Crustal thickness anomalies in the North Atlantic Ocean basin from gravity analysis
Figure S1: Locations of 18 MBA gravity profiles (white lines) illustrated in Figure S2, plotted on a map of calculated gravity effects of lithospheric cooling. (294.6Kb)
Figure S2: Comparison of the calculated gravity effects of lithospheric cooling and MBA along the 18 profiles shown in Figure S1. (111.0Kb)
Figure S3: Comparison of seismic refraction profiles with our gravity-derived crustal thickness. (1.063Mb)
Tucholke, Brian E.
Chen, Yongshun J.
MetadataShow full item record
Gravity-derived crustal thickness models were calculated for the North Atlantic Ocean between 76°N and the Chain Fracture Zone and calibrated using seismically determined crustal thickness. About 7% of the ocean crust is <4 km thick (designated as thin crust), and 58% is 4–7 km thick (normal crust); the remaining 35% is >7 km thick and is interpreted to have been affected by excess magmatism. Thin crust probably reflects reduced melt production from relatively cold or refractory mantle at scales of up to hundreds of kilometers along the spreading axis. By far the most prominent thick crust anomaly is associated with Iceland and adjacent areas, which accounts for 57% of total crustal volume in excess of 7 km. Much smaller anomalies include the Azores (8%), Cape Verde Islands (6%), Canary Islands (5%), Madeira (<4%), and New England–Great Meteor Seamount chain (2%), all of which appear to be associated with hot spots. Hot spot–related crustal thickening is largely intermittent, suggesting that melt production is episodic on time scales of tens of millions of years. Thickened crust shows both symmetrical and asymmetrical patterns about the Mid-Atlantic Ridge (MAR) axis, reflecting whether melt anomalies were or were not centered on the MAR axis, respectively. Thickened crust at the Bermuda and Cape Verde rises appears to have been formed by isolated melt anomalies over periods of only ∼20–25 Myr. Crustal thickness anomalies on the African plate generally are larger than those on the North American plate; this most likely results from slower absolute plate speed of the African plate over relatively fixed hot spots.
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): Q0AE02, doi:10.1029/2010GC003402.
Showing items related by title, author, creator and subject.
Quantitative analysis of abyssal hills in the Atlantic Ocean : a correlation between inferred crustal thickness and extensional faulting Goff, John A.; Tucholke, Brian E.; Lin, Jian; Jaroslow, Gary E.; Kleinrock, Martin C. (American Geophysical Union, 1995-11-10)A recent cruise to the Office of Naval Research Atlantic Natural Laboratory obtained ∼100% Hydrosweep bathymetrie coverage, >200% Hawaii MRl (HMRl) side scan coverage, gravity and magnetics over an area spanning three ridge ...
Heterogeneous and asymmetric crustal accretion : new constraints from multibeam bathymetry and potential field data from the Rainbow area of the Mid-Atlantic Ridge (36°15'N) Paulatto, Michele; Canales, J. Pablo; Dunn, Robert A.; Sohn, Robert A. (John Wiley & Sons, 2015-09-13)At slow-spreading mid-ocean ridges, crustal accretion style can vary significantly along and across ridge segments. In magma-poor regions, seafloor spreading can be accommodated largely by tectonic processes, however, the ...
Crustal Evolution of the Mid-Atlantic Ridge near the Fifteen-Twenty Fracture Zone in the last 5 Ma Fujiwara, Toshiya; Lin, Jian; Matsumoto, Takeshi; Kelemen, Peter B.; Tucholke, Brian E.; Casey, John F. (American Geophysical Union, 2003-03-08)The Mid-Atlantic Ridge around the Fifteen-Twenty Fracture Zone is unique in that outcrops of lower crust and mantle rocks are extensive on both flanks of the axial valley walls over an unusually long distance along-axis, ...