Multiple expressions of plume-ridge interaction in the Galapagos : volcanic lineaments and ridge jumps
Soule, Samuel A.
Harpp, Karen S.
Fornari, Daniel J.
Tivey, Maurice A.
Geist, Dennis J.
Kurz, Mark D.
MetadataShow full item record
Anomalous volcanism and tectonics between near-ridge mantle plumes and mid-ocean ridges provide important insights into the mechanics of plume-lithosphere interaction. We present new observations and analysis of multibeam, side scan sonar, sub-bottom chirp, and total magnetic field data collected during the R/V Melville FLAMINGO cruise (MV1007; May–June, 2010) to the Northern Galápagos Volcanic Province (NGVP), the region between the Galápagos Archipelago and the Galápagos Spreading Center (GSC) on the Nazca Plate, and to the region east of the Galápagos Transform Fault (GTF) on the Cocos Plate. The NGVP exhibits pervasive off-axis volcanism related to the nearby Galápagos hot spot, which has dominated the tectonic evolution of the region. Observations indicate that ~94% of the excess volcanism in our survey area occurs on the Nazca Plate in three volcanic lineaments. Identified faults in the NGVP are consistent with normal ridge spreading except for those within a ~60 km wide swath of transform-oblique faults centered on the GTF. These transform-oblique faults are sub-parallel to the elongation direction of larger lineament volcanoes, suggesting that lineament formation is influenced by the lithospheric stress field. We evaluate current models for lineament formation using existing and new observations as well as numerical models of mantle upwelling and melting. The data support a model where the lithospheric stress field controls the location of volcanism along the lineaments while several processes likely supply melt to these eruptions. Synthetic magnetic models and an inversion for crustal magnetization are used to determine the tectonic history of the study area. Results are consistent with creation of the GTF by two southward ridge jumps, part of a series of jumps that have maintained a plume-ridge separation distance of 145 km to 215 km since ~5 Ma.
Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 13 (2012): Q05018, doi:10.1029/2012GC004093.
Showing items related by title, author, creator and subject.
Asymmetric shallow mantle structure beneath the Hawaiian Swell—evidence from Rayleigh waves recorded by the PLUME network Laske, Gabi; Markee, Amanda; Orcutt, John A.; Wolfe, Cecily J.; Collins, John A.; Solomon, Sean C.; Detrick, Robert S.; Bercovici, David; Hauri, Erik H. (John Wiley & Sons, 2011-10-31)We present models of the 3-D shear velocity structure of the lithosphere and asthenosphere beneath the Hawaiian hotspot and surrounding region. The models are derived from long-period Rayleigh-wave phase velocities that ...
Thomson, James M.; Horner-Devine, Alex R.; Zippel, Seth; Rusch, Curtis; Geyer, W. Rockwell (John Wiley & Sons, 2014-12-19)Observations at the Columbia River plume show that wave breaking is an important source of turbulence at the offshore front, which may contribute to plume mixing. The lateral gradient of current associated with the plume ...
Lai, Zhigang; Ma, Ronghua; Gao, Guangyin; Chen, Changsheng; Beardsley, Robert C. (John Wiley & Sons, 2015-08-21)Impacts of the multichannel river network on plume dynamics in the Pearl River estuary were examined using a high-resolution 3-D circulation model. The results showed that during the dry season the plume was a distinct ...