1. DATING THE GLACIATION OF SOUTHERN PART OF NORTH CASCADE RANGE by: James Leask

2. Main Drift Sheets Lakedale (youngest; 11,050-16,000 years ago) – Hyak – Domerie – Ronald – Bullfrog Kittitas (intermediate; over 120,000 years ago) – Indian John – Swauk Prairie Thorp (oldest; over 700,000 years ago)

5. Dating Criteria Upper limit of erratics Moraine size/position Outwash terrace position Estimated glacial limit position Thickness of weathering rinds Soil Profile

6. Soil Measurements % Clay Silt to Clay ratio pH Levels % Magnetic Minerals Moist Color

8. Thermoluminescence Dating Procedure 1.Once buried, rock accumulates energy at the atomic level. 2.Rock samples are taken to lab and exposed to various doses of radiation. 3.Photons emitted are recorded.

10. Intro to OSL OSL – Optically stimulated luminescense According to Berger, OSL has the potential to produce more accurate dates than TL.