Carboniferous Maritimes Basin
The Late Paleozoic Maritimes Basin of Atlantic Canada is an extensive
successor basin that formed in the wake of the Early to Middle Devonian
Acadian Orogeny. In New Brunswick the basin is characterized by thick
accumulations of dominantly sedimentary rocks deposited in alluvial,
fluvial, lacustrine and marine environments. Exploration in the southern
New Brunswick segment of the Maritimes Basin is currently focused on a
wide range of economic and potentially economic hydrocarbon and metallic
Research has determined that specific stratigraphic intervals within
the sedimentary pile are responsible for sourcing and accumulating
resources, and that the structural and depositional history of the basin
played critical roles in the formation, timing and distribution of
Distribution of Late Devonian-Permian rocks in the
Distribution of subbasins and uplifts in the Maritimes
Regional Geology Map
Simplified geology map of southwestern New Brunswick. Click the
blue Group names in the map legend for detailed descriptions.
Numbered blue dots are links to Field Trip Stop
Stratigraphic column of Carboniferous formations in southeastern New
Brunswick and adjacent Nova Scotia.
This stratigraphic column shows the major groups of strata that occur
throughout the Maritimes Basin in southeastern New Brunswick. The basin
fill is characterized by dominantly sedimentary rocks deposited in
alluvial, fluvial, lacustrine and marine environments. Research has
determined that specific stratigraphic intervals within the sedimentary
pile are responsible for sourcing and accumulating hydrocarbon
resources. The structural and depositional history of the basin also
played critical roles in the formation timing and distribution of these
Click formation names for detailed descriptions.
Metallic Mineral Occurrences
There are 3 major types of base metal sulphide occurrences in
Vein-type (barite +/- calcite +/ quartz +/- celestite) associated
with basin-bounding faults
Mississippi Valley-type (Marine carbonate-hosted Pb-Zn) restricted
to marine limestones of the Windsor Group in this area
Continental Red Bed-type (Cu-Pb-Zn-Ag) associated with carbonized
plant material or diagenetic pyrite within grey; fluvial sandstone
bodies above thick red bed +/- evaporate sequences
There are 2 major types of uranium occurrences in Carboniferous
The Maritimes Basin contains two deep subbasins that have known
petroleum potential: the 3700 square kilometre Moncton Subbasin and the
800 square kilometre Sackville Subbasin. There have been 79 exploration
wells and 181 development and production wells drilled in these
subbasins over the last 100 years.
This region of New Brunswick has long been known as an oil and gas
producer, beginning with the discovery of the
Stoney Creek Field near Moncton in
1909. Throughout its 80-year history, the Stoney Creek Field yielded 30
billion cubic feet of sweet gas and about 800,000 barrels of paraffinic
Recent exploration in the historic Stoney Creek Field includes a
3D seismic survey conducted over the field and a drilling program of
horizontal wells in the main productive sandstone reservoir. An
extensive test of approximately 24 shut-in gas wells and 6 oil wells
was carried out to confirm productive capacity.
The Province had a major discovery of natural gas at the
McCully Gas Field near Sussex in 2000. From this field there are
presently two producing wells providing fuel for the Potash Corporation
of Saskatchewan Inc. (PCS) potash mill at the rate of 2 million cubic
feet per day. Seventeen wells have already been drilled and readied for
production, with another 16 wells planned over the next two years. The
McCully Field is estimated to contain an in-place gas resource of one
trillion cubic feet. Plans have been submitted to construct a 45 km long
lateral pipeline to connect the McCully Field with the Maritimes and
Northeast mainline. The pipeline is scheduled to be completed by May
Another possible potential hydrocarbon resource in New Brunswick is
“shale natural gas”. This rather unconventional source of natural gas
has over the past decade become a significant contributor to the North
American gas supply. For example, unconventional gas resources currently
account for nearly 10% of the total natural gas production in the United
States. In 1985 there were about 100 shale gas wells drilled in North
America, today there are over 12,000 of these wells.
In New Brunswick,
organic-rich shales acted as the source rocks for the natural gas
now held in conventional sandstone reservoirs, such as Stoney Creek and
McCully. The thick organic-bearing shales of the Albert Formation of New
Brunswick are believed to have potential for holding large volumes of
natural gas. The Albert shales are just one example of several similar
shales in other onshore and offshore basins in eastern Canada.
SSubstantial thicknesses of potassium, sodium-, and
magnesium-bearing salts have accumulated in three areas of the
Moncton Subbasin, namely, the Penobsquis, Cassidy Lake and
Millstream potash/salt deposits. Click blue dots
for more information about each deposit.
The deposits are situated within the Early Carboniferous Windsor
Group. The stratigraphy of the Windsor Group is outlined here.
Two depositional evaporate cycles are represented in the Moncton
Subbasin near Sussex. The first and most significant event led to
the deposition of a regional carbonate/sulphate (Parleeville, Gays
River, Macumber formations/Upperton Formation) sequence, with highly
concentrated evaporates (Cassidy Lake Formation) preserved in local
depositional troughs; one 5 km east of Sussex (Penobsquis),
a second about 25 km southwest (Cassidy
Lake), and a third 10 km west (Millstream).
At Penobsquis and Cassidy Lake basal evaporates consist of clean
halite with minor anhydrite while nearby at Millstream the same
interval is represented by claystone. These units are in turn
overlain, at all three deposits, by argillaceous halite, then potash
(sylvinite), and capped by a heterogeneous halite unit interbedded
with varying thicknesses of sylvinite and, locally, carnallite.
The first-cycle evaporate deposits are characterized by:
- They have extremely thick potash sequences, particularly in the
upper halite member at Millstream, despite the deposit’s limited aerial
- Penobsquis and Cassidy Lake deposits show evidence of deep to
shallow water deposition while at Millstream the opposite appears to be
- A diverse suite of borate minerals are prominent in the upper halite
of all deposits.
The Penobsquis and Cassidy Lake deposits represent the infilling of
deep depressions at the southern end of the Moncton Subbasin by salts
derived from marine brines that had been progressively concentrated in a
series of fore-basins and modified by hydrothermal solutions. Bitterns
(bitter liquid that is left after salt has crystallized from sea water)
from the larger stages of this infilling were periodically flushed into
the more remote, and isolated Millstream depression, leading to the
development of an extreme thickness of potassium and magnesium salts.
This depositional event was brought to an abrupt conclusion with a
second major influx of the Windsor Sea into the Moncton Subbasin.
Although not as widespread as the first, a sequence of shallow water
evaporates (Clover Hill Formation) were deposited in the lower lying
areas of the original depositional troughs in the Sussex area. Brines
associated with this second transgression did not reach levels of
concentration resulting in the deposition of potassium and magnesium
salts. Instead, most deposits are sulphate dominated with localized
occurrences of argillaceous halite. This phase of deposition gradually
ended as continental sedimentation buried the entire Windsor evaporate
Field Trip Stops
Albert formation (Frederick brook mbr / Hiram brook mbr
boundary); highway 1 near Sussex
Base-metal sulphide-bearing barite vein; highway 1 south of
Contact between Albert and Bloomfield formations (Horton
group); highway 1 near Bloomfield
Horton group / Sussex group unconformity; highway 1 at lower
Sussex group / Windsor group boundary; Dutch valley area
Contact between the Hillsborough and Macumber formations
(Windsor group); Sussex corner water tower
Goshen copper; secondary road off route 895, west of Elgin
Gas well heads; McCully gas field, Penobsquis
- Boyd, J. A.1977. Dorchester Copper area, Westmorland County, New
Brunswick, Report of Work. Gulf Minerals Canada Limited. Mineral
Exploration Report of Work, Assessment File 470479.
- Carroll, B.M.W. (editor) 2003. New Brunswick’s mineral industry,
2002. Mineral Resource Report 2003-3, 98 p.
- Graves, M.C. and Hein, F.J. 1994. Compilation, synthesis and
stratigraphic framework of mineral deposits within the basal Windsor
Group, Atlantic Provinces, Canada. Geological Survey of Canada, Open
File Report 2914, pp. A8-1 to A8-9.
- Hinds, S.J. and St. Peter, C. 2005. Carboniferous geology of the
Waterford and Urney areas (part of NTS 21H/11), Kings County, Plate
- Kiss, F., Potvin, J., and Coyle, M. 2004. Shaded Magnetic First
Vertical Derivative, Waterford, New Brunswick (NTS 21H/11); Geological
Survey of Canada, Open File 4646. Plate 2004-6A.
- MacDonald, B.I. 1974. Dorchester Group, Dorchester-Sackville area,
New Brunswick, Summary Report on CAN-AM Joint Venture, Project 536.
Canerpa Limited. Mineral Exploration Report of Work, Assessment File
- McCutcheon, S.R. 1981. Stratigraphy and paleogeography of the
Windsor Group in southern New Brunswick. Open File Report 81-31, 210 p.
- McCutcheon, S.R. 1983. Potash in the central New Brunswick platform.
Canadian Institute of Mining and Metallurgy Bulletin, 76, No. 857, pp.
- McLeod, M.J. 1997. Base-metal sulphides at Demoiselle Creek and Gold
at Aboushagan Road: models for sediment-hosted mineralization in
southeastern New Brunswick. In Current Research 1996. Edited by B.M.W.
Carroll. Mineral Resource Report 97-4, pp. 149-173.
- Shewmann, R.W., Beckmann, H., and Sexsmith, D. 1975. Peekaboo Corner
Property, Kings County, New Brunswick, Geological and Geophysical
Report. Rio Tinto Canadian Exploration Limited. Mineral Exploration
Report of Work, Assessment File 470583.
- McKenzie, C. 1977. Peekaboo Corner Property, Kings County, New
Brunswick, Diamond Drilling Report. Rio Tinto Canadian Exploration
Limited. Mineral Exploration Report of Work, Assessment File 470431.
- Webb, T.C. 1984. The Millstream potash prospect,
Kings County, Reference 208, p. 24
- Webb, T.C. and Roulston, B.V. 1994. Geology and development of New
Brunswick's potash deposits. Nova Scotia Department of Natural Resources
and New Brunswick Department of Natural Resources and Energy, 30th Forum
on the Geology of Industrial Minerals, May 21-27, 1994, Fredericton,
N.B. and Halifax, N.S., Field Trip #1, 33 p.
- Wells, S. 1992. Report of work, Demoiselle Creek property, Project
4252, Albert County, N.B. (NTS 21H/15). Noranda Mining and Exploration
Inc. report for Brunswick Mining and Smelting Corporation Ltd. Mineral
Exploration Report of Work, Assessment File 474263.
- Wilson, P. 2005. Stratigraphy, structural geology and tectonic
history of the McCully area of the Moncton Subbasin, southeastern, New
Brunswick. Mineral Resource Report 2005-5, 104 p.
- Woods, G. 1993. Report of work, Demoiselle Creek, Hopewell Cape,
Hopewell East and Hopewell North. (NTS 21H/15E). Noranda Mining and
Exploration Inc. report for Brunswick Mining and Smelting Corporation
Ltd. Mineral Exploration Report of Work, Assessment File 474389.