Summary of 40Ar/39Ar results from sediment core CRP-2A (Table 1)
40Ar/39Ar analyses of tephra and clasts of volcanic rock provide age constraints for upper parts of the CRP-2A core. Single-crystal laser-fusion analyses of anorthoclase phenocrysts from three tephra-bearing layers yielded the most precise age constraints for CRP-2A. The dated tephra layers are: 1)...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.194709 2023-05-15T13:45:35+02:00 Summary of 40Ar/39Ar results from sediment core CRP-2A (Table 1) McIntosh, W C LATITUDE: -77.005980 * LONGITUDE: 163.719450 * DATE/TIME START: 1998-10-16T07:30:00 * DATE/TIME END: 1998-11-25T14:20:00 * MINIMUM DEPTH, sediment/rock: 36.02 m * MAXIMUM DEPTH, sediment/rock: 453.58 m 2004-07-12 text/tab-separated-values, 103 data points https://doi.pangaea.de/10.1594/PANGAEA.194709 https://doi.org/10.1594/PANGAEA.194709 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.194709 https://doi.org/10.1594/PANGAEA.194709 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Supplement to: McIntosh, W C (2000): 40Ar/39Ar geochronology of tephra and volcanic clasts in CRP-2A, Victoria Land Basin, Antarctica. Terra Antartica, 7(4), 621-630, hdl:10013/epic.28247.d001 14.2 km at 096° true from Cape Roberts Age dated dated material error Argon-39 Calcium/Potassium ratio Cape Roberts Project Comment Core wireline system CRP CRP-2 CRP-2A CWS DEPTH sediment/rock Isotope ratio mass spectrometry Number off Cape Roberts Ross Sea Antarctica Sample comment Sample ID Sample method Sampling/drilling from ice see comment Dataset 2004 ftpangaea https://doi.org/10.1594/PANGAEA.194709 2023-01-20T07:50:16Z 40Ar/39Ar analyses of tephra and clasts of volcanic rock provide age constraints for upper parts of the CRP-2A core. Single-crystal laser-fusion analyses of anorthoclase phenocrysts from three tephra-bearing layers yielded the most precise age constraints for CRP-2A. The dated tephra layers are: 1) a 2.7-m-thick interval of pumice and ash layers between 111.5 and 114.2 meters below sea floor (mbsf) (weighted mean age = 21.44 ± 0.05 Ma, +2.2); 2) a concentration of pumice near 193.4 mbsf (23.98 ± 0.13 Ma): and 3) a concentration of pumice near 280 mbsf (24,22 ± 0.03 Ma) (all ages are calibrated relative to Fish Canyon Tuff sanidine at 27.84 Ma). The 111 to 114 mbsf tephra is almost entirely non-reworked, and the 193 mbsf and 280 mbsf tephra concentrations are interpreted as being reworked and redeposited soon after eruption. All three of the tephra ages are therefore considered to be equivalent to depositional ages. The variation in precision of these three age determinations is largely a function of phenocryst size and abundance. The accuracy of these ages is equal to the accuracy of the current calibration of the 40Ar/39Ar methode (about ± 1 %). 40Ar/39Ar results from volcanic clasts provide three additional maximum age constraints for the CRP-2A core. Single-crystal laser-fusion of sanidine phenocrysts from a rhyolitic clast from 294 mbsf yielded a precise maximum depositional age of 24.98 ± 0.08 Ma, and plateau ages of groundmass concentrates from basaltic clasts near 36.02 mbsf and 125.92 mbsf yielded maximum depositional ages of 19.18 ± 0.12 Ma, and 22.56 ± 0.14 Ma, respectively. The 40Ar/39Ar data, in association with biostratigraphic, paleomagnetic, and isotopic age constraints for CRP-2A, confirm interpretation for rapid sedimentation rates in the 36 to 280 mbsf interval, particularly in the 193 to 280 mbsf interval where they support interpretations for sedimentation cycles spanning 100 k.y. intervals. In addition to the 19 to 25 Ma ages measured from thephra layers and clasts, provenance-related ages ... Dataset Antarc* Antarctica Ross Sea PANGAEA - Data Publisher for Earth & Environmental Science Ross Sea Cape Roberts ENVELOPE(-70.467,-70.467,-68.950,-68.950) ENVELOPE(163.719450,163.719450,-77.005980,-77.005980) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
14.2 km at 096° true from Cape Roberts Age dated dated material error Argon-39 Calcium/Potassium ratio Cape Roberts Project Comment Core wireline system CRP CRP-2 CRP-2A CWS DEPTH sediment/rock Isotope ratio mass spectrometry Number off Cape Roberts Ross Sea Antarctica Sample comment Sample ID Sample method Sampling/drilling from ice see comment |
spellingShingle |
14.2 km at 096° true from Cape Roberts Age dated dated material error Argon-39 Calcium/Potassium ratio Cape Roberts Project Comment Core wireline system CRP CRP-2 CRP-2A CWS DEPTH sediment/rock Isotope ratio mass spectrometry Number off Cape Roberts Ross Sea Antarctica Sample comment Sample ID Sample method Sampling/drilling from ice see comment McIntosh, W C Summary of 40Ar/39Ar results from sediment core CRP-2A (Table 1) |
topic_facet |
14.2 km at 096° true from Cape Roberts Age dated dated material error Argon-39 Calcium/Potassium ratio Cape Roberts Project Comment Core wireline system CRP CRP-2 CRP-2A CWS DEPTH sediment/rock Isotope ratio mass spectrometry Number off Cape Roberts Ross Sea Antarctica Sample comment Sample ID Sample method Sampling/drilling from ice see comment |
description |
40Ar/39Ar analyses of tephra and clasts of volcanic rock provide age constraints for upper parts of the CRP-2A core. Single-crystal laser-fusion analyses of anorthoclase phenocrysts from three tephra-bearing layers yielded the most precise age constraints for CRP-2A. The dated tephra layers are: 1) a 2.7-m-thick interval of pumice and ash layers between 111.5 and 114.2 meters below sea floor (mbsf) (weighted mean age = 21.44 ± 0.05 Ma, +2.2); 2) a concentration of pumice near 193.4 mbsf (23.98 ± 0.13 Ma): and 3) a concentration of pumice near 280 mbsf (24,22 ± 0.03 Ma) (all ages are calibrated relative to Fish Canyon Tuff sanidine at 27.84 Ma). The 111 to 114 mbsf tephra is almost entirely non-reworked, and the 193 mbsf and 280 mbsf tephra concentrations are interpreted as being reworked and redeposited soon after eruption. All three of the tephra ages are therefore considered to be equivalent to depositional ages. The variation in precision of these three age determinations is largely a function of phenocryst size and abundance. The accuracy of these ages is equal to the accuracy of the current calibration of the 40Ar/39Ar methode (about ± 1 %). 40Ar/39Ar results from volcanic clasts provide three additional maximum age constraints for the CRP-2A core. Single-crystal laser-fusion of sanidine phenocrysts from a rhyolitic clast from 294 mbsf yielded a precise maximum depositional age of 24.98 ± 0.08 Ma, and plateau ages of groundmass concentrates from basaltic clasts near 36.02 mbsf and 125.92 mbsf yielded maximum depositional ages of 19.18 ± 0.12 Ma, and 22.56 ± 0.14 Ma, respectively. The 40Ar/39Ar data, in association with biostratigraphic, paleomagnetic, and isotopic age constraints for CRP-2A, confirm interpretation for rapid sedimentation rates in the 36 to 280 mbsf interval, particularly in the 193 to 280 mbsf interval where they support interpretations for sedimentation cycles spanning 100 k.y. intervals. In addition to the 19 to 25 Ma ages measured from thephra layers and clasts, provenance-related ages ... |
format |
Dataset |
author |
McIntosh, W C |
author_facet |
McIntosh, W C |
author_sort |
McIntosh, W C |
title |
Summary of 40Ar/39Ar results from sediment core CRP-2A (Table 1) |
title_short |
Summary of 40Ar/39Ar results from sediment core CRP-2A (Table 1) |
title_full |
Summary of 40Ar/39Ar results from sediment core CRP-2A (Table 1) |
title_fullStr |
Summary of 40Ar/39Ar results from sediment core CRP-2A (Table 1) |
title_full_unstemmed |
Summary of 40Ar/39Ar results from sediment core CRP-2A (Table 1) |
title_sort |
summary of 40ar/39ar results from sediment core crp-2a (table 1) |
publisher |
PANGAEA |
publishDate |
2004 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.194709 https://doi.org/10.1594/PANGAEA.194709 |
op_coverage |
LATITUDE: -77.005980 * LONGITUDE: 163.719450 * DATE/TIME START: 1998-10-16T07:30:00 * DATE/TIME END: 1998-11-25T14:20:00 * MINIMUM DEPTH, sediment/rock: 36.02 m * MAXIMUM DEPTH, sediment/rock: 453.58 m |
long_lat |
ENVELOPE(-70.467,-70.467,-68.950,-68.950) ENVELOPE(163.719450,163.719450,-77.005980,-77.005980) |
geographic |
Ross Sea Cape Roberts |
geographic_facet |
Ross Sea Cape Roberts |
genre |
Antarc* Antarctica Ross Sea |
genre_facet |
Antarc* Antarctica Ross Sea |
op_source |
Supplement to: McIntosh, W C (2000): 40Ar/39Ar geochronology of tephra and volcanic clasts in CRP-2A, Victoria Land Basin, Antarctica. Terra Antartica, 7(4), 621-630, hdl:10013/epic.28247.d001 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.194709 https://doi.org/10.1594/PANGAEA.194709 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/PANGAEA.194709 |
_version_ |
1766227770594033664 |