Grand Banks Area Research Articles

Machine learning analysis and nowcasting of marine fog visibility using FATIMA Grand Banks campaign measurements

Introduction: This study presents the application of machine learning (ML) to evaluate marine fog visibility conditions and nowcasting of visibility based on the FATIMA (Fog and turbulence interactions in the marine atmosphere) campaign observations collected during July 2022 in the North Atlantic in the Grand Banks area and vicinity of Sable Island, northeast of Canada.Methods: The measurements were collected using instrumentation mounted on the Research Vessel Atlantic Condor. The collected meteorological parameters were: visibility (Vis), precipitation rate, air temperature, relative humidity with respect to water, pressure, wind speed, and direction. Using all variables, the droplet number concentration was used to qualitatively indicate and assess characteristics of the fog using the t-distributed stochastic neighbor embedding projection method (t-SNE), which clustered the data into groups. Following t-SNE analysis, a correlation heatmap was used to select relevant meteorological variables for visibility nowcasting, which were wind speed, relative humidity, and dew point depression. Prior to nowcasting, the input variables were preprocessed to generate additional time-lagged variables using a 120-minute lookback window in order to take advantage of the intrinsic time-varying features of the time series data. Nowcasting of Vis time series for lead times of 30 and 60 minutes was performed using the ML regression methods of support vector regression (SVR), least-squares gradient boosting (LSB), and deep learning at visibility thresholds of Vis < 1 km and < 10 km.Results: Vis nowcasting at the 60 min lead time was best with LSB and was significantly more skillful than persistence analysis. Specifically, using LSB the overall nowcasts at Vis 1 < km and Vis 10 < km were RMSE = 0.172 km and RMSE = 2.924 km, respectively. The nowcasting skill of SVR for dense fog (Vis ≤ 400 m) was significantly better than persistence at all Vis thresholds and lead times, even when it was less skillful than persistence at predicting high visibility.Discussion: Thus, ML techniques can significantly improve Vis prediction when either observations or modelbased accurate time-dependent variables are available. The results suggest that there is potential for future ML analysis that focuses on modeling the underlying factors of fog formation.

Cartographical Perspectives on the Evolution of Fisheries in Newfoundland’s Grand Banks Area and Adjacent North Atlantic Waters in the Sixteenth and Seventeenth Centuries

At the turn of the sixteenth century, John Cabot and his successors discovered abundant fish stocks in the north west Atlantic waters near Newfoundland. This article accounts for how sixteenth- and seventeenth-century mapping provide another strand of evidence that supplement our knowledge of the subsequent Iberian, French, and British fisheries. Such cartography exhibited significant mutations and innovations in rendering fishing locations, and illustrating fishing practices and fish species. Fishermen’s knowledge must have informed such mapping. The innovation of hydrographical indicators in esthetically appealing maps recognized from an early stage the status of the Grand Banks as a globally important feature of submarine topography. More refined and accurate delineations of its submarine plateaus and other adjacent continental shelves closely followed the development of fishing activities, encompassing both Newfoundland’s nearshore and the Grand Banks themselves. Furthermore, such cartography reflected transformative and reciprocal relationships with commerce and inter-state politics across the North Atlantic.

Forecasting the severity of the Newfoundland iceberg season using a control systems model

ABSTRACT The iceberg hazard for the Grand Banks area to the east of Newfoundland varies dramatically from one year to the next. In some years no icebergs penetrate south of 48°N, while in others well over 1000 icebergs enter the main shipping lanes between Europe and NE North America. Advance knowledge of this seasonal hazard would have major implications for ship routing, as well as the resources required for maintaining an effective ice hazard service. Here, a Windowed Error Reduction Ratio control system identification approach is used to forecast the severity of the 2018 iceberg season off Newfoundland, in terms of the predicted number of icebergs crossing 48°N, as well as to hindcast iceberg numbers for 2017. The best estimates are for 766 ± 297 icebergs crossing 48°N before the end of September 2017 and 685 ± 207 for 2018. These are both above the recent observed average of 592 icebergs for that date, and substantially so for 2017. Given the bimodal nature of the annual iceberg number, this means that our predictions for both 2017 and 2018 are for a high iceberg season, with a 71% level of confidence. However, it is most likely that the 2018 iceberg numbers will be somewhat less than 1000, while our higher hindcast for 2017 is consistent with the observed level of 1008. Our verification analysis, covering the 20-year period up to 2016, shows our model's correspondence to the high or low nature of the 48°N iceberg numbers is statistically robust to the 0.05% level, with a skill level of 80%.

The decline of Norwegian kittiwake populations: modelling the role of ocean warming

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 60:91-102 (2014) - DOI: https://doi.org/10.3354/cr01227 The decline of Norwegian kittiwake populations: modelling the role of ocean warming Hanno Sandvik1,*, Tone K. Reiertsen2,3, Kjell Einar Erikstad1,3, Tycho Anker-Nilssen4, Robert T. Barrett2, Svein-Håkon Lorentsen4, Geir Helge Systad3, Mari S. Myksvoll5 1Centre for Biodiversity Dynamics (CBD), Department of Biology, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway 2Tromsø Museum, University of Tromsø, PO Box 6050 Langnes, 9037 Tromsø, Norway 3Norwegian Institute for Nature Research (NINA), FRAM - High North Research Centre for Climate and the Environment, 9296 Tromsø, Norway 4Norwegian Institute for Nature Research (NINA), PO Box 5685 Sluppen, 7485 Trondheim, Norway 5Institute for Marine Research, PO Box 1870 Nordnes, 5817 Bergen, Norway *Corresponding author: hanno@evol.no ABSTRACT: The black-legged kittiwake Rissa tridactyla is a pelagic seabird whose population has recently declined in most parts of the North Atlantic and which is red-listed in most bordering countries. To investigate a possible cause for this decline, we analysed the population dynamics of 5 kittiwake colonies along the Norwegian coast, ranging from 62° to 71°N, over the last 20 to 35 yr. By quantifying the importance of sea surface temperatures (SST) in relevant areas of the North Atlantic, we tested the importance of climatic conditions throughout the populations’ annual cycles. We found no synchrony among colonies; however, SST affected population dynamics, explaining between 6% and 37% (average 18%) of the variation in annual population growth rate. While dynamics of the southerly colonies were mainly affected by winter conditions in the Grand Banks area, dynamics of the northernmost colonies were dominated by autumn conditions off Svalbard. Negative slopes indicated stronger population decline under warmer ocean conditions. Population dynamics were affected both via adult survival and offspring recruitment, as evidenced by the presence of unlagged effects as well as effects lagged by the age at recruitment. Finally, we performed population viability analyses taking into account the projected warming trends for the future. The median time to extinction of the Norwegian colonies was 52 to 181 yr without considering covariates; 45 to 94 yr when considering the effects of SST but ignoring future warming; and 10 to 48 yr when ocean warming, based on a ‘business as usual’ scenario, was taken into account. KEY WORDS: Global warming · Non-breeding distribution · Population dynamics · Population viability analysis · Rissa tridactyla · Sea surface temperature Full text in pdf format Supplementary material NextCite this article as: Sandvik H, Reiertsen TK, Erikstad KE, Anker-Nilssen T and others (2014) The decline of Norwegian kittiwake populations: modelling the role of ocean warming. Clim Res 60:91-102. https://doi.org/10.3354/cr01227 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 60, No. 2. Online publication date: June 17, 2014 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2014 Inter-Research.

Modelling Extreme Storm-Induced Currents over the Grand Banks

Extreme storm-induced currents over the Grand Banks are investigated using a three-dimensional (3-D) ocean circulation model forced by 22 storms selected from the past 50 years with return intervals ranging from 1 to 34 years. Wind data for the storms are historical atmospheric data. The modelled currents are compared with current meter measurements made during a storm in March 1983. The results indicate good agreement between the model and measurements. In the surface layer of the Grand Banks, the model extreme current speeds are approximately 80 cm s−1 over a large portion of the Grand Banks, and some areas have extreme current speeds higher than 120 cm s−1. The highest extreme current speeds occur at St. Pierre Bank, where the speed reaches 140 cm s−1. In the bottom layer, the region with high extreme current speeds is mainly in the periphery of the Grand Banks, with magnitudes over 40 cm s−1. The results also show that the response of the water to storm forcing in the Grand Banks area varies from place to place because the mechanisms of current generation are different at different locations.

Le courant du Labrador et quelques-unes de ses conséquences géographiques

Le courant du Labrador et quelques-unes de ses conséquences géographiques

Egret-Hibernia(!), a significant petroleum system, northern Grand Banks area, offshore eastern Canada

Egret-Hibernia(!) is a well-explored petroleum system (3.25 billion barrels oil equivalent [BOE]) located in the Jeanne d'Arc Basin on the Labrador–Newfoundland shelf. Rifting and sediment fill began in the Late Triassic. Egret source rock was deposited in the Late Jurassic at about 153 Ma. After this time, alternating reservoir rock and seal rock were deposited with some syndepositional faulting. By the end of the Early Cretaceous, faults and folds had formed numerous structural traps. For the next 100 m.y., overburden rock thermally matured the source rock when it reached almost 4 km (2.5 mi) burial depth. For 2 km (1.25 mi) below this depth, oil and gas were expelled, until the source was depleted. The expelled petroleum migrated updip to nearby faulted, anticlinal traps, where much of it migrated across faults and upsection to the Hibernia Formation (44% recoverable oil) and Avalon Formation (28%). Accumulation size decreased, and gas content increased from west to east, independent of trap size. These changes correspond to a decrease in source rock richness and quality from west to east.Almost all (96%) of the discovered petroleum resides in the Lower Cretaceous or older reservoir rock units. All accumulations found to date are normally pressured in structural traps. Fifty-two exploration wells found eighteen discoveries. Their size ranges from 1.2 to 0.01 billion BOE. Most discoveries were made between 1979 and 1991. The discovery cycle began with larger accumulations and progressed to smaller accumulations. The estimated sizes of the larger accumulations have grown since 1990. Estimated mean value for undiscovered hydrocarbons is 3.8 billion BOE, thereby raising the ultimate size of Egret-Hibernia(!) to 6.19 billion BOE.

Labrador Sea Water Tracked by Profiling Floats—From the Boundary Current into the Open North Atlantic

Fifteen profiling floats were injected into the deep boundary current off Labrador. They were ballasted to drift in the core depth of Labrador Sea Water (LSW) at 1500-m depth and were deployed in two groups during March and July/August 1997. Initially, for about three months, the floats were drifting within the boundary current, and the flow vectors were used to determine the mean horizontal structure of the Deep Labrador Current, which was found to be about 100 km wide with an average core speed of 18 cm s−1. North of Flemish Cap the boundary current encounters complicated topography around “Orphan Knoll,” and there the LSW outflow splits up into different routes. One obvious LSW path is eastward through the Charlie Gibbs Fracture Zone and another route is a narrow recirculation toward the central Labrador Sea. A surprising result was that none of the floats were able to follow the boundary current southward to the Grand Banks area and exit into the subtropics. Trajectories and temperature profiles of the eastward drifting floats indicate the importance of the North Atlantic Current for dispersing the floats, even at the level of LSW.

Mitochondrial DNA analysis confirms the existence of two glacial races of rainbow smelt Osmerus mordax and their reproductive isolation in the St Lawrence River estuary (Quebec, Canada)

A phylogeographic analysis of mitochondrial DNA variation was performed in order to test the hypothesis that north‐eastern North America has been postglacially recolonized by two races of rainbow smelt Osmerus mordax. This was accomplished by documenting the geographical distribution of two major mtDNA phylogenetic clades among 1290 smelt from 49 lacustrine and anadromous populations covering most of the species' native range. The data set was built by combining previously published results with those generated in this study. The two mtDNA clades showed a geographical dichotomy, independent of life‐history types, whereby the more eastern populations were either fixed or largely dominated by one clade and western populations for the other. Such geographical pattern implying a phylogenetic discontinuity provided strong evidence for the persistence of smelt in two distinct glacial refugia as well as their differential postglacial dispersal. The most likely refugium for the so‐called Atlantic race was the Atlantic coastal plains, whereas that of the so‐called Acadian race was the exundated Grand Banks area. Patterns of postglacial dispersal interpreted from palaeogeographic events suggested that the Atlantic race recolonized northern regions about 5000 years prior the Acadian race. Both races came into contact in the St Lawrence River estuary. While gene flow has been possible, the sympatric occurrence in the estuary of anadromous populations alternatively dominated by one mtDNA clade or the other indicated that reproductive isolation mechanisms between the two races developed within this contact zone. This represents the first evidence of secondary intergradation among distinct races of aquatic organisms in an estuarine environment.

Age and mode of emplacement of the collector anomalY, (Canada): Is it the northwestern boundary of Gondwana?

A direct study of the Collector Anomaly, a prominent positive gravity and magnetic anomaly, located between Boston (U.S.A.) and southern Spain, suggests that this Paleozoic feature, which follows or corresponds with a suture, may be modelled magnetically, in the Grand Banks area, by a northward dipping dyke-like body. This body could have originated when Gondwanaland and Avalon collided. The magnetic and seismic data available in the eastern part of the Grand Banks do not permit us to understand the geometric relationship where this body intersects with two post-Givetian south deepening thrusts, the roots of which are located in the Ghomarids of northern Morocco. Since, in plan view, the body causing the Collector Anomaly cuts Meguma sediments—which are Emsian in their upper part—this mafic body could be younger than Emsian. But recent geochronological data have been interpreted to indicate a 400–415 Ma metamorphic age as the collision age between Avalon and Meguma. The study of the previous seismic lines cutting across the Avalon-Meguma boundary, in the Gulf of Maine, in the Bay of Fundy and east of Nova-Scotia, show a western extension of the Morroccan-Grand Banks south dipping thrust system. This system is cut by the suture which separates Meguma from Avalon. The geometrical relationship suggests that the seismic and mafic suture between the two zones cannot be older than the Frasnian, which therefore gives a maximum age for the last docking of Meguma. This is the first study where the magnetic modelling of the Collector Anomaly is associated with the seismic reflection data along its entire length. The Collector magnetic trend is not as clear in southern Spain as in Canada, because of Hercynian southward thrusting involving the mafic and ultramafic rocks which developed in Spain during the pre-Variscan northward subduction. These data show that the magnetic rocks responsible for the Collector Anomaly are sometimes affected by tectonic transport which locally may differ in age and direction. As a consequence, the northwestern plate boundary of Gondwanaland imaged on the deep seismic data does not everywhere correspond with the shallow expression of the Collector Anomaly.

Overview of LIMEX'87 ice observations

Ice observations, results, and conclusions are summarized for the March 1987 Labrador Ice Margin Experiment (LIMEX'87), an international oceanographic study conducted in the pack ice of the Grand Banks area off the coast of Newfoundland. Included are the ice extent, flow size and thickness, ice kinematics and rheology, ice microwave properties, oceanic properties under the ice, and penetration of swell into the ice.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An Ordovician continental-margin sequence of turbidite and seamount deposits in the Roberts Mountains allochthon, Independence Range, Nevada

The Roberts Mountains allochthon in the northern Independence Range, Nevada, includes a 1.9-km-thick section of Ordovician rocks which were deposited west of the North American continental shelf. Lower Ordovician (upper Arenig) graptolitic mud-stone, distal turbidites, and chert were deposited in a continental-rise setting. Overlying Middle Ordovician (probably Llanvirn) basalts represent a seamount sequence. Clastsupported basaltic breccia and bedded volcaniclastics represent a debris apron deposited on the seamount flank, and carbonate deposition on a higher summit is indicated by common limestone clasts with a shallow-marine fauna. Seamount subsidence is represented by the stratigraphically highest volcanics, which consist of nonvesicular pillow basalt of deep-marine origin. Seamount deposits were overlapped in Middle Ordovician (Late Llanvirn to Llandeilo) time by quartz-sand turbidites and mudstone of possible lower-fan origin. These deposits are overlain conformably by Upper Ordovician (lower Caradoc), thick-bedded, gravity-displaced, quartz sandstones, which represent the middle to upper part of a large submarine fan. Cutoff of sand supply in the Late Ordovician (middle Caradoc) resulted in deposition of mudstone and chest over fan surfaces. Ordovician rocks of the Roberts Mountains allochthon represent a continental-rise setting in which sea-mount construction occurred during fan-related turbidite deposition. A grossly similar type of margin exists today in the Grand Banks area of the North Atlantic.

Geotechnical aspects of seabed pits in the Grand Banks area : Clark, J L; Landva, J Can Geotech JV25, N3, Aug 1988, P448–454

Geotechnical aspects of seabed pits in the Grand Banks area : Clark, J L; Landva, J Can Geotech JV25, N3, Aug 1988, P448–454

Evolution of Mesozoic-Cenozoic Sedimentary Basins in the Grand Banks Area of Newfoundland and Comparison with Falvey's (1974) Rift Model

ABSTRACT A review of three Mesozoic-Cenozoic periods of sedimentation, igneous activity, and structuring in Grand Banks basins is presented. This review is followed by an attempt to deduce the timing and tensional orientations of rifting and seafloor spreading on the margins of the North Atlantic, through recognition of the geological responses to that rift history as defined by Falvey (1974) and others. Three rift periods, defined in this report, affected the Grand Banks. The first was Triassic - Early Jurassic rifting, during a period of NW-SE extension and synchronous sedimentation, followed by the break-up of Africa and North America in the mid-Pliensbachian. The second was Tithonian - early Valanginian rifting, during a period of E-W to ESE-WNW extension and synchronous sedimentation, followed by the break-up of Iberia and the Grand Banks, possibly as early as mid-Valanginian. The third was Aptian-Albian rifting, during a period of NE-SW extension and synchronous sedimentation, followed by the break-up of Europe and North America in the Cenomanian or latest Albian. Each of these tectonic periods was preceded by a period of broad regional warping or arching, and each was followed by a period of thermal subsidence and postrift sedimentation. This tectonic evolution has controlled many factors important to petroleum generation and accumulation, and its definition can assist in petroleum exploration in the Grand Banks area. EVOLUTION DES BASSINS SEDIMENTAIRES DU MESOZOIQUE ET DU CENOZOIQUE SOUS LES GRANDS BANCS DE TERRENEUVE, ET LA COMPARAISON AVEC LE MODELE DE FORMATION DE FOSSES TECTONIQUES (RIFT) DE FALVEY (1974) RESUME Un examen de trois periodes de sedimentation Mesozoique-Cenozoique, de l'activite ignee et de la formation de structures sous les Grands Bancs est presente. Cet examen est suivi d'une tentative de determination de la date et des directions des tensions de la formation de fosses (rifting) et de l'expansion oceanique en bordure de l'Atlantique Nord, a travers la decouverte des reactions geologiques a cette evolution des fosses oceaniques, comme le definissent Falvey (1974) et d'autres chercheurs. Trois periodes de formation de fosses, presentees dans ce rapport, affecterent la region des Grands Banks. La premiere eut lieu durant le Triassique-Jurassique inferieur, durant une extention en direction N.-O. S.-E. et une sedimentation synchrone, suivis par la separation de l'Afrique et de l'Amerique du Nord durant le Pliensbachien moyen. La seconde date du Tithonien-Valanginien inferieur, durant une extension en direction E.-O, a E.-S.-E. O.-N.-O. et une sedimentation synchrone, suivis par la rupture entre l'Ibenie et les Grands Bancs, peut-etre aussi tot que le Valanginien moyen. La troisieme se produisit durant l'Aptien-Albien, representant un temps d'extension en direction N.-E. S.-O. et de sedimentation synchrone, suivis par la separation entre l'Europe et l'Amerique du Nord durant le Cenomanien ou l'Albien le plus tartif. Chacun de ces episodes tectoniques fut precede par une periode de grand soulevement a l'echelle regionale, puis suivi par un episode de subsidence thermique et de sedimentation post-fosse tectonique. Cette evolution tectonique exerca un controle sur plusieurs facteurs importants a la production et a l'accumulation du petrole, et sa definition peut aider a l'exploration petroliere dans la region des Grands Bancs. Traduit par Marc Charest

Geotechnical aspects of seabed pits in the Grand Banks area

Ice-created seabed pits found on the Grand Banks of Newfoundland can be analysed in terms of probable range of soil strength properties and failure mechanisms to determine the ice loads transmitted to the seabed. Almost all pits are less than 3 m deep; their existence can be explained by indentation failures caused by rolling icebergs. About 3.5% of the pits are more than 5 m deep and cannot be explained by iceberg impact. This paper presents a possible mechanism for their formation consisting of two actions: (1) the hard grounding of an iceberg, such that the keel becomes embedded in the seabed, and (2) the passive failure of the soil after the grounding event, predominantly caused by the loads associated with wave forces on the iceberg at the time of grounding or shortly thereafter. A 10 m deep pit located in the Hibernia area is analysed with respect to its configuration and soil parameters. Calculations have shown that, though waves in the Grand Banks area cause forces on the iceberg of a sufficient magnitude to create pits of the order of 10 m deep or more in the stiff Grand Banks soils, the controlling factor of pit depth is the ability of the iceberg keel to deliver these loads to the soil. Key words: iceberg pits, iceberg scour, pit formation, ice–seabed interaction.

Evaluation of a Model for Predicting the Drift of Iceberg Ensembles

This paper describes the evaluation of a model for predicting the drift of iceberg ensembles. The model was developed in preparation for providing an iceberg forecasting service off the Canadian east coast north of about 45°N. It was envisaged that 1–5 day forecasts of iceberg ensemble drift will be available. Following a critical examination of all available data, 10 data sets containing up to 404 icebergs in the Grand Banks area off Newfoundland were selected for detailed study. The winds measured in the vicinity of the study area as well as the detailed current system developed by the International Ice Patrol were used as inputs to the model. A discussion on the accuracy and limitations of the input data is presented. Qualitative and quantitative criteria were used to evaluate model performance. Applying these criteria to the results of the computer simulations, it is shown that the model provides good predictions. The degree of predictive success varied from one data set to another. The study demonstrated the validity of the assumption of random positioning for icebergs within a grid block, especially for ensembles with large numbers of icebergs. It was found that an “average” iceberg size can be used to represent all icebergs. The study also showed that in order to achieve improved results it will be necessary to account for the deterioration (complete melting of icebergs), especially during the summer months.

Baseline Levels of Volatile Hydrocarbons and Petroleum Residues in the Waters and Sediments of the Grand Banks

Baseline levels of low molecular weight volatile hydrocarbons and petroleum residues in the Grand Banks area were measured in April 1981 with a focus on the Hibernia and South Tempest sites where exploration for oil was occurring. Concentrations of volatile hydrocarbons ranged from 0.41 to 1.80 nmol/L (geometric mean = 0.74 nmol/L) in the water column and 0.05–3.20 mmol/L in the surficial bottom sediments. The former, almost exclusively methane, were of recent biological origin, while the latter, which also contained ethane, propane, and butane, were probably related to petroleum. There was no visible evidence of surface slicks at the time, and floating particulate petroleum residues were absent from most locations. Concentrations of dissolved/dispersed petroleum residues in the sea surface microlayer ranged from 14 to 440 μg/L (geometric mean = 28.9 μg/L) and in the water column from 0.05 to 4.1 μg/L. Concentrations of petroleum residues in the surficial bottom sediments ranged from 0 to 7.3 μg/g. While these levels are among the lowest found anywhere in the waters and sediments off eastern Canada and in the eastern Arctic, there was evidence that the oil industry, even at the level of its activity at the time, was having a detectable impact on background levels of petroleum-related substances in the sea surface microlayer and the surficial bottom sediments.

HIBERNIA- a Petrophysical And Geological Review

Abstract Since the discovery well, Chevron et al. Hibernia P-15, was drilled in late 1979, five step-outs have subsequently been drilled on the Hibernia structure. This paper focuses on a detailed petrophysical and geological evaluation of the three main reservoirs in the Hibernia field. These zones include: the Avalon zone, the "B" Seismic Marker zone and the Hibernia zone. Detailed petrophysical analyses were conducted on these zones generating: effective porosity corrected for shaliness, hydrocarbon effect and compaction; litho logy calculated using matrix solution, shale volume and water saturation. Cross plots of porosity, permeability and individual log responses were used to calibrate the log data and select evaluation parameters. The results of the petrophysical analyses were summarized on depth plots and used to prepare stratigraphic and structural cross sections in order to illustrate the complex lateral and vertical relationships of the reservoirs. Cutoffs were applied to the calculated profiles over the reservoir intervals in order to provide data on reservoir distribution and quality. These results were used to prepare a suite of geological maps for each reservoir. The resource potential of each of the three main reservoirs was determined by a Monte Carlo simulation technique. This analysis indicates that the Hibernia is truly a "Giant Oil Field". The study was conducted by the Newfoundland and Labrador Petroleum Directorate and Intercomp Resource Development and Engineering Ltd. Introduction Surficial Geology The Hibernia Field is located on the Grand Bank of Newfoundland approximately 315 kilometres (170 nautical miles) southeast of St. John's, in water depths ranging from 76 to 86 metres (249 to 282 feet) (Fig. 1). Extending more than 400 kilometres eastward into the Atlantic Ocean, the Grand Bank lies exposed to Greenland icebergs drifting southward in the cold Labrador current. On the average, 400 bergs each year drift into the Grand Banks area. Most bergs are swept with the main branch of the current around the eastern flank of the Grand Bank; others are carried by the western branch down the Avalon Channel close to the island of Newfoundland. Many bergs, however, deviate from these paths onto the bank itself. The Hibernia discovery area is clearly vulnerable both to the iceberg scouring threat and to disturbance by currents and waves from ocean and storm-generated water movement(5). Welisite surveys of the Hibernia area indicate the seabed to be a very gently dipping surface toward the east. One to five metres of surficial sediment overlying semi-consolidated Tertiary bedrock are largely composed of coarse-grained material. Zones of well-rounded lag gravel with shell debris are aligned north-south alternatively with zones of well-sorted sand possibly over gravel (Fig. 2). Ripple marks within the well-sorted sand indicate at least sporadically active transport by current and wave action within the area. The bedrock geology of the Hibernia area and areas westward is shown on Figure 3. In the Hibernia area, the bedrock- (Figure in full paper) consists of Cretaceous and Tertiary rocks.

Regional Geology of Grand Banks

Geophysical and drilling operations within the Grand Banks area have established the existence of a thick sedimentary section that includes Tertiary, Mesozoic, and Paleozoic strata. An angular unconformity that developed in Early Cretaceous time divides the section into 2 distinct geologic units: the "upper wedge," comprised of Tertiary and Cretaceous strata, and the "subunconformity basins," containing Jurassic and older rocks. The relatively simple upper wedge has regionally gentle dip, disturbed by salt-dome structures. The subunconformity basins contain many structural types, including salt domes, salt ridges, faults, drape folds over basement blocks, and major sedimentary truncations at the unconformity.

United States Coast Guard activities in oceanographic work and plans for the future

This year the Coast Guard oceanographic program in connection with International Ice Patrol has been reactivated on a full scale basis. The oceanographic vessel, fully equipped and staffed, has already begun its observational program in the Grand Banks area to construct the first dynamic current chart in that region since before the War. Throughout the ice season periodic oceanographic surveys will be made of the most critical of the ice‐infested regions. The surface‐current maps resulting from these surveys are used immediately by the patrol cutters, and the Commander International Ice Patrol at Argentia, Newfoundland, to plan ice scouting by sea and air, and to predict ice movement. As usual the results of this research will be published in the annual report of the Ice Patrol. Coast Guard Bulletin No. 32 International Ice Observation and lee Patrol Service in the North Atlantic Ocean. Season of 1946. which covers 1942 to 1945 also, has already been distributed. Bulletin No. 31, for 1941 is still in preparation.