EAS 1540 Lecture Notes - Lecture 1: Subduction, Geologic Time Scale, Divergent Boundary
27 Jun 2016
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Document Summary
Single-beam sonar creates a trackline of bottom depth as the ship moves forward. Multi-beam sonar creates a swath of bottom depth as the ship moves forward. Towed multi-beam sonar creates a high-resolution swath of bottom depth as the ship moves forward. Continental shelf - ocean right next to the land, relatively flat and shallow. Fit of continents - appeared to have fit together at some point. Paleobiogeography - distribution of fossil and mineral belts made sense if continents were together. Main forces - convection in the mantle (mantle pushes through and rises up at divergent boundaries) and slab pull (crust pulled back into mantle at subduction boundaries). Mid-ocean ridges - extensional faulting (produced ridges) creates movement along the ridge axis. Magnetic anomalies are a measure of geologic time - each anomaly can be assigned a specific geologic date. Rock is symmetrically older from the middle of the ridge on each side.
