EARTHSC 1122 Lecture Notes - Lecture 10: Unconformity, Nonconformist, Decay Product
4 Dec 2015
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Unconformities: erosion (or non-deposition) surfaces, types, nonconformity, angular unconformity, disconformity. Angular unconformity: strata are folded, then eroded. Next, flat-lying strata are deposited over tilted strata. Disconformity: strata above and below the unconformity show little evidence of a time gap, gaps commonly determined from fossils (or other evidence of erosion such as subtle truncation of strata) Sequence stratigraphy: sequence boundaries (disconformities) are time-parallel. Geophysical correlation techniques: radioactivity of rock layers (gamma-ray intensity, geomagnetism (reversals of magnetic polarity recorded in rock layers)
