The geological record of oceanic crustal accretion and tectonism at slow-spreading ridges
Citable URI
https://hdl.handle.net/1912/5693Location
25°25'N-27°10'NMid-Atlantic Ridge
DOI
10.1575/1912/5693Keyword
Sea-floor spreading; Structural geology; Plate tectonics; Geodynamics; Geology; Maurice Ewing (Ship) Cruise EW9208; Knorr (Ship : 1970-) Cruise KN138Abstract
The objective of this Thesis was to interpret the structural development of slowspreading
ridge segments by: 1) delineating the nature, magnitude, and relative importance
of primary tectonic and volcanic processes that control crustal morphology, 2) investigating
the spatial and temporal variability of these processes, and 3) examining how rheological
variations in the lithosphere control its structural configuration. To that end, this Thesis
provides detailed documentation of faults and volcanoes (seamounts) at the Mid-Atlantic
Ridge from 25°25'N to 27°10'N and extending from zero-age crust at the ridge axis to -29
Ma crust on the ridge flank. This information was used to analyze the evolution of ocean
crust from initial formation in the rift valley to degradation by aging processes on the ridge
flank. Accumulation of sediments affects the seafloor morphological expression of ocean
crustal structure, and sediment thicknesses were also mapped to facilitate study of the
morphological record of crustal accretion and tectonism. In addition, deformation
conditions in the lithosphere were analyzed by study of microstructure and geothermometry
of abyssal peridotite mylonites recovered from fault zones at slow-spreading ridges.
Description
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution December 1996
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Suggested Citation
Thesis: Jaroslow, Gary E., "The geological record of oceanic crustal accretion and tectonism at slow-spreading ridges", 1996-12, DOI:10.1575/1912/5693, https://hdl.handle.net/1912/5693Related items
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Ridge segmentation, tectonic evolution and rheology of slow-spreading oceanic crust
Escartin Guiral, Javier E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-08)Two-thirds of the Earth's surface is oceanic crust formed by magmatic and tectonic processes along mid-ocean ridges. Slow-spreading ridges, such as the Mid-Atlantic Ridge, are discontinuous and composed of ridge segments. ... -
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Ito, Garrett T. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-09)We analyze bathymetric and gravity anomalies at five plume-ridge systems to constrain crustal and mantle density structure at these prominent oceanic features. Numerical models are then used to explore the physical ... -
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