Isotopic geochemistry of lavas at DSDP Holes 81-553 and 81-555
It is demonstrated by K-Ar analyses that the age of reversely magnetized basalts, which immediately predate magnetic Anomaly 24B, is 53.5 ± 1.9 m.y. Samples from deep levels appear to be grossly contaminated by an extraneous argon component with a uniform argon-40/argon-36 ratio 440. This component...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.807006 2023-05-15T17:35:15+02:00 Isotopic geochemistry of lavas at DSDP Holes 81-553 and 81-555 Macintyre, RM Hamilton, P J MEDIAN LATITUDE: 56.325200 * MEDIAN LONGITUDE: -22.062850 * SOUTH-BOUND LATITUDE: 56.088700 * WEST-BOUND LONGITUDE: -23.343500 * NORTH-BOUND LATITUDE: 56.561700 * EAST-BOUND LONGITUDE: -20.782200 * DATE/TIME START: 1981-08-07T00:00:00 * DATE/TIME END: 1981-08-31T00:00:00 1984-02-09 application/zip, 3 datasets https://doi.pangaea.de/10.1594/PANGAEA.807006 https://doi.org/10.1594/PANGAEA.807006 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.807006 https://doi.org/10.1594/PANGAEA.807006 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Supplement to: Macintyre, RM; Hamilton, P J (1984): Isotopic geochemistry of lavas from Sites 553 and 555. In: Roberts, DG; Schnittker, D; et al. (eds.), Initial Reports of the Deep Sea Drilling Project, Washington (U.S. Govt. Printing Office), 81, 775-781, https://doi.org/10.2973/dsdp.proc.81.130.1984 Deep Sea Drilling Project DSDP Dataset 1984 ftpangaea https://doi.org/10.1594/PANGAEA.807006 https://doi.org/10.2973/dsdp.proc.81.130.1984 2023-01-20T07:32:53Z It is demonstrated by K-Ar analyses that the age of reversely magnetized basalts, which immediately predate magnetic Anomaly 24B, is 53.5 ± 1.9 m.y. Samples from deep levels appear to be grossly contaminated by an extraneous argon component with a uniform argon-40/argon-36 ratio 440. This component is thought to have been derived from fluids circulating in the lava pile during burial. The age result corroborates the assignment previously made to Anomaly 24B by Hailwood et al. (1979) and Lowrie and Alvarez (1981). It additionally suggests that lava extrusion formed part of a much larger magmatic event, which affected wide areas of the North Atlantic margins around the Paleocene/Eocene boundary, and can therefore probably be considered a good estimate of the age of this boundary. Initial 143Nd/144Nd ratios lie in the very restricted range 0.512920 ± 19 to 0.513026 ± 24 and initial 8 7Sr/86Sr ratios from ca. 0.703 to ca. 0.705. Acid leaching reduces the latter range to 0.70264 ± 4 to 0.70384 ± 4, suggesting that the higher 87Sr/86Sr ratios resulted from interaction with seawater. The array of data for treated samples is closely conformable on a 143Nd/144Nd-87Sr/86Sr diagram with the main oceanic mantle array and with previously published fields for Atlantic Ocean basalts. No evidence for any continental crustal contamination has been found. This suggests, but does not prove, that continental crust played no part in the genesis of these rocks. Dataset North Atlantic PANGAEA - Data Publisher for Earth & Environmental Science Alvarez ENVELOPE(-64.483,-64.483,-65.633,-65.633) ENVELOPE(-23.343500,-20.782200,56.561700,56.088700) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
Deep Sea Drilling Project DSDP |
spellingShingle |
Deep Sea Drilling Project DSDP Macintyre, RM Hamilton, P J Isotopic geochemistry of lavas at DSDP Holes 81-553 and 81-555 |
topic_facet |
Deep Sea Drilling Project DSDP |
description |
It is demonstrated by K-Ar analyses that the age of reversely magnetized basalts, which immediately predate magnetic Anomaly 24B, is 53.5 ± 1.9 m.y. Samples from deep levels appear to be grossly contaminated by an extraneous argon component with a uniform argon-40/argon-36 ratio 440. This component is thought to have been derived from fluids circulating in the lava pile during burial. The age result corroborates the assignment previously made to Anomaly 24B by Hailwood et al. (1979) and Lowrie and Alvarez (1981). It additionally suggests that lava extrusion formed part of a much larger magmatic event, which affected wide areas of the North Atlantic margins around the Paleocene/Eocene boundary, and can therefore probably be considered a good estimate of the age of this boundary. Initial 143Nd/144Nd ratios lie in the very restricted range 0.512920 ± 19 to 0.513026 ± 24 and initial 8 7Sr/86Sr ratios from ca. 0.703 to ca. 0.705. Acid leaching reduces the latter range to 0.70264 ± 4 to 0.70384 ± 4, suggesting that the higher 87Sr/86Sr ratios resulted from interaction with seawater. The array of data for treated samples is closely conformable on a 143Nd/144Nd-87Sr/86Sr diagram with the main oceanic mantle array and with previously published fields for Atlantic Ocean basalts. No evidence for any continental crustal contamination has been found. This suggests, but does not prove, that continental crust played no part in the genesis of these rocks. |
format |
Dataset |
author |
Macintyre, RM Hamilton, P J |
author_facet |
Macintyre, RM Hamilton, P J |
author_sort |
Macintyre, RM |
title |
Isotopic geochemistry of lavas at DSDP Holes 81-553 and 81-555 |
title_short |
Isotopic geochemistry of lavas at DSDP Holes 81-553 and 81-555 |
title_full |
Isotopic geochemistry of lavas at DSDP Holes 81-553 and 81-555 |
title_fullStr |
Isotopic geochemistry of lavas at DSDP Holes 81-553 and 81-555 |
title_full_unstemmed |
Isotopic geochemistry of lavas at DSDP Holes 81-553 and 81-555 |
title_sort |
isotopic geochemistry of lavas at dsdp holes 81-553 and 81-555 |
publisher |
PANGAEA |
publishDate |
1984 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.807006 https://doi.org/10.1594/PANGAEA.807006 |
op_coverage |
MEDIAN LATITUDE: 56.325200 * MEDIAN LONGITUDE: -22.062850 * SOUTH-BOUND LATITUDE: 56.088700 * WEST-BOUND LONGITUDE: -23.343500 * NORTH-BOUND LATITUDE: 56.561700 * EAST-BOUND LONGITUDE: -20.782200 * DATE/TIME START: 1981-08-07T00:00:00 * DATE/TIME END: 1981-08-31T00:00:00 |
long_lat |
ENVELOPE(-64.483,-64.483,-65.633,-65.633) ENVELOPE(-23.343500,-20.782200,56.561700,56.088700) |
geographic |
Alvarez |
geographic_facet |
Alvarez |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Supplement to: Macintyre, RM; Hamilton, P J (1984): Isotopic geochemistry of lavas from Sites 553 and 555. In: Roberts, DG; Schnittker, D; et al. (eds.), Initial Reports of the Deep Sea Drilling Project, Washington (U.S. Govt. Printing Office), 81, 775-781, https://doi.org/10.2973/dsdp.proc.81.130.1984 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.807006 https://doi.org/10.1594/PANGAEA.807006 |
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.807006 https://doi.org/10.2973/dsdp.proc.81.130.1984 |
_version_ |
1766134363093729280 |