The Asp Creek zeolite showing outcrops along the northern outskirts of the town of Princeton, between Asp Creek and the Tulameen River bridge, over a distance of 1 kilometre.

The deposit occurs near the centre of the Princeton Basin, a northerly striking fault-bounded trough filled by Eocene volcanic rocks of mainly intermediate composition, comprising the Lower Volcanic Formation, and an overlying Eocene sedimentary sequence of sandstone, shale, waterlain rhyolite tephra (tuff) and coal, up to 2000 metres thick, comprising the Allenby Formation.

Zeolite mineralization is contained in a zeolitized, waterlain rhyolite crystal-vitric tuff in the lower part of the Allenby Formation (Princeton Group), known informally as the Asp Creek ash. The tuff consists of bedded white ash, with intercalations of vitric-crystal tuff. A cliff exposure on the west bank of Asp Creek exhibits a section of zeolitized tuff, 7.3 metres thick, overlain by fine-grained sandstone and underlain by carbonaceous shale. The sequence strikes 078 to 080 degrees for an exposed length of 1000 metres and dips 21 to 23 degrees south.

Zeolite mineralization consists of clinoptilolite, which is accompanied by sanidine, plagioclase, quartz and biotite. Exchangeable cation analyses and cation exchange capacity (CEC) in milli-equivalents per 100 grams on two samples are as follows (Open File 1987-19):

________________________________________________________________

Sample Magnesium Calcium Potassium Sodium CEC

Z2 2.5 12.6 8.4 37.9 75.7

Z3 2.2 17.2 8.6 52.7 95.2

________________________________________________________________

Sample Z2 is a grab sample from a roadcut along the Princeton-Tulameen highway, at the northwest end of the Tulameen River bridge, while sample Z3 is a composite chip sample across the 7.3-metre thick cliff exposure on Asp Creek.

Western Industrial Clay Products Inc. took a 20 to 30-tonne bulk sample for testing in 1998.