EESA06H3 Chapter 19: Chapter 19
Document Summary
Chapter 19: time and geology: determining age relationships between geographically widely separated rock units is necessary for understanding the geologic history of a region, continent, or whole earth. Relative time: geology of grand canyon can be analyzed in four parts, horizontal layers of rock, inclined layers, rock underlying the inclined layers (plutonic and metamorphic rock, canyon itself, carved into these rocks. original horizontality: states that beds of sediment deposited in water formed as horizontal or nearly horizontal layers. superposition: within a sequence of undisturbed sedimentary or volcanic rocks the payers get younger going from bottom to top. lateral continuity: an original sedimentary layer extends laterally until it tapers or thins at its edges. cross-cutting relationships: a disrupted pattern is older than the cause of disruption: contacts representing buried erosion surfaces such as these are called unconformities, pages 513 to 516 for examples. Inclusion: fragments included in a host rock are older than the host rock.
