How to evaluate the responsible mechanism for a transverse drainage using established criteria?
First, watch the movie and look at the diagram below to better visualize how overflow, piracy, superimposition, and antecedence generate transverse drainages:*Big Transverse Drainage Movie*
*Diagrams for each transverse drainage*
Sorry about superimposition, those experiments failed. Below is a chart with each mechanism and their associated criteria. The mechanisms are split based on whether the drainage is older (antecedence and superimposition) or younger (overflow and piracy) than the bedrock high (the mountain the river cuts through). Click on the individual criteria for examples to help familiarize yourself with all the possible evidence associated with transverse drainage incision.
Let's practice! Click on the one of the locations listed below in blue. These transverse drainages will give you some practice in trying to figure whether antecedence, superimposition, overflow, or piracy is responsible for the four different transverse drainages. PRINT OUT the above diagram for EACH of the four transverse drainage sites provided below. As you go through each site, highlight the criteria you find on your diagram. Some criteria are tricky, and it will take some interpretation on your part to figure out the significance of the information provided. This might frustrate you, but its good practice for the big event, trying to figure out the formation of the Grand Canyon. Once you think you know the answer for each one, click where it says answers on the bottom of the page. Good luck and have fun!
In this module, your goal is to decipher the mechanism responsible for Grand Canyon incision, so be sure to take your time and really understand these criteria before embarking on the virtual field trip. TAKE notes as you go through virtual field trip. PRINT out the above chart and mark the evidence you find as you go along. Keep an eye out for the symbol below. When present, it indicates that an important piece of evidence is on that page and you should consult your chart (but, not all important pieces of information are so easily discovered):
Good luck, by clicking "next" you will enter the Grand Canyon Virtual Field Trip, be safe and have fun!
