Nd, Sr and Pb isotopic composition of eolian dust deposited in the central North Pacific
The silicate fractions of recent pelagic sediments in the central north Pacific Ocean are dominated by eolian dust derived from central Asia. An 11 Myr sedimentary record at ODP Sites 885/886 at 44.7°N, 168.3°W allows the evaluation of how such dust and its sources have changed in response to late C...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.711212 2024-09-15T18:16:04+00:00 Nd, Sr and Pb isotopic composition of eolian dust deposited in the central North Pacific Pettke, Thomas Halliday, Alex N Hall, Chris M Rea, David K MEDIAN LATITUDE: 44.688767 * MEDIAN LONGITUDE: 176.101333 * SOUTH-BOUND LATITUDE: 44.688300 * WEST-BOUND LONGITUDE: 168.272000 * NORTH-BOUND LATITUDE: 44.689700 * EAST-BOUND LONGITUDE: -168.240000 * DATE/TIME START: 1992-04-09T18:15:00 * DATE/TIME END: 1992-09-05T06:15:00 2000 application/zip, 3 datasets https://doi.pangaea.de/10.1594/PANGAEA.711212 https://doi.org/10.1594/PANGAEA.711212 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.711212 https://doi.org/10.1594/PANGAEA.711212 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess Supplement to: Pettke, Thomas; Halliday, Alex N; Hall, Chris M; Rea, David K (2000): Dust production and deposition in Asia and the north Pacific Ocean over the past 12 Myr. Earth and Planetary Science Letters, 178(3-4), 397-413, https://doi.org/10.1016/S0012-821X(00)00083-2 145-885A 145-886B DRILL Drilling/drill rig Joides Resolution Leg145 North Pacific Ocean Ocean Drilling Program ODP dataset publication series 2000 ftpangaea https://doi.org/10.1594/PANGAEA.71121210.1016/S0012-821X(00)00083-2 2024-07-24T02:31:42Z The silicate fractions of recent pelagic sediments in the central north Pacific Ocean are dominated by eolian dust derived from central Asia. An 11 Myr sedimentary record at ODP Sites 885/886 at 44.7°N, 168.3°W allows the evaluation of how such dust and its sources have changed in response to late Cenozoic climate and tectonics. The extracted eolian fraction contains variable amounts (>70%) of clay minerals with subordinate quartz and plagioclase. Uniform Nd isotopic compositions (epsilon-Nd =38.6 to 310.5) and Sm/Nd ratios (0.170-0.192) for most of the 11 Myr record demonstrate a well-mixed provenance in the basins north of the Tibetan Plateau and the Gobi Desert that was a source of dust long before the oldest preserved Asian loess formed. epsilon-Nd values of up to 36.5 for samples 62.9 Ma indicate <=35 wt% admixture of a young, Kamchatka-like volcanic arc component. The coherence of Pb and Nd in the erosional cycle allows us to constrain the Pb isotopic composition of Asian loess devoid of anthropogenic contamination to 206Pb/204Pb =18.97 +/- 0.06, 207Pb/204Pb =15.67 +/- 0.02, 208Pb/204Pb =39.19 +/- 0.11. 87Sr/86Sr (0.711-0.721) and Rb/Sr ratios (0.39-1.1) vary with dust mineralogy and provide an age indication of ~250 Ma. 40Ar/39Ar ages of six dust samples are uniform around 200 Ma and match the K-Ar ages of modern dust deposited on Hawaii. These data reflect the weighted age average of illite formation. Changes from illite- smectite with significant kaolinite to illite- and chlorite-rich, kaolinite-free assemblages since the late Pliocene document changes in the intensity of chemical weathering in the source region. Such weathering evidently did not disturb the K-Ar systematics, and only induced scatter in the Rb-Sr data. We propose that when smectite forms at the expense of illite, K and Ar are quantitatively lost from what becomes smectite, but are quantitatively retained in adjacent illite layers. 40Ar/39Ar age data, therefore, are insensitive to smectite formation during chemical weathering but ... Other/Unknown Material Kamchatka PANGAEA - Data Publisher for Earth & Environmental Science ENVELOPE(168.272000,-168.240000,44.689700,44.688300) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
145-885A 145-886B DRILL Drilling/drill rig Joides Resolution Leg145 North Pacific Ocean Ocean Drilling Program ODP |
spellingShingle |
145-885A 145-886B DRILL Drilling/drill rig Joides Resolution Leg145 North Pacific Ocean Ocean Drilling Program ODP Pettke, Thomas Halliday, Alex N Hall, Chris M Rea, David K Nd, Sr and Pb isotopic composition of eolian dust deposited in the central North Pacific |
topic_facet |
145-885A 145-886B DRILL Drilling/drill rig Joides Resolution Leg145 North Pacific Ocean Ocean Drilling Program ODP |
description |
The silicate fractions of recent pelagic sediments in the central north Pacific Ocean are dominated by eolian dust derived from central Asia. An 11 Myr sedimentary record at ODP Sites 885/886 at 44.7°N, 168.3°W allows the evaluation of how such dust and its sources have changed in response to late Cenozoic climate and tectonics. The extracted eolian fraction contains variable amounts (>70%) of clay minerals with subordinate quartz and plagioclase. Uniform Nd isotopic compositions (epsilon-Nd =38.6 to 310.5) and Sm/Nd ratios (0.170-0.192) for most of the 11 Myr record demonstrate a well-mixed provenance in the basins north of the Tibetan Plateau and the Gobi Desert that was a source of dust long before the oldest preserved Asian loess formed. epsilon-Nd values of up to 36.5 for samples 62.9 Ma indicate <=35 wt% admixture of a young, Kamchatka-like volcanic arc component. The coherence of Pb and Nd in the erosional cycle allows us to constrain the Pb isotopic composition of Asian loess devoid of anthropogenic contamination to 206Pb/204Pb =18.97 +/- 0.06, 207Pb/204Pb =15.67 +/- 0.02, 208Pb/204Pb =39.19 +/- 0.11. 87Sr/86Sr (0.711-0.721) and Rb/Sr ratios (0.39-1.1) vary with dust mineralogy and provide an age indication of ~250 Ma. 40Ar/39Ar ages of six dust samples are uniform around 200 Ma and match the K-Ar ages of modern dust deposited on Hawaii. These data reflect the weighted age average of illite formation. Changes from illite- smectite with significant kaolinite to illite- and chlorite-rich, kaolinite-free assemblages since the late Pliocene document changes in the intensity of chemical weathering in the source region. Such weathering evidently did not disturb the K-Ar systematics, and only induced scatter in the Rb-Sr data. We propose that when smectite forms at the expense of illite, K and Ar are quantitatively lost from what becomes smectite, but are quantitatively retained in adjacent illite layers. 40Ar/39Ar age data, therefore, are insensitive to smectite formation during chemical weathering but ... |
format |
Other/Unknown Material |
author |
Pettke, Thomas Halliday, Alex N Hall, Chris M Rea, David K |
author_facet |
Pettke, Thomas Halliday, Alex N Hall, Chris M Rea, David K |
author_sort |
Pettke, Thomas |
title |
Nd, Sr and Pb isotopic composition of eolian dust deposited in the central North Pacific |
title_short |
Nd, Sr and Pb isotopic composition of eolian dust deposited in the central North Pacific |
title_full |
Nd, Sr and Pb isotopic composition of eolian dust deposited in the central North Pacific |
title_fullStr |
Nd, Sr and Pb isotopic composition of eolian dust deposited in the central North Pacific |
title_full_unstemmed |
Nd, Sr and Pb isotopic composition of eolian dust deposited in the central North Pacific |
title_sort |
nd, sr and pb isotopic composition of eolian dust deposited in the central north pacific |
publisher |
PANGAEA |
publishDate |
2000 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.711212 https://doi.org/10.1594/PANGAEA.711212 |
op_coverage |
MEDIAN LATITUDE: 44.688767 * MEDIAN LONGITUDE: 176.101333 * SOUTH-BOUND LATITUDE: 44.688300 * WEST-BOUND LONGITUDE: 168.272000 * NORTH-BOUND LATITUDE: 44.689700 * EAST-BOUND LONGITUDE: -168.240000 * DATE/TIME START: 1992-04-09T18:15:00 * DATE/TIME END: 1992-09-05T06:15:00 |
long_lat |
ENVELOPE(168.272000,-168.240000,44.689700,44.688300) |
genre |
Kamchatka |
genre_facet |
Kamchatka |
op_source |
Supplement to: Pettke, Thomas; Halliday, Alex N; Hall, Chris M; Rea, David K (2000): Dust production and deposition in Asia and the north Pacific Ocean over the past 12 Myr. Earth and Planetary Science Letters, 178(3-4), 397-413, https://doi.org/10.1016/S0012-821X(00)00083-2 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.711212 https://doi.org/10.1594/PANGAEA.711212 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1594/PANGAEA.71121210.1016/S0012-821X(00)00083-2 |
_version_ |
1810454041279332352 |