The Clinton hydromagnesite deposits are located 1 kilometre east of the town of Clinton in the Clinton Creek valley.
The Clinton deposits are located in the "Green Timber Plateau" area (EMPR Bulletin 4), a semi-arid plateau area averaging 1130 metres elevation which is part of the Cariboo Plateau and host to several semi-evaporitic playa lakes. The area is underlain by alkaline plateau basalt flows of the Miocene to Pleistocene Chilcotin Group, mantled by a thin cover of glacial till and glaciofluvial sediments. Basement rocks are Permian to Upper Trissic ribbon chert, limestone, argillite and basic volcanic flows and tuffs of the Cache Creek complex. Annual precipitation averages between 300 and 400 millimetres (EMPR Paper 1991-1).
Three small areas of pure hydromagnesite occur within a larger area of impure hydromagnesite covering a combined area of about 0.28 hectare. The material is in the order of 0.6 to 1.4 metres thick and is underlain by a brown hydromagnesite to a depth of about 1.5 metres. Sand and clay underlie the deposit.
Sample No. 1 (Reinecke, 1920) was collected from 0 to 61 centimetres from one of the three hydromagnesite occurrences. Sample 2, 3 and 4 (Reinecke, 1920) were collected from the hillside above and to the southeast of the hydromagnesite and indicate the probable source for the mineral is within the actinolite schist and carbonaceous argillites of the Cache Creek Group of sediments and volcanics.
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MgO CaO CO2 SiO2 Al2O3 Fe2O3 SO2 H2O H2O
+105 -105
#1 41.60 0.22 35.88 2.30 0.63 0.13 0.36 17.53 1.12
#2 2.49 23.04 14.64 42.0 1.75 2.25 6.29 3.73 3.62
#3 2.39 3.30 2.52 77.54 3.87 4.04 0.51 3.82 1.97
#4 3.33 13.84 10.44 60.10 2.62 2.69 1.37 3.07 1.76
#1 - Area 3, 0 to 61 centimetres; #2, 3, 4 - on hillside above
hydromagnesite.
The total amount of magnesite is estimated to be about 2400 tonnes, of which approximately 900 is of doubtful quality (GSC Memoir 118, page 44).
