Volcanogenic Massive Sulphide (VMS) Deposits

Earth Sciences 3210
Laboratory #5 – Volcanogenic Massive Sulphide (VMS) Deposits – Part II
This Lab involves samples from two examples of very large VMS deposits – the bimodal
mafic Kidd Creek, ON and bimodal felsic Buchans, NL. Use the short summary
monographs (Buchans summary from Swinden, H.C and Kean, B.F. (eds.), 1988, The
Volcanogenic Sulphide Districts of Central Newfoundland, GAC Guidebook. 248pp; Kidd
Creek summary from GAC-MDD Newsletter, Issue 78, 2003) to assist you with this lab.
Both these examples of VMS show more variety in their host-rock lithologies than those in
Lab#3. Some samples include thin sections illustrative of different types of metasomatic
and post-depositional metamorphic alteration of both host rocks and ore.
A.1
Examine the following samples of Kidd Creek host rocks:
KC-6 (EG1257)
(hand sample + thin section (3)
KC-22 (EG1081)
(hand sample + thin section (4))
KC-20 (EG1083)
(hand sample + thin section (4))
EG-1085
(hand sample + thin section (4))
Briefly describe the texture and mineralogy of each sample. Based on this, assign each
sample a descriptive name. [HINT: Sample EG-1085 is a slightly less felsic composition
than the first three.]
A.2
Examine the following samples of Buchans host rocks:
EGN-61
(hand sample only)
15-2
(hand sample(s) only)
EGN-51
(hand sample + thin section(4))
EGN-66
(hand sample + thin section(5))
Briefly describe the texture and mineralogy of each sample. Based on this, assign each
sample a descriptive name. EGN-61 and 15-2 show distinctive textures related to explosive
volcanism. Pay particular attention to the alteration evident in EGN-66.
B.1
Examine the following samples of Kidd Creek ores:
KC-3 (EG1254)
(hand sample + polished thins (2))
KC-11 (EG1262)
(hand sample + polished thin(3) + polished section)
KC-17 (EG1201)
(hand sample + polished thin(4))
KC-18 (EG1202)
(hand sample + polished thin(3) + polished section)
EG-1080
(hand sample + polished thin(3))
Briefly describe the ore mineralogy of alteration of host rock/gangue, and any evidence
of post-depositional disruption or metamorphism that you observe. Do a detailed
paragenesis for sample EG1254/KC-3.
B.2
Examine the following samples of Buchans ores:
EGN-41
(hand sample + polished thin(4))
EGN-94
(hand sample + polished thin(3))
EGN-89
(hand sample + polished thin(2))
EGN-40
(hand sample + polished thin(3))
EGN-86(BuchNf22)
(hand sample + polished thin(2))
The first three samples illustrate different styles of ore at Buchans. Briefly describe the ore
and gangue mineralogy evident in these hand samples, and any informative textures that
are visible in hand sample. Use the thin sections to assist you in this.
For EGN-40 and EGN-86 make a reasonably detailed description of the ore mineralogy and
paragenesis, using both hand samples and polished thins, and compare the overall
textures of these two ore samples. Can you say something about where in the system
these two ore-types might have formed?
C. Based on the samples observed in the lab, briefly discuss two similarities AND two
differences in the broad characteristics of these two VMS deposits.

Download Report