10Be exposure ages of Quaternary Glaciers in Antarctica

In situ terrestrial cosmogenic nuclide(TCN)has been widely applied to date the ages of Quaternary glacial deposits in Antarctica and plays an important role in reconstructing the glacial evolution and climate change.It helps to under‐stand the Antarctic ice sheet's evolution process in Quaternary and shed light on the application of Cosmogenic Nu‐clide exposure dating technique in Glacial Geomorphology.In this paper,we retrieved 49510Be age samples in Ant‐arctica from literature published between 2004 and 2020 and recalculated the TCN ages using version 3.0 online cal‐culator of Cosmic-Ray Produced Nuclide Systematics on Earth(CRONUS-Earth).Several conclusions can be drawn from the results:(1)75%of the exposure ages are younger than 400 ka,and 91%younger than 1,100 ka.Northern Antarctic Peninsula exposure result is visibly younger than the main glaciers in East Antarctica due to climate change and geological evaluation since the LGM(Last Glacial Maximum).(2)TCN ages are relevant to the samples'relative positions in the Antarctic continent,but a relationship between their ages and elevations is yet to be determined based on the collected data.

Measurement of ice flow velocities from GPS positions logged by short-period seismographs in East Antarctica

The ice flow velocity is a basic feature of glaciers and ice sheets. Measuring ice flow velocities is very important for estimating the mass balance of ice sheets in the Arctic and Antarctic. Traditional methods for measuring ice flow velocity include the use of stakes, snow pits and on-site geodetic GPS and remote sensing measurement methods. Geodetic GPS measurements have high accuracy, but geodetic GPS monitoring points only sparsely cover the Antarctic ice sheets. Moreover, the resolution and accuracy of ice flow velocities based on remote sensing measurements are low. Although the accuracy of the location data recorded by the navigation-grade GPS receivers embedded in short-period seismographs is not as good as that of geodetic GPS,the ice flow velocity can be accurately measured by these navigation-grade GPS data collected over a sufficiently long period. In this paper, navigation-grade GPS location data obtained by passive seismic observations during the 36 th Chinese National Antarctic Research Expedition were used to accurately track the movement characteristics of the ice sheet in the Larsemann Hills of East Antarctica and the Taishan Station area. The results showed that the ice sheet in the two study areas is basically moving northwestward with an average ice flow velocity of approximately 1 m mon-1. The results in the Taishan Station area are basically consistent with the geodetic GPS results, indicating that it is feasible to use the embedded GPS location data from shortperiod seismographs to track the movement characteristics of ice sheets. The ice flow characteristics in the Larsemann Hills are more complex. The measured ice flow velocities in the Larsemann Hills with a resolution of 200 m help to understand its characteristics. In summary, the ice flow velocities derived from GPS location data are of great significance for studying ice sheet dynamics and glacier mass balance and for evaluating the systematic errors caused by ice sheet movements in seismic imaging.