Why are some rock layers missing from the sequence in some outcrops?
193 Page 4 DISCUSSION QUESTIONS: (Answer in Conpleie Sentences) 1. Explain why some rock layers can be missing from the sequence in some outcrops. They were weathered and eroded or never deposited. reconstruct a sequence of events?
How an older rock layer would appear on top of a younger rock layer?
downstream to the riverbed. However, the most common mechanism to produce older rocks on top of younger is by thrust faulting. Thrust faults form where rocks are being compressed, usually by plate tectonic mechanisms. Thrust faults rip up older strata and pile it on top of younger rocks.
What are the factors that affect the stratification of rocks?
The most common cause of stratification is variation in the transporting ability of the depositing agent. Water and wind sort sediments according to size, weight, and shape of particles, and these sediments settle in layers of relative homogeneity.
What are the process on stratification of rocks?
stratification (Lat.,=made in layers), layered structure formed by the deposition of sedimentary rocks. Changes between strata are interpreted as the result of fluctuations in the intensity and persistence of the depositional agent, e.g., currents, wind, or waves, or in changes in the source of the sediment.
How does lithostratigraphy work?
Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. When an igneous rock cuts across a formation of sedimentary rock, then we can say that the igneous intrusion is younger than the sedimentary rock.
What is Biostratigraphic unit?
Biostratigraphic units (biozones) are bodies of rock strata that are defined or characterized on the basis of their contained fossils. Biostratigraphic units exist only where the particular diagnostic biostratigraphic feature or attribute on which they are based has been identified.
What are the four Biozones?
Biozonations have been established for the fossil record of different microfossils: planktonic Foraminifera, calcareous nannofossils, diatoms, Radiolaria, and dinoflagellates. The planktonic Foraminifera biozonation and the calcareous nannoplankton biozonation are the major tools for subdividing marine sediments.
What makes a good zone fossil?
A useful index fossil must be distinctive or easily recognizable, abundant, and have a wide geographic distribution and a short range through time. Index fossils are the basis for defining boundaries in the geologic time scale and for the correlation of strata.