103

defined, fine-grained bodies. They have essentially the same mineral
composition as the pegmatites, from which they appear to differ only by
reason of their fine-grained, sugary, interlocking texture, and, in many
places, by their regular, apparently chiefly fracture-filling form. Some
of the aplites are composed almost entirely of quartz and potash feldspar,
with little or no mica. A few contain scattered grains of pyrite, arseno-
pyrite, and pyrrhotite.

Granophyre Porphyry

The largest stock of grey granodiorite near Blackpine Lake is cut by
numerous dykes, and irregular bodies, up to 600 feet in diameter, of light
buff-grey fine-grained porphyry. The rock contains about 20 per cent
oligoclase phenocrysts up to 3 mm. long, much altered to sericite, and about
5 per cent ragged green hornblende, commonly accompanied by clinozoisite,
in a quartz-feldspar groundmass, with well-developed granophyric texture.
Accessory minerals are mainly magnetite and zircon. ‘There is much
evidence of repeated corrosion and recrystallization of feldspar, and clots
of non-granophyric feldspar, in semi-polygonal outline surrounded by a
rim of clinozoisite grains and containing a core of corroded euhedral horn-
blende, are common; these may be the result of alteration and replacement
of original pyroxene phenocrysts.

Granophyric porphyries were not found in the gneisses and migmatites
surrounding the granodiorite stock. Their presence in the granodiorite may
be purely fortuitous, as they appear to be identical with the small grano-
phyre intrusions in the Tenakihi and Ingenika group rocks in the Tenakihi
Range and on Chase Mountain (See page 108).

Andesite Dykes

A few thin dykes of fine-grained andesite porphyry cut the granodiorite
stocks and the quartz-mica-feldspar gneisses northeast of Blackpine Lake.
All observed are less than 5 feet wide, of uniform width, and are remark-
ably straight for lengths up to 500 feet. The rock contains scattered
altered hornblende phenocrysts about 2 mm. long in a groundmass composed
principally of chlorite, clinozoisite-epidote, and cloudy decomposed feldspar.
The dykes have chilled contacts and a well-developed foliation parallel
with the walls. In detail the dyke walls are irregular, and show numerous
apophyses into the adjoining rocks; xenoliths of the wall-rocks are found
in the dyke margins.

All andesite dykes observed are steeply dipping, and most of them
strike northeasterly. In one place, the hornblende phenocrysts show a fair
lineation trending directly down the dip. The dykes cut granodiorite,
leucogranite, and pegmatite.

ORIGIN

It is readily apparent that the term ‘Wolverine complex’ as here used
applies primarily to the products of a condition of metamorphism and rock
replacement rather than to an assemblage of rocks of any particular age
range or lithologic character. In Aiken Lake map-area the sedimentary
rocks involved belong to the Tenakihi and Ingenika groups, and all grada-