Abstract:
The dataset comprises of lake site photos, data and multiproxy data from Lake L15 (aka GPS Lake), a small lake basin at 62.24057 S, 58.6776 W on Potter Peninsula, King George Island, South Shetland Islands. The data have been used to constrain deglaciation and glacier dynamics on Potter Peninsula.
Data for the Lake L15 (GPS Lake) sediment record consist of downcore measurements of chronology, geochemistry, and sedimentology proxy data collected from the depocentre in November 2011.
Data collected in this study were funded by: Centro de Investigaciones en Ciencias de la Tierra (CICTERRA), the Direccion Nacional del Antartico/Instituto Antartico Argentino (DNA/IAA) in the framework of the Project PICTA, 2011 - 0102, IAA "Geomorfologia y Geologia Glaciar del Archipielago James Ross e Islas Shetland del Sur, Sector Norte de la Peninsula Antartica"; the Alfred Wegener Institute (AWI) research program Polar regions and Coasts in a changing Earth System (PACES II); IMCONet (FP7 IRSES, action no. 318718); the Natural Environment Research Council (NERC/BAS-CGS Grant no.81); the NERC/BAS science programmes CACHE-PEP: Natural climate variability - extending the Americas palaeoclimate transect through the Antarctic Peninsula to the pole and GRADES-QWAD: Quaternary West Antarctic Deglaciations. We thank the crews of the Argentine research station "Carlini" and the adjoined German Dallmann-Labor (AWI) Laboratory, the Uruguayan research station "Artigas", the Russian Bellingshausen Station, the Chinese Great Wall Station, Base Presidente Eduardo Frei Montalva, the Brazilian Navy Almirante Maximiano, the UK Navy HMS Endurance and NERC/BAS James Clark Ross for logistical support during the 2006, 2011, 2014 and 2015 field seasons.
Keywords:
Deglaciation, South Shetland Islands, geomorphological mapping, glacial readvance, radiocarbon dating, stratigraphy
Roberts, S., Pearson, E., Czalbowski, T., Davies, S., Grosjean, M., Arcusa, S., & Perren, B. (2022). Chronological, geochemical and sedimentological data from a lake sediment record extracted from Lake L15 (GPS Lake) on Potter Peninsula, South Shetland Islands in 2011 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/2031310d-1e35-4ea1-a1cc-cd318e82d394
| Access Constraints: | No restrictions apply. |
|---|---|
| Use Constraints: | Data released under Open Government Licence V3.0: http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/. |
| Creation Date: | 2022-11-18 |
|---|---|
| Dataset Progress: | Complete |
| Dataset Language: | English |
| ISO Topic Categories: |
|
| Parameters: |
|
| Personnel: | |
| Name | UK Polar Data Centre |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Dr Stephen J Roberts |
| Role(s) | Technical Contact, Investigator |
| Organisation | British Antarctic Survey |
| Name | Emma J Pearson |
| Role(s) | Investigator |
| Organisation | Newcastle University |
| Name | Tamara M Czalbowski |
| Role(s) | Investigator |
| Organisation | Instituto Antartico Argentino (I.A.A.) |
| Name | Sarah J Davies |
| Role(s) | Investigator |
| Organisation | Aberystwyth University |
| Name | Martin Grosjean |
| Role(s) | Investigator |
| Organisation | University of Bern |
| Name | Stephanie Arcusa |
| Role(s) | Investigator |
| Organisation | University of Bern |
| Name | Dr Bianca Perren |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Parent Dataset: | N/A |
| Reference: | Methodology: Appleby PG and Oldfield F. (1978) The calculation of lead-210 dates assuming a constant rate of supply of unsupported 210Pb to the sediment. CATENA 5: 1-8. Butz C, Grosjean M, Fischer D, et al. (2015) Hyperspectral imaging spectroscopy: a promising method for the biogeochemical analysis of lake sediments. Journal of Applied Remote Sensing 9: 096031. Reimer RW, and Reimer PJ. (2004). CALIbomb - calibration of post-bomb C-14 data (www.calib.org). Rein B and Sirocko F. (2002) In-situ reflectance spectroscopy - analysing techniques for high-resolution pigment logging in sediment cores. International Journal of Earth Sciences 91: 950-954. Associated papers: Heredia Barion, P., Roberts, S.J., Spiegel, C., et al. (2023). Holocene deglaciation and glacier readvances on the Fildes Peninsula, King George Island, NW Antarctic Peninsula. The Holocene. https://doi.org/10.1177/09596836231157059 Heredia Barion, P.A., Strelin, J.A., Roberts, S.J., et al. (2022). The impact of Holocene deglaciation and glacial dynamics on the landscapes and geomorphology of Potter Peninsula, King George Island (Isla 25 Mayo), NW Antarctic Peninsula. Frontiers in Earth Science https://doi.org/10.3389/feart.2022.1073075 Hogg AG, Heaton TJ, Hua Q, Palmer JG, Turney CSM, Southon J, et al. (2020) SHCal20 Southern Hemisphere Calibration, 0-55,000 Years cal BP. Radiocarbon 62: 759-778. Hua Q, Barbetti M, and Rakowski AZ (2013). Atmospheric radiocarbon for the period 1950-2010. Radiocarbon 55, 1-14. |
|
|---|---|---|
| Quality: | Chronology Pb-210 age estimates were derived using the constant rate of supply (CRS) method (Appleby and Oldfield, 1978) and incorporated into Bayesian age-depth models. The prerequisite for the CRS model was not fulfilled because the flux of Pb-210 has changed through time and is not constant, but Pb-210 data are consistent with the radiocarbon ages that show sediment between 6 and 6.5 cm dates to 620 plus-minus 80 a cal BP, and 3-3.5 cm and 0-0.5 cm depth were deposited in the 'post-bomb' (post-1950 CE) era, most likely between -40 - -44 cal yr BP (1990-1994 CE) The Cs-137 data are inconsistent with the Pb-210 CRS age model and it is possible that the steep increase in Cs-137 in the upper 2 cm relates to a Cs-137 'soil reservoir', which is leaching Cs-137 into the lake from snow or lake-ice melting. Geochemistry and Sedimentology ITRAX-XRF Raw count per second (cps) data were analysed using the Q-spec software v8.6.0 (Cox Analytical), with MSE values minimised to optimise the fit of 'as measured' spectra to a modelled spectrum. Data are presented as percentages of the Total Scatter Normalised ratio sum (percent sigma TSN or, more simply, percent TSN, which are equivalent to percentages of the cps sum, or percent cps) to account for downcore variations in count rate, density, water and organic content. Data less than mean minus two-sigma kcps (mainly due to gaps in the core) and greater than MSE plus two-sigma (representing a poor fit between measured to modelled spectra) were filtered before analysis. 'Noisy' elements were eliminated by comparing cps and using percent TSN thresholds of more than 0.1 percent mean and more than 0.5 percent maximum, and by examining autocorrelation profiles for each element. Elements are presented as natural log (log n or Ln) ratios. |
|
| Lineage: | Core collection: Sediment cores were collected using a Russian and Livingston corers from the deepest point (around 2 m of water depth) in Lake L15 (GPS Lake) (L15: -62.24057 degrees S, -58.67760 degrees W, around 30 m a.s.l., 11-55 cm total recovered sediment depth). Eight cores were collected from a grid of 25 (around1 m spaced) holes drilled through the around 75-100 cm thick lake ice above the deepest accessible point (around 2 m): Data from L15-H2 (-62.24057 degrees S, -58.67760 degrees W) with 30 cm of sediment and L15-H16 (-62.24056 degrees S, -58.67757 degrees W) with 55 cm of sediment are included in this dataset. Other cores taken at this site were: L15-H4 = 11 cm, L15-H9 = 39 cm, L15-H17 = 45 cm, L15-H19 = 34 cm, L15-H20 = 61 cm and L15-H22 = 49 cm. Chronology: Pb-210 Cs-137 and Am-241 dating of the uppermost 10 cm of the lake sediment records was undertaken and dating model calculations followed standard procedures defined in Appleby and Oldfield (1978). Pb-210 age estimates were derived using the constant rate of supply (CRS) method (Appleby and Oldfield, 1978) and incorporated into Bayesian age-depth models. The Pb-210 CRS age model produced a low sedimentation rate in the top 10 cm and the sample at around 4-5 cm is likely to be at least 150 years old. Radiocarbon ages of aquatic moss and macrophytic material from the uppermost lithological Unit 3 in Lake L15 were calibrated using the Southern Hemisphere SHCal20 calibration curve in Oxcal v. 4.4 (Hogg et al., 2020). Post-bomb (more than 1950 CE) ages were corrected according to 13C/12C isotopic ratios from measured pMC with the 'present day' pMC value defined as 107.5 percent (2010 CE) and calibrated using the SHCal13 SH Zone 1-2 Bomb curve in CALIBomb (Reimer and Reimer, 2004; Hua et al., 2013). Calibrated ages range from post 1950 CE to c. 0.6 ka cal BP. Geochemistry & Sedimentology: Physical properties (gamma-ray density (GRD), magnetic susceptibility, fractional porosity, resistivity and impedance) were measured using Geotek multi-sensor core logger (MSCL). Non-destructive ITRAXTM (Cox Analytical) micro-X-ray fluorescence (micro-XRF) and Bartington Magnetic Susceptibility High Resolution Surface Scanning Sensor (MS2E) measurements were undertaken at Aberystwyth University. Contiguous bulk, wet sediment geochemical Energy Dispersive XRF-CS (Energy Dispersive Spectroscopy) analysis was obtained using a chromium (Cr) X-ray tube (X-radiography image settings: 40 kV, 40 mA, 200 ms; XRF-CSCr settings: 30 kV, 40 mA, dwell time of 10 seconds, at 100 micrometer or 2 mm. Hyperspectral image (HSI) scanning was performed using the Specim Ltd. single core scanner (PFD-CL-65-V10E line scan camera, 400-1000 nm) according to the protocol of Butz et al. (2015). The spatial resolution (pixel size) was set at 69 micrometer x 69 micrometer and the spectral resolution is 2.8 nm sampled at an interval of 0.78 nm. Raw data were normalised with a BaSO4 reference and spectral endmembers were calculated using the software ENVI 5.03. Quantitative estimates of pigments were obtained using the Relative Absorption Band Depth (RABD) method, which uses ratios and normalised reflectance data from distinct wavelengths. The spectral index RABD660;670 (RABD at 660-670 nm) was calculated from the continuum between 590 and 730 nm (Butz et al., 2015) with I-band wavelengths between 660 and 670 nm using equations RABD660;670 = (6 R590+7 R730)/13/Rmin(660;670) and RABD660;670 (I-Band) = (6 R590+7 R730)/13/ Rmin(660;670)/Rmean (Rein and Sirocko, 2002). Additional statistical analysis was undertaken, and figures constructed, using R v. 4.1.0/RStudio v. 1.4.1717 (primarily packages Tidyverse, ggplot2, Vegan, Rioja, Ggally v. 2.1.2, RBacon, Rcarbon, Bchron), Sigmaplot v. 14.0, C2 (Juggins, 2007), MATLAB v. R2021a, with final layouts achieved in Adobe Illustrator v. 26.2.1 or CorelDRAW v. 2020. Code, data, all packages used, and package references can be found at: https://github.com/stever60/Potter_Peninsula |
|
| Temporal Coverage: | |
|---|---|
| Start Date | 2011-11-01 |
| End Date | 2011-11-30 |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | 62.24057 |
| Northernmost | 62.24057 |
| Longitude | |
| Westernmost | 58.6776 |
| Easternmost | 58.6776 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | N/A |
| Depth | |
| Min Depth | N/A |
| Max Depth | N/A |
| Location: | |
| Location | Antarctica |
| Detailed Location | Potter Peninsula, South Shetland Islands |
| Data Collection: | Chronology Pb-210 Cs-137 and Am-241 dating of the uppermost 10 cm of the lake sediment records was undertaken on a well-type gamma spectrometry (Ge-detector, GWC 2522-7500 SL, Canberra Industries Inc., USA) and processed with GENIE 2000 3.0 (Canberra Industries Inc., USA). Geochemistry and Sedimentology Geotek multi-sensor core logger (MSCL) ITRAX XRF core scanner fitted with a Molybdenum (Mo) anode X-ray tube and a Bartington Magnetic Susceptibility High Resolution Surface Scanning Sensor (MS2E) Hyperspectral image (HSI) scanning was performed using the Specim Ltd. single core scanner (PFD-CL-65-V10E line scan camera, 400?1000 nm) according to the protocol of Butz et al. (2015). |
|---|
| Data Storage: | This entry contains the following data folders and subfolders (in alphabetical order): Chronology L15 C14 data.csv - radiocarbon age data for Lake L15 L15 Pb210 S3.csv - Pb-210 age data for Lake L15 CRS is constant rate of supply model; DMAR is dry mass accumulation rate Geochemistry and sedimentology GEOTEK data folder containing: L15 GEOTEK MSCL.csv - GEOTEK MSCL data for cores from Lake L15 (GPS Lake) ITRAX data folder containing: L15 H2 folder containing: document XRF.txt - run and set up data for the core section XRF scan document XRAD.txt - run and set up data for the core section radiography scan optical.tif - raw optical image of the core section scan optical1.tif - autotune/autocontrast/autocolour processed optical image of the core section scan in Photoshop v23.2.0 optical2.tif - vertically rotated version of optical1.tif radiograph.tif - raw X ray image of the core section scan radiograph1.tif - autotune/autocontrast/autocolour processed X ray image of the core section scan section scan in Photoshop v23.2.0 result.txt - summary set up and cps datafile for the core section sumspectra.txt - average spectra output datafile the core section XRF-spectra.zip folder - individual run data and spectra channel energy data for the core section in sequence from the top of the section, e.g., L000001.txt, L00001.txt etc. L15 H2 Cr 2mm cps.csv - filtered cps X ray fluorescence (XRF) core scanning (XRF-CS) data L15 H2 Cr 2mm percentTSN.csv - percent TSN (percentage of the total scatter normalised sum) X ray fluorescence (XRF) core scanning (XRF-CS) data L15 H2 MS.csv - X ray fluorescence (XRF) core scanning (XRF-CS) MS data L15 H16 folder containing: document XRF.txt - run and set up data for the core section XRF scan document XRAD.txt - run and set up data for the core section radiography scan optical.tif - raw optical image of the core section scan optical1.tif - autotune/autocontrast/autocolour processed optical image of the core section scan in Photoshop v23.2.0 optical2.tif - vertically rotated version of optical1.tif radiograph.tif - raw X ray image of the core section scan radiograph1.tif - autotune/autocontrast/autocolour processed X ray image of the core section scan section scan in Photoshop v23.2.0 result.txt - summary set up and cps datafile for the core section sumspectra.txt - average spectra output datafile the core section XRF-spectra.zip folder - individual run data and spectra channel energy data for the core section in sequence from the top of the section, e.g., L000001.txt, L00001.txt etc. L15 H16 Cr 2mm cps.csv - filtered cps X ray fluorescence (XRF) core scanning (XRF-CS) data L15 H16 Cr 2mm percentTSN.csv - percent TSN (percentage of the total scatter normalised sum) X ray fluorescence (XRF) core scanning (XRF-CS) data L15 H16 MS.csv - X ray fluorescence (XRF) core scanning (XRF-CS) MS data SPECIM data folder containing: L15 H2 SPECIM.csv - summary output of Specim data used L15 H16 SPECIM.csv - summary of Specim data used L15 H2 SPECIM archive.zip - archive of Specim imagery and data L15 H16 SPECIM archive.zip - archive of Specim imagery and data Lake chemistry data folder containing: L15 Water chemistry.csv Notes: DOpercent: Run for 10-15 minutes to stabilise inside sealed beaker with damp sponge; Calibrated using atmospheric pressure of 1012.0 mbar (from Garmin barGPS); Air temp = -1 degrees C; stable temp/press Photos Folder containing: L15 site photos |
|---|