Preliminary Map 10 presents the geology and mineral occurrences of the Aspen Grove area (92H/15E) in south central British Columbia. The map contains a legend, a list of crown granted claims in the area, and descriptive notes. The map is published at scale 4 inches to 1 mile or 1:15840. For more details about the area, see Bulletin 69.
The area is underlain mainly by rocks of the Upper Triassic Nicola belt, an island arc volcanic-sedimentary succession. Massive andesite flows and coarse pyroclastic rocks predominate in the central part of the map; a sequence of layered and massive volcanogenic rocks predominates along the eastern margin. The southwestern section is underlain by intercalated volcaniclastic rocks, flows and calcareous sediments that are partly covered (?) by coarse volcanic breccia.
The Nicola Group consists of 8 main units. Units 1, 2 and 3 are sedimentary rocks. They consist of limy siltstone, argillite and limestone layers. Massive andesite comprises unit 4. Flows, dikes and sills are common. Unit 5, 6 and 7 consist of massive volcanic rocks. Volcanic breccia, volcanic conglomerate, and lahar deposits characterize unit 5. Augite porphyries make up most of unit 6; some form ropy lavas and agglomerates. Massive and amygdaloidal augite porphyry comprises unit 7. Unit 8 consists of volcanic siltstone and sandstone.
Intrusive rocks in the area are mainly dioritic and partly comagmatic with the Nicola volcanic rocks. Small monzonite bodies also occur and small breccia pipes, some of which have copper mineralization.
Two major north-trending fault zones with many splays dissect the area, and brittle faulting is characteristic of the area.
Copper-bearing occurrences dominate the mineral occurrences in the area. Four main occurrence types are: copper minerals in fine grained and brecciated zones in the intrusive rocks; chalcopyrite, bornite, pyrite and magnetite in breccia zones in andesite and diorite; chalcocite, native copper and hematite in fracture zones in the volcanics; and copper minerals and pyrite in limestone and argillite.