Figure 1. Grand Canyon nationwide playground conserves a renowned geologic landscape and info including 1,840 to 270 million yrs . old, including diverse paleontological budget;

Figure 1. Grand Canyon nationwide playground conserves a renowned geologic landscape and info including 1,840 to 270 million yrs . old, including diverse paleontological budget;

unconsolidated surface deposits; a complicated tectonic and erosion background; and Pliocene to Holocene volcanic build up. The Colorado River set up its course through canyon about six million years back, and likely progressed from pre-existing drainages to its recent program. Geologic procedures, including erosion of tributaries and mountains, and productive tectonics still figure the canyon today. The geologic record in large Canyon is a vital systematic chronicle and is largely accountable for its motivational vistas.


Renowned because of its geologic relevance, the Grand Canyon is one of the most analyzed geologic scenery worldwide. It gives an excellent record of three of this four eras of geological time, an abundant and varied non-renewable record, a huge selection of geologic properties and stone kinds, and various caverns that contain substantial and significant geological, paleontological, archeological and biological methods. It’s considered one of the greatest samples of arid-land erosion around. The Canyon, incised by Colorado lake, are tremendous, averaging 4,000 ft deep because of its whole 277 miles. It’s 6,000 ft deep at the greatest point and 15 kilometers at their largest. The graphics below programs the layers of rock which can be uncovered when you look at the canyon.

Figure 2. Diagram showing the positioning, age and width of this rock models uncovered during the great Canyon.

This is a geologic cross section (not attracted to size) that displays the stratigraphy of the fantastic Canyon. This means that, it symbolizes exactly what the rock layers would appear to be if you grabbed a knife and sliced all the way down through the world at a given area, like easy. You are looking at those levels from the “side” of the piece of cake within this picture. Note that all three forms of stone (sedimentary, metamorphic, and igneous) can be found contained in this cross section. Note how years associated with the rock decline in era from base to the top. Whether or not it weren’t currently labeled, you think you’ll be in a position to spot the Great Unconformity around the bottom of this canyon?

How Old could be the Grand Canyon? (recommended)

Tune in to researchers explore the age of the fantastic Canyon additionally the debate over the dating. Push the enjoy option on the left associated with webpage to concentrate. (Transcripts available on the left menu besides.)

This associated informative document comes from the Grand Canyon guidelines newspaper, published by Grand Canyon state Park.


You’ll end up determining the general dating an atheist purchase whereby geological activities happened, as found contained in this generic stratigraphic cross section (below). Stratigraphy could be the research on the rock strata, or layers, and is usually put on sedimentary (and quite often eruptive) rocks.

Figure 3. drawing showing cross-cutting connections in geology. These relations can be used to offer frameworks a family member years. Details: A – folded stone strata cut by a thrust failing; B – large breach (cutting through A); C – erosional angular unconformity (cutting-off A & B) which rock strata comprise deposited; D – volcanic dyke (cutting through A, B & C); Age – actually more youthful stone strata (overlying C & D); F – normal mistake (slicing through A, B, C & E).

  1. Examine the 3-D cross-section above. The cross section consists of proof folding in layer grams (a squeeze associated with the stone because of compression— we’ll find out about that in module 11) and faulting one of the numerous rock levels.
  2. Just what rock type(s) were represented in each one of the layers B, G, D, E (sedimentary, igneous, or metamorphic)? Describe the manner in which you determined this.
  3. Which kind of unconformity do C represent? Mention. (Hint: the options include disconformity, nonconformity, angular unconformity, or paraconformity.)
  4. To which letter(s) or layer(s) of stone does the concept of Superposition use, and just why? Mention.
  5. Prepare your order for which each lettered show (A-H) took place the series, from eldest to youngest. (clue: understand that A and F is fault contours, D is a dike, and C is an unconformity.)
  6. At what point in the series do you consider the folding of unit grams were held, and exactly why? Mention.
  7. In 3 – 4 sentences, describe how laws of Cross lowering Relations applies to the cross-section therefore the sequence in which you ordered the occasions.
  8. Perform some searching on the Internet (or someplace else) to track down another easy geologic cross section of your choosing.
    • Add an image for this cross section inside write-up, and describe the order which happenings took place the part.
    • Please set labels on the cross-section whether or not it will not already have all of them, so that it is obvious which happenings you may be discussing.
    • Cite the source for the cross-section, kindly!

Grading Rubric

10 points: All issues comprise answered thoroughly and correctly. Complete phrases were used to respond to the sample concerns.

8 guidelines: All issues had been responded and had been primarily accurate. Merely two or three minor problems.

5 points: responses happened to be also quick and 1 – 2 concerns happened to be unanswered.

2 details: best very partial suggestions provided.

0 guidelines: didn’t accomplish the assignment.

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