We are heading towards our study area where we will arrive tomorrow morning around 6 am local time. We took this long transit of more than two days to install the labs, setting up the quarters and organize life on board and discuss among ourselves the detailed road map for the campaign. Those of us who are already working on the Southwest Indian Ridge have also presented the results of their work to those who do not yet know the area well.
We did not direct route to our study area since the meeting but have made a slight detour north of the trace Rodrigues triple point (see map of roads in the countryside).
This trace is the limit on the African plate between the domain set up the axis of the Southwest Indian Ridge and the area set up with the axis of the Central Indian Ridge. There is another trace on the Antarctic plate between the area south-west Indian and East Indian. These traces and the axes of the three backbones of the Indian Ocean (south-west, central and eastern Indian) occur at the triple point of Rodrigues near 25 ° S 70 ° E, the junction between the plates of Africa, Asia and Antarctica . The surface of the plate back to Africa increased by the surrounding (Such as the Mid Atlantic Ridge south-west Indian, Central Indian Ridge etc. ..). The trace of the triple point Rodrigues on the African plate is simply the boundary between the fields created by two ridges that surround it.
A long north-south profile from the trace of the triple point on the African plate to the axial valley of the Southwest Indian Ridge and will allow us to collect data from an area that has experienced the birth the Southwest Indian Ridge (there are about 40 Ma in this area) until the current axis of the ridge. We will register and identify the particular sequence of magnetic anomalies along this profile, which will allow us to date the ocean floor and to calculate the variation of opening rate of the Southwest Indian Ridge from 40 Ma Indeed, if the main feature of this ridge is to be ultra-slow (that is to say open with a rate of about 14mm/an) we know that the rate has varied over time and has not always been ultra-slow.
At the end of the North-South profile, we will water the TOBI sidescan sonar that will allow us to collect images of the seafloor with a resolution of about 5m. This will be a future post.
(Photo: Part of the team Scientific)
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