初探南湖大山第四紀冰川漂礫風化面強度與曝曬年代之關係

The Relationships between Weathered Rock Surface Hardness and Exposure Dates of Quaternary Erratic Boulders in Nanhutashan of Taiwan

10.6161/jgs.2012.67.02

何立德(Lih-Der Ho)；劉睿紘(Ray-Hong Liu)

陸域宇生核素定年法 ； 史密特錘 ； 冰川定年學 ； 南湖大山 ； 臺灣 ； Terrestrial cosmogenic nuclide dating (TCND) ； Schmidt hammer ； glacial geochronology ； Nanhutashan ； Taiwan

地理學報

67期（2012 / 12 / 01）

31 - 47

繁體中文

Terrestrial cosmogenic nuclide dating (TCND) is widely used to determine the ages of Quaternary erratic boulders or glacier-polished surface. Researchers tend to process a substantial amount of samples in order to overcome the age uncertainty induced by sample itself and the dating method, which makes the research approach economically impractical. Therefore, this study aims to use relative dating data and absolute dates to build a calibrated curve to help geochronologists to determine the time spans that rock surface samples belong, and then choose proper samples for TCND processes. We used five TCND dates and 196 Schmidt hammer rebound values from Quaternary erratic boulders in Nanhutashan of northern Taiwan to build a Schmidt-hammer exposure-age calibrated curve. We also introduced a method for normalization of Schmidt hammer rebound values (Basu and Aydin 2004) to modify Schmidt hammer measurement procedure. Results showed that there was a well linear relationship between the rebound values and TCND dates. By using the calibrated curve, we also obtained reasonable dates of unknown age erratic boulders in Nanhutashan.

Terrestrial cosmogenic nuclide dating (TCND) is widely used to determine the ages of Quaternary erratic boulders or glacier-polished surface. Researchers tend to process a substantial amount of samples in order to overcome the age uncertainty induced by sample itself and the dating method, which makes the research approach economically impractical. Therefore, this study aims to use relative dating data and absolute dates to build a calibrated curve to help geochronologists to determine the time spans that rock surface samples belong, and then choose proper samples for TCND processes. We used five TCND dates and 196 Schmidt hammer rebound values from Quaternary erratic boulders in Nanhutashan of northern Taiwan to build a Schmidt-hammer exposure-age calibrated curve. We also introduced a method for normalization of Schmidt hammer rebound values (Basu and Aydin 2004) to modify Schmidt hammer measurement procedure. Results showed that there was a well linear relationship between the rebound values and TCND dates. By using the calibrated curve, we also obtained reasonable dates of unknown age erratic boulders in Nanhutashan.

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