GEOL 1001 Chapter : Chapter 8 Ouline
Document Summary
Relative ages- based upon order of formation. Qualitive method developed hundreds of years ago. Numerical ages-actual number of years since an event. The stratigraphic record and relative age (fig. 10. 2: nicholas steno- came up with relative age, principle of original horizontality and continuity, sediments are deposited as laterally extensive horizontal sheets, subsequent erosion dissects once continuous layers, principle of superposition- Each bed is older than the one above, and . Youngster strata are on top; older strata below: cross-cutting relationships. Younger features truncate (cut across) older features. Faults, dikes erosion, ect, must be younger than the material that is faulted, intruded, or eroded. Igneous xenoliths- country rock that fell into magma. Weathering rubble- debris from preexisting rocks: the inclusion is older than the material enclosing it, baked contacts. Thermal metamorphism occurs when country rock is invaded bt an igneous intrusion. 10. 5)- is a time gap, a hiatus, in the rock record due to non- deposition or erosion (missing time)
