Record Details
A geologic and mineralogic study of the Bethlehem Copper property at Highland Valley, British Columbia
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | A geologic and mineralogic study of the Bethlehem Copper property at Highland Valley, British Columbia |
| Names |
Wood, Allan Deane, 1936-
(creator) Field, Cyrus W. (advisor) |
| Date Issued | 1968-06-02 (iso8601) |
| Note | Graduation date: 1968 |
| Abstract | The Bethlehem Copper Mine, a porphyry copper deposit, is situated near the geographical center of the Guichon Creek batholith. The Guichon Creek batholith is located on the east flank of the Canadian Coast Range in south central British Columbia approximately 250 miles northeast of Vancouver, B. C. The batholith trends northerly, is 40 miles long, 16 miles wide and divided in half by a broad easterly trending saddle, the Highland Valley. Moreover, it is composite and consists of two principal phases, an older quartz diorite and a younger granodiorite. The Bethlehem copper deposit is situated on the contact between these two phases. Seven igneous rock types and several breccia bodies have been recognized. The Guichon quartz diorite, Early Jurassic in age, has been intruded by Bethlehem quartz diorite, leucocratic porphyritic dacite, granite, granodiorite, dacite porphyry, and mesocratic porphyritic dacite. The Bethlehem quartz diorite is thought to be a marginal or cupola phase of the granodiorite. Dacite porphyry, granodiorite, mesocratic porphyritic dacite and possibly leucocratic porphyritic dacite occur as dike rocks. The breccia bodies are believed to be related to the emplacement of Bethlehem quartz diorite and leucocratic porphyritic dacite with coincident or later explosive events. Mining operations in the Jersey pit have exposed Guichon quartz diorite, Bethlehem quartz diorite, dacite porphyry and breccia. Bethlehem quartz diorite and breccia nearly circumscribe a huge block of Guichon quartz diorite some 700 feet in diameter. All rocks in the pit have been faulted, fractured, mineralized and hydrothermally altered. Faults consist of a northerly trending, west dipping essentially parallel set. Obvious fractures are related to faults while the more significant, indistinct, and randomly orientated hairline fractures that control mineralization apparently are not. Chalcopyrite, bornite and other metallic minerals occur as scattered grains on fracture surfaces or less commonly as disseminations replacing secondary mafics. The degree and extent of mineralization is a function of permeability produced by fracturing. Hydrothermal alteration associated with the Jersey pit is of both the propylitic and argillic types. Propylitic alteration fringes and Jersey ore body and is characterized by the development of epidote and chlorite at the expense of primary hornblende, biotite, and less commonly plagioclase. Argillic alteration is restricted to the central area of the pit, as is most of the significant mineralization and is characterized by strong lime leaching and the development of fine grained, but optically unresolvable, minerals believed to be one or more types of clay minerals. |
| Genre | Thesis/Dissertation |
| Topic | Geology -- British Columbia -- Highland Valley |
| Identifier | http://hdl.handle.net/1957/48467 |
