Gravity and seismic study of crustal structure along the Juan de Fuca Ridge axis and across pseudofaults on the ridge flanks
Carbotte, Suzanne M.
Nedimovic, Mladen R.
Canales, J. Pablo
MetadataShow full item record
Variations in topography and seismic structure are observed along the Juan de Fuca (JdF) Ridge axis and in the vicinity of pseudofaults on the ridge flanks left by former episodes of ridge propagation. Here we analyze gravity data coregistered with multichannel seismic data from the JdF Ridge and flanks in order to better understand the origin of crustal structure variations in this area. The data were collected along the ridge axis and along three ridge-perpendicular transects at the Endeavor, Northern Symmetric, and Cleft segments. Negative Mantle Bouguer anomalies of −21 to −28 mGal are observed at the axis of the three segments. Thicker crust at the Endeavor and Cleft segments is inferred from seismic data and can account for the small differences in axial gravity anomalies (3–7 mGal). Additional low densities/elevated temperatures within and/or below the axial crust are required to explain the remaining axial MBA low at all segments. Gravity models indicate that the region of low densities is wider beneath the Cleft segment. Gravity models for pseudofaults crossed along the three transects support the presence of thinner and denser crust within the pseudofault zones that we attribute to iron-enriched crust. On the young crust side of the pseudofaults, a 10–20 km wide zone of thicker crust is found. Reflection events interpreted as subcrustal sills underlie the zones of thicker crust and are the presumed source for the iron enrichment.
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): Q05008, doi:10.1029/2010GC003439.
Suggested CitationArticle: Marjanovic, Milena, Carbotte, Suzanne M., Nedimovic, Mladen R., Canales, J. Pablo, "Gravity and seismic study of crustal structure along the Juan de Fuca Ridge axis and across pseudofaults on the ridge flanks", Geochemistry Geophysics Geosystems 12 (2011): Q05008, DOI:10.1029/2010GC003439, https://hdl.handle.net/1912/4638
Showing items related by title, author, creator and subject.
Nonlinear adjustment of a localized layer of buoyant, uniform potential vorticity fluid against a vertical wall Helfrich, Karl R. (2006-01-29)The nonlinear evolution of a localized layer of buoyant, uniform potential vorticity fluid of uniform depth H, width w0 and length L released adjacent to a wall in a rotating system is studied using reduced-gravity ...
Sun, Wen-Yih; Sun, Oliver M. T.; Tsuboki, Kazuhisa (International Meteorological Institute, 2013-06-28)Sun et al. (2012) proposed a modified non-hydrostatic model (MNH), in which the left-hand side of the continuity equation is multiplied by a parameter δ(4 ≤ δ≤16 in the article) to suppress high-frequency acoustic waves. ...
Density currents in the Chicago River : characterization, effects on water quality, and potential sources Jackson, P. Ryan; Garcia, Carlos M.; Oberg, Kevin A.; Johnson, Kevin K.; Garcia, Marcelo H. (2008-03)Bidirectional flows in a river system can occur under stratified flow conditions and in addition to creating significant errors in discharge estimates, the upstream propagating currents are capable of transporting contaminants ...