The MPMPS, a leading-edge technique to
develop Québec’s territory
Two new products derived from the Mineral
Potential Map Production System (MPMPS) will be released at
the Geological Research Information Seminar, to be held next
November 27 and 28 in Québec. A new map showing
the potential for volcanogenic massive sulphide deposits in
the Senneterre area (NTS 32C) will be presented. A compilation
map showing the potential for Olympic Dam-Kiruna type deposits
in the Manitou-Wakeham area (NTS 22I, 22P, 12K,
12L, 12M and 12N) will also be on display. Moreover, during
the Seminar, a workshop on the MPMPS will be hosted by the
MPMPS, a knowledge-driven approach suitable for Québec
The Système de production des cartes de
potentiel minéral (SPCPM) is a mineral potential assessment
tool, which makes it possible to produce maps based on an ore deposit
model that show zones favourable to the presence of mineralization.
A new worldwide trend
Mineral potential assessment via integration of
spatially georeferenced data is an approach that is now used on
a global scale, and it keeps generating more and more interest.
The growing number of articles dealing with this technique confirms
this. This new trend was strongly influenced by the development
of new software making the process possible on a personal computer,
and by the availability of new digital databases.
Formerly, zones favourable to the discovery of new deposits were
generally identified by overlapping several layers of polyester,
each illustrating a geological feature potentially indicating the
presence of a given type of ore deposit (fault, geophysical anomaly,
geochemical anomaly, etc.). Target areas were selected among those
showing the largest number of overlapping features. The digital
integration of georeferenced data revolutionized this approach,
by making it possible to target, with pinpoint accuracy, the type
of data (or theme) to process, to adapt the processing based on
data-driven or knowledge-driven methods,
and finally, to combine the results according to the relative importance
of each theme.
The various methods used to process the data are grouped into two
categories: first, data-driven methods that rely on
statistical analysis to determine relevant spatial associations
of various geological, geophysical or geochemical elements with
known ore deposits; second, knowledge-driven methods
which, based on the expert assessment of the processing geologist,
rely on the definition and spatial processing of relevant metallogenic
parameters for a selected model.
Data-driven methods use a training set generally derived
from a digital map where a sufficient number of known deposits corresponding
to the selected ore deposit model are located in the study area.
The processing consists in calculating the statistical correlation
between this training set and a certain number of digital maps each
representing a parameter (or theme) relevant to the model (map of
felsic intrusions, iron alteration, synvolcanic dykes, etc.). Data-driven
methods essentially use three techniques: regression analysis, neural
networks and weight of evidence.
Knowledge-driven methods (used to produce MPMPS maps)
are based on an ore deposit model that is relevant for the study
area. This model is based on geological parameters (heat source,
favourable lithologies, faults allowing fluid circulation, etc.)
which are considered as essential or favourable elements for the
formation of deposits. To these parameters are also added discrete
indicators (mineral occurrences, alteration indicator minerals,
geochemical anomalies, etc.) signalling the presence of mineralization.
In each case, these elements constitute a modelling theme. Data
processing is guided by the expert’s evaluation of the role
and importance of each theme in the emplacement of potential deposits.
The weight attributed to the various themes and their combination
may be derived either from the arbitrary assessment of an ore deposit
expert, or from combination methods based on concepts such as fuzzy
logic, or the Dempster-Shafer belief theory.
Data-driven methods that require a significant number
of occurrences related to the selected model can only be used in
areas that have already been extensively explored. The advantage
of these methods lies in the fact that they are based on a factual
approach that may be demonstrated and verified. However, they are
based on occasionally complex statistical correlations which, from
a geological standpoint, are not always meaningful. Knowledge-driven
methods are more suitable in poorly explored areas where little
or no favourable mineralization has been recognized to date. Since
the evolution of the product is guided by the expert judgment of
a metallogenist, this method yields a product that closely resembles
ore deposit models already known and studied by exploration companies.
On the other hand, the arbitrary weight attributed to parameters
in this approach is determined by the expert preferences of the
metallogenist, which may vary from one expert to another.
Triennial Plan of Appalachian Exploration:
Implementation in the Gaspésie Region
Serge Chevé, Pierre Verpaelst, Daniel Brisebois, André
Gobeil, Serge Lachance and Pierre Pilote (Géologie Québec
Through Géologie Québec, the ministère
des Ressources naturelles has long been conducting ongoing acquisition
and updating of geological data on the Appalachians. Up to 2001
these activities consisted of inventories of aggregates and studies
of industrial minerals in addition to geological surveys. However,
a comprehensive view of exploration needs for the Appalachians as
a whole had been lacking.
Consequently, during the autumn of 2000, the Service géologique
de Québec (SGQ) conducted a consultation on need for geoscientific
information on the Appalachians with a view to encouraging and facilitating
exploration for minerals. In order to carry this out, the principal
agents of exploration in the Appalachians, namely the exploration
companies, mining funds and university researchers, were first asked
to answer a questionnaire on the general approach Géologie
Québec should take and on the areas or topics that should
be given priority. Through this consultation, the main needs were
identified and six regions where intervention by the SGQ was deemed
advisable were consequently targeted:
Click on the map to see a larger version in GIF
- Estrie - Centre du Québec (Region 1 on the map)
- Chaudière-Appalaches (Region 2)
- Témiscouata (Region 3), Sud de la Gaspésie (Region
- “Corridor” Pilote - Mont-Louis (Region 5)
- Couronne nord du Bas-Saint-Laurent (Region 6A) and Gaspésie
Prioritization of these intervention areas appeared
necessary inasmuch as Géologie Québec wished to focus
its human and budgetary resources and its strategies on regional
targets rather than on topics relating to the Appalachians as a
whole. On the basis of the presence of likely geological environments
(metallotects), diversity of potential minerals, availability of
information, and newness (metallogenic models or sectors), Géologie
Québec proposed focusing on Region 4 (Sud de la Gaspésie).
Further to this, a meeting was held on October 31, 2001, bringing
together the principal agents involved in the field of mining exploration
in the Appalachians. The meeting resulted in improvement of the
triennial action plan and verification of the degree to which it
met the needs expressed during the consultation. For the period
2002-2005, this plan calls for:
- updating the geological map;
- conducting integrated metallogenic and lithogeochemical studies;
- a new analysis of stream samples; and
- updating geophysical data coverage.
In the light of initial information yielded by
the consultation, and despite the fact that the triennial action
plan covers the period from 2002 to 2005, Géologie Québec
decided to add a project to re-examine the Unité des Pics
and Dôme de Lemieux gitology contexts to its program for 2001-2002.
During the summer of 2002, as part of the first year of the triennial
plan, the work focused on the western sector of the Sud de la Gaspésie
region. This work consisted of: 1) reviewing the geological maps
of the Oak Bay (22B/02) and Ruisseau Jérôme (22B/07)
areas, with an emphasis on the internal structuring (organization
and facies) of Dalhousie Formation volcanites; 2) re-examining gold
mineralizations and their gitology context; 3) initiating lithogeochemical
characterization of the Arsenault and Garin Formations; 4) completing
a pilot project aimed at re-analysing stream sediment samples from
the area of the Saint-André de Restigouche and Reboul showings;
and 5) conducting a gravimetric survey.
Although the consultation exercise led to selecting Sud de la Gaspésie
(Region 4) for action in the short term, Géologie Québec
may include work proposed in the other priority regions of the Appalachians
in its mid- and long-term programming.
You may obtain a copy of the triennial plan together with a description
of the various target regions by contacting Mr. Pierre Verpaelst,
Department Head of the Service géologique de Québec
(tel.:1 (418) 627-6276, ext. 5059; fax:1
(418) 643-2816; e-mail: email@example.com).
Potential for Discovery of Hydrocarbons in the
Bas-Saint-Laurent and Gaspésie Resource Regions
Oil and gas exploration companies have been attempting
to develop the hydrocarbon resources in the Bas-Saint-Laurent
and Gaspésie resource regions for more than 140 years.
The first drilling work was not based on in-depth geological
information, but instead was done near places where surface seepage
of petroleum had been observed.
At the turn of the last century, the Service des mines de Québec
recommended that the geology of the Gaspé peninsula be studied.
As soon as the first surface geology maps appeared, the petroleum
companies of the day, including Imperial Oil, rushed in to drill
and verify the potential of several major anticlinal axes, including
the Mississippi and Haldimand. The results were negative. Next,
the arrival of the geophysical method known as seismic reflection
enabled other oil companies to continue the exploration research
and set up drilling sites targeted by seismic operations. After
a number of commendable but unfruitful attempts the petroleum companies,
such as Gulf, Esso, Petrofina and their partners, returned to exploring
less complex geological areas with already proven potential.
As a result, the Bas-Saint-Laurent and Gaspésie
resource regions have not benefited for a number of years from the
assistance and new geoscientific data needed to support exploration
research in this high-risk activity sector and generate
the new private investment essential to success. Exploration in
Bas-Saint-Laurent and Gaspésie therefore needed
direct encouragement and new basic information to gain a better
understanding of the subsurface geology.
Finally, good shows and a discovery
In view of recent developments at Val-Brillant
where a junior exploration company succeeded in identifying significant
crude petroleum shows in large quantities and another junior exploration
company announced startup of operations on an initial deposit of
natural gas near Gaspé, regional authorities
have asked the ministère des Ressources naturelles for assistance.
To help them continue to evaluate oil and gas potential, these partners
have requested support in the form of improved information about
this extensive territory.
The Ministère becomes involved
During the autumn of 2000 the Ministère
began carrying out a 98-kilometre geophysical seismic
reflection survey program to better assess the structural nature
and hydrodynamics of hydrocarbon formation in the Val-Brillant
More than 6,000 geophones like
this one were monitoring constantly.
Since the official publication of the autumn 2000
survey results at the MINESPACE 2001 conference (Canadian Institute
of Mining, Metallurgy and Petroleum), exploration companies have
made twenty requests for geophysical survey data on the Val-Brillant
area. And, the Direction du développement des hydrocarbures
has delivered 90 new permits covering more than 1,700,000 hectares
for exploration research in these areas.
Map showing location of current exploration research
permits in Bas-Saint-Laurent, Gaspésie and on Île d'Anticosti.
(PDF Format, 178 kb)
The power for transmitting seismic
pulses though the subsurface was provided by four vibrator trucks
producing a fully synchronized force of 120 tonnes.
In view of the results obtained and the interest
generated in universities and research facilities as well as among
exploration companies, the Ministère, in September 2001,
announced that new work would be carried out to better assess oil
and gas potential in Bas-Saint-Laurent and Gaspésie.
A call for tenders was issued in this regard and the selected supplier,
a consortium made up of GPR International Inc., Boyd PetroSearch
Inc. and Kinetex Inc., was mandated to conduct 10 new seismic profiles
aver a total of 345 kilometres between Mont-Joli
and Cap-Chat in the north and between Nouvelle and
Chandler in the south. One of the profiles cuts across the Gaspé
peninsula from north to south between Cap-Chat and
Miguacha. The work was carried out in two stages. Phase I of this
new program was completed on October 25, 2001, covering 117 km.
Preliminary findings confirm that the data is of excellent quality.
Phase II (230 km) was completed July 18, 2002.
Presentation of results
Acquisition of new basic information at a cost
of $2.3 million has enhanced the value of these regions and
helped target the most favourable areas for pursuing development
of hydrocarbon potential. The bank of already-existing
geological data compiled by the Ministère together with the
addition of new geophysical data will permit assessment of hydrocarbon
resources in this vast area to continue.
Seismic profile of the Lake Humqui anticline,
showing an amplitude anomaly on the structure's ridge at a depth
of 2,500 meters.(PDF Format, 238 kb)
The ministère des Ressources naturelles
was the project manager for all stages of these surveys. Processing
is underway and the geological interpretation will be presented
at the 23e Séminaire d'information sur la
recherche géologique to be held November 27 and 28,
2002 at the Château Frontenac in Québec.
We invite you to attend the visual presentations as well as the
conference entitled Une nouvelle image structurale : Résultats
des Méga-transects de la sismique réflexion
à travers la ceinture appalachienne de la péninsule
gaspésienne presented by Claude Morin and Jean-Yves
Laliberté from the Direction du développement des
Map showing location of seismic profiles obtained
in 2000, 2001 and 2002 (PDF Format, 135 kb)