Evolution of Fine‐Scale Segmentation at Intermediate‐Spreading Rate Ridges.

Le Saout, Morgane , Clague, D. A. and Paduan, J. B. (2019) Evolution of Fine‐Scale Segmentation at Intermediate‐Spreading Rate Ridges. Open Access Geochemistry, Geophysics, Geosystems, 20 (8). pp. 3841-3860. DOI 10.1029/2019GC008218.

[thumbnail of Saout_et_al-2019-Geochemistry,_Geophysics,_Geosystems.pdf]
Preview
Text
Saout_et_al-2019-Geochemistry,_Geophysics,_Geosystems.pdf - Published Version
Available under License Creative Commons: Attribution-Noncommercial-No Derivative Works 4.0.

Download (4MB) | Preview

Supplementary data:

Abstract

Mid‐ocean ridge axes are marked by segmentation of the axes and underlying magmatic systems. Fine‐scale segmentation has mainly been studied along fast‐spreading ridges. Here we offer insight into the third‐ and fourth‐order segmentation of intermediate‐spreading ridges and their temporal evolution. The Alarcón Rise and the Endeavour Segment have similar spreading rates (49 and 52.5 mm/year, respectively) but contrasting morphologies that vary from an axial high with a relatively narrow axial summit trough to an axial valley. One‐meter resolution bathymetry acquired by autonomous underwater vehicles, lava geochemistry, and ages from sediment cores is combined with available seismic reflection profiles to analyze variations in (1) geometry and orientation of the axial summit trough or valley, (2) seafloor depth near the axis, and (3) distribution of hydrothermal vents, (4) lava chemistry, and (5) flow ages between contiguous axes. Along both intermediate‐spreading segments, third‐ and fourth‐order discontinuities and associated segments are similar in dimension to what has been observed along fast‐spreading ridges. The Alarcón Rise and the Endeavour Segment also allow the study of the evolution of fine‐scale segmentation over periods of 300 to 4,000 years. Comparison between old and young axes reveals that the evolution of fine‐scale segmentation depends on the intensity of the magmatic activity. High magmatic periods are associated with rapid evolution of third‐order segments, while low magmatic activity periods, dominated by tectonic deformation and/or hydrothermal activity, are associated with little to no change in segmentation.

Document Type: Article
Keywords: mid-ocean ridge, segmentation, intermediate-spreading rate
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS
Refereed: Yes
Open Access Journal?: No
Publisher: AGU (American Geophysical Union), Wiley
Date Deposited: 05 Aug 2019 11:18
Last Modified: 31 Jan 2022 09:18
URI: https://oceanrep.geomar.de/id/eprint/47351

Actions (login required)

View Item View Item