Cosmogenic Be-10 and Al-26 data for glacial erratics from the Marble Hills, southern Ellsworth Mountains, Antarctica

Please cite: Todd C.E., Stone J.O. and Mann D.; Deglaciation of the southern Ellsworth Mountains, Weddell Sea Sector of the West Antarctic Ice Sheet. 2004 West Antarctic Ice Sheet workshop abstract, in reference to these data.

Sample Latitude Longitude Altitude Scaling (1) Scaling (1) Thickness Horizon Be-10 prod'n rate (2) [Be-10] (3) Exposure age (4) Internal error (5) [Al] qtz Natural Al-26/Al-27 Al-26 prod'n rate (2) [Al-26] (6) Exposure age (4) Internal error (5)
(deg S) (deg W) (m asl) (spallation) (muons) correction correction (atom/g/yr) (106 atom/g) (kyr) (kyr) (ppm) (x10-12) (atom/g/yr) (106 atom/g) (kyr) (kyr)
Site B (1390 m)
MH-008-BA 80.2631 82.1872 1390 4.522 2.189 0.931 1.000 21.08 ± 1.25 12.56 ± 0.15 697 ± 50 10 108.1 ± 0.8 26.04 ± 0.81 128.4 ± 7.8 62.8 ± 1.9 667 ± 64 29
MH-010-BC 80.2631 82.1872 1390 4.522 2.189 0.953 1.000 21.57 ± 1.28 9.19 ± 0.15 474 ± 33 9 225.5 ± 3.7 10.12 ± 0.41 131.4 ± 8.0 50.9 ± 1.9 488 ± 44 23
MH-012-BE 80.2631 821872 1390 4.522 2.189 0.944 1.000 21.36 ± 1.27 12.15 ± 0.18 660 ± 47 11 201 ± 1.3 14.30 ± 0.37 130.1 ± 7.9 64.2 ± 1.6 675 ± 63 24
MH-012-BE-RPT 80.2631 82.1872 1390 4.522 2.189 0.944 1.000 21.36 ± 1.27 12.00 ± 0.14 651 ± 46 9 187 ± 0.5 15.53 ± 0.38 130.1 ± 7.9 64.8 ± 1.6 685 ± 64 24
MH-013-BF 80.2631 82.1872 1390 4.522 2.189 0.950 1.000 21.50 ± 1.27 13.69 ± 0.17 754 ± 55 11 145.7 ± 1.0 22.60 ± 0.68 131.0 ± 7.9 73.5 ± 2.1 816 ± 84 36
Site C (1340 m)
MH-014-C1 80.2650 82.1906 1340 4.342 2.140 0.965 1.000 20.97 ± 1.24 1.38 ± 0.06 66.9 ± 5.0 2.9
MH-015-C2 80.2650 82.1906 1340 4.342 2.140 0.969 1.000 21.06 ± 1.25 1.23 ± 0.03 59.0 ± 3.9 1.6 118.5 ± 0.5 2.61 ± 0.11 128.3 ± 7.8 6.90 ± 0.30 55.3 ± 4.2 2.4
MH-016-C3 80.2650 82.1906 1340 4.342 2.140 0.961 1.000 20.89 ± 1.24 1.37 ± 0.03 66.7 ± 4.3 1.4 142.3 ± 0.7 2.08 ± 0.07 127.3 ± 7.7 6.62 ± 0.22 53.4 ± 3.8 1.9
MH-018-C5 80.2650 82.1903 1340 4.342 2.140 0.948 1.000 20.60 ± 1.22 0.81 ± 0.019 39.7 ± 2.6 1.0 115.7 ± 1.1 1.69 ± 0.09 125.5 ± 7.6 4.37 ± 0.22 35.4 ± 2.9 1.9
Site A (1250 m)
MH-001-A1 80.2672 82.1289 1250 4.032 2.055 0.959 1.000 19.36 ± 1.15 0.204 ± 0.017 10.6 ± 1.1 0.9
MH-001-A1-RPT 80.2672 82.1289 1250 4.032 2.055 0.959 1.000 19.36 ± 1.15 0.200 ± 0.021 10.3 ± 1.3 1.1
MH-002-A2 80.2672 82.1289 1250 4.032 2.055 0.951 1.000 19.20 ± 1.14 0.133 ± 0.003 6.9 ± 0.4 0.2
MH-002-A2-RPT 80.2672 82.1289 1250 4.032 2.055 0.951 1.000 19.20 ± 1.14 0.126 ± 0.005 6.6 ± 0.5 0.3
MH-003-A3 80.2672 82.1289 1250 4.032 2.055 0.947 1.000 19.12 ± 1.13 0.216 ± 0.010 11.3 ± 0.9 0.5
MH-004-A4 80.2669 82.1358 1250 4.032 2.055 0.942 1.000 19.02 ± 1.13 0.554 ± 0.027 29.4 ± 2.3 1.5
MH-007-A7 80.2669 82.1358 1250 4.032 2.055 0.943 1.000 19.04 ± 1.13 0.191 ± 0.005 10.1 ± 0.6 0.2
Site D (1130 m)
MH-019-DA 80.2664 82.1047 1130 3.646 1.944 0.956 0.994 17.36 ± 1.03 0.925 ± 0.028 54.0 ± 3.6 1.7
MH-019-DA-RPT 80.2664 82.1047 1130 3.646 1.944 0.956 0.994 17.36 ± 1.03 0.899 ± 0.051 52.4 ± 4.4 3.0
MH-020-DB 80.2828 82.1033 1130 3.646 1.944 0.973 1.000 17.78 ± 1.05 0.416 ± 0.031 23.5 ± 2.2 1.7
MH-022-DD 80.2828 82.1036 1130 3.646 1.944 0.965 1.000 17.62 ± 1.04 2.79 ± 0.06 165 ± 11 4.0 179.3 ± 0.8 4.11 ± 0.14 107.4 ± 6.5 16.43 ± 0.55 166 ± 12 6
Site E (980 m)
MH-025-E2 80.2408 82.1992 980 3.205 1.812 0.969 1.000 15.57 ± 0.92 0.058 ± 0.012 3.7 ± 0.8 0.7
MH-026-E3 80.2406 82.1986 980 3.205 1.812 0.940 1.000 15.10 ± 0.90 0.063 ± 0.019 4.2 ± 1.3 1.2
MH-027-E4 80.2406 82.1986 980 3.205 1.812 0.965 1.000 15.50 ± 0.92 1.026 ± 0.028 67.2 ± 4.5 1.9
Site F (870 m)
MH-029-F1 80.2414 82.1506 870 2.909 1.720 0.969 1.000 14.14 ± 0.84 0.018 ± 0.039 1.3 ± 2.7 2.7
MH-031-F3 80.2414 82.1506 870 2.909 1.720 0.969 1.000 14.14 ± 0.84 0.005 ± 0.0004 0.35 ± 0.03 0.03

(1) Correction factor relative to 1013.25 mbar and latitude > 60 degrees based on estimated mean annual air pressure, as described by Stone (2000).

(2) Assumed surface production rates: (1) Be-10: Spallation: 4.95 +/- 0.30; negative muon capture: 0.11 +/- 0.02 atom/g SiO2/yr (2) Al-26: Spallation: 30.2 +/- 1.8; negative muon capture: 0.67 +/- 0.12 atom/g SiO2/yr, at 1013.25 mbar and latitude > 60 degrees (Stone, 2000).

(3) Measured relative to LLNL working Be-10/Be-9 standards, traceable to ICN Be-10 standard. Uncertainties propagated at ±1 sigma level including all known sources of analytical error.

(4) Calculated simple exposure ages. If pre-exposed samples are old erratics that were overrun and buried during previous glaciations, these are lower limits to the cumulative exposure time. Uncertainties are ±1 sigma (68% confidence) including Be-10 measurement uncertainties (see above) and assumed ±6% error in Be-10 production rate. Use this uncertainty when comparing to the results of other geochronological methods.

(5) Internal error, based on measurement uncertainties only, propagated at ±1 sigma (68% confidence) level. Use this uncertainty when comparing to Be-10 and Al-26 exposure ages based on the production rates listed above.

(6) Measured relative to KNSTD/Livermore Al-26 standards. Uncertainties propagated at ±1 sigma level including all known sources of analytical error.