Investigation of Axial Magma Chamber and its Segmentation Beneath the East Pacific Rise 9°N from Seismic Data

摘要

It is believed that the discontinuities that are readily seen along spreading centers in bathymetric data are related to magma supply within the crust. TheAxial Magma Chambers (AMC) within which the magma supply is pounding have been imaged before but the resolution of the multichannel seismic data (MCS) was not sufficient to clearly define geometry of theAMC along the whole segment and deduct any relationship between the surface discontinuities and the behavior of theAMC. In the summer 2008 we conducted the first academic multi-streamer MCS survey. The survey included one 3D cross axis box at 9° 50'N and several ridge parallel lines that we used for 3D (where three or more parallel lines were collected) and 2D processing. TheAMC shows variation in depth that is very well correlated with the discontinuities identified in bathymetry. In the area for which we have 3D seismic data we were able to examine theAMC geometry in more detail and map changes in lineation, discontinued reflection from the top of theAMC (e.g. at 9°44'N and 9°51'N). Interestingly all these mapped changes inAMC are very closely related to locations of the bathymetrically expressed discontinuities.