New insights on the THO-Superior boundary: Tectonic and ...
New insights on the THO-Superior boundary: Tectonic and ...
New insights on the THO-Superior boundary: Tectonic and ...
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John Percival, GSC<br />
Nicole Rayner, GSC<br />
Herman Zwanzig, MGS<br />
Linda Murphy, MGS<br />
Joe Whalen, GSC<br />
Martha Growd<strong>on</strong>, Indiana U.<br />
<str<strong>on</strong>g>New</str<strong>on</strong>g> <str<strong>on</strong>g>insights</str<strong>on</strong>g> <strong>on</strong> <strong>the</strong><br />
<strong>THO</strong>-<strong>Superior</strong> <strong>THO</strong> <strong>Superior</strong> <strong>boundary</strong>:<br />
Tect<strong>on</strong>ic <strong>and</strong><br />
metallogenic implicati<strong>on</strong>s<br />
Tullibee Lake<br />
July 2006
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Kisseynew<br />
Domain:<br />
Poor cousin to <strong>the</strong> Flin Fl<strong>on</strong>, Thomps<strong>on</strong> &<br />
Lynn Lake belts<br />
“Sea Sea”<br />
of Burntwood<br />
migmatite<br />
Upper amphibolite to granulite facies<br />
metamorphism<br />
Poorly exposed<br />
Few geophysical anomalies<br />
Discouraging tect<strong>on</strong>ic, crustal structure<br />
models
White et al. 2002
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Motivati<strong>on</strong><br />
Declining Ni reserves (TGI 3 directive)<br />
Mel z<strong>on</strong>e discovery<br />
Granite crustal probes suggest Archean<br />
c<strong>on</strong>taminati<strong>on</strong><br />
Quartz-rich Quartz rich (Ospwagan?) sediments<br />
Cr, Ni anomalies in till (e.g. ( e.g. Osik<br />
Lk) Lk<br />
Aeromagnetic anomalies <strong>on</strong> 2006 TGI 3<br />
Wuskwatim<br />
Lake survey
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Significant<br />
findings<br />
1890-1880 Ma magmatic arc built <strong>on</strong> <strong>the</strong><br />
<strong>Superior</strong> margin: possible back-arc back arc<br />
setting of 1883 Ma Mols<strong>on</strong> <strong>and</strong><br />
Thomps<strong>on</strong>-type Thomps<strong>on</strong> type mafic-ultramafic<br />
mafic ultramafic<br />
magmatism<br />
<strong>Superior</strong> crust with Ospwagan cover<br />
extends at least 90 km west of <strong>the</strong><br />
“<strong>Superior</strong> <strong>boundary</strong> z<strong>on</strong>e”, including<br />
exposed Thomps<strong>on</strong>-type Thomps<strong>on</strong> type targets
1883 Ma Josl<strong>and</strong> sills<br />
1883 Ma Thomps<strong>on</strong>-type<br />
mafic-ultramafic magmatism 1883 M<br />
1883 Ma Mols<strong>on</strong> dykes
EXTRACT OF 2006 WUSKWATIM LAKE SURVEY<br />
Silicate,-<br />
sulphide-facies<br />
BIF<br />
Wuskwatim Lake<br />
Basement<br />
orthogneiss<br />
culminati<strong>on</strong>s
Multicomp<strong>on</strong>ent<br />
orthogneiss
Basement-cover Basement cover unc<strong>on</strong>formity<br />
Quartzite<br />
T<strong>on</strong>alite orthogneiss
Composite stratigraphic secti<strong>on</strong>
Basement<br />
Geochr<strong>on</strong>ology
SHRIMP results for granulite-facies<br />
granulite facies<br />
t<strong>on</strong>alitic orthogneiss<br />
Probable<br />
crystallizati<strong>on</strong><br />
age<br />
Probable metamorphic<br />
resetting/regrowth<br />
Probable inheritance
SHRIMP results for charnockite<br />
n=34<br />
late metamorphism<br />
1.80 Ga<br />
emplacement at granulite<br />
or mm overprint<br />
2.66 Ga<br />
mixing<br />
inheritance or crystallizati<strong>on</strong><br />
3.2 Ga<br />
T DM = 3.1 Ga<br />
1.8<br />
3.1 2.6
Cover sequence<br />
Geochr<strong>on</strong>ology<br />
Typical Burnt-<br />
wood wacke<br />
Pipe Fm in<br />
Pipe Pit<br />
Quartzite<br />
cut by dyke<br />
Quartzite at<br />
unc<strong>on</strong>formity
Atik Lake<br />
Plut<strong>on</strong> Geochr<strong>on</strong>ology
SHRIMP results for Footprint Lake<br />
crystallizati<strong>on</strong> age<br />
1879 -1882 Ma<br />
Th/U typically > 1<br />
granodiorite<br />
εNd = -9.3
SHRIMP results for Atik<br />
crystallizati<strong>on</strong> age<br />
ca. 1.88 Ga<br />
Th/U typically > 1<br />
εNd = -10.3<br />
granodiorite<br />
Lake
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Geochr<strong>on</strong>ology-summary<br />
Geochr<strong>on</strong>ology summary<br />
Archean basement: 3.2-2.8 Ga<br />
crystallizati<strong>on</strong>, 2.65 Ga metamorphism<br />
Quartzites in cover sequence have<br />
Archean provenance, like Ospwagan Gp.<br />
Paleoproterozoic plut<strong>on</strong>s are 1880 Ma,<br />
c<strong>on</strong>taminated by Archean crust
1890-70<br />
Stratigraphic<br />
correlati<strong>on</strong><br />
1880
Structural Geometry<br />
F 4<br />
F 3
Autochth<strong>on</strong>ous basement<br />
interpretati<strong>on</strong>
Basement-cored Basement cored nappe<br />
interpretati<strong>on</strong>
Bouguer Gravity Anomalies<br />
White et al. 2005
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Potential mineralizati<strong>on</strong> types<br />
Thomps<strong>on</strong>-type Thomps<strong>on</strong> type Ni in mafic-ultramafic<br />
mafic ultramafic<br />
intrusi<strong>on</strong>s in equivalents of Pipe Formati<strong>on</strong><br />
Ir<strong>on</strong> formati<strong>on</strong>-hosted formati<strong>on</strong> hosted gold (Lupin ( Lupin, ,<br />
Musselwhite<br />
type)<br />
Diam<strong>on</strong>ds in Archean lithosphere:<br />
kimberlites in eastern Kisseynew?<br />
Kisseynew
<str<strong>on</strong>g>New</str<strong>on</strong>g> Explorati<strong>on</strong> targets<br />
Wuskwatim Lake- Lake Burntwood River<br />
Sulphide-silicate facies ir<strong>on</strong> formati<strong>on</strong> (probable Pipe Fm<br />
equivalent)<br />
Kawaweyak Lake<br />
Sulphide-silicate facies ir<strong>on</strong> formati<strong>on</strong><br />
Mafic-ultramafic intrusi<strong>on</strong>s<br />
Sulphide (po) occurrences<br />
Tullibee-Neuls<br />
Tullibee Neuls Lake<br />
Probable basement<br />
Ir<strong>on</strong> formati<strong>on</strong><br />
Mafic-ultramafic sills<br />
Osik Lake<br />
Cr, Ni anomaly in till
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C<strong>on</strong>clusi<strong>on</strong>s; Questi<strong>on</strong>s<br />
1880 Ma magmatism <strong>on</strong> <strong>Superior</strong> margin:<br />
-was <strong>the</strong> Flin Fl<strong>on</strong>-Snow Lake belt<br />
proximal?<br />
-back-arc explorati<strong>on</strong> models?
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C<strong>on</strong>clusi<strong>on</strong>s; Questi<strong>on</strong>s<br />
1880 Ma magmatism <strong>on</strong> <strong>Superior</strong> margin:<br />
-was <strong>the</strong> Flin Fl<strong>on</strong>-Snow Lake belt<br />
proximal?<br />
-back-arc explorati<strong>on</strong> models?<br />
NE Kisseynew<br />
domain is underlain by<br />
<strong>Superior</strong> basement <strong>and</strong> probable<br />
Ospwagan Gp<br />
cover:<br />
-is basement c<strong>on</strong>tiguous, or a rifted<br />
fragment?<br />
-what is its southwestern extent?
•<br />
•<br />
•<br />
C<strong>on</strong>clusi<strong>on</strong>s; Questi<strong>on</strong>s<br />
1880 Ma magmatism <strong>on</strong> <strong>Superior</strong> margin:<br />
-was <strong>the</strong> Flin Fl<strong>on</strong>-Snow Lake belt proximal?<br />
-back-arc explorati<strong>on</strong> models?<br />
NE Kisseynew<br />
domain is underlain by <strong>Superior</strong><br />
basement <strong>and</strong> probable Ospwagan Gp<br />
cover:<br />
-is basement c<strong>on</strong>tiguous, or a rifted fragment?<br />
-what is its southwestern extent?<br />
Sulphide-bearing Sulphide bearing mafic-ultramafic mafic ultramafic sills within<br />
BIF-bearing BIF bearing units are possible Pipe Fm<br />
equivalents<br />
-are Thomps<strong>on</strong>-type orebodies present?
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