The vast majority of theses in this collection are open access and freely available. There are a small number of theses that have access restricted to the WWU campus. For off-campus access to a thesis labeled "Campus Only Access," please log in here with your WWU universal ID, or talk to your librarian about requesting the restricted thesis through interlibrary loan.

Date Permissions Signed

5-21-2018

Date of Award

Fall 1986

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Wodzicki, Antoni

Second Advisor

Brown, Edwin H.

Third Advisor

Babcock, R. Scott (Randall Scott)

Abstract

The Lone Jack group of claims is in the Mt. Baker Mining District, northern Whatcom County, Washington. Three prominent gold-quartz veins are present, two of which were mined and produced 945 kg of gold between 1901 and 1924. Since then mining operations have not been renewed.

The quartz veins are within 3 km of surface exposures of the Miocene Chilliwack Batholith, above and within a zone of deformation related to the mid-Late Cretaceous Shuksan fault. This major Northern Cascades structure has juxtaposed the Upper Mesozoic Carrington Phyl lite over the Paleozoic volcanic and sedimentary rocks of the Chilliwack Group. The quartz veins are genetically related to local Tertiary block faulting which postdated the metamorphism and deformation related to the Shuksan fault. The style of deformation and timing of these Tertiary faults suggests that they are related to the emplacement of the nearby batholith. The quartz veins were emplaced during, perhaps in the waning stages of, this intrusive activity.

Two generations of mineralization are present; each has a similar paragenesis. Vein minerals other than quartz include pyrrhotite, pyrite, chalcopyrite, tellurbismuth, and free gold. Gold was deposited in equilibrium with pyrrhotite, sericite, and graphite.

Fluid inclusion analyses were used to determine that the ore-forming solutions were boiling, dilute, and contained an average of 0.25 mol% CO2. Crystallization occurred at about 285oC and 625 bars of lithostatic pressure. Thermodynamic calculations indicate that the gold may have been transported as the Au(HS)ˉ2 complex, and that precipitation of the gold resulted from the physiochemical changes caused by boiling.

Prospecting for similar deposits in the area should be directed toward locating post-metamorphic quartz veins near the Shuksan fault and the Chilliwack Batholith, which show evidence of boiling.

Type

Text

Keywords

Gold mineralization, Miocene Chilliwack Batholith

Publisher

Western Washington University

OCLC Number

1055678113

Digital Format

application/pdf

Comments

Page 20 was not included in the original hard copy.

Subjects – Names (LCNAF)

Lone Jack Gold Mine (Whatcom County, Wash.)

Geographic Coverage

Whatcom County (Wash.)

Genre/Form

masters theses

Language

English

Rights

Copying of this thesis in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

1986christensonliefthesismap.pdf (1481 kB)
Lulu Workings: Geology and Sample Locations

1986christensonthesismap2.pdf (1270 kB)
Lone Jack Workings: Geology and Sample Locations

Included in

Geology Commons

Share

COinS