Cosmogenic in situ 14C data and calculated surface exposure ages for 9 erratic cobbles collected from Mount Murphy, West Antarctica

This dataset consists of measurements of cosmogenic 14C in quartz for cobbles collected from a series of nunataks (Turtle Rock, Notebook Cliffs, scoria cone) proximal to Mount Murphy, a volcanic edifice located between Pope and Thwaites glaciers, West Antarctica. The cobbles were collected during the 2015-2016 Antarctic field season. The dataset includes 13 cosmogenic nuclide surface exposure ages and all field (location, elevation, shielding, thickness) and analytical laboratory data required to calculate in situ 14C exposure ages. Analytical data includes quartz sample mass, total CO2 liberated from the sample, delta-13C, 14C/12C AMS ratios and 14C/12C AMS ratios of procedural blanks.

Funding source: Natural Environment Research Council (NERC): Grants NE/S006710/1, NE/S006753/1 and NE/K012088/1 and National Science Foundation (NSF): Grant: OPP-1738989. The dataset is a component of the "Geological History Constraints" project of the NERC-NSF funded International Thwaites Glacier Collaboration (ITGC).

Alternate title: Polar Data Centre (PDC) record GB/NERC/BAS/PDC/01925

Date (Publication): 2024-11-20

Citation identifier: http://www.antarctica.ac.uk/dms/metadata.php?id= / GB/NERC/BAS/PDC/01925

Point of contact

Organisation name	Individual name	Electronic mail address	Role
British Antarctic Survey		pdc@bas.ac.uk	Custodian
NERC EDS UK Polar Data Centre	Adams, J.A., Venturelli, R.A., Goehring, B.M., Johnson, J.S., Roberts, S.J., & Rood, D.H.	pdc@bas.ac.uk	Originator

Maintenance and update frequency: Unknown

Keywords

NDGO0001

NERC OAI Harvesting

NERC_DDC

GCMD Parameter Valids

EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets > Glaciers
EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets > Ice Sheets
EARTH SCIENCE > Solid Earth > Geochemistry > Isotopes

BAS Free-text keywords

Accelerator Mass Spectrometry
Amundsen Sea Embayment
Carbon-14
Pope Glacier
Surface exposure ages
erratic cobbles

Use limitation: This data is governed by the NERC data policy http://www.nerc.ac.uk/research/sites/data/policy/ and supplied under Open Government Licence v.3 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/.

Access constraints: Other restrictions

Other constraints: This data is governed by the NERC data policy http://www.nerc.ac.uk/research/sites/data/policy/ and supplied under Open Government Licence v.3 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/.

Language: English

Topic category

Climatology, meteorology, atmosphere
Geoscientific information

Begin date: 2015-12-10

End date: 2016-01-31

Reference system identifier: OGP / urn:ogc:def:crs:EPSG::4326

Distribution format

Distributor contact

Organisation name	Individual name	Electronic mail address	Role
Polar Data Centre - British Antarctic Survey		pdc@bas.ac.uk	Distributor

OnLine resource

Protocol	Linkage	Name
http	http://ramadda.data.bas.ac.uk/repository/entry/show?entryid=dbb30962-bbf3-434a-9f27-6de2f61a86e2	GET DATA

Hierarchy level: Dataset

Domain consistency

Measure identification: INSPIRE / Conformity_001

Conformance result

Title: INSPIRE Data Specification on unknown theme Guidelines

Date

Explanation: See the referenced specification

Pass: No

Statement: Quartz purity was tested using inductively coupled plasma optical emission spectrometry (ICP-OES).

Nine in situ 14C measurements, and four in situ 14C replicate measurements were made. In table AMS_14C.csv aliquot A indicates initial in situ 14C concentrations measured in each sample and aliquot B indicates repeat in situ 14C measurements on the same sample.

A long-term average 14C blank used to correct the initial measurements of in situ 14C (n = 9) is 4.53 +/- 0.24 x 10^4 atoms g-1. For replicate measurements (n = 4), a higher short-term average 14C blank of 7.14 +/- 0.30 x 10^4 14C atoms g-1 was used. A 6 % (1 sigma) uncertainty was assigned to each in 14C measurement concentration reported by AMS before calculating exposure ages. The 6 % uncertainty exceeds the reported analytical uncertainty for all in situ 14C measurements made for this study and reflects the repeatability of measurements of CRONUS-A extracted at Tulane. The in situ 14C concentration of CRONUS-A extracted at Tulane is reported with a long-term value of 6.12 +/- 0.32 x 10^5 (n = 10) (Goehring et al., 2019). The distribution of the long-term 14C measurement background of samples from the Tulane University extraction facility is long-tailed and non-time dependent (Balco et al., 2022).

Blank correction using a long tailed distribution is, therefore, appropriate for low concentration samples such as subglacial bedrock cores (Balco et al., 2023) where blank variability constitutes the dominant source of uncertainty in the in situ 14C measurements (Balco et al., 2022). Blank correction procedures for low concentration samples are discussed at length in Balco et al., (2022) and can be viewed directly via the following link: https://doi.org/10.5194/tc-2022-172-AC2