Using inherited cosmogenic 36Cl to constrain gl

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• journal_title：Geology
• Contributor：Jason P. Briner ; Terry W. Swanson
• Publisher：Geological Society of America
• Date：1998-
• Format：text/html
• Language：en
• Identifier：10.1130/0091-7613(1998)026<0003:UICCTC>2.3.CO;2
• journal_abbrev：Geology
• issn：0091-7613
• volume：26
• issue：1
• firstpage：3

摘要

<p id="p-1">Cosmogenic p>36p>Cl/Cl ratios measured from glacially eroded bedrock provide the first quantitative constraints on the magnitude, rate, and spatial distribution of glacial erosion over the last glacial cycle. Of 23 p>36p>Cl/Cl ratios, 8 yield exposure ages that predate the well-constrained deglaciation of the Puget Lowland, Washington, and are inferred to result from p>36p>Cl inherited from prior exposure during the last interglaciation where ice did not erode enough rock (∼1.80–2.95 m) to reset p>36p>Cl/Cl ratios to background levels. Surfaces possessing inherited p>36p>Cl evidently were abraded only 0.25–1.06 m, corresponding to abrasion rates of 0.09–0.35 mm ṁ yrp>−1p>. These results indicate that in the absence of glacial quarrying, the Cordilleran ice sheet may have abraded as little as 1–2 m of bedrock near its equilibrium-line altitude over the last glacial cycle, equating to only tens of meters over the entire Quaternary. p>