Archive · collection · 2018
Downcore variations of sedimentary detrital (238U/232Th) ratio of sediment core SU90-08
Listed in PANGAEA
Excess 231 Pa and 230 Th ( 231 Pa xs and 230 Th xs ) can be used to reconstruct past oceanic sedimentation ( 230 Th-normalized flux) and circulation changes (( 231 Pa/ 230 Th) xs,0 , hereafter Pa/Th).
Description
These quantities are determined by computing the detrital and authigenic contributions from bulk sediment measurement. The method relies on the use of a chosen constant value of the detrital ( 238 U/ 232 Th) activity ratio (hereafter (U/Th) det ).
In this study, we have extracted the detrital fraction of the sediments from North Atlantic deep-sea core SU90-08 (43°03'1N, 30°02'5W, 3080m) and determined its (U/Th) det value over the last 40 ky. We find that (U/Th) det varied significantly through time with a minimum value of 0.4 during the Holocene and a maximum value of 0.7 during the Last Glacial Maximum (LGM). The sensitivity of sedimentary 230 Th-normalized flux and Pa/Th is tested for our study site and for other North-Atlantic sites.
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We show that the sensitivity is highly dependent on the core location and its terrigenous material supply. The 230 Th-normalized flux and Pa/Th signals are very robust in cores with low detrital contributions, whereas they are very sensitive to (U/Th) det changes in cores with higher detrital contribution. In the latter case, changes in 230 Th-normalized flux and Pa/Th due to the choice of a constant (U/Th) det can largely exceed the uncertainty on the 230 Th-normalized flux and Pa/Th, inducing potential biases in the amplitude and temporal variability of reconstructed sedimentation and ocean circulation changes.
Links
Where it is published
- DOI doi.org/10.1594/pangaea.889695 ↗
DOI / persistent id · from PANGAEA
Catalogue records · 1
- OAI-PMH record ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=oai_dc&identifier=o… ↗
metadata API · from PANGAEA
Topics
- From keywords
- Earth & Environmental Science
- Inferred from text
- Geochemistry 71%
Provenance · 1 source records, 8 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| PANGAEA | oai:pangaea.de:doi:10.1594/PANGAEA.889695 | 15 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · PANGAEA | connector:pangaea@1.0.0 | |
| concepts[field].anzsrc:group:3703 | enrichment · PANGAEA | taxonomy-embedding@1.1.0 | title+keywords+description (71%) |
| concepts[field].local:field:earth-environmental | mapping · PANGAEA | connector:pangaea@1.0.0 | |
| description | source · PANGAEA | connector:pangaea@1.0.0 | /metadata/dc/description |
| license | source · PANGAEA | connector:pangaea@1.0.0 | /metadata/dc/rights |
| publication_date | source · PANGAEA | connector:pangaea@1.0.0 | |
| spatial | source · PANGAEA | connector:pangaea@1.0.0 | |
| title | source · PANGAEA | connector:pangaea@1.0.0 | /metadata/dc/title |