichthyopterygian, was collected as a counterpart slab from the Vega-Phroso Siltstone Member (Lower Triassic) of the Sulphur Mountain Formation in east-central British Columbia, Canada. Previous investigations of its postcranial skeleton resulted in ambiguous taxonomic affinities, with it being identified as eitherGrippiacf.longirostrisorParvinatator wapitiensis. More recently, the part slab of TMP 89.127.3 was collected and prepared, revealing important new cranial data that permits its systematic relationships to be more thoroughly assessed and previously proposed taxonomic affinities to be tested. By integrating both cranial and postcranial data, phylogenetic analysis recovers TMP 89.127.3 andGrippiaas members of Grippidia, nested within Eoichthyosauria. TMP 89.127.3 can be distinguished fromGrippiaby possessing the following autapomorphies: metacarpal I with a notched peripheral shaft; cylindrical anterior teeth with a crown shape index >5.0; and a postfrontal-frontal contact at the rostral limit of the anterior margin of the supratemporal terrace. A new taxon,Gulosaurus helmi, is erected to accommodate this suite of features. The placement ofGulosaurus helmiwithin Grippidia reaffirms the Early Triassic distribution of this clade to include western and northern Laurasia, which is represented by outcrop in present-day Canada and Norway (Spitzbergen), respectively. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free atwww.tandfonline/UJVP [ABSTRACT FROM PUBLISHER]

Dinosaur bones were discovered in 1971 during uranium exploration in the Sustut Basin, northern British Columbia, Canada. These bones have more recently been prepared and described and represent an indeterminate cerapodan dinosaur. Although dinosaur bones have been reported from British Columbia before now, this specimen represents their earliest recorded discovery from the province. The bones were collected from loose blocks in a talus slope, near the intersection of Birdflat Creek and the Sustut River. They are encased in hard siltstone that shares characteristics with adjacent outcrops of the Upper Cretaceous Brothers Peak Formation. Bones collected include the right humerus, right radius, the distal portion of the right tibia and fibula, two right pedal phalanges, including two unguals, and several unidentifiable fragments. Des ossements de dinosaures ont été découverts en 1971 dans le cadre de travaux d’exploration de l’uranium dans le bassin Sustut du Nord de la Colombie-Britannique (Canada). Plus récemment, ces ossements ont été préparés et décrits; ils représentent un dinosaure cérapode indéterminé. Bien que des ossements de dinosaures aient déjà été signalés en Colombie-Britannique, ce spécimen constitue la découverte la plus ancienne dans cette province. Les ossements proviennent de blocs meubles dans un talus d’éboulis situé près de l’intersection du ruisseau Birdflat et de la rivière Sustut. Ils sont encastrés dans une siltite dure qui présente des similitudes avec les roches d’affleurements attenants de la Formation de Brothers Peak, du Crétacé supérieur. Les ossements recueillis comprennent l’humérus droit, le radius droit, les parties distales du tibia et du péroné droits, deux phalanges du pied droit dont deux unguéales, et plusieurs fragments non identifiables. [ABSTRACT FROM AUTHOR]

Massive sulfides at the Myra Falls volcanic-hosted massive sulfide (VHMS) camp, Vancouver Island, British Columbia, Canada, are overlain by white chert, black chert, argillite, and siltstone. White chert is best developed above the Battle orebody, where it forms a siliceous caprock (3-5 m thick) above the massive sulfides. There is a gradational lateral change from white chert above massive sulfides to black chert and unaltered argillite, 100 to 150 m south of the Battle orebody. Chert horizons are 'also located above the Ridge and Extension ore zones, but only minor chert lies above the HW orebody, which is instead overlain by a thick argillite sequence. The chert and argillite share similar sedimentologic and petrologic features, including abundant parallel laminations, interbedded turbidites, radiolarian-rich layers, soft-sediment deformation, scours, flame structures, and small phosphatic concretions. These features indicate that white and black chert formed as a replacement of mudstone rather than as exhalative or biogenic deposits. Silicification occurred early in the depositional history of the fine-grained sediments and was contemporaneous with some ore formation. Early syndepositional features are still visible in the chert, with primary pore spaces such as radiolarian tests filled by silica, rutile, apatite, and minor sulfides displaying open-space crystal growth. The presence of minor ore-clast breccias above the orebody indicates that at least parts of the Battle orebody were exposed on the sea floor. Metal zoning is observed in the cap-rock horizon above the Battle orebody, with higher Cu, Zn, and Cd contentrations in chert directly above massive sulfides, higher Pb, Sb, and Ag contentrations in black chert at the edge of the siliceous cap rocks and lower metal concentrations in the distal argillite. Primary fluid inclusions in spherical quartz patches in chert above the Battle orebody indicate that hydrothermal fluids passing through sediment were between 135 to 250°C and had salinities ranging from 3.0 to 12.1 wt percent NaCl equiv. These data are similar to those for fluid inclusions measured in quartz interstitial to sulfides in the underlying Battle orebody, which have temperatures of homogenization ranging from 140° to 250°C and salinities from 3.0 to 12.4 wt percent NaCl equiv. Fluid inclusions in the Battle orebody display a slight increase in salinity and homogenization temperature with depth, which may reflect the overprinting of earlier high temperature stages by cooler fluids as the hydrothermal system waned or varying degrees of mixing between hydrothermal fluids and seawater. A minimum depth for deposition of the cap rocks (>200 m) is estimated, based on sedimentologic features such as fine parallel laminations and interbedded sandstone turbidites, which indicate deposition below storm wave base. Greater water depths (1,000-1,500 m) are suggested by the lack of evidence of boiling in fluid inclusions. Low O2 concentrations in the bottom water of the Battle basin are suggested by the absence of bioturbation, lack of fossils of benthic fauna, degree of pyritization v',dues >0.90, elevated Zn, Pb, Cu, Cd, As, Sb, Ag, Ba, and V, low Fe and Mn, and W(V + Ni) > 0.8 in the unaltered argillite. Paleosea-floor reconstructions indicate that the Battle and HW orebodies formed in small basins along a northwest-trending ridge. The finegrained sediments were deposited in depocenters within paleotopographic lows.… [ABSTRACT FROM AUTHOR]

Clastic strata preserved on Sidney Island, Barnes Island, and adjacent islands of the southernmost Gulf Islands of British Columbia and the northern San Juan Islands of Washington State are assigned to new stratigraphic units: the Sidney Island Formation and the Barnes Island Formation. The Sidney Island Formation consists of basal conglomerate and sandstone that grades upward through planar-stratified sandstone into hummocky cross-stratified sandstone and siltstone, all of which are deposited in relatively shallow-marine environments. The Barnes Island Formation, in contrast, consists of deep-marine conglomerate, sandstone, and mudstone that was deposited in a submarine-fan setting. Mollusk fossils from the Sidney Island Formation are of Early to Middle Turonian age, whereas ammonites and foraminifers from the Barnes Island Formation indicate a Late Turonian age. The Sidney Island Formation thus records initial marine transgression and inundation of basement rocks, followed by basin deepening that is transitional to the deep-marine submarine-fan deposits of the Barnes Island Formation. Sidney Island Formation strata have been considered previously as derived from uplift along the nearby San Juan thrust system in mid-Cretaceous time. However, the shallow-marine strata are internally well organized, and the facies succession is persistent across the formation's outcrop area. In addition, the formation lacks the distinctive detrital metamorphic mineral assemblages that are characteristic of older rocks of the San Juan Islands. These observations suggest that strata of the Sidney Island Formation did not accumulate immediately adjacent to active thrusting but rather in a more distal setting relative to the thrust system. [ABSTRACT FROM AUTHOR]

A partial articulated skeleton of a desmostylian was found in siltstone of the Sooke Formation in the streambed at the mouth of the Sombrio River in Juan De Fuca Provincial Park, Vancouver Island, British Columbia, Canada. Another exposure of the Sooke Formation southeast of the locality has been dated to Chron C6Cr age, 24.1–24.8 Ma. This specimen includes the left side of the skull, two molars, a premolar, canines, partial scapula, nearly complete humerus, and numerous vertebrae and ribs. Molar characteristics are the same as material ofBehemotops proteusfrom the Pysht Formation of Washington State, which is near the type locality ofBehemotops proteusof the upper Oligocene Pysht Formation, Washington State. Previous specimens ofB. proteuswere limited to lower jaws and portions of the upper and lower postcanine dentitions. The slightly smallerBehemotops katsuieifrom Japan is known from more elements, yet its cranial material is limited to the posterior portion of the cranium and a small portion of the zygomatic arch. This new material allows us to see thatBehemotopscf.B. proteushad cranial features much like those seen inCornwallius sookensisof North America. These include a postorbital process of the jugal, with the zygomatic process of the squamosal not dorsally expanded, a concave hard palate, enlarged canine tusks that point ventrally, and a narrow, curved incisor arcade on a narrow rostrum. This is different from specimens previously referred to asBehemotops emlongiand then synonymized withB. proteus, which have a broad symphysis with large tusks. These specimens formerly known asB. emlongiare now referred to a new genus. http://zoobank.org/urn:lsid:zoobank.org:pub:A528C91D-8ED7-4A7E-BBF2-82BA296D10E4 [ABSTRACT FROM PUBLISHER]