NEHRP Clearinghouse
- Title
- Variations in Structure and Tectonics along the Mid-Atlantic Ridge, 23 deg N and 26 deg N.
- File
- PB92112796.pdf
- Author(s)
- Kong, L. S. L.
- Source
- National Science Foundation, Washington, DC., cJanuary 1990, 343 p.
- Identifying Number(s)
- WHOI-90-28
- Abstract
- The variation in the depth and width of the median valley along the Mid-Atlantic Ridge (MAR) suggests that the formation of ocean crust at slow spreading centers is not a simple two-dimensional process in which accretion occurs uniformly both along the axis and with time. Rather, it has been proposed that the ridge can be divided into a number of distinct spreading cells, or segments. The thesis investigates the segmentation model by studying the variability in the structure and tectonics within the cells along the MAR. The observations are based on the interpretation of side scan sonar data and multibeam bathymetry at 23 N, the hypocentral distribution and source characteristics of microearthquakes near an active hydrothermal field at 26 N, the two-dimensional P wave crustal structure beneath the median valley as determined from travel time and waveform modelling and the tomographic inversion of travel time residuals at 26 N, and the measurement of P and S wave travel time delays from teleseismically-located ridge earthquakes near 26 N. The results support the segmentation model in which accretion varies along the ridge, evolving as independent spreading cells, with different portions of the ridge system being in different stages of volcanic and tectonic evolution. (Copyright (c) Laura S. L. Kong, 1990.)
- Keywords
- ; Marine geology; Bathymetry; Tectonics; Mid-Atlantic Ridge; Geologic formations; Two-dimensional calculations; Hydrothermal alteration; Theses; Sea-floor spreading; Oceanic crust; Structural geology; Earthquakes; Geomorphology