Law Dome and Mount Brown South ice core stratigraphy from ILCS images

Full description

This collection contains high resolution images (as png files) of ice cores from East Antarctica. The images have been produced using Intermediate Layer ice Core Scanning (ILCS). For details on the process used to produce the ILCS images, see Zhang et al., 2023 (https://doi.org/10.5194/egusphere-2023-611).

The collection includes images from the DSSW10K, DSS1617 and MBS1718 ice core sites from Law Dome, Wilkes land, East Antarctica and Mount Brown South (MBS) in Wilhelm II Land, East Antarctica respectively. There are ~126 DSSW10K 1m ice core samples, and each sample has been scanned 3 to 6 times, so there are 3-6 images per 1m sample. The DSS1617 ice core is a surface core spanning approximately 30 metres, with associated overlapping surface cores (refer to DSS1617 description in Jong et al., 2022 https://doi.org/10.5194/essd-14-3313-2022) for core information, depth scale and chronologies. Each DSS1617 sample has been scanned 3 to 6 times, so there are 3-6 images per 1m sample.
For the MBS ice core images collection, images from a 25 metre surface core (‘MBS Charlie’) and the deep 295 metre main core (‘MBS-Main’) have been produced. Refer to Vance et al., 2024 for details of the MBS sampling, depth model and chronologies (https://doi.org/10.5194/cp-20-969-2024). There are ~350 1m ice core samples in the MBS collection, and each sample has been scanned 3 to 6 times, so there are 3-6 images per 1m sample.

Each line scan image (.png file) has a corresponding text file (.txt file) that contains the line scan settings. The image and its corresponding text file have the same base name.

Generally, the naming convention is:

[site]_[bag_number]_[scan_number]_[YYYYMMDD].png
[site]_[bag_number]_[scan_number]_[YYYYMMDD].txt

Where the site is MBS1718/DSSW10K/DSS1617, bag_number is the number that corresponds to a 1m sample, scan_number is an integer from 1 to 6, and the date is in the format YYYYMMDDD.

Example text file:

Site:MBS
Site_Specific:1718
Bag_Number:83
Core:MBS1718_83
Date_Text:20190628
Slab_Thickness_Top_mm:18
Slab_Thickness_Bottom_mm:17
Focus_Height_Z_mm:54
Brightness_%:15
CIT_A_ms:
CIT_B_ms:
Scan_Number:4
Scan_File_Name:MBS1718_83_4_20190628
Notes:


Slab_Thickness_Top_mm: the thickness of the slab at the top, in mm
Slab_Thickness_Bottom_mm: the thickness of the slab at the bottom, in mm
Focus_Height_Z_mm: the focus height of the camera, in mm
Brightness_%: the brightness of the dark field illumination units, as a percentage
CIT_A_ms: Camera integration time - Control in ms
CIT_B_ms: Camera integration time - adjustment range in ms

The files have been sorted into folders, with one folder for each site, ie DSS1617, DSSW10K, MBS1718

Within the site folders, there are folders containing groups of cores, eg for 5-19, 20-49, etc, and each of those folders contains one folder per ~1m core sample, which contains 3-6 png files of the ice core using different ILCS settings, and a text file describing each png file. There may be an extra text file describing any ice core material missing from the images (e.g. from prior destructive sampling) or other specific notes about the specific core section.

Note that the zero point on the scale bar does not necessarily reflect the top of each core, as the cores were scanned without reference to any missing core material. Where cores have been previously sampled, there may be material missing. Refer to the relevant depth scales, processing logs, and chronologies for each site to determine the actual relative depth of any features of interest in the images. A trouble shooting document is provided which provides a non-exhaustive list of images which have known material missing from the scanned ice core. Most of this missing material applies to sections of the DSS W10k cores which were destructively sampled for density measurements.

Lineage

Progress Code: completed

Notes

Purpose
This dataset provides high resolution stratigraphic images via Intermediate Layer Ice Core scanning (ILCS) of East Antarctic ice cores archived by the Australian Antarctic program. The images can be used to investigate stratigraphic features in the ice core records.