5001 23RD AVE W Geotech Report 2022-10-25

Oat ml ( a! Otu ' 4 i I ‘. ` __ ml t t 1 i .� , 1t �� C. • Crif - • , . s l .,,ill. ''' r L . "'SITE LOCATION _- QV . 7 * , . • i k•, Qv IS...\\11111/4\••:. . LEGEND I Qtb TRANSITIONAL BEDS(Fraser Glaciation to pre-Fraser time)- These Tte transitional beds occupy the stratigraphic position (early glacial and non-glacial deposits occur beneath sand of the Vashort advance outwash and consist mostly of thick beds of gray 2lay, �ashon age) of the Pilehuck Clay Member of Newcomb 12952) arni silt, and fine- to very-fine sand. Some lavers of peaty sane and the upper part (late pre-Fraser time) of the Whidbey Formation gravel may be present in the lower part. The fine-grained of Smith (197E). Where passible, both tie transitional beds and sediment mostly was deposited in lakes some distance from the the Whidbey Formation are mapped in the quadrangle. Where the ice front, and in iluv.al systems prior to the advance of the ice. Whidbey directly underlies the advance outwash, it may or May Clast composition is similar to the other units which are derived not include beds in its upper part that closely resemble from similar a urce.s and from each other. The transitional beds seem to grade up Into the base of the overlying advance outwash transitional beds. Because of poor exposures, such beds, if at some localities, bt.t elsewhere this contact between the two present, are not mapped separately. units is sharp and distract. The transitional beds are as much as 80 to 90 m thick. Where th.ckest, they may include in the base, in areas of poor eaoosures, some upper beds of the Whidbey Formation. The transitional beds are firm-appearing in outcrop, but because of a high water content and jointing. they can become unstable in steep slopes and are included in numerous landslides. In the Everett quadrangle to the east (Minard, 1981), the fine-grained beds have been used in the manufacture of brick. 0 REFERENCE U.S. GEOLOGIC SURVEY r mx?'b4O.' OTC 1lVnjuxcnittssom FIGURE 3: GEOLOGIC MAP