This dataset comprises 52 cosmogenic 10Be surface exposure ages and associated analytical data from quartz-bearing rocks from Mount Murphy and surrounding nunataks in Marie Byrd Land, Antarctica. The samples - glacial erratics and bedrock - were collected between 2006 and 2016 by Joanne Johnson, Stephen Roberts and James Smith (British Antarctic Survey), in order to determine timing and duration of ice sheet thinning in the Amundsen Sea sector of the West Antarctic Ice Sheet, specifically thinning of Pope Glacier. The data are published and interpreted in the following paper: Johnson, J.S., Roberts, S.J., Rood, D.H., Pollard, D., Schaefer, J.M., Whitehouse, P.L., Ireland, L.C., Lamp, J.L., in review. Deglaciation of Pope Glacier implies widespread early Holocene ice sheet thinning in the Amundsen Sea sector of Antarctica. Earth & Planetary Science Letters. doi: xxxxx This data forms part of the ANiSEED project (''Amundsen Sea Embayment Exposure Dating''), funded by the Natural Environment Research Council (grants NE/K012088/1 and NE/K011278/1).

The data consists of proxy data with associated ages from six moss bank cores from four locations on the Antarctic Peninsula. Proxies included are: 13C, microbial productivity (derived from testate amoeba concentration values), mass accumulation rate and moss growth rate. Sites are Elephant Island (core ELE3), Ardley Island (cores ARD1 and ARD3) and Green Island (cores GRE1 and GRE2). Elephant Island (61.111 S, 54.824 W) and Ardley Island (62.213 S, 58.935 W) cores were collected in January 2012. Green Island (65.322 S, 64.151 W) cores were collected in January 2013. Funding was provided by the NERC grants NE/H014896/1, NE/H014632/1 and NE/H014810/1.

200+ erratic and bedrock samples were collected for cosmogenic isotope analysis, as well as several depth profiles of tills. Samples were collected from 11 sites along a 350km transect stretching from Pirrit Hills in the south to the ridge between Mt Bentley and Mt Hubley in the north. Most sites were on the western (West Antarctic Ice Sheet) side of the range but includes Flowers Hills on the east side of the range, adjacent to the Rutford Ice Stream. Throughout, the emphasis was on taking samples to allow dating of any changes in ice altitude/extent.

Accelerator Mass Spectrometry (AMS) measurements of cosmogenic isotopes were made from erratic and bedrock samples collected in the Ellsworth Mountains, 2005-2006. Pressed AMS targets were analysed at SUERC (Scottish Universities Environmental Research Centre) to yield exposure ages.

Powders, solutions and residues related to erratic and bedrock samples collected in the Ellsworth Mountains during the 2005-2006 field season. For each of the rock samples analysed in the lab, a (variable) number of laboratory stages are created, including sawing and crushing residues, pure quartz separates, chemical solutions, and AMS (Accelerator Mass Spectrometry) targets.

Glacial geomorphological data from the Ellsworth Mountains, Weddell Sea embayment. Satellite imagery and aerial photography, ground truthing, surveying and GPS traverses were used for geomorphological mapping. Additional photographic and weathering data were used to complement the field work. The project resulted in one of the most detailed geomorphological studies of any part of the WAIS (West Antarctic Ice Sheet), as well as the most comprehensive coverage for cosmogenic isotope analysis.