This and several other nearby uranium-thorium-REE deposits (DE015 to DE030) are spatially and genetically related to a stock of Jurassic, peralkaline granite about 2 miles in outcrop diameter centered on Bokan Mountain. It commonly is referred to as the Bokan Mountain peralkaline granite or Bokan Mountain complex. The intrusion and its deposits have been mapped in detail several times using slightly different subdivisions of the granite (MacKevett, 1963; Thompson and others, 1980, 1982; Saint-Andre and others, 1983; Gehrels, 1992; Thompson, 1997). This description largely follows Gehrels' (1992) map units. The intrusion is a ring-dike complex with an outer border zone up to 14 meters thick of pegmatite and aplite; a nearly complete intermediate zone of aegirine granite porphyry, 15 to 180 meters thick; and a core of several varieties of riebeckite granite porphyry. It has been dated by several methods at 151 Ma to 191 Ma (Lanphere and others, 1964; Saint-Andre and others, 1983; Armstrong, 1985; Gehrels, 1992; Thompson, 1997). The peralkaline granite mainly intrudes a regionally extensive body of Silurian or Ordovician quartz monzonite, granite, and quartz diorite that makes up much of the southeast tip of Prince of Wales Island. The south and west sides of the peralkaline granite are in contact with a band up to about 3,000 feet wide of shale and argillite of the Silurian or Ordovician Descon Formation. The Bokan Mountain complex and surrounding Paleozoic rocks are cut by numerous pegmatite, andesite, dacite, and aplite dikes. The dikes are genetically related to the complex and commonly are associated with the uranium, thorium, and REE deposits. The deposits are marked by intense albitization, pervasive or fracture-controlled chloritization, calcite-fluorite replacement of aegirine, and hematitization. Three types of U-Th-REE deposits occur in the Bokan Mountain complex: 1) irregular cylindrical pipes; 2) steep, shear-zone-related pods or lenses ('veins'); and 3) quartz veins.

The Geoduck occurrences are related to a system of equigranular, fine- to medium-grained, andesite dikes that strike N40-50W for about 10,000 feet, west of the head of Kendrick Bay (MacKevett, 1963; Warner and Barker, 1989). The dikes have steep to vertical dips, cut Silurian or Ordovician quartz monzonite, granite, and quartz diorite, and typically have wall rocks marked by chlorite and epidote alteration. The ore mineralogy has not been worked out in detail but it is probably similar to that in the mineralized dikes at the Carol Ann/Dotson prospects (DE027), which may be extensions of the Geoduck dikes. In the northwest part of the Geoduck dike system, individual dikes average about 1.4 feet thick; in the southeast part, they average about 0.8 foot thick. Many samples contain elevated values of beryllium, thorium, yttrium, REE, columbium, uranium, and zirconium.

In 2009, Ucore Uranium (2010) drilled two holes near the Geoduck prospect for rare-earth elements. The holes are along what they term the 'Geoduck trend' that is oriented northwest along the andesite dike. The analyses for the samples were reported as the light rare-earth-element oxides or LREO (lanthanum, cerium, praesodymium, neodymium, and samarium) and the heavy rare-earth-element oxides or HREO (europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium); together they are termed the TREO, the total rare-earth-element oxides. The most notable intercept in the two holes was 0.4 meter with 3.4 percent TREO. The ratio of the the HREO to the TREO in the three best intercepts varied between 41.9 and 46.6 percent; in other words nearly half of the rare-earth elements in the samples are the heavy rare-earth elements.