Planktonic foraminifera in late Quaternary turbidite sequences at ODP Leg 139 holes, supplement to: Brunner, Charlotte A (1994): Planktonic foraminiferal biostratigraphy and paleoceanography of late Quaternary turbidite sequences at Holes 856A, 857A, and 857C, Leg 139. In: Mottl, MJ; Davis, EE; Fisher, AT; Slack, JF (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 139, 39-58
Late Quaternary planktonic foraminiferal biostratigraphy and paleoceanography were examined at two sites from the east margin of Middle Valley of the northern Juan de Fuca Ridge. Calcareous microfossils are abundant and well preserved in the upper sequences where thermal and hydrothermal alteration...
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1994
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ftdatacite:10.1594/pangaea.819489 2023-05-15T17:15:01+02:00 Planktonic foraminifera in late Quaternary turbidite sequences at ODP Leg 139 holes, supplement to: Brunner, Charlotte A (1994): Planktonic foraminiferal biostratigraphy and paleoceanography of late Quaternary turbidite sequences at Holes 856A, 857A, and 857C, Leg 139. In: Mottl, MJ; Davis, EE; Fisher, AT; Slack, JF (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 139, 39-58 Brunner, Charlotte A 1994 application/zip https://dx.doi.org/10.1594/pangaea.819489 https://doi.pangaea.de/10.1594/PANGAEA.819489 en eng PANGAEA - Data Publisher for Earth & Environmental Science https://dx.doi.org/10.2973/odp.proc.sr.139.206.1994 Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode cc-by-3.0 CC-BY Ocean Drilling Program ODP Supplementary Collection of Datasets Collection article 1994 ftdatacite https://doi.org/10.1594/pangaea.819489 https://doi.org/10.2973/odp.proc.sr.139.206.1994 2022-02-08T16:24:46Z Late Quaternary planktonic foraminiferal biostratigraphy and paleoceanography were examined at two sites from the east margin of Middle Valley of the northern Juan de Fuca Ridge. Calcareous microfossils are abundant and well preserved in the upper sequences where thermal and hydrothermal alteration is minimal and where deposition occurred after sites were tectonically raised above the turbidite plain of the axial valley. Approximately 200 samples were examined to determine depositional style and foraminiferal content including a census of planktonic foraminifers. Approximately 60% of the samples contain turbiditic material, so paleontologic interpretations must be made with caution.Ocean Drilling Program (ODP) Holes 856Aand 857 A contain abundant foraminifers above 52 and 85 mbsf, respectively. The fossiliferous sequences are divided into four informal coiling direction zones based on the species Neogloboquadrina pachyderma (Ehrenberg) and numbered from 1 to 4 from top to bottom of the sequences. Coiling direction zones 1 and 3 contain <90% sinistral forms and include the lower part of the present and penultimate interglacial periods and perhaps part of the glacial termination. Coiling direction zones 2 and 4 contain >90% sinistral forms and span most of the last two glacial periods. The bases of coiling direction zones 1 and 3 define two datum levels tentatively dated at 11,000 and 125,000 yr ago, respectively.Cluster analysis identified three assemblages: a subarctic assemblage, a transitional assemblage, and a subarctic dissolution assemblage. The subarctic dissolution assemblage occurs infrequently and sporadically throughout the unaltered glacial intervals in Holes 856A and 857A. In contrast, the dissolution assemblage dominates Hole 856A below 22 mbsf and is related to calcite precipitation driven by hydrothermal processes. The transitional assemblage appears in coiling direction zone 3 and records the close approach of the subpolar boundary to the ODP Leg 139 locale during the penultimate interglacial period. The subpolar boundary remained south of the study site at approximately 48°30'N latitude throughout the late Quaternary. Article in Journal/Newspaper Neogloboquadrina pachyderma Planktonic foraminifera Subarctic DataCite Metadata Store (German National Library of Science and Technology) |
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Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
English |
topic |
Ocean Drilling Program ODP |
spellingShingle |
Ocean Drilling Program ODP Brunner, Charlotte A Planktonic foraminifera in late Quaternary turbidite sequences at ODP Leg 139 holes, supplement to: Brunner, Charlotte A (1994): Planktonic foraminiferal biostratigraphy and paleoceanography of late Quaternary turbidite sequences at Holes 856A, 857A, and 857C, Leg 139. In: Mottl, MJ; Davis, EE; Fisher, AT; Slack, JF (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 139, 39-58 |
topic_facet |
Ocean Drilling Program ODP |
description |
Late Quaternary planktonic foraminiferal biostratigraphy and paleoceanography were examined at two sites from the east margin of Middle Valley of the northern Juan de Fuca Ridge. Calcareous microfossils are abundant and well preserved in the upper sequences where thermal and hydrothermal alteration is minimal and where deposition occurred after sites were tectonically raised above the turbidite plain of the axial valley. Approximately 200 samples were examined to determine depositional style and foraminiferal content including a census of planktonic foraminifers. Approximately 60% of the samples contain turbiditic material, so paleontologic interpretations must be made with caution.Ocean Drilling Program (ODP) Holes 856Aand 857 A contain abundant foraminifers above 52 and 85 mbsf, respectively. The fossiliferous sequences are divided into four informal coiling direction zones based on the species Neogloboquadrina pachyderma (Ehrenberg) and numbered from 1 to 4 from top to bottom of the sequences. Coiling direction zones 1 and 3 contain <90% sinistral forms and include the lower part of the present and penultimate interglacial periods and perhaps part of the glacial termination. Coiling direction zones 2 and 4 contain >90% sinistral forms and span most of the last two glacial periods. The bases of coiling direction zones 1 and 3 define two datum levels tentatively dated at 11,000 and 125,000 yr ago, respectively.Cluster analysis identified three assemblages: a subarctic assemblage, a transitional assemblage, and a subarctic dissolution assemblage. The subarctic dissolution assemblage occurs infrequently and sporadically throughout the unaltered glacial intervals in Holes 856A and 857A. In contrast, the dissolution assemblage dominates Hole 856A below 22 mbsf and is related to calcite precipitation driven by hydrothermal processes. The transitional assemblage appears in coiling direction zone 3 and records the close approach of the subpolar boundary to the ODP Leg 139 locale during the penultimate interglacial period. The subpolar boundary remained south of the study site at approximately 48°30'N latitude throughout the late Quaternary. |
format |
Article in Journal/Newspaper |
author |
Brunner, Charlotte A |
author_facet |
Brunner, Charlotte A |
author_sort |
Brunner, Charlotte A |
title |
Planktonic foraminifera in late Quaternary turbidite sequences at ODP Leg 139 holes, supplement to: Brunner, Charlotte A (1994): Planktonic foraminiferal biostratigraphy and paleoceanography of late Quaternary turbidite sequences at Holes 856A, 857A, and 857C, Leg 139. In: Mottl, MJ; Davis, EE; Fisher, AT; Slack, JF (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 139, 39-58 |
title_short |
Planktonic foraminifera in late Quaternary turbidite sequences at ODP Leg 139 holes, supplement to: Brunner, Charlotte A (1994): Planktonic foraminiferal biostratigraphy and paleoceanography of late Quaternary turbidite sequences at Holes 856A, 857A, and 857C, Leg 139. In: Mottl, MJ; Davis, EE; Fisher, AT; Slack, JF (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 139, 39-58 |
title_full |
Planktonic foraminifera in late Quaternary turbidite sequences at ODP Leg 139 holes, supplement to: Brunner, Charlotte A (1994): Planktonic foraminiferal biostratigraphy and paleoceanography of late Quaternary turbidite sequences at Holes 856A, 857A, and 857C, Leg 139. In: Mottl, MJ; Davis, EE; Fisher, AT; Slack, JF (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 139, 39-58 |
title_fullStr |
Planktonic foraminifera in late Quaternary turbidite sequences at ODP Leg 139 holes, supplement to: Brunner, Charlotte A (1994): Planktonic foraminiferal biostratigraphy and paleoceanography of late Quaternary turbidite sequences at Holes 856A, 857A, and 857C, Leg 139. In: Mottl, MJ; Davis, EE; Fisher, AT; Slack, JF (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 139, 39-58 |
title_full_unstemmed |
Planktonic foraminifera in late Quaternary turbidite sequences at ODP Leg 139 holes, supplement to: Brunner, Charlotte A (1994): Planktonic foraminiferal biostratigraphy and paleoceanography of late Quaternary turbidite sequences at Holes 856A, 857A, and 857C, Leg 139. In: Mottl, MJ; Davis, EE; Fisher, AT; Slack, JF (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 139, 39-58 |
title_sort |
planktonic foraminifera in late quaternary turbidite sequences at odp leg 139 holes, supplement to: brunner, charlotte a (1994): planktonic foraminiferal biostratigraphy and paleoceanography of late quaternary turbidite sequences at holes 856a, 857a, and 857c, leg 139. in: mottl, mj; davis, ee; fisher, at; slack, jf (eds.), proceedings of the ocean drilling program, scientific results, college station, tx (ocean drilling program), 139, 39-58 |
publisher |
PANGAEA - Data Publisher for Earth & Environmental Science |
publishDate |
1994 |
url |
https://dx.doi.org/10.1594/pangaea.819489 https://doi.pangaea.de/10.1594/PANGAEA.819489 |
genre |
Neogloboquadrina pachyderma Planktonic foraminifera Subarctic |
genre_facet |
Neogloboquadrina pachyderma Planktonic foraminifera Subarctic |
op_relation |
https://dx.doi.org/10.2973/odp.proc.sr.139.206.1994 |
op_rights |
Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode cc-by-3.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/pangaea.819489 https://doi.org/10.2973/odp.proc.sr.139.206.1994 |
_version_ |
1766073155434053632 |