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Era

Paleozoic
and possibly
Proterozoic

Proterozoic

Period or Epoch

Includes Lower
Cambrian beds

Probably late
Proterozoic

Formation

and thickness

(feet)

Intrusive contact

Ingenika group
+18,000

Possible erosion interval

Tenakihi group
+13,000

Lithology

Quartz-chlorite schist,

crystalline Jime-
stone, sericite schist
quartzite, quart-
zitic conglomerate,
slate, phyllite,
chloritoid schist,
tourmaline-zoisite
schist. Part, in-
cluded in Wolverine
complex, altered to
feldspathic quart-
zite, quartz-mica-
feldspar gneiss, mig-
matite, leucogran-
ite, silicated marble,
skarn, and amphi-
bolite

Quartz-mica schist,

quartzite, quartz-
mica-feldspar
schist, garnetiferous
schist, cyanite, and
staurolite schist.
Part, included in the
Wolverine complex,
altered to felds-
pathic quartzite
and quartz-mica-
feldspar gneiss

Post-Lower
Cambrian; may be
Tertiary

Post-Lower
Cambrian

Feldspar porphyry,

granophyre, dacite

Diorite(?) porphyry,

altered to chlorite-
sericite-carbonate
rock; andesite(?)

TENAKIHI GROUP!

NAME AND

DISTRIBUTION

The oldest recognized rocks within Aiken Lake map-area consist of
interbedded quartz-mica schists, micaceous quartzites, and quartzites
exposed in an irregular belt 4 to 8 miles wide extending diagonally across

1 This group was first named the Ruby group in the preliminary account of Aiken Lake map-area
by Armstrong and Roots (1948), but it has seemed best, in the interests of conventional formational
nomenclature, to rename it after the range of mountains in which it is typically exposed.

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