Distributed deformation ahead of the Cocos-Nazca Rift at the Galapagos triple junction
Smith, Deborah K.
Schouten, Hans A.
Montesi, Laurent G. J.
Cann, Johnson R.
MetadataShow full item record
The Galapagos triple junction is not a simple ridge-ridge-ridge (RRR) triple junction. The Cocos-Nazca Rift (C-N Rift) tip does not meet the East Pacific Rise (EPR). Instead, two secondary rifts form the link: Incipient Rift at 2°40′N and Dietz Deep volcanic ridge, the southern boundary of the Galapagos microplate (GMP), at 1°10′N. Recently collected bathymetry data are used to investigate the regional tectonics prior to the establishment of the GMP (∼1.5 Ma). South of C-N Rift a band of northeast-trending cracks cuts EPR-generated abyssal hills. It is a mirror image of a band of cracks previously identified north of C-N Rift on the same age crust. In both areas, the western ends of the cracks terminate against intact abyssal hills suggesting that each crack initiated at the EPR spreading center and cut eastward into pre-existing topography. Each crack formed a short-lived triple junction until it was abandoned and a new crack and triple junction initiated nearby. Between 2.5 and 1.5 Ma, the pattern of cracking is remarkably symmetric about C-N Rift providing support for a crack interaction model in which crack initiation at the EPR axis is controlled by stresses associated with the tip of the westward-propagating C-N Rift. The model also shows that offsets of the EPR axis may explain times when cracking is not symmetric. South of C-N Rift, cracks are observed on seafloor as old as 10.5 Ma suggesting that this triple junction has not been a simple RRR triple junction during that time.
Author Posting. © American Geophysical Union, 2011. 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 12 (2011): Q11003, doi:10.1029/2011GC003689.
Showing items related by title, author, creator and subject.
Smith, Deborah K.; Schouten, Hans A.; Montesi, Laurent G. J.; Zhu, Wenlu (2013-04)At the Galapagos triple junction, the Cocos and Nazca plates are broken by a succession of transient rifts north and south of the Cocos-Nazca (C-N) Rift. Modeling has suggested that each rift initiated at the East Pacific ...
Hemichannel composition and electrical synaptic transmission : molecular diversity and its implications for electrical rectification Palacios-Prado, Nicolas; Huetteroth, Wolf; Pereda, Alberto E. (Frontiers Media, 2014-10-15)Unapposed hemichannels (HCs) formed by hexamers of gap junction proteins are now known to be involved in various cellular processes under both physiological and pathological conditions. On the other hand, less is known ...
Kaess, Michael; Johannsson, Hordur; Roberts, Richard; Ila, Viorela; Leonard, John J.; Dellaert, Frank (2011-04-06)We present a novel data structure, the Bayes tree, that provides an algorithmic foundation enabling a better understanding of existing graphical model inference algorithms and their connection to sparse matrix factorization ...