Silver Diamond occurrence, Surprise Lake, Atlin Mining Division, British Columbia, Canadai

Regional Level Types
Silver Diamond occurrence	Occurrence
Surprise Lake	Lake
Atlin Mining Division	Division
British Columbia	Province
Canada	Country

The Silver Diamond occurrence is located on the west side of Boulder Creek, which drains into Surprise Lake, about 19 kilometres north-east of Atlin, British Columbia.
There is a brief description of the occurrence and its history, on the British Columbia “Minfile” site, current to 2013; excerpts are quoted below:
“The showing is hosted primarily in variably talc-altered peridotite. These rocks are upper Mississippian to Permian in age and may be coeval with the mafic volcanic rocks (greenstone) of the Nakina Formation of the lower Cache Creek Complex. The volcanic rocks, which outcrop to the northwest of the occurrence, contain narrow, interbedded bodies of chert and limestone. The Late Cretaceous Surprise Lake batholith (Surprise Lake Plutonic Suite) outcrops just to the east of the occurrence and is composed of varitextured quartz monzonites often referred to as alaskite.”
“Mineralization consists of skarn-type zones of massive pyrite and pyrrhotite with lesser amounts of cassiterite, scheelite, fluorite, galena, sphalerite, chalcopyrite and tetrahedrite. A minor zone mineralized with molybdenite occurs just northeast of the main zones.”
Additional comments by Giles Peatfield on this and other occurrences in the area:
Silver Diamond is one of several occurrences of tungsten ¬+ tin + molybdenum + base metal mineralization in the region immediately south of, but not necessarily related to, the Adanac molybdenum deposit (“Minfile” No. 104N 052). Others of interest are: Black Diamond Vein (“Minfile” No. 104N 006); Black Diamond South (“Minfile” No. 104N 053) and Black Diamond North (“Minfile” No. 104N 054). It is best to view these together, because the various reports available are not always perfectly clear as to which specific occurrence geological data refer to, and even the names given are not always consistent.
Comments by Giles Peatfield on some of the minerals reported from the locality:
Anglesite: Tribe (1964) identified anglesite in polished section, as an alteration product of galena.
Arsenopyrite: Tribe (1964) identified arsenopyrite in polished section.
Cassiterite: Cassiterite was reported by Tribe (1964), by Gutrath (1970), and by Kikauka (2002). Of interest is that Heddle (1964) reported cassiterite as tentative, commenting that “Garnet may be cassiterite?” – garnet would not be impossible as an explanation for the tin content of the mineralized skarn. For example, andradite garnet from the Lost River tin deposit in Alaska contains up to 6 weight percent SnO2 (Dobson, 1982).
Cerrusite: Tribe (1964) identified cerrusite in polished section, as an alteration product of galena.
“Garnet”: This was reported by numerous workers, in the skarn, but with no further data.
Magnetite: Reported only by McCue (1963), in minor to moderate amounts in volcanic rocks.
Marcasite: Reported by McCue (1963) and by Tribe (1964) in polished section.
Molybdenite: Gutrath (1970) mentioned that “Minor molybdenite mineralization has been located in the northerly trench on the Bub Claim #15.”
Pyroxene group: Tribe (1964) reported, in a thin section of norite, two pyroxene group minerals which he called “orthopyroxene – hypersthene” and “clinopyroxene – diopside.”
Stannite: Tribe (1964) found a small grain (20 to 30 microns) contained in chalcopyrite, which he identified as stannite based on microscopy. However, his microchemical tests were positive for copper but “not definite” for tin. The mineral should be regarded as possible for the locality.
Wolframite group: Tribe (1964) identified “wolframite” in polished section. His microchemical test for Fe was positive, but he did not report a test for Mn – it would seem likely that he was dealing with ferberite rather than hübnerite.

References

Other Databases

Link to British Columbia Minfile:	104N 069

Other Regions, Features and Areas containing this locality