technical report on the nechalacho deposit, thor lake project ...
technical report on the nechalacho deposit, thor lake project ...
technical report on the nechalacho deposit, thor lake project ...
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south of Hearne Channel dem<strong>on</strong>strates that <strong>the</strong> two structures represent extensi<strong>on</strong>al fractures<br />
bordering a basin that was subsequently filled with sedimentary and volcanic rocks.<br />
Later phases of tect<strong>on</strong>ic movement were principally compressi<strong>on</strong>al and relate to closure of <strong>the</strong><br />
rift, over-thrusting, nappe emplacement and recumbent folding in <strong>the</strong> East Arm, and collisi<strong>on</strong> of<br />
<strong>the</strong> Great Bear Magmatic terrain. Younger (Proterozoic) metasedimentary and metavolcanic<br />
rocks south of Thor Lake were <strong>deposit</strong>ed in <strong>the</strong> failed arm of <strong>the</strong> triple juncti<strong>on</strong> rift, and <strong>the</strong>ir<br />
positi<strong>on</strong> now represents <strong>the</strong> locati<strong>on</strong> of this feature.<br />
DIABASE DYKES<br />
Two ages of diabase dyke swarms are present known as <strong>the</strong> Mackenzie and <strong>the</strong> Hearne. The<br />
Mackenzie dykes are dated at 1.27 billi<strong>on</strong> years, have a north-nor<strong>the</strong>ast strike orientati<strong>on</strong> and<br />
are part of <strong>the</strong> largest dyke swarm <strong>on</strong> Earth. Although <strong>the</strong>re are Mackenzie dykes in <strong>the</strong> general<br />
vicinity of Thor Lake n<strong>on</strong>e are known to cut <strong>the</strong> Nechalacho <strong>deposit</strong>.<br />
The Hearne dykes are dated at 1.902by and trend ENE. Diabase dykes locally cut <strong>the</strong><br />
Nechalacho <strong>deposit</strong> and <strong>the</strong>se are interpreted as Hearne-age dykes. At present, <strong>the</strong> dykes are<br />
not well c<strong>on</strong>strained as drill intercepts are infrequent, due to <strong>the</strong> near vertical nature of <strong>the</strong><br />
dykes and <strong>the</strong> mainly vertical drilling. However, in a few cases, vertical drilling has g<strong>on</strong>e down<br />
<strong>the</strong> interior of dykes, and also where <strong>the</strong>re are multiple intercepts, <strong>the</strong> steep nature of <strong>the</strong> dykes<br />
is clear. At present, <strong>the</strong>re is no evidence that <strong>the</strong> Hearne dykes are implaced in fault structures<br />
that have experienced significant displacement. However, this possibility should not be ignored<br />
during <strong>the</strong> explorati<strong>on</strong> program.<br />
STRUCTURE AND TECTONICS<br />
It is interpreted that <strong>the</strong> Nechalacho <strong>deposit</strong> is a virtually undeformed <strong>deposit</strong> where most of <strong>the</strong><br />
features observed were generated by <strong>the</strong> magmatic and hydro<strong>the</strong>rmal processes. In <strong>the</strong> least<br />
altered porti<strong>on</strong>s of <strong>the</strong> <strong>deposit</strong>, delicate primary textures are well preserved and no penetrative<br />
tect<strong>on</strong>ic or metamorphic fabric is observed.<br />
The distributi<strong>on</strong> of most of <strong>the</strong> rock units and <strong>the</strong> mineralizati<strong>on</strong> generally follows a subhoriz<strong>on</strong>tal<br />
pattern that can be traced for several hundreds of metres. However, <strong>the</strong> subhoriz<strong>on</strong>tal<br />
pattern is interpreted to be locally disturbed by changes in elevati<strong>on</strong> of up to 40 m.<br />
These changes in elevati<strong>on</strong> may occur erratically or al<strong>on</strong>g linear trends. As noted above, <strong>the</strong><br />
<strong>deposit</strong> is also cut by late diabase dykes, which are part of <strong>the</strong> ENE trending Hearne dyke<br />
swarm.<br />
Technical Report 43-101 – March 13, 2011 Page 7-5<br />
Prepared by Aval<strong>on</strong> Rare Metals Inc.