Frozen magma lenses below the oceanic crust
Mladen R Nedimović1, Suzanne M Carbotte, Alistair J Harding
1Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, PO Box 1000, Palisades, New York 10964-8000, USA. mladen@ldeo.columbia.edu
Abstract:
The Earth's oceanic crust crystallizes from magmatic systems generated at mid-ocean ridges. Whereas a single magma body residing within the mid-crust is thought to be responsible for the generation of the upper oceanic crust, it remains unclear if the lower crust is formed from the same magma body, or if it mainly crystallizes from magma lenses located at the base of the crust. Thermal modelling, tomography, compliance and wide-angle seismic studies, supported by geological evidence, suggest the presence of gabbroic-melt accumulations within the Moho transition zone in the vicinity of fast- to intermediate-spreading centres. Until now, however, no reflection images have been obtained of such a structure within the Moho transition zone. Here we show images of groups of Moho transition zone reflection events that resulted from the analysis of approximately 1,500 km of multichannel seismic data collected across the intermediate-spreading-rate Juan de Fuca ridge. From our observations we suggest that gabbro lenses and melt accumulations embedded within dunite or residual mantle peridotite are the most probable cause for the observed reflectivity, thus providing support for the hypothesis that the crust is generated from multiple magma bodies.
More Related Videos
07:58Data Processing Methods for 3D Seismic Imaging of Subsurface Volcanoes: Applications to the Tarim Flood Basalt
Published on: August 7, 2017
13:38Laser-Induced Fluorescence Emission L.I.F.E. as Novel Non-Invasive Tool for In-Situ Measurements of Biomarkers in Cryospheric Habitats
Published on: October 26, 2019
Related Concept Videos
Phase Transitions: Melting and Freezing
Minerals
Major...
Frost Action on Concrete
This freeze-thaw cycle primarily causes surface scaling, where...
Diversity of Protists III
Microbial Mats
Deep Sea Microbial Ecology
