Portland State University. Department of Geography
Daniel M. Johnson
Term of Graduation
Date of Publication
Master of Science (M.S.) in Geography
Soil formation -- Oregon -- Cascade Range, Moraines -- Oregon -- Cascade Range, Soil chronosequences -- Oregon -- Cascade Range
1 online resource (ix, 174 pages)
Soil development of two catenas in the central Oregon Cascades near Sisters, Oregon was examined on the Suttle Lake (Late Wisconsin age) (44° 25' N, 121 ° 43' W) and the Jack Creek (lllinoian age) moraines (44° 28' N, 121 ° 41' W) with regard to the factors of time as well as slope position.
Soils on both catenas are classified as Typic Vitricryands, regardless of slope position. The uniformity of soil classification suggests a limited development, perhaps the result of localized volcanic activity (Blue Lake event, 3500 YBP) adding pyroclastic material to the soils and retarding soil development. High NaF pH readings confirm the volcanic ash additions to the soils. Field and laboratory results characterize the texture of the soils as containing low clay percentages and having loamy-sand to sand textures. The 1:1 water pH tests are slightly acidic for both catenas, ranging from 5.8 to 6.9. Soil color hues for the soils are pdmarily 10YR. Organic matter percentages decrease with depth and are higher on the Jack Creek catena, ranging from 2.9 to 1.2 %, compared to the Suttle Lake catena (1.6 to 0.2 %).
Soil indices such as the Profile Development Index (POI) and Color Development Equivalent (COE) have been used in past chronosequence studies. A paired t-test of the POI values shows that soils are more developed on the Jack Creek catena at a 0.05 confidence level. Correlation coefficients of slope positions and POI values suggest that soil development on the Jack Creek catena is fairly uniform. On the Suttle Lake catena, soil development increases downslope. COE values suggest the shoulder position of the Jack Creek catena to have the maximum development while the toe slope position of the Suttle Lake catena has the most developed soil.
This study recommends the use of soils for future chronosequence studies, but in conjunction with other methodologies due to the high levels of volcanic disturbance in the area.
Haugland, Jason Erik, "Soil Catenas on Glacial Moraines of the Central Oregon Cascades" (1998). Dissertations and Theses. Paper 6326.