Watsons Beach, Clutha District, Otago Region, South Island, New Zealand
|Latitude & Longitude (WGS84):||46° 9' 47'' South , 170° 9' 6'' East|
|Latitude & Longitude (decimal):||-46.16306,170.15181|
|Köppen climate type:||Cfb : Temperate oceanic climate|
Type locality for Coombsite, named after Professor D.S. Coombs from the University of Otago, found in a rhodonite and quartz lens at Watsons Beach.
The lens covers an area 0.5 by one metre in a beach exposure in pumpellyite-actinolite to pumpellyite-prehnite facies metagreywacke-argillite sequence in the Chrystalls Beach accretionary melange complex of the Tuapeka Group, Caples Terrane.
The lens consists of rhodonite and quartz, sub-ordinate rhodochrosite, and rare kutnohorite, manganoan calcite, spessartine, apatite, parsettensite, caryopilite, and coombsite.
The quartz in the lens forms anastromising veins, with also late generation cross-cutting veins. Rhodonite are large sphenoid crystals to 0.5 mms across in a fine grained quartz matrix. The lens also contains veins of rhodochrosite, manganoan calcite, and rare kutnohorite.
Fe rich parsettensite form dark coloured patches to 5 cms across, isolated laths, and fan shaped crystal aggregates often associated with coombsite. Fe rich caryopilite is found as brown aggregates a few mms across in rhodochrosite.
Coombsite is found as brown patchy aggregates a few mms across amongst rhodonite and quartz, sometimes associated with parsettensite, and spessartine.
Specimens are only occasionally seen. Hand specimens show as brown patches of coombsite in pink rhodonite. As such it is very similar to the material found 3.5 kilometres to the north, as the akatoreite type locality, and the two could easily be confused. Further parsettensite and caryopilite at the Watsons Beach locality would look similar to coombsite.
12 valid minerals. 1 (TL) - type locality of valid minerals.
Rock Types Recorded
Select Rock List TypeAlphabetical List Tree Diagram
Entries shown in red are rocks recorded for this region.
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
0 - 2.588 Ma
|Late Quaternary beach and terrace cover deposits|
Age: Pleistocene (0 - 2.588 Ma)
Stratigraphic Name: Pakihi Supergroup
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.