Archive · collection · 1999
Chemistry and age determination of basement fluids from Juan de Fuca Ridge
Listed in PANGAEA and DataCite — shown once because both records carry DOI 10.1594/pangaea.725407
The geochemical implications of thermally driven flow of seawater through oceanic crust on the mid-ocean ridge flank have been examined on a well-studied 80 km transect across the eastern flank of the Juan de Fuca Ridge at 48°N, using porewater and basement fluid samples obtained on ODP Leg 168.
Description
Fluid flow is recognised by near-basement reversals in porewater concentration gradients from altered values in the sediment section to seawater-like values in basaltic basement.
In general, the basement fluids become more geochemically evolved with distance from the ridge and broadly follow basement temperature which ranges from not, vert, similar16° to 63°C. Although thermal effects of advective heat exchange are only seen within 20 km east of where basement is exposed near the ridge crest, chemical reactivity extends to all sites. Seawater passing through oceanic crust has reacted with basement rocks leading to increases in Ca2+ and decreases in alkalinity, Mg2+, Na+, K+, SO42- and delta18O.
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Sr isotope exchange between seawater and oceanic crust off axis is unequivocally demonstrated with endmember 87Sr/86Sr ~ 0.707. Evidence of more evolved fluids is seen at sites where rapid upwelling of fluids through sediments occurs. Chlorinities of the basement fluids are consistent with post-glacial seawater and thus a short residence time in the crust.
Rates of lateral flow have been by estimated by modelling porewater sulphate gradients, using Cl as a glacial chronometer, and from radiocarbon dating of basal fluids. All three methods reveal fluid flow with 14C ages less than 10,000 yr and particle velocities of ~1-5 m/yr, in agreement with thermally constrained volumetric flow rates through a ~600 m thick permeable layer of ~10% porosity. Delta(element)/Delta(heat) extraction ratios are similar to values for ridge-crest hydrothermal systems.
Links
Where it is published
- Repository landing page doi.pangaea.de/10.1594/PANGAEA.725407 ↗
landing page · from DataCite
- DOI doi.org/10.1594/pangaea.725407 ↗
DOI / persistent id · from PANGAEA
Documentation and papers
- Creative Commons Attribution 3.0 Unported creativecommons.org/licenses/by/3.0/legalcode ↗
license · from DataCite
- IsSupplementTo 10.1016/s0012-821x(99)00191-0 doi.org/10.1016/s0012-821x(99)00191-0 ↗
publication · from DataCite
Catalogue records · 3
- OAI-PMH record ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=oai_dc&identifier=o… ↗
metadata API · from PANGAEA
- DataCite API api.datacite.org/dois/10.1594/pangaea.725407 ↗
metadata API · from DataCite
- DataCite Commons commons.datacite.org/doi.org/10.1594/pangaea.725407 ↗
catalogue entry · from DataCite
Topics
- From keywords
- Earth & Environmental Science
- Inferred from text
- Geochemistry 75%
Provenance · 2 source records, 8 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| PANGAEA | oai:pangaea.de:doi:10.1594/PANGAEA.725407 | 10 d ago | JSON v1 |
| DataCite | 10.1594/pangaea.725407 | 10 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · PANGAEA | connector:pangaea@1.0.0 | |
| concepts[field].anzsrc:group:3703 | enrichment · DataCite | taxonomy-embedding@1.1.0 | title+keywords+description (75%) |
| 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 |