|
LOCAL GEOLOGY |
 |
Glacial gravel, sand and till obscure the
bedrock throughout a wide area and may be up to 70 metres
(230 feet) thick in places.
|
GEOLOGICAL STRATA |
|
|
|
MESOZOIC |
|
|
Ikh |
Horton River
Formation (Lower Cretaceous - Ikh).
Soft, plastic black shale and ironstone. This
unit covers a limited portion of the
west-central part of the Anomaly ("DBA") in the
core of a broad syncline. |
|
IkI |
Langton Bay
Formation (Lower Cretaceous - IKI).
Sandstone and
minor coal, mudstone and siltstone. This unit
outcrops in a limited area flanking the Horton
River Formation. Both these units are probably
frozen (permafrost). |
|
PALEOZOIC |
|
|
ImD |
Bear Rock
Formation (Devonian - ImD).
Dolomite and maroon shale. This unit outcrops
only in the southern portion of the DBA and is
apparently truncated at a disconformity between
IKI and COS. |
|
COS |
Ronning Group,
Saline River, Mount Cap and Old Fort Island
Formations (Cambrian to Devonian - COS). Grading from dolomite and maroon shale at the top, through shale with
minor gypsum, glauconitic sandstone and shale to
friable sandstone at the base. This unit
probably covers the entire DBA. |
|
PROTEROZOIC (Precambrian) |
|
PC |
Shaler Group
(Precambrian - PC).
Stromatolitic dolomite with minor gypsum,
sandstone, argillite and siltstone, locally
intruded by Franklin (723 Ma) gabbroic dykes and
sills. |
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SUBSURFACE GEOLOGY |
|
|
In 2000, a vertical diamond drill hole on the
Thrasher Zone encountered considerable problems prior to
reaching its targeted depth at 2,300 metres. It was terminated
at a depth of 1,812 metres due to extreme ground water pressure
and gravel run-in from aquifers.
|
From |
To
(m) |
Strata |
GEOLOGICAL
FORMATION |
|
OVERBURDEN |
|
|
0 |
31.09 |
Q |
Glacial and glacio-fluvial sediments |
|
MESOZOIC |
|
|
31.09 |
136.60 |
Ikh |
Gilmore Lake Member of the Langton Bay Formation
(Lower Cretaceous)Sandstones, siltstone with
minor mudstone and thin coal measures |
|
PALEOZOIC |
|
|
136.60 |
364.65 |
ImD |
Hume Formation (Middle Devonian) Interlayered
buff to grey-coloured carbonate |
|
364.65 |
377.00 |
Bear Rock Formation (Lower (?) and Middle
Devonian) Maroon shale |
|
377.00 |
964.50 |
COS |
Ronning Group / Franklin Mountain Formation
(Upper Cambrian to Lower Ordovician)From
377 to 570 m is the upper unit consisting of grey to
minor buff-coloured, silicified carbonate. From 570
to 964.5 m is the lower unit consisting of layers of
carbonate mud and sand |
|
964.50 |
1051.40 |
Saline River Formation (Cambrian) |
|
1051.40 |
1091.00 |
Mount Cap Formation (Cambrian)Dark-grey,
dark-green and black mudstones interbedded with
light grey sandstones |
|
1091.00 |
1137.50 |
Mount Clark Formation (Cambrian) Light-grey
to pale-white |
|
1137.50 |
1167.55 |
Old Fort Island Formation (Cambrian) White to
locally pink, |
|
PROTEROZOIC (Precambrian) |
|
|
1167.55 |
1812.06
End of Hole |
PC
|
Shaler Group (Precambrian)Escape Rapids
Formation, the Bloody Falls Protozoic MemberPale-green
mudstone locally overprinted by red staining in
upper portions. |
The drill hole revealed a considerable amount
of information about the geology of the region having
intersected the contact between the Precambrian and younger
overlying sediments at a depth of 1,167.50 metres. The
Precambrian formation outcrops just east of the Anomaly
suggesting that the igneous intrusive may be shallower to the
east.
Ref: Aurora Geosciences Ltd. |
Geology