Geoscience at BIO: The First Forty Years - Gordon Fader and Graham Williams
Introduction
This is a brief summary of forty years of the Geological Survey of Canada's geoscientific research at the Bedford Institute of Oceanography, which includes geology, geophysics, geochemistry, and related disciplines. It has been an important component of the marine research carried out at BIO since its opening in 1962. In such a review it is difficult to be inclusive of all-important contributions by many scientists. Because of space restrictions, we have focussed on the major programs and discoveries and the evolutionary stages in marine geoscience without citing individuals or providing references. For a chronological history of geoscience events, we recommend a summary produced by M. J. Keen in Keen (1990).
We recognize three phases in the conduct of geoscience at the Bedford Institute of Oceanography. The first phase, in some ways the most exciting, because it covered the pioneering days, was one of exploration and discovery. This lasted from the opening of the Institute in 1962 until the late 1970s and early 1980s. It was a time to learn the intricacies of marine as opposed to land-based geology and to build up a regional understanding of the vast area that is our offshore Canadian domain. During this phase, teams of geologists and geophysicists conducted numerous scientific cruises mapping and collecting baseline reconnaissance data.
In Phase II, extending from the 1980s until the early 1990s, the focus was on detailed and process studies and the birth of modelling. There was a need to know how structures and features were formed and their long-term implications. An even more important question, however, was how to make predictions.
A) A portion of a surficial geology map of the inner Scotian Shelf off Halifax, Nova Scotia, interpreted in 1970, showing the distribution of sediments at the seafloor and a few bathymetric contours.
B) A multibeam bathymetric map of the same region showing the true morphology and complexity of the seabed. Multibeam bathymetric maps like this will provide the future basis for sediment and bedrock mapping, seabed engineering, habitat assessments, and overall management.
Phase III, from the mid-1990s until the new millennium, has seen the generation of more sophisticated models and continued integration with other disciplines, a time of transgressing some of the old boundaries and expanding our horizons. A new need for precision, accuracy, and even higher resolution images resulted in detailed surveys and models. Much of the impetus for this was a requirement to manage the offshore and to have input on policy and direction. This was carried out with reduced resources, both in staff and facilities, as geoscience agencies around the world began to shrink in response to reduced budgets and changing priorities.
Now BIO geoscience is entering uncharted seas, with the emphasis on issue-driven and applied programs. Long-term research has been reduced and fewer projects are undertaken. The release of older data and interpretations in digital format has taken on a new priority.
Two other important issues in the geoscience story were the invention and application of instrumentation and the development of databases. Since it is usually impossible or impractical to see or sample seabed rocks directly, BIO geoscientists have utilized an impressive array of equipment. Sometimes this development has been in collaboration with industry as with the Huntec Deep-Towed Seismic Reflection System (DTSTM), sometimes alone as with the BIO drill, Ocean Bottom Seismometers, and RALPH (an instrumented tripod to monitor sediment transport rate and direction). Additional information on the development of instrumentation at BIO is contained in the article with that title later in this section of the report.
Phase I
With the opening of Bedford Institute of Oceanography, the federal government established a major presence in marine scientific research for the east coast offshore. Previously, this had been the domain of the universities (both in Canada and the USA) and industry. The federal presence meant the initiation of major ship-based studies, and especially the introduction of multiparameter cruises. The collection of potential field data (gravity and magnetic) on all hydrographic cruises started in 1965 and was pursued for almost thirty years. It provided BIO scientists with the most comprehensive potential field data, later supplemented with seismic data, for any continental margin in the world. This, coupled with the presence of a magnificent field laboratory stretching from about 44° N latitude to beyond the Arctic Circle, led to some dramatic discoveries.
Prior to the first multiparameter cruise, tests were being carried out on the use of potential field and seismic instrumentation on ships and on the seabed. In 1963, a geophysical survey in Baffin Bay and Nares Strait indicated that the Tertiary basalts of western Greenland extended offshore. Subsequent acquisition of single-channel seismic capability in 1965 confirmed the presence of sedimentary as well as basement rocks on the Labrador Shelf. This was of major significance to oil companies leading to petroleum exploration and discoveries.
In the more liberal days of the 1960s, scientists conducted research throughout the Atlantic in such places as the Mid-Atlantic Ridge, Iceland, Bermuda, and the Azores. A major incentive was to test the newly developed model of plate tectonics and sea floor spreading. The results were new insights into the opening of the North Atlantic and the structure of the Mid-Atlantic Ridge, the recognition of magnetic delineations, and the honing of expertise invaluable to the Deep Sea Drilling Project (DSDP) and its offspring, the Ocean Drilling Program (ODP). Consequently, several BIO geoscientists have served on DSDP and ODP cruises, sometimes as chief scientist, or have been involved in post-cruise studies. Highlights have included recognition of Orphan Knoll as a fragment of continental crust, the determination of the time of opening of the Labrador Sea, and the definition of the onset of glaciation in Baffin Bay.
Regional mapping was a high priority in the early days and led to some exciting finds. A major breakthrough in seabed geological mapping was the realization that acoustic reflection characteristics from echosounders, boomers, and airgun systems differentiated surficial sedimentary facies. The importance of this finding is confirmed by the continuing and extensive reliance on acoustic technology in seabed mapping. Surficial features on the sea floor that were first recognized and named included: pockmarks (gas escape craters), end moraines (glacial ridges), and iceberg furrows (large depressions from moving grounded icebergs) to name a few. Subsequently, pockmarks have been found on shelves all over the world and are an important indicator of hydrocarbons as well as playing an as yet undefined role in global climate change. The first in a series of regional surficial geology maps, the Halifax-Sable Island area, was published in 1970 followed by six more. In 1976, the first bedrock geology map of any Canadian offshore area was produced. The Huntec Deep-Towed Seismic Reflection System played an important role in studies of east coast offshore surficial sediments and continues to this day to be a superior sediment mapping system.
BIO scientists were not constrained to the East Coast. Sidescan sonar records from Arctic cruises in the early days identified sea-floor ice scour and pingos (dangerous shallow ice-cored mounds)in the Beaufort Sea. Canada and the USA mounted major expeditions to investigate the Arctic Ocean in the 1970s and 1980s. These included the Fram series (named after the ship of the Arctic explorer, Fridtjof Nansen), LOREX (the Lomonosov Ridge Expedition), and CESAR (the Canadian Expedition to study the Alpha Ridge). Results revealed that the Arctic mid-oceanic ridge is spreading slowly with cyclical sedimentation in the Cretaceous (142 to 65 million years ago).
An understanding of the regional tectonic framework of the continental margins of eastern Canada developed through the multiparameter surveys of the 1970s and 1980. The bathymetric, magnetic, gravity, and reflection and refraction seismic data gathered on such cruises were published in a series of maps in 1988.
Four perspective surfaces illustrating the Cenozoic evolution of the northeastern corner of the Grand Banks of Newfoundland (white outline on the map). These ancient sea floor images were interpreted from seismic data provided to the Geological Survey of Canada Atlantic by the Ex-Parex Group. Red is shallow and purple is deep. Each surface shows how the sea floor morphology has changed as sediment was deposited on the margin. a) 65 million years (m.y.) ago the area formed a shallow sea with canyons eroding into the western margin of what was the Jeanne d'Arc Basin. b) By 40 m.y. ago, the relief of the Jeanne d'Arc Basin had filled in. c) By 5 m.y. ago, enough sediment accumulated to form a broad shelf that began to resemble the modern Grand Banks of Newfoundland as we know them today shown in d) - image courtesy of Mark Deptuck and map courtesy of John Shaw.
Environmental impact studies became of paramount importance, focussed by the grounding of the tanker Arrow in Chedabucto Bay, 4th February 1970. The resulting multidisciplinary assessment of the oil spill and its impact on the surrounding habitats and beaches was the forerunner of investigations in the Strait of Canso and Miramichi Estuary.
The increased exploration for offshore oil and gas led to the decision for BIO to develop expertise in the offshore sedimentary basins. The studies, with the emphasis on lithostratigraphy, biostratigraphy, and deep reflection seismic data, commenced in 1971. Some of the resulting publications focussed on estimates of the hydrocarbon resources and reserves of offshore eastern Canada, and were important in determining federal government policy.
Technological innovations continued throughout the 1970s and early 1980s. The BIO drill, originally with 20' capability but subsequently extended to 30', revealed the nature of bedrock in previously unexplored areas.
Phase II
Interest in processes, as opposed to regional surveys, developed in the 1970s as BIO geoscientists tried to explain how some of the Quaternary seabed and subsurface features had formed, and define when and how glaciation occurred. The earth's maturation history could be used to predict promising exploration areas and targets, and provide a better understanding of the deep crust.
The glacial history of the East Coast offshore was little understood until studied by BIO scientists. For example, the onset of deglaciation on the Labrador Shelf was originally believed to be only a few thousand years ago, but is now known to have happened much earlier. Following the application of AMS dating (accurate dating method using accelerator mass spectrometry) and extensive regional mapping, syntheses of the Quaternary ( 1.8 million years to the present) geology of this and other continental shelves appeared in the late 1980s.
Concern over damage resulting from oil spills led to geological studies of coastal regimes and modern processes such as barrier-island systems and strand plain deposits. All the coastlines of New Brunswick, Nova Scotia, and Prince Edward Island have been video taped and the tapes made available to the public. Similar footage is also available for the Arctic. A systematic multidisciplinary evaluation of Baffin Island fjords, many of which have glaciers at tide water, allowed comparison with river-dominated fjords of British Columbia and wave-dominated fjords of Nova Scotia.
In the 1980s, sedimentary processes were studied both on the shelf and in deeper water, from the slope to the abyssal plain. A major change to the surficial mapping program shifted emphasis to the nearshore, an area largely neglected during Phase 1. Detailed sidescan sonar imaging provided a more precise delineation of variations in facies of deeper waters and revealed much about turbidites, especially those resulting from the Grand Banks earthquake of 1929. Another discovery showed that the continental slope of offshore eastern Canada was molded by the most recent glaciation about 20,000 years ago. The glacial and sea level history of the Quaternary has had a dominant impact on the land and sea boundaries in the Maritimes.
Comparison of a light micrograph image (A) and scanning electron microscope (SEM) image (B) of the fossil dinoflagellate Samlandia chlamydophora (about 35 million years old). The SEM image shows the relationship of the two wall layers and that the outer membrane is arranged into distinct areas or plates.
The integration of maturation studies of organic material and modelling in the late 1970s and early 1980s led to some impressive predictions. Visual kerogen (fossilized insoluble organic material) studies pinpointed the oil and natural gas potential of the Jeanne d'Arc Basin two years before the first Hibernia discovery well. This was followed by the first modelling of the margins of Eastern Canada, using lithospheric stretching. The results yielded predictions of the thermal maturation of the sediments and substantiated the visual kerogen data. The first thermo-mechanical models of the East Coast offshore predicted the mechanical properties of the lithosphere and its response to loading of sediments and water.
Since BIO is located on the margin of the North Atlantic, this has been a major stimulus for studies of the rift-drift history of this imposing ocean. Comparative studies of the formation of sedimentary basins, formed as the super-continent Pangea broke up (about 200 million years ago) have provided insights into the spreading history and comparable geological evolution on both sides of the Atlantic Ocean. Few people realize that we are also located close to Earth's largest igneous province, the Central Atlantic Magmatic Province (CAMP), which includes basalts on both the African and North American margins of the Atlantic Ocean. Outpourings of basaltic lava of the CAMP ring the Bay of Fundy and coincide with the initial stages of rifting before the onset of drifting.
During the Phase II era, analyses of offshore wells also revealed the existence of younger basalts and confirmed the occurrence on the Scotian Shelf of Meguma basement. One of the most dramatic discoveries was the first identified submarine impact crater, the Montagnais, which is on the southern margin of the Scotian Shelf. The meteor that formed this crater hurtled to Earth several million years after the extinction of the dinosaurs.
An important stimulus to research during Phase II was the Frontier Geoscience Program, introduced in 1984. This program provided extensive funding for geoscientific studies of the Arctic Islands, the Western Arctic, the East Coast, and the West Coast. It led to some impressive compilations, including atlases of the Labrador Sea and Scotian Shelf, and the seismic atlas of the Scotian Basin. Parallelling these developments was the publication in 1990 of "Geology of the Continental Margin of Eastern Canada", published as part of the Geology of Canada series and Decade of North American Geology. This provided a synthesis of the knowledge of geology, surficial and bedrock, and geophysics of offshore eastern Canada. Perhaps now is the time to plan a sequel to include advances made in the last decade.
Phase III
Geological modelling of new data marked the development of this phase. A good example of this is provided by the Lithoprobe Project and Frontier Geoscience Program (FGP), which saw the collection of deep, marine, multichannel seismic reflection data across the continental margins and adjacent continental regions. These data provided a means of profiling the structure of Earth's crust and upper mantle, using techniques pioneered by industry and adapted by academic and government groups to penetrate to deeper regions. At BIO these surveys, conducted between 1984 and 1990, established the nature of the crust beneath the Appalachians, northeast of Newfoundland, in the Gulf of St. Lawrence, and below the continental margins and sedimentary basins off Nova Scotia, the Grand Banks, and in the region of the Labrador Sea. There was a multidisciplinary aspect, however, which did not end with the collection and interpretation of the seismic data. These data were combined with other datasets and with numerical models of the subsidence and thermal history of the region, to determine the tectonic history and the nature of the forces driving continental break-up. Some of the questions addressed were: the nature and extent of continental crustal thinning near the margins; the role of volcanism during break-up; and the character of the ocean-continental transition. Thus, the combination of several kinds of data with predictive quantitative modelling has enhanced predictability.
Incredible advances have taken place since the digitization of data and the continual development of more sophisticated personal computers. Nowhere is this more apparent than in the seabed mapping program. Bathymetric data are now collected with multibeam survey techniques developed by the Canadian Hydrographic Service in partnership with the Geological Survey of Canada (GSC). This has revolutionized the collection and display of these data and revealed previously unknown sea-floor features such as relict river channels from former episodes of lowered sea level and new moraines and bedrock features. Through the combined use of sidescan sonar and multibeam backscatter systems, it is possible to produce high resolution imagery covering 100% of the sea floor. This highlights shipwrecks, pipelines, and cables and yields priceless information on sediment distribution and processes. This technology has provided some surprising insights into, for example, Halifax Harbour, in which abandoned cars are clearly visible. The technology has played a major role in an analysis of the degree of contamination of sediments lying on the floor of the harbour and provided essential information for the siting of wastewater marine outfalls. It has greatly assisted surveys for potential pipeline sites for oil and natural gas development, such as the Sable and Hibernia fields.
Geological work on the slope became a higher priority during the 1980s, when the oil companies became interested in the area and drilled five wells in water depths of 1000-1500 metres on the Scotian Slope. Although detailed studies were restricted to those areas in the immediate vicinity of the wells, major field programs were completed in 1999 and 2000, utilizing the Global Positioning System (GPS) and multibeam bathymetry. These and subsequent studies have highlighted the complex nature of the slope, with deep canyons in some areas, and build-up of sediments in others. Surveys in The Gully, the largest offshore submarine canyon, have provided information on geological characteristics and marine habitats for rare coral that have led to a proposal for declaration of the area as a Marine Protected Area (MPA).
Closer to shore, multidisciplinary studies of climate-change impact on coastal regions have evaluated changing sea level, storm-surge flooding, changes in sea ice, and coastal erosion. A goal of the studies is to identify critical factors associated with climate change and sea-level rise so that coastal communities will be able to react to concerns.
Contrary to popular belief, issue-driven science is not a new concept. An example is the impact of the 1982 United Nations Law of the Sea Convention on the BIO program. Although this convention is not as yet ratified by Canada, it highlighted how little we knew about the area beyond the 200 mile limit, and even much of the continental margin within that boundary. Concurrent with these concerns were boundary issues in the Gulf of Maine and on the Grand Banks, both important fishing grounds and potential areas for hydrocarbon exploration. These issues galvanized mapping studies of the sea floor and the underlying sediments and basement. Such motivation resulted in the Geological Survey of Canada covering the cost of a multichannel seismic survey of the St. Pierre Bank. The data collected demonstrated the lateral extent of the Scotian Basin and proved of considerable interest to the oil companies.
The 1990s and the new millenium have witnessed dramatic strides in website development and digitization. This has transformed management of the databases now available to aid research at BIO. Notable examples are BASIN and the Expedition Database, colloquially known as ED. BASIN provides geological data on all the offshore wells in a format that can be readily manipulated. For example, it is extremely easy to plot logarithmic data against lithology, biostratigraphy, and maturation data whatever the source. Several companies have purchased BASIN and it is being extensively used by staff and students of universities throughout Canada. ED contains all the data related to cruises on which geoscientific data has been collected by GSC Atlantic or GSC Pacific, or their precursors. Besides accessing the data, one can also obtain a "Trackplot" of the survey or seismic lines together with location of samples.
Merging and digitization of magnetic data from various organizations and covering the Arctic, Labrador Sea, and Atlantic Ocean north of the 30°N latitude began at GSC Atlantic in 1988. This has provided an unparalleled database, which has and is still being used to produce a superb series of maps such as the new series of detailed magnetic anomaly maps for Atlantic Canada.
Studies of sedimentary basins have been revitalized with the increasingly detailed multichannel and 3D seismic profiles now available. The multichannel data shows that salt under the Scotian Margin does not simply form the classic diapirs but often occurs as detached bodies. Use of 3D data has led to some spectacular time structure maps of specific horizons, showing erosional features such as submarine canyons and faults. To better understand the maturation history in basins such as the Scotian and Jeanne d'Arc, the Tertiary is being studied in greater detail.
Future
A severe handicap to progress during Phase III was a major cutback in staff in 1995, when many of the experienced staff left the Geological Survey of Canada and certain programs, such as paleoceanography and deepwater geophysics were curtailed. This affected progress in many disciplines. However, it is apparent that the reconnaissance survey phase of research is over and that the new direction will be more issues-driven and applied. This could mean greater emphasis on the Canadian North, the Law of the Sea, the SeaMap project (systematic multibeam bathymetric studies), climate change, habitat characterization, high resolution mapping, and the environment. It will also result in efforts to make all data, past and present, readily available in digital format.
Such an applied agenda will also mean rapidly changing priorities, shorter-term research projects, and targeted research on fewer issues. As a priority, we will need to replace staff as they retire. Whatever the future holds, it is obvious that over the past 40 years Canada has had an extremely creative and productive geoscience team on the cutting edge of research and representing an excellent investment in marine geoscience studies. Through regional reconnaissance studies, we now have some understanding of most Canadian offshore regions. In so many fields, marine geoscientists at BIO have provided leadership on global issues, marine geoscience technology, and applied local and international projects. They have, and continue to contribute, critical information to the understanding of the offshore so that both development of resources and protection of ecosystems can proceed in a framework of knowledge and sustainability.
Literature Cited
Keen, M.J. 1990. The history of exploration of the continental margin of eastern Canada. Appendix, in Geology of the Continental Margin of Eastern Canada, M.J. Keen and G.L. Williams (ed.): Geological Survey of Canada, Geology of Canada, no. 2, p. 833-846 (also Geological Society of America, The Geology of North America, v. I-1).
