Question

Sometimes we have to take into account IGNEOUS INTRUSIONS. These are masses of magma that formed within the crust keep in mind that magma bodies do not usually follow the principle of superposition. Take a look at the diagrams below and answer the following questions ground surface a) Which sedimentary layers are younger than this granite intrusion? List all that apply. b) Which sedimentary layers are older than this granite intrusion? List all that apply. GRANITE c. Based on the information above, between the formation of which two consecutive sedimentary layers did this granitic magma chamber form? a) Order these three granites from Oldest to Youngest: ground surface Upper-most layers b) If Granite A wasn't there, would we be able to determine the relative age of Granite B compared to the upper-most two sedimentary layers? Explain, using complete sentences. 107 Assignment #1A Page 4 of 9

Answer 1

(a) C.DE : Cross-cutting relationship: nonconformity plome Cutting the granite body ie unconformity. is younger than granite body so all deposition above the unconformity also younger than granite 16) A, B. : Known by cross cutting method: granite intrusle in A and B so A, B must be older than granite (C) A,B, tuo consecutine sedimentery layer did this grauite magma Chamber formed 191 A is cutting B, and B is cutting c so from Cross cutting relationship. ( which one cut the another the younger one I youngest A< BTC oldest (b) If granite A is not there, so we think that these upper most two sedimentery layer older than granite B. but due to presence of A we got the correct relative age ie that two layer younger than granite B.