Silvertown, Stewart Island, Southland District, Southland Region, South Island, New Zealand
| Latitude & Longitude (WGS84): | 46° 55' 50'' South , 167° 59' 14'' East |
|---|---|
| Latitude & Longitude (decimal): | -46.93083,167.98729 |
| KΓΆppen climate type: | Cfb : Temperate oceanic climate |
James Thomson was one of the original prospectors who discovered cassiterite at Port Pegasus on Stewart Island. Quickly noting the lack of ore at this location, he prospected further afield finding silver in quartz veins on the eastern shoreline of South West Arm on Paterson Inlet in 1889.
Samples were sent to Dunedin, but the results were poor. An adit is at the location from the testing. The lease was named Silvertown, although no town ever existed here.
(Allibone et. al., 2006) mentions Ag within an alphabet soup of other elements, in particular acanthite. No mention is made of galena. The veins are described as a scheelite bearing ilmenite syenogranite core of the Euchre Pluton. They name it the Ogles Creek-Silvertown Hydrothermal system. It is part of the regional Freshwater Fault system which crosses the island north-west to south-east.
There are elevated levels of W, Mo, Te, Ag, Bi, Co, and Au, the latter at sub-ppm levels. The scheelite is found as inclusions in magmatic ilmenite grains. Molybdenite is intergrown with green biotite. Various (un-named) Cu, Mo, Bi, Zn, and Ag sulphides occur as inclusions in disseminated and vein pyrite. Pyrite and silicate gange mm-cm scale clots are found in cavities. Quartz veins locally contain acanthite, (un-named) Au-Ag tellurides, and an (un-named) Pb phosphate mineral. More research is needed on the location to identify species.
The un-mineralised Euchre Pluton consists of magnetite rich monzogranite, granodiorite, and tonalite.
Mineral List
7 valid minerals.
Rock Types Recorded
Select Rock List Type
Alphabetical List Tree DiagramRegional Geology
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
| Mesozoic - Paleozoic 66 - 541 Ma ID: 3188901 | Paleozoic-Mesozoic intrusive rocks Age: Phanerozoic (66 - 541 Ma) Lithology: Intrusive igneous rocks Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154] |
| Early Cretaceous - Late Jurassic 100.5 - 163.5 Ma ID: 1308465 | Paterson Group Age: Mesozoic (100.5 - 163.5 Ma) Stratigraphic Name: Paterson Group Description: Variably foliated, greenschist to amphibolite facies volcaniclastic sandstone, tuff, breccia and conglomerate; local andesitic and dacitic lavas. Comments: Eastern Province (Drumduan Terrane) Rocks Lithology: Greenschist, amphibolite, sandstone, tuff, breccia, conglomerate, andesite, dacite Reference: Edbrooke, S.W., Heron, D.W., Forsyth, P.J., Jongens, R. (compilers). Geology Map of New Zealand 1:1 000 000. GNS Science Geological Map 2. [12] |
| Bajocian 168.3 - 170.3 Ma ID: 1336916 | South West Arm Pluton (Rakeahua Granite Batholith) Age: Middle Jurassic (168.3 - 170.3 Ma) Stratigraphic Name: South West Arm Pluton Description: Massive medium locally megacrystic biotite titanite granodiorite and granite; locally foliated. Comments: Basement (Median Batholith) igneous rocks. Age based on U Pb dating Lithology: Major:: {granite},Minor:: {granodiorite} Reference: Heron, D.W. . Geology Map of New Zealand 1:250 000. GNS Science Geological Map 1. [13] |
Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License
References
