Which of the following principles are key to relative dating
(Hammerhead for scale) [SE] Figure 8.6b Rip-up clasts of shale embedded in Gabriola Formation sandstone, Gabriola Island, B. The pieces of shale were eroded as the sandstone was deposited, so the shale is older than the sandstone.
[SE] The principle of cross-cutting relationships states that any geological feature that cuts across, or disrupts another feature must be younger than the feature that is disrupted.
Exercise 8.1 Cross-Cutting Relationships The outcrop shown here (at Horseshoe Bay, B. Buff/pink felsic intrusive igneous rock present as somewhat irregular masses trending from lower right to upper left 2. A 50 cm wide light-grey felsic intrusive igneous dyke extending from the lower left to the middle right – offset in several places Using the principle of cross-cutting relationships outlined above, determine the relative ages of these three rock types.
(The near-vertical stripes are blasting drill holes.
Figure 8.6a A xenolith of diorite incorporated into a basalt lava flow, Mauna Kea volcano, Hawaii.
The lava flow took place some time after the diorite cooled, was uplifted, and then eroded.
A third fact emerges from the study of stratigraphy - the UNCONFORMITY.These ages have been derived from relative dating and absolute dating (radiometric dating) of rock layers and fossils.(a) Relative Dating This technique uses principles of stratigraphy (rock strata) and the study of fossils (palaeontology) to determine the relative ages of rocks and sediments. Field geologists' rely on a number of simple techniques for dating rocks and constructing geological successions. The Law of Strata Identified by Fossils is a little bit more complex.The principle of inclusions states that any rock fragments that are included in rock must be older than the rock in which they are included.For example, a xenolith in an igneous rock or a clast in sedimentary rock must be older than the rock that includes it (Figure 8.6).
Search for which of the following principles are key to relative dating:
The laws of physics and chemistry that governed geologic processes in the past are the same as those that govern processes now and in the future.