Grain-scale stable isotope disequilibrium during fluid-rock interaction; 2, An example from the Penninic-Austroalpine tectonic contact in eastern Switzerland

Clicks: 1
ID: 304892
1997
Free PDF
Article Quality & Performance Metrics
Overall Quality
Not rated
Combines reader engagement with the AI quality analysis. This article has not been analysed, so there is no overall score — reader engagement is measured and shown alongside.
AI Quality Assessment
Not analyzed
Readership in this journal

Ranked #7,939 of 8,486 articles by views in american journal of science

Most read Least read

Bar heights use a square-root scale. Only the 120 most-read articles are drawn; the journal has 8,486 in total.

Mint this article as an NFT
Not yet minted

Create a permanent, verifiable on-chain record of this article on the Scimatic Network. The NFT is held in your Journament account, and you can withdraw it to your own wallet at any time.

5 SUSD one-off · no wallet required
Sign in to mint
Abstract
At the tectonic contact between the Penninic Platta Nappe and the Lower-Austroalpine Err Unit in eastern Switzerland carbon and oxygen isotope fronts are preserved at the interface of serpentinites and low-grade regional metamorphic metacarbonates. The carbon and oxygen isotope compositions of calcite are delta 13 C = 2.3 per mil (PDB) and delta 18 O = 21.0 per mil (SMOW) in the unaltered metacarbonates at a distance of about 20 m from the lithologic contact, and they are delta 13 C = 0.0 per mil and delta 18 O = 14.0 per mil at the metacarbonate-serpentinite interface. The concomitant shift in the oxygen isotope composition of quartz is from 24.0 to 17.0 per mil. A peculiarity of the isotope pattern is the systematic variation of the quartz-calcite oxygen isotope fractionations across the isotopic front. Quartz-calcite fractionations are relatively small ( nearly equal 3.0 per mil) in the unaltered metacarbonate and at the metacarbonate-serpentinite interface, and they increase in the transitional zone in between with a maximum of 7.1 per mil at a distance of about 2 m from the contact. This pattern is interpreted as a result of advective-dispersive material transport across the lithologic contact and coupled first-order kinetic mineral-fluid exchange. The oxygen isotope systematics indicate that calcite-fluid isotope exchange was fast, and local calcite-fluid equilibrium prevailed during fluid-rock interaction. In contrast, quartz-fluid exchange was relatively sluggish, and the quartz-calcite oxygen isotope fractionations deviated significantly from their equilibrium values. Front geometries suggest that dispersive processes contributed substantially to material transport across the metacarbonate-serpentinite contact. Cross-layer advective flow was minor with a maximum time-integrated volumetric flux of 21 m 3 /m 2 . From the influence of quartz-fluid exchange kinetics on the intermineral fractionations quantitative relations among transport velocities, the rates of mineral-fluid exchange and the duration of fluid-rock interaction are derived. These relations are then combined with geologic and experimental data to identify "feasible" scenarios of fluid-rock interaction.
Reference Key
openalex_W2332197615 Use this key to autocite in the manuscript while using SciMatic Manuscript Manager or Thesis Manager
Authors H. Eppel, Rainer Abart
Journal american journal of science
Year 1997
DOI
10.2475/ajs.297.7.707
URL
https://doi.org/10.2475/ajs.297.7.707
Keywords Keywords not found

Citations

No citations found. To add a citation, contact the admin at info@scimatic.org

Comments

No comments yet. Be the first to comment on this article.