Mantle Flow, Melt Migration and Segmentation of a Fast-Spreading Mid- Ocean Ridge

Project Investigator

Doctor Graham Heinson

Project Collaborators

Steven Constable

Kerry Key (Scripps Institution of Oceanography)

Project Details

The aim of this project was to provide answers to fundamental geological questions raised in the RIDGE 2000 science plan. This involves three main research questions:

1. What is the relationships between mantle flow, composition, ridge morphology and segmentation?

2. How is melt transport organised within the mantle and crust?

3. How does hydrothermal circulation affect characteristics of the melt zone, crustal structure and composition, and ridge morphology?

This research involved a research voyage across the East Pacific Rise (Fig. 1) to conduct a large-scale magnetotelluric and controlled source electromagnetic experiment (Fig. 2).

Fig. 1. Location of the East Pacific Rise, the mid-ocean ridge that drives the spreading of the Pacific Ocean. Current motion of the western pacific is around 86 km/Myr in a west-north-westerly direction.		Fig. 2. Detail of the site for the MT experiments across the northern section of the East Pacific Rise. Blue points indicate MT sample sites.

The data collected was procesed, with individual team members focussing on specific aspects:

• Graham Heinson (UA), Chet Weiss (US National Labs) and Kerry Key (SIO) to process up long- period MT for mantle melt structure.

• Kerry Key (SIO) to process up High-Frequency MT data for melt and magma chamber delineation.

• Steve Constable (SIO) to process up transmitter EM data for hydrothermal mapping and sub-crustal magma.

Research Links

Scripps Institute of Oceanography (SIO)

East Pacific Rise project page (SIO)