Citation:

tc-11-2427-2017

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Abstract:

Ice sheets provide exceptional archives of past changes in polar climate, regional environment and global atmospheric composition. The oldest dated deep ice core drilled in Antarctica has been retrieved at EPICA Dome C (EDC), reaching ~800,000 years. Obtaining an older paleoclimatic record from Antarctica is one of the greatest challenges of the ice core community. Here, we use internal isochrones, identified from airborne radar coupled to ice-flow modelling to estimate the age of basal ice along transects in the Dome C area. Three glaciological properties are inverted from isochrones: surface accumulation rate; geothermal flux; and the exponent of the Lliboutry velocity profile. We find that old ice (>1 Myr, 1 million years) likely exists in two regions: one ~40 km south-west of Dome C along the ice divide to Vostok, close to a secondary dome that we name "Little Dome C" (LDC); and a second region named "North Patch" (NP) located 10-30 km north-east of Dome C, in a region where the geothermal flux is apparently relatively low. Our work demonstrates the value of combining radar observations with ice flow modelling to accurately represent the true nature of ice flow, and the formation of ice-sheet architecture, in the centre of large ice sheets.

Coverage:

Median Latitude: -75.501334 * Median Longitude: 121.726843 * South-bound Latitude: -77.048737 * West-bound Longitude: 112.418242 * North-bound Latitude: -73.770612 * East-bound Longitude: 127.557975

Event(s):

DomeC_area * Latitude Start: -74.220000 * Longitude Start: 111.970000 * Latitude End: -76.680000 * Longitude End: 128.650000 * Location: Antarctica * Method/Device: Multiple investigations (MULT)

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Comment
1	LONGITUDE	Longitude		Parrenin, Frédéric	Geocode
2	LATITUDE	Latitude		Parrenin, Frédéric	Geocode
3	Distance	Distance	km	Parrenin, Frédéric	along a radar line
4	Ice thickness	Ice thick	m	Parrenin, Frédéric
5	Accumulation rate in ice equivalent per year	Acc rate ice per year	m/a	Parrenin, Frédéric	surface accumulation
6	Accumulation rate, standard deviation	Acc rate std dev	±	Parrenin, Frédéric
7	Ground heat, flux	Ground heat flux	W/m²	Parrenin, Frédéric
8	Ground heat, flux, standard deviation	Ground heat flux std dev	±	Parrenin, Frédéric
9	Factor	Factor		Parrenin, Frédéric	pprime = log(p+1), p is the Llibourty exponent of the velocity profile
10	Standard deviation	Std dev	±	Parrenin, Frédéric	pprime
11	Melt rate	Melt rate	m/a	Parrenin, Frédéric	basal melting
12	Melt rate, standard deviation	Melt rate std dev	±	Parrenin, Frédéric
13	AGE	Age	ka BP	Parrenin, Frédéric	Geocode – 60 m above bedrock
14	AGE	Age	ka BP	Parrenin, Frédéric	Geocode – Minimum age of the ice (at 1 sigma) 60 m above bedrock
15	AGE	Age	ka BP	Parrenin, Frédéric	Geocode – 100 m above bedrock
16	AGE	Age	ka BP	Parrenin, Frédéric	Geocode – 150 m above bedrock
17	AGE	Age	ka BP	Parrenin, Frédéric	Geocode – 200 m above bedrock
18	AGE	Age	ka BP	Parrenin, Frédéric	Geocode – 250 m above bedrock
19	Number of years	Years	a	Parrenin, Frédéric	per meter at 1 Myr
20	Number of years	Years	a	Parrenin, Frédéric	per meter at 1.2 Myr
21	Number of years	Years	a	Parrenin, Frédéric	per meter at 1.5 Myr
22	Height	Height	m	Parrenin, Frédéric	above the bed of the 0.6 Myr isochrone
23	Height	Height	m	Parrenin, Frédéric	above the bed of the 0.8 Myr isochrone
24	Height	Height	m	Parrenin, Frédéric	above the bed of the 1 Myr isochrone
25	Height	Height	m	Parrenin, Frédéric	above the bed of the 1.2 Myr isochrone
26	Height	Height	m	Parrenin, Frédéric	above the bed of the 1.5 Myr isochrone

License:

Creative Commons Attribution 3.0 Unported (CC-BY-3.0)

Size:

95189 data points

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