Archive · collection · 1980
Nd and Sr isotopic composition of Cretaceous MORB
Listed in PANGAEA and DataCite — shown once because both records carry DOI 10.1594/pangaea.714978
Chemical and isotopic (Nd and Sr) compositions have been determined for 12 Cretaceous basaltic samples (108 Ma old) from Holes 417D and 418A of Legs 51,52 and 53.
Description
We have found that: (1) The chemical compositions are typical of MORB. They do not vary systematically with the stratigraphic positions of the analyzed samples; thus, the chemical evolution is independent of the eruption sequence that occurred at this Cretaceous ridge.
(2) REE patterns for all rocks are characterized by a strong LREE depletion with (La/Sm)N = 0.38-0.50; no significant Eu anomalies are found; HREE are nearly flat or slightly depleted towards Yb-Lu and have 12-18
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- chondritic abundances. Combining the results of previous studies, it suggests that no significant temporal and spatial variation in magma chemistry (especially for LIL elements) has occurred in the 'normal' ridge segments over the last 150 Ma. (3) lsotopically, 143Nd/144Nd ratios vary from 0.513026 to 0.513154, corresponding to epsilon-Nd(0) = +7.5 to +10, and they fall in the typical range of MORB. However, these rocks have unexpectedly high 87Sr/86Sr ratios (0.70355-0.70470) which are attributed to the result of seawater-rock interaction. (4) The Nd model ages (Tin), ranging from 1.53 to 2.47 (average 2.06) AE, suggest that the upper mantle source(s) underwent a large scale chemical differentiation leading to LREE and other LIL element depletion about 2 AE ago, assuming a simple two-stage model. More realistically, the variation in Tm(Nd) or epsilon-Nd could be derived from mixing of heterogeneous mantle sources that were a consequence of continuous mantle differentiation and continental formation. (5) Because of the low mg values (0.52-0.63), the analyzed basaltic rocks do not represent primary liquids of mantle melting. The variation in La/Sm ratios and TiO2 are not compatible with a model in which all rocks are genetically related by a simple fractional crystallization. Rather, it is proposed that the basaltic rocks might have been derived from some heterogeneous upper mantle source with or without later magmatic mixing, and followed by some shallow-level fraetionations.
Links
Where it is published
- Repository landing page doi.pangaea.de/10.1594/PANGAEA.714978 ↗
landing page · from DataCite
- DOI doi.org/10.1594/pangaea.714978 ↗
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 10.1016/0012-821x(80)90180-6 doi.org/10.1016/0012-821x(80)90180-6 ↗
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.714978 ↗
metadata API · from DataCite
- DataCite Commons commons.datacite.org/doi.org/10.1594/pangaea.714978 ↗
catalogue entry · from DataCite
Topics
- From keywords
- Earth & Environmental Science
- Inferred from text
- Geochemistry 72%
Provenance · 2 source records, 8 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| PANGAEA | oai:pangaea.de:doi:10.1594/PANGAEA.714978 | 12 d ago | JSON v1 |
| DataCite | 10.1594/pangaea.714978 | 12 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 (72%) |
| 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 |